Av blockade 1 degree what to do. Atrioventricular block. Clinical manifestations of different degrees

From this article you will learn: what is AV blockade, how treatment and prognosis depend on the severity, what is the life expectancy after implantation of a pacemaker, how to support the heart at home.

Article publication date: 04/22/2017

Article last updated: 05/29/2019

Atrioventricular blockade is the cessation of the conduction of a nerve impulse between the atria and ventricles of the heart.

Here's what happens in the most severe atrioventricular block (3rd degree)

The coordinated work of the heart is coordinated by the autonomous conduction system of the heart. It consists of special muscle fibers that are able to conduct nerve impulse. The "leader" of the autonomic conduction system of the heart is the autonomic nervous system.

The peculiarity of the conduction system of the heart is that its fibers are able to independently generate the impulse necessary for contraction. In this case, the number of impulses decreases from top to bottom.

The conduction system of the heart is called autonomous, because it itself generates impulses for myocardial contraction. This gives a person a margin of safety for survival. With severe injuries, loss of consciousness and other catastrophes, the heart continues to beat, increasing the chances of life.

Normally, the sinus node generates a rhythm with a frequency of 60 to 90 beats per minute. At this rate, the atria contract. The task of the atrioventricular part is to delay the wave of excitation on its way to the ventricles. The contraction of the ventricles begins only after the atria have finished their work. The frequency from the atrioventricular part is 40–60 pulses. This is not enough for a full life, but still better than nothing.

A condition in which an impulse is not conducted from the sinus node is called AV block. The lower its level, the fewer impulses the heart receives. A decrease in heart rate makes blood circulation inefficient, in severe cases life threatening.

2 degree

Blockade of the second degree of the second and third types is an indication for immediate hospitalization. Restoring rhythm is an urgent task. The doctor's goal is to facilitate the passage of the impulse from the atria to the ventricles; with AV blockade at the level of the atrioventricular node, atropine is used for this, but at a lower location, the medicine will not help.

If a break in conduction is registered at the level of the left bundle branch of His or even lower, then electrical stimulation is needed. It is possible to restore a normal rhythm with the help of electrical stimulation; for this, temporary stimulation is used when the probe-electrode is inserted into the right atrium. This is the preparatory stage for .

3 degree

A complete transverse blockade is life-threatening, it is treated in the intensive care unit. If the condition is caused by an organic lesion of the heart (heart attack, Lenegre's syndrome or idiopathic bilateral lesion of the His bundle, cardiosclerosis), then adrenomimetics - orciprenaline or isoprenaline - are first used. Then the general condition of the person is assessed, whether his body can cope with a heart attack or adapt to cardiosclerosis. If adaptation does not occur and the rhythm does not hold, then a pacemaker is installed.

An artificial pacemaker is also called a pacemaker. The operation to install it is small, it is performed under local anesthesia. An active electrode under X-ray control through the lateral saphenous vein of the hand will be inserted into the right atrium, and a small titanium case is placed under the subcutaneous fat on the chest, usually on the left.

Forecast

Various AV blockades are the fourth most common cause of cardiac arrhythmias. On average, the prognosis for these conditions looks like this:

Patients with a pacemaker should avoid exposure to radar and high voltage equipment. They cannot undergo MRI examinations and receive thermal physiotherapy. You can return to normal life in a month and a half. The replacement of the pacemaker is carried out in a period of 5 to 15 years, such is their average service life.

RCHD (Republican Center for Health Development of the Ministry of Health of the Republic of Kazakhstan)
Version: Clinical Protocols of the Ministry of Health of the Republic of Kazakhstan - 2014

Bifascicular block (I45.2), Other and unspecified atrioventricular block (I44.3), Second-degree atrioventricular block (I44.1), First-degree atrioventricular block (I44.0), Complete atrioventricular block (I44.2), Sick sinus syndrome (I49.5), Trifascicular block (I45.3)

Cardiology

general information

Short description

Approved
at the Expert Commission on Health Development
Ministry of Health of the Republic of Kazakhstan
Protocol No. 10 dated July 04, 2014

AV block represents a slowdown or cessation of the conduction of impulses from the atria to the ventricles. For the development of AV blockade, the level of damage to the conduction system may be different. This may be conduction disturbance in the atria, AV junction, and ventricles.

I. INTRODUCTION

Protocol name: Conduction disorders of the heart

Protocol code

ICD-10 codes:
I44.0 First-degree atrioventricular block
I44.1 Second-degree atrioventricular block
I44.2 Atrioventricular block, complete
I44.3 Atrioventricular block, other and unspecified
I45.2 Bifascicular block
I45.2 Trifascicular block
I49.5 Sick sinus syndrome

Abbreviations used in the protocol:
HRS - Heart Rhythm Society
NYHA - New York Heart Association
AV block - atrioventricular block
BP - blood pressure
ACE - angiotensin converting enzyme
VVFSU - sinus node function recovery time
HIV - human immunodeficiency virus
VSAP - sinoauricular conduction time
ACE inhibitors - angiotensin-converting enzyme inhibitors
coronary artery disease - ischemic disease hearts
Interval HV - the time of the impulse according to the His-Purkinje system
ELISA - enzyme immunoassay
LV - left ventricle
MPCS - maximum duration of the stimulation cycle
PSC - duration of the sinus cycle
PCS - the duration of the stimulation cycle
SA blockade - sinoatrial blockade
HF - heart failure
SPU - sinoatrial node
FGDS - fibrogastroduodenoscopy
HR - heart rate
ECG - electrocardiogram
EKS - pacemaker
ERP - effective refractory period
EFI - electrophysiological study
EchoCG - echocardiography
EEG - electroencephalography

Protocol development date: year 2014

Protocol Users: interventional arrhythmologists, cardiologists, therapists, physicians general practice, cardiac surgeons, pediatricians, emergency doctors, paramedics.

Classification

Classification of AV blockade by degrees:

AV blockade of the first degree is characterized by a slowdown in the conduction of impulses from the atria to the ventricles. On the ECG, there is a prolongation of the P-Q interval for more than 0.18-0.2 seconds.

. With second-degree AV block, single impulses from the atria sometimes do not pass into the ventricles. If such a phenomenon occurs rarely and only one ventricular complex falls out, patients may not feel anything, but sometimes they feel moments of cardiac arrest, in which dizziness or blackout appears.

AV block II degree type Mobitz I - on the ECG there is a periodic lengthening of the P-Q interval, followed by a single P wave that does not have a ventricular complex following it (type I block with Wenckebach's periodicity). This type of AV block usually occurs at the level of the AV junction.

Second-degree AV block, type Mobitz II, is manifested by periodic prolapse of QRS complexes without previous PQ prolongation. The level of blockade is usually the His-Purkinje system, the QRS complexes are wide.

. AV block III degree(complete atrioventricular block, complete transverse block) occurs when electrical impulses from the atria are not conducted to the ventricles. In this case, the atria contract at a normal rate, and the ventricles rarely contract. The frequency of contractions of the ventricles depends on the level at which the center of automatism is located.

Sick sinus syndrome
SSSU is a dysfunction of the sinus node, manifested by bradycardia and accompanying arrhythmias.
Sinus bradycardia- decrease in heart rate less than 20% below the age limit, migration of the pacemaker.
SA block is the slowing (below 40 beats per minute) or cessation of the conduction of an impulse from the sinus node through the sinoatrial junction.

Classification of SA blockade by degrees :

I degree SA blockade does not cause any changes in cardiac activity and does not appear on a normal ECG. With this type of blockade, all sinus impulses pass to the atria.

In second-degree SA block, sinus impulses sometimes do not pass through the SA junction. This is accompanied by the loss of one or more consecutive atrioventricular complexes. With second-degree blockade, dizziness, a feeling of irregular heart activity, or fainting may occur. During pauses of SA blockade, escape contractions or rhythms from underlying sources (AV connection, Purkinje fibers) may appear.

With SA blockade of the III degree, impulses from the STC do not pass through the SA junction and the activity of the heart will be associated with the activation of the following sources of rhythm.

Tachycardia-bradycardia syndrome- combination of sinus bradycardia with supraventricular heterotopic tachycardia.

sinus arrest is a sudden cessation of cardiac activity with the absence of atrial and ventricular contractions due to the fact that the sinus node cannot generate an impulse to contract them.

Chronotropic insufficiency(incompetence) - an inadequate increase in heart rate in response to physical activity.

Clinical classification AV blockade

According to the degree of AV blockade:
. AV block I degree

AV block II degree
- type Mobitz I

Type Mobitz II
- AV block 2:1
- AV blockade of high degree - 3:1, 4:1

3rd degree AV block

Fascicular block
- Bifascicular blockade
- Trifascicular blockade

By time of occurrence:
. congenital AV block
. Acquired AV block

According to the stability of AV blockade:
. Permanent AV block
. Transient AV block

Sinus node dysfunction:
. Sinus bradycardia
. sinus arrest
. SA blockade
. Tachycardia-bradycardia syndrome
. Chronotropic insufficiency

Diagnostics

II. METHODS, APPROACHES AND PROCEDURES FOR DIAGNOSIS AND TREATMENT

List of basic and additional diagnostic measures

Basic (mandatory) diagnostic examinations carried out at the outpatient level:
. ECG;
. Holter ECG monitoring;
. Echocardiography.

Additional diagnostic examinations performed at the outpatient level:
If organic cerebral pathology is suspected or in syncope of unknown origin:

X-ray of the skull and cervical spine;

. EEG;
. 12/24-hour EEG (with suspicion of epileptic genesis of paroxysms);


. ultrasonic dopplerography (if a pathology of extra- and intracranial vessels is suspected);

Complete blood count (6 parameters)

General urine analysis;


. coagulogram;
. ELISA for HIV;



. FGDS;

The minimum list of examinations that must be carried out when referring to planned hospitalization:
. general analysis blood (6 parameters);
. general urine analysis;
. precipitation microreaction with antilipid antigen;
. biochemical blood test (ALAT, AST, total protein, bilirubin, creatinine, urea, glucose);
. coagulogram;
. ELISA for HIV;
. ELISA for markers viral hepatitis B, C;
. blood type, Rh factor;
. survey radiography of the chest;
. FGDS;
. additional consultations of specialized specialists in the presence of concomitant pathology (endocrinologist, pulmonologist);
. consultation of a dentist, an otolaryngologist to exclude foci of chronic infection.

The main (mandatory) diagnostic examinations carried out at the hospital level:
. ECG;
. Holter ECG monitoring;
. Echocardiography.

Additional diagnostic examinations carried out at the hospital level:
. carotid sinus massage;
. sample from physical activity;
. pharmacological tests with isoproterenol, propranolol, atropine;
. EFI (performed in patients with the presence of clinical symptoms in whom the cause of the symptoms is unclear; in patients with asymptomatic bundle branch block, if pharmacotherapy is planned, which can cause AV block);

If an organic cerebral pathology is suspected or in case of syncope of unknown origin:
. radiography of the skull and cervical spine;
. examination of the fundus and visual fields;
. EEG;
. 12/24 - hour EEG (with suspicion of epileptic genesis of paroxysms);
. echoencephaloscopy (with suspicion of volumetric brain processes and intracranial hypertension);
. CT scan(with suspicion of volumetric processes of the brain and intracranial hypertension);
. ultrasonic dopplerography (if a pathology of extra- and intracranial vessels is suspected);

Diagnostic measures carried out at the ambulance stage emergency care :
. measurement of blood pressure;
. ECG.

Diagnostic criteria

Complaints and anamnesis- main symptoms
. Loss of consciousness
. Dizziness
. Headache
. General weakness
. Determine the presence of diseases predisposing to the development of AV blockade

Physical examination
. Pallor skin
. sweating
. rare pulse
. Auscultatory - bradycardia, I heart sound of varying intensity, systolic murmur over the sternum or between the apex of the heart and the left edge of the sternum
. Hypotension

Laboratory studies: not carried out.

Instrumental Research
ECG and 24-hour ECG monitoring (basic criteria):

For AV block:
. Rhythm pauses for more than 2.5 seconds (R-R interval)
. Signs of AV dissociation (lack of conduction of all P waves to the ventricles, leading to complete dissociation between P waves and QRS complexes)

With SSSU:
. Rhythm pauses for more than 2.5 sec ( P-P interval)
. Increase R-R interval 2 or more times the normal RR interval
. Sinus bradycardia
. No increase in heart rate during emotional / physical stress (chronotropic SPL insufficiency)

EchoCG:
. Hypokinesis, akinesis, dyskinesia of the walls of the left ventricle
. Changes in the anatomy of the walls and cavities of the heart, their relationship, the structure of the valvular apparatus, systolic and diastolic function of the left ventricle

EFI (additional criteria):

. With SSSU:

For AV block:

HV interval extension more than 100 ms

Indications for consultation of specialists (if necessary, by decision of the attending physician):

Dentist - sanitation of foci of infection

Otolaryngologist - to exclude foci of infection

Gynecologist - to exclude pregnancy, foci of infection

Differential Diagnosis

Differential diagnosis of cardiac conduction disorders: SA and AV blockade

Treatment abroad

Get treatment in Korea, Israel, Germany, USA

Get advice on medical tourism

Treatment

Treatment goals:

Improving the prognosis of life (prevention of sudden cardiac death, increase in life expectancy);

Improving the quality of life of the patient.

Treatment tactics

Non-drug treatment:

Bed rest;

Diet number 10.

Medical treatment

with acute development of AV blockade, SSSU before the installation of a pacemaker(mandatory, 100% chance)

Drug treatment provided on an outpatient basis before hospitalization to a hospital:

List of Essential Medicines(having a 100% cast chance).

List of additional medicines(less than 100% chance of application)

Medical treatment provided at the inpatient level

List of Essential Medicines(having a 100% cast chance)

List of additional medicines c (less than 100% probability of application).

Drug treatment provided at the stage of emergency emergency care

Other treatments:(at all levels of medical care)

For hemodynamically significant bradycardia:

Lay the patient with the lower limbs raised at an angle of 20 ° (if there is no pronounced stagnation in the lungs);

oxygen therapy;

If necessary (depending on the patient's condition) - closed heart massage or rhythmic tapping on the sternum ("fist rhythm");

It is necessary to stop drugs that could cause or aggravate AV blockade (beta-blockers, slow calcium channel blockers, class I and III antiarrhythmic drugs, digoxin).

These measures are carried out until the stabilization of the patient's hemodynamics.

Surgical intervention

pacing- the main method of treatment of cardiac conduction disorders. Bradyarrhythmias account for 20-30% of all cardiac arrhythmias. Critical bradycardia threatens the development of asystole and is a risk factor for sudden death. Severe bradycardia worsens the quality of life of patients, leads to dizziness and syncope. Elimination and prevention of bradyarrhythmias will solve the problem of life threatening and disability of patients. EKS - the implantable automatic devices intended for prevention of bradycardic episodes. The electrical stimulation system includes the apparatus itself and electrodes. According to the number of electrodes used, EKS are divided into single-chamber and two-chamber.

Surgical intervention provided on an outpatient basis: no.

Surgical intervention provided in a hospital setting

Indications for permanent pacing in AV block

Class I

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level associated with symptomatic bradycardia (including heart failure) and ventricular arrhythmias due to AV block (Evidence level: C)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomic level associated with arrhythmias and other medical conditions requiring medical treatment that cause symptomatic bradycardia (Evidence level: C)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level with documented periods of asystole greater than or equal to 2.5 seconds, or any escape rhythm<40 ударов в минуту, либо выскальзывающий ритм ниже уровня АВ узла в бодрствующем состоянии у бессимптомных пациентов с синусовым ритмом (Уровень доказанности: С)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level in asymptomatic patients with AF and documented at least one (or more) pause of 5 seconds or more (Evidence level: C)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level in patients after catheter ablation of the AV node or bundle of His (Evidence level: C)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level in patients with postoperative AV block that is not expected to resolve after cardiac surgery (Evidence level: C)

3rd-degree AV block and progressive 2nd-degree AV block at any anatomical level in patients with neuromuscular disease with AV block, such as myotonic muscular dystrophy, Kearns-Sayre syndrome, Leiden's dystrophy, peroneal muscular atrophy, with or without symptoms (Level of Evidence: B )

Third-degree AV block, regardless of type and site of block, with concomitant symptomatic bradycardia (Level of Evidence: B)

Persistent 3rd-degree AV block at any anatomical level with an awake escape rate of less than 40 beats per minute in patients with cardiomegaly, LV dysfunction, or escape rhythm below the AV node level without clinical manifestations of bradycardia (Evidence level: B)

Second- or third-degree AV block occurring on an exercise test in the absence of evidence of coronary artery disease (Level of Evidence: C)

Class IIa

Asymptomatic persistent 3rd-degree AV block at any anatomic site, with an awake mean ventricular rate >40 beats per minute, especially in cardiomegaly or left ventricular dysfunction (Level of Evidence: B,C)

Asymptomatic AV blockade II degree type II at the intra- or infrahysial level, detected by EPS (Evidence level: B)

Asymptomatic type II degree AV block with narrow QRS. If asymptomatic 2nd-degree AV block occurs with a widened QRS, including isolated RBBB, the indication for pacing moves to a Class I recommendation (see next section on chronic bifascicular and trifascicular block) (Evidence level: B)

AV block I or II degree with hemodynamic disturbances (Level of Evidence: B)

Class IIb

Neuromuscular disorders: myotonic muscular dystonia, Kearns-Sayre syndrome, Leiden's dystrophy, peroneal muscular atrophy with any degree of AV block (including 1st degree AV block), with or without symptoms, as there may be unpredictable disease progression and worsening of AV conduction (Level of Evidence: B)

When AV block occurs due to drug use and/or drug toxicity, when resolution of the block is not expected, even in the setting of discontinuation of the drug (Evidence level: B)

First-degree AV block with PR interval greater than 0.30 sec in patients with left ventricular dysfunction and congestive heart failure, in whom a shorter AV interval leads to hemodynamic improvement, presumably by reducing left atrial pressure (Level of Evidence: C)

Class IIa

The absence of a visible connection between syncope and AV block, with the exclusion of their connection with

Ventricular tachycardia (Level of Evidence: B))

Incidental detection during invasive EPS of a clearly prolonged HV interval >100 ms in asymptomatic patients (Evidence level: B)

Identification during an invasive electrophysiological study of non-physiological AV blockade below the bundle of His, developing during stimulation (Evidence level: B)

Class IIv

Neuromuscular diseases such as myotonic muscular dystonia, Kearns-Sayre syndrome, Leiden's dystrophy, peroneal muscular atrophy with any degree of fascicular block, with or without symptoms, as there may be an unpredictable increase in atrioventricular conduction disturbance (Level of Evidence: C)

Indications for planned hospitalization:

AV block II-III degree

Indications for emergency hospitalization:

Syncope, dizziness, hemodynamic instability (systolic blood pressure less than 80 mm Hg).

Information

Sources and literature

1. Minutes of the meetings of the Expert Commission on Health Development of the Ministry of Health of the Republic of Kazakhstan, 2014
   1. 1. Brignole M, Auricchio A. et al. 2013 ESC The Task Force on cardiac pacing and resynchronization therapy of the European Society of Cardiology (ESC). Developed in collaboration with the European Heart Rhythm Association (EHRA). Guidelines on cardiac pacing and cardiac resynchronization therapy. European Heart Journal (2013) 34, 2281–2329. 2. Brignole M, Alboni P, Benditt DG, Bergfeldt L, Blanc JJ, Bloch Thomsen PE, van Dijk JG, Fitzpatrick A, Hohnloser S, Janousek J, Kapoor W, Kenny RA, Kulakowski P, Masotti G, Moya A, Raviele A, Sutton R, Theodorakis G, Ungar A, Wieling W; Task Force on Syncope, European Society of Cardiology. Guidelines on management (diagnosis and treatment) of syncope-update 2004. Europace 2004;6:467 – 537 3. Epstein A., DiMarco J., Ellenbogen K. et al. ACC/AHA/HRS 2008 guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2008;117:2820-2840. 4. Fraser JD, Gillis AM, Irwin ME, Nishimura S, Tyers GF, Philippon F. Guidelines for pacemaker follow-up in Canada: a consensus statement of the Canadian Working Group on Cardiac Pacing. Can J Cardiol 2000;16:355-76 5. Gregoratos G, Abrams J, Epstein AE, et al. ACC/AHA/NASPE 2002 17 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices-summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/NASPE Committee to Update the 1998 Pacemaker guidelines). J AmCollCardiol. 40: 2002; 1703–19 6. Lamas GA, Lee K, Sweeney M, et al. The mode selection trial (MOST) in sinus node dysfunction: design, rationale, and baseline characteristics of the first 1000 patients. Am Heart J. 140: 2000; 541–51 7. Moya A., Sutton R., Ammirati F., Blanc J.-J., Brignole M, Dahm, J.B., Deharo J-C, Gajek J., Gjesdal K., Krahn A., Massin M., Pepi M., Pezawas T., Granell R. R., Sarasin F., Ungar A., ​​J. Gert van Dijk, Walma E. P. Wieling W.; Guidelines for the diagnosis and management of syncope (version 2009). Europace 2009. doi:10.1093/eurheartj/ehp29 8. Vardas P., Auricchio A. et al. Guidelines for cardiac pacing and cardiac recynchronization therapy. The Task Force for Cardiac Pacing and Cardiac Recynchronization Therapy of the European Society of Cardiology. Developed in Collaboration with the European Heart Rhythm Association. European Heart Journal (2007) 28, 2256-2295 9. Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death). J AmCollCardiol. 48: 2006; e247–e346 10. Bockeria L.A., Revishvili A.Sh. et al. Clinical guidelines for electrophysiological studies and catheter ablation and for the use of implantable antiarrhythmic devices. Moscow, 2013

   
   Indication of no conflict of interest: absent.

   Reviewer:
   Madaliev K.N. - head of the department of arrhythmology of the Republican State Enterprise "Research Institute of Cardiology and Internal Diseases", candidate of medical sciences, cardiosurgeon of the highest category.

   Conditions for revision of the protocol: Once every 5 years, or upon receipt of new data on the diagnosis and treatment of the relevant disease, condition or syndrome.

   
   

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AV blockade is one of the types of pathology of the conduction of the heart and is easily diagnosed using an electrocardiographic study.

Electrocardiographic examination allows diagnosing various cardiac pathologies. What do different degrees of AV blockade look like on a cardiogram, what is their clinical picture.

What is a cardiogram

A cardiogram is a recording on a special film of electrical impulses produced by the myocardium. Such a record allows you to judge the state of the heart, diagnose various pathologies:

• violations of the conduction of the heart muscle - blockade;
• violations of the rhythm of contractions of the heart - arrhythmias;
• myocardial deformation - ischemia, necrosis (heart attack).

To decipher the electrocardiogram, certain notations have been created. With their help, the function of the atria and ventricles of the heart, the state of the conduction nodes and the myocardium itself are described. Evaluating all the elements of the cardiogram, the specialist gives a conclusion about the state of the heart.

Knowing the conventions, a specialist can decipher any cardiogram

How is an ECG done?

There are some rules for conducting an electrocardiographic study. An ECG can be performed at any age and with any concomitant pathology. The procedure has no contraindications.

The study is carried out using a cardiograph apparatus. In hospitals there are large devices, portable portable cardiographs are used for ambulance doctors. It is arranged as follows:

• the main part that analyzes the incoming electrical impulses;
• a recording device that marks electrical impulses in the form of a curve on a paper film;
• electrodes applied to the anterior surface of the chest and to the extremities.

During the removal of the cardiogram, the patient is in the supine position. He is warned to remove all metal jewelry, watches and other metal objects. The places where the electrodes will be applied are moistened with water. This is necessary for a better connection of the electrode with the skin and conduction of the impulse.

There are certain points on the body for applying electrodes.

There are standard points for applying electrodes - one is applied to the limbs, and eight electrodes are applied to the anterior surface of the chest. Standard leads are removed from the limbs, forming the Einthoven triangle. Additional chest leads are removed from the chest, allowing more accurate localization of the pathology. In case of urgent need to remove the cardiogram, only standard leads from the limbs are used.

• An electrode with a red mark is applied to the right hand.
• On the left hand - yellow.
• On the left leg - green.
• On the right leg - black, which is grounding.

What is AV block

AV blockade is a type of pathology of the conduction system of the heart. It consists in slowing down or completely stopping the conduction of an electrical impulse from the atria to the ventricles.

The reason for this is a violation of the function of the atrioventricular node, which passes an electrical impulse through itself. Its function can be impaired due to a number of conditions: pathology of the parasympathetic nervous system, long-term use of certain cardiac drugs (glycosides, beta-blockers), organic damage - fibrosis or inflammation of this area of ​​the myocardium.

Causes of AV blocks

The reasons for the violation of the conduction of an electrical impulse in the tissue of the heart can be different conditions. They can be functional - that is, without the presence of changes in the tissue of the heart. There are also organic causes - with any deformations of cardiomyocytes.

Functional reasons include:

• long-term use of cardiac drugs;
• violation of the innervation of the heart;
• sometimes blockades occur in athletes as an adaptive reaction.

Organic causes include:

• insufficient blood supply to cardiomyocytes and their ischemia;
• replacement of a portion of the heart tissue with connective tissue;
• formation of necrosis of cardiomyocytes.

Types of blockade on the cardiogram

Depending on how many impulses this node is able to pass, three degrees of blockade are distinguished. On the ECG, all degrees are manifested by their signs.

At 1 degree, the duration of the PQ interval is more than 200 ms. The correct heart rate is maintained.

In first-degree AV block, there is a persistently prolonged PQ interval

At 2 degrees, there are two options. The first type, or blockade according to Mobitz 1 (Wenckebach's period), is characterized by a gradual lengthening of the PQ interval with each heartbeat, at the end of the period the ventricular complex (QRS) falls out and the period begins again. The second type, or Mobitz 2, is characterized by the fact that there is a sudden prolapse of the ventricular complex. The PQ interval can be all the time of normal duration or all the time increased.

Second-degree AV block is characterized by gradual prolongation of the PQ interval followed by prolapse of the ventricular complex

At grade 3, there is a complete cessation of impulse transmission to the ventricles. The atria and ventricles contract at different rates. Complete AV block - ECG at this degree produces an overlay of atrial contraction waves on the ventricular contraction waves. The P waves and QRS complexes are randomly distributed.

With the third degree of AV blockade, a complete dissociation of the rhythm of atrial and ventricular contractions is seen.

For each degree of blockade, there are varieties that have distinctive features on the cardiographic film.

First-degree AV block comes in the following forms:

• nodular form - only pathological prolongation of the PQ interval is observed;
• atrial form - in addition to PQ lengthening, a deformed P wave can be detected;
• the distal form is characterized by a long PQ and deformation of the QRS complex.

In the second degree, the above forms are distinguished (Mobitz 1 and Mobitz 2). Less commonly, two more forms are noted:

• blockade 2:1 - there is a periodic loss of contractions of the ventricles (every second);
• progressive form - several ventricular complexes may fall out in a row, without a specific sequence.

In the third degree, two forms are noted:

• proximal - dissociation of the rhythm of atrial and ventricular contractions, the QRS complex is not deformed;
• distal - there is an uncoordinated contraction of the ventricles and atria, the ventricular complex is deformed and widened.

There are also clinical syndromes that are a combination of AV blockade with other pathologies:

• Frederick's syndrome - signs of this condition consist in fixing F or f waves on the cardiogram, which indicate atrial fibrillation or flutter;
• with MAS syndrome (Morgagni-Adams-Stokes), periods of ventricular asystole are detected on the ECG.

Clinical manifestations of different degrees

AV blocks can be transient (quickly passing) and permanent. Transient blockades are difficult to diagnose. To detect them, Holter monitoring is required - registration of a cardiogram during the day.

At the first degree of atrioventricular blockade, there are no obvious clinical manifestations. The only symptom is bradycardia. Some patients may feel weak and fatigued.

A more pronounced clinical picture is observed in the second degree:

• palpation can detect periodic loss of a pulse wave;
• clinically, this will manifest itself as a feeling by patients of interruptions in the work of the heart;
• patients also feel weak and tired.

The most dangerous is the third degree of blockade:

• intermittent or persistent dizziness;
• noise in the ears, flies before the eyes;
• pain in the chest;
• feeling of interruptions in the work of the heart;
• episodes of loss of consciousness.

When listening to the heart with a stethoscope, you can hear the correctness of the rhythm, but with the appearance of long pauses, this is the loss of ventricular contraction. Bradycardia of varying severity is noted. A cannon-shaped heart sound, characteristic of blockades, called Strazhesko's tone, appears.

A complication of blockade can be ventricular tachycardia leading to asystole. In the MAS syndrome, observed in conjunction with this blockade, attacks of ventricular asystole may also occur, threatening rhythm disruption and cessation of cardiac activity.

Treatment

Treatment of AV blockade consists in prescribing drugs to improve myocardial conduction, eliminating the underlying disease. In severe blockade, the installation of an artificial pacemaker is required.

First-degree blockade does not require special treatment. Only observation of the patient is shown, periodic Holter monitoring to determine the dynamics of the development of blockades.

In the second degree, the use of drugs, for example, Corinfar, is indicated. The patient is also monitored.

A necrotic or fibrosed area of ​​the myocardium can no longer be restored. In this case, first a course is taken with beta-adrenergic stimulators, and then a pacemaker is implanted.

In some cases, AV blockade is not accompanied by any symptoms and a violation of the general condition.

Types of atrioventricular blockades:

Features of transient AV blockade of the 1st degree

Transient or acute atrioventricular block may last only a few seconds. During this time, a sharp drop in pressure leads to a stop in the conduction of an electrical impulse caused by a malfunction of the ANS (autonomic nervous system).

Transient AV block can lead to tachycardia, ventricular ectopia, or fibrillation. It is possible to prevent complete transient blockade by pre-administration of atropine.

In the absence of damage and changes in the AV node, the transistor blockade has a vagal character, which occurs with a sharp decrease in pressure during stress, blood transfusion, or severe vomiting. It can also disturb with a sharp transition from a lying position to a sitting position.

In elderly people with increased vagal tone, there is a strong slowing of the sinus rhythm and the manifestation of blockade in stage 1, which is eliminated by atropine.

Etiology of impulse conduction disorders

• Increased tone of the vagus (vagus nerve).
• Electrolytic disturbances with severe vomiting.
• Overdose of drugs.
• Stress and overwork.

Treatment

Transistor atrioventricular blockade of the 1st stage is considered the norm for young active people and does not require treatment.

Therapeutic measures are carried out upon detection of concomitant problems in the work of the heart muscle and the heart as a whole, they are aimed at eliminating the cause of conduction disturbances in the AV node.

If blockade is suspected, the patient is sent for diagnostic measures:

Stage 1 blockade can be caused by taking medications:

• cardiac glycosides;
• antiarrhythmic drugs;
• beta blockers.

In such cases, these drugs are canceled, if it is impossible to cancel, adjust the dose.

Conduction disorders in the AV node in children

Transistor AV block 1 degree in childhood is a common occurrence. Its cause can be a pathological pregnancy of the mother, a negative environment, excessive physical exertion.

In newborns, the heart rate ranges from 140 to 170 beats, a decrease in the rhythm to 100 is considered bradycardia and requires additional diagnostics to identify the problem.

In case of violation of the first degree, clinical manifestations may not bother the child, but parents need to pay attention to the appearance of such signs:

• Bluish or very pale skin.
• Highlighted nasolabial triangle.
• The baby does not take the breast or sucks very weakly.
• The baby sweats profusely.

If the disorder is functional in nature, then the prognosis is usually favorable, the problem does not worsen in the future, and relapses are not observed.

To prevent first-degree blockade, cardiologists prescribe regular monitoring of the condition of children, at least twice a year.

Providing first aid during an attack

An attack of blockade requires immediate action. It is necessary to call an ambulance, but even before the arrival of the doctors, the patient is given first aid.

The person is laid on his back, a pillow is placed under his head. To relieve the condition, you can give isadrin, one tablet under the tongue. If the patient has lost consciousness, artificial respiration and chest compressions will help bring him to his senses.

The ambulance will take the following steps:

• The introduction of adrenaline and norepinephrine intravenously.
• Atropine is injected subcutaneously.
• A blockade of the cardio-aortic plexus is carried out with novocaine.
• A defibrillator is being used.

The patient is urgently admitted to the intensive care unit.

Diet food

After diagnosing a patient with transient blockade of the 1st degree, cardiologists recommend changing the diet.

To improve conduction in the AV node, it is necessary that the foods consumed have enough potassium, magnesium, and calcium.

Foods that improve AV node conduction:

Salty and smoked foods, confectionery sweets, artificial fats are excluded from the diet. With obesity, it is necessary to lose those extra pounds that create a load on the heart.

Transient AV block: what not to eat:

• lard, meat with fat;
• animal fats, butter;
• strong broths;
• canned food and marinades;
• sour cabbage;
• seasonings and sauces with hot peppers;
• chocolate;
• coffee;
• cocoa;
• Black tea;
• alcoholic drinks;
• carbonated waters.

On the table of a patient with a cardiac disease should be vegetables, preferably fresh or stewed in olive oil, cereals, boiled, lean meat, dairy products.

With high cholesterol, the number of eggs is limited, it is advisable not to serve them as a whole, but add them to dishes according to the recipe. Fresh white flour bread is replaced with wholemeal bread, baked yesterday.

Transient heart block. Lifestyle

In addition to a diet aimed at strengthening the body and restoring conductivity, patients should give up bad habits, alcohol, cigarettes, and drugs.

Properly organized daily routine, physical activity contribute to the rapid restoration of a healthy state.

Patients with impaired transient conduction are prohibited from physical overload, work associated with stress.

With an increase in health problems, cardiologists recommend that people who have undergone a transient blockade undergo a complete examination, since a blockade that develops into a severe degree can be fatal.

Transient AV block. Treatment with folk remedies

Traditional medicine recommends rose hips to restore the condition after attacks. Five tablespoons of rose hips are boiled in water (500 ml), boiled fruits are rubbed with honey. The decoction is drunk before meals, half a glass.

Valerian root is used to restore the passage of an electrical impulse in the AV block. A decoction of the root soothes, restores the functioning of the heart muscles and AV block.

Horsetail preparations restore the functioning of blood vessels and the heart as a whole. To prepare the product, two teaspoons of raw materials are poured into a glass of boiling water, after which they insist for fifteen minutes. Take horsetail every two hours, two teaspoons.

Hawthorn helps to normalize blood circulation, pressure and relieve the excitability of the central nervous system. To prepare the product, ten grams of dry raw materials and 100 ml of vodka are used.

The drug is infused for ten days. Ready, filtered drug is taken three times a day, ten drops in water, before meals.

Melissa infusion has a sedative effect and restores the nervous system. To prepare the infusion, you need to take one tablespoon of dry grass and pour a glass of water. The drug is taken four times a day for a quarter cup.

When taking folk remedies, it must be remembered that no decoction can replace the advice of a cardiologist, therefore regular examinations for people with cardiological problems are a necessity that helps to prolong life, and often save it.

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AV block

Depending on the severity of the AV block (atrioventricular block) can be 1st, 2nd and 3rd degree (complete).

1st degree AV block is a prolongation of the PQ interval greater than 0.20 s. It is found in 0.5% of young people without signs of heart disease. In the elderly, 1st-degree AV block is most often the result of an isolated disease of the conduction system (Lenegre's disease).

In 2nd degree AV block, part of the atrial impulses do not reach the ventricles. Blockade can develop at the level of the AV node and the His-Purkinje system.

2nd degree AV block with 3:1 conduction.

• If in AV block (for example, with a 4:3 or 3:2 conduction) the PQ intervals are not the same and Wenckebach's periodicity is observed, they speak of Mobitz type I AV block of the 2nd degree.

• In Mobitz type I 2nd-degree AV block, the QRS complexes are usually narrow because the block occurs above the bundle of His at the level of the AV node.

• Even if there is bundle branch block in Mobitz type I AV block, the level of AV block is most likely at the level of the AV node. However, in this case, an electrogram of the bundle of His is needed to confirm the level of blockade.

Advanced AV block (3:1, 4:1 or greater) refers to 2nd-degree Mobitz II AV block. In this case, the QRS complexes are usually wide (blockade of the right or left bundle branch block is typical), and the level of the blockade is below the AV node. Mobitz II AV block usually occurs at or below the His-Purkinje system. It often progresses to complete AV block.

3rd-degree AV block, or complete AV block, can be acquired or congenital.

all systemic lupus erythematosus.

Clinical picture

1st degree AV block is usually asymptomatic.

• With the prolongation of the PQ interval, I heart sound becomes quieter, therefore, for AV blockade of the 1st degree, a quiet I tone is characteristic, with AV blockade of the 2nd degree of the Mobitz type I, the volume of the I tone decreases from cycle to cycle, and with complete AV blockade she is different all the time.

• With complete AV block, a functional mesosystolic murmur may occur.

Etiology

The causes of AV block are shown in the table. The most common cause is an isolated disease of the conduction system (Lenegre's disease). In addition, AV block can occur with myocardial infarction, usually within the first 24 hours. It occurs in patients with inferior myocardial infarction and in 2% of patients with anterior myocardial infarction.

• Digoxin
• Beta blockers
• Some calcium antagonists
• Antiarrhythmic drugs with quinidine-like action

• Infective endocarditis
• Myocarditis (Chagas disease, Lyme disease, rheumatism, tuberculosis, measles, mumps)

• Primary adrenal insufficiency

• Operations on the heart
• Irradiation of the mediastinum
• Cardiac catheterization
• catheter destruction

• carotid sinus syndrome
• Vasovagal reactions

Diagnostics

1st degree AV block

This diagnosis is made with a PQ interval of more than 0.20 s in adults and more than 0.18 s in children. Each P wave is followed by a QRS complex, and the shape of the P wave and QRS complex is normal.

2nd degree AV block

Mobitz type I AV block 2nd degree is placed in the presence of the following signs:

• The PQ interval gradually lengthens, and then after the next P wave, the QRS complex falls out.

• The PQ interval gradually lengthens, but with each cycle by an ever smaller amount, so that the RR interval from cycle to cycle becomes shorter until the next ventricular complex prolapse occurs.

• The pause at the end of the Wenckebach period is less than any two consecutive RR intervals.

• The PQ interval after the pause is less than the PQ interval before the pause.

• QRS complexes form groups called Wenckebach periods.

Mobitz II type 2nd degree AV block is less common than Mobitz I. It is characterized by the following features:

• The PQ interval is the same all the time, but part of the atrial impulses are not conducted. At the same time, unlike blocked atrial extrasystoles, the RR interval is constant.

• In advanced AV block, there is more than one P wave per QRS complex (this is called AV block with conduction 3:1, 4:1, etc.). The QRS complexes are often wide (in contrast to the Mobitz type I block, which is characterized by narrow complexes).

Complete AV block

AV dissociation is characteristic, that is, the complete absence of a temporal relationship between the P waves and the QRS complexes. P waves can be used to calculate the atrial rate.

Treatment

No treatment is required for 1st-degree and 2nd-degree Mobitz type I AV block. In Mobitz II type 2nd degree AV block and complete AV block, permanent pacing is usually indicated.

• Atropine can reduce AV block if it is due to increased parasympathetic tone, but not ischemia.

• Atropine is more effective in AV blockade against the background of lower than against the background of anterior myocardial infarction.

• Atropine does not affect conduction in the His-Purkinje system and is therefore ineffective in complete AV block, as well as in 2nd degree AV block due to blockade at the level of the His-Purkinje system.

• Atropine does not affect the transplanted heart.

• In Mobitz II type 2nd-degree AV block, atropine should be used with caution as it may decrease the ventricular rate. Thus, 2:1 conduction AV block at an atrial rate of 80 beats per minute can progress to 3:1 AV block at an atrial rate of 90 beats per minute, causing the ventricular rate to drop from 40 to 30 beats per minute.

Antidigoxin (Fab fragments of antibodies to digoxin) is used for hemodynamically significant AV block caused by digoxin. The dose is calculated as follows:

Number of Vials = Weight (kg) × Serum Digoxin Concentration (ng/mL) ⁄ 100

Complete AV block in inferior myocardial infarction is often transient, so a temporary pacing is usually sufficient.

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Atrioventricular (AV) blockade 1 degree - what is it and how to treat

Atrioventricular blockade of the 1st degree is a pathological (less often physiological) sign, which is determined on an electrocardiogram, reflecting a violation of the conduction of a nerve impulse through the conduction system of the heart.

To understand what this condition is and how to treat 1st degree AV block, it is necessary to explain that there is a conduction system in the heart that has a clear hierarchy. The AV node (Ashoff-Tavar node) is located in the interatrial septum and is responsible for conducting the signal to contract from the atria to the ventricles.

Epidemiology

Degree 1 AV block is a fairly common condition. The incidence increases in direct proportion to age, since over time the risk of developing cardiac pathology (especially coronary artery disease) increases significantly.

There is evidence that AV - block 1 degree is observed in 5% of people with cardiac disorders. As for children, their frequency of occurrence varies from 0.6 to 8%.

Classification

According to the frequency and frequency of development:

• persistent - is identified and persists in the future;
• transient (transient) - was found once, but subsequently disappeared;
• intermittent - after the definition passed, but then was found again.

According to the localization of the block of the AV blockade, they are divided into:

• proximal (violation in the part of the node closest to the atria);
• distal (the affected part is close to the ventricles);
• There are blockades of the combined type.

By predictive value

• Relatively favorable: functional grade 1 proximal AV block;
• Favorable: complete blockade of acute type, with QRS expansion (distal block).

Causes of AV blockade

The causes of the disease can be divided into organic and functional.

There are also a number of syndromes in which isolated degeneration of the AV node and bundle of His is noted.

1) At the first, a partial anatomical (structural) lesion of the conduction system is observed. This is observed, for example, when the node is involved in fibrosis after myocardial damage, with myocarditis, coronary artery disease, Lyme disease. Rarely, congenital ab - blockade occurs (children from mothers with CTD suffer). Often the AV node is involved in inferior myocardial infarctions.

2) With a functional blockade, the morphology of the node is not disturbed, only the function suffers, which, of course, lends itself better to correction.

This condition occurs with the predominance of the tone of the parasympathetic nervous system, taking antiarrhythmics (beta-blockers - bisoprolol, atenolol; calcium channel blockers - verapamil, diltiazem; glycosides - corglicon, strophanthin), electrolyte disorders (hyper- / hypokalemia).

It should also be said that AV blockade of the 1st degree can also occur normally, and treatment is not required. This happens, for example, among professional athletes, young people.

3) Degenerative changes in the AV node with genetic pathology.

They develop with mutations in the gene encoding the synthesis of sodium channel proteins in cardiomyocytes.

The following syndromes are specific: Leva, Lenegra, idiopathic calcification of the node.

Manifestations

What is a heart block? In this case, the diagnostic ECG criterion for this condition is a prolongation of the PQ interval of more than 0.2 seconds, while the P waves are normal, the QRS complexes do not fall out.

Clinically, this condition does not manifest itself in any way, since the heart contracts correctly, although less often than normal.

Therefore, this finding on the ECG does not indicate the need for treatment; rather, monitoring of the condition is necessary.

Perhaps the appearance of symptoms under the action of a trigger - physical. load. With the appearance of syncopal attacks (fainting), dizziness, the transition of the blockade to the second degree (next stage) should be suspected.

Patient monitoring program

In order to notice the progression of an incomplete blockade in time and start its correction in time, the following is shown:

• repeated ECG - studies (the multiplicity is determined by the doctor);
• daily (Holter) ECG monitoring.

Of course, the ECG provides comprehensive information regarding rhythm disturbances, which is AV blockade of the 1st degree. But in order to identify the causes, additional studies, for example, echocardiography, will be useful. Diagnostically important may be the determination of the concentration of drugs taken in the blood, the study of the ionic composition of the blood.

Treatment

1st degree AV block does not require medical treatment. Dynamic control over the state of such people is shown. However, if the cause is identified and can be eliminated, it must be done.

With the development of pathology as a result of taking drugs - reduce the dose or cancel the medicine with the selection of another, in case of electrolyte disorders - correction of the electrolyte balance. Summarizing, we can say that it is possible and necessary to influence the functional AV blockade of the 1st degree, in the case of an organic lesion of the node, expectant tactics should be chosen.

With a proven blockade of the functional type, it is possible to carefully adjust the tone of the autonomic innervation. Apply drugs such as belloid, teopek.

Features in children

Violations of the impulse through the heart in children are quite common. This is due to the pathology of pregnancy resulting from maternal diseases (diabetes mellitus, SLE), exposure to environmental factors, etc.

Heart rate is assessed differently in infants than in adults: HR 100 bpm. already considered bradycardia and requires attention. Therefore, first-degree AV block at birth is noticeable.

The following symptoms are noted: pallor or cyanosis, lethargy, weakness, refusal of the breast, increased sweating. At the same time, there may not be clinical manifestations in grade 1.

Forecast

With functional disorders - favorable, with organic ones, a progressive course of pathology is likely. Distal atrioventricular blocks are much more dangerous in terms of the risk of complications than proximal ones.

Prevention

There are no specific measures to prevent first-degree AV block.

As a measure of secondary prevention (prevention of progression), monitoring of the condition, implantation of a pacemaker (in case of deterioration) can be distinguished.

Atrioventricular block

Atrioventricular (atrioventricular) blockade (AV blockade) is a violation of the conduction function, which is expressed in slowing down or stopping the passage of an electrical impulse between the atria and ventricles and leading to heart rhythm and hemodynamic disorders. AV block may be asymptomatic or accompanied by bradycardia, weakness, dizziness, angina, and loss of consciousness. Atrioventricular blockade is confirmed by electrocardiography, Holter ECG monitoring, EFI. Treatment of atrioventricular blockade can be medical or cardiac surgery (implantation of a pacemaker).

Atrioventricular block

Atrioventricular block is based on the slowing down or complete cessation of the passage of the impulse from the atria to the ventricles due to damage to the AV node itself, the bundle of His, or the legs of the bundle of His. At the same time, the lower the level of damage, the more severe the manifestations of the blockade and the more unsatisfactory the prognosis. The prevalence of atrioventricular block is higher among patients suffering from concomitant cardiopathology. Among people with heart disease, I degree AV block occurs in 5% of cases, II degree - in 2% of cases, III degree AV block usually develops in patients older than 70 years. Sudden cardiac death is reported to occur in 17% of patients with complete AV block.

The atrioventricular node (AV node) is part of the conduction system of the heart, providing consistent contraction of the atria and ventricles. The movement of electrical impulses coming from the sinus node slows down in the AV node, allowing the atrial contraction and pumping blood into the ventricles. After a short delay, the impulses propagate along the bundle of His and its legs to the right and left ventricles, contributing to their excitation and contraction. This mechanism ensures alternate contraction of the atrial and ventricular myocardium and maintains stable hemodynamics.

Classification of AV blocks

Depending on the level at which a violation of the conduction of an electrical impulse develops, proximal, distal and combined atrioventricular blockades are distinguished. With proximal AV blockade, impulse conduction may be impaired at the level of the atria, the AV node, the trunk of the His bundle; with distal - at the level of the branches of the bundle of His; with combined - there are multilevel conduction disturbances.

Taking into account the duration of the development of atrioventricular blockade, its acute (with myocardial infarction, drug overdose, etc.), intermittent (intermittent - with coronary artery disease, accompanied by transient coronary insufficiency) and chronic forms are distinguished. According to electrocardiographic criteria (slowdown, periodicity or complete absence of impulse conduction to the ventricles), three degrees of atrioventricular blockade are distinguished:

• I degree - atrioventricular conduction through the AV node is slowed down, however, all impulses from the atria reach the ventricles. Clinically not recognized; on the ECG, the P-Q interval is prolonged> 0.20 seconds.
• II degree - incomplete atrioventricular blockade; not all atrial impulses reach the ventricles. On the ECG - periodic loss of ventricular complexes. There are three types of Mobitz II degree AV block:

1. Type I Mobitz - the delay of each subsequent impulse in the AV node leads to a complete delay of one of them and the prolapse of the ventricular complex (Samoilov-Wenckebach period).
1. Type II Mobitz - the critical impulse delay develops suddenly, without a previous prolongation of the delay period. At the same time, there is a lack of conduction of every second (2:1) or third (3:1) impulse.

• III degree - (complete atrioventricular block) - complete cessation of the passage of impulses from the atria to the ventricles. The atria contract under the influence of the sinus node, the ventricles - in their own rhythm, at least 40 times per minute, which is not enough to ensure adequate blood circulation.

Atrioventricular blocks of I and II degrees are partial (incomplete), blockade of the III degree is complete.

Reasons for the development of AV blocks

According to the etiology, functional and organic atrioventricular blockades are distinguished. Functional AV blockade is due to an increase in the tone of the parasympathetic nervous system. Atrioventricular block I and II degree in isolated cases observed in young physically healthy individuals, trained athletes, pilots. It usually develops during sleep and disappears during physical activity, which is explained by increased activity of the vagus nerve and is considered as a variant of the norm.

AV blockade of organic (cardiac) origin develops as a result of idiopathic fibrosis and sclerosis of the conduction system of the heart in various diseases. The causes of cardiac AV blockade can be rheumatic processes in the myocardium, cardiosclerosis, syphilitic heart disease, ventricular septal infarction, heart defects, cardiomyopathies, myxedema, diffuse connective tissue diseases, myocarditis of various origins (autoimmune, diphtheria, thyrotoxic), amyloidosis, sarcoidosis, hemochromatosis , tumors of the heart, etc. With cardiac AV blockade, a partial blockade may initially be observed, however, as the cardiopathology progresses, a third-degree blockade develops.

Various surgical procedures can lead to the development of atrioventricular blockades: aortic valve replacement, plastic surgery of congenital heart defects, atrioventricular RFA of the heart, catheterization of the right heart, etc.

Quite rarely in cardiology, a congenital form of atrioventricular blockade (1: newborns) occurs. In the case of congenital AV blocks, there is a lack of sections of the conduction system (between the atria and the AV node, between the AV node and the ventricles, or both legs of the bundle of His) with the development of the corresponding level of blockade. In a quarter of newborns, atrioventricular blockade is combined with other cardiac anomalies of a congenital nature.

Among the reasons for the development of atrioventricular blockades, drug intoxication is often found: cardiac glycosides (digitalis), β-blockers, calcium channel blockers (verapamil, diltiazem, less often corinfar), antiarrhythmics (quinidine), lithium salts, some other drugs and their combinations.

Symptoms of AV block

The nature of the clinical manifestations of atrioventricular blockade depends on the level of conduction disturbance, the degree of blockade, the etiology and severity of concomitant heart disease. Blockades that have developed at the level of the atrioventricular node and do not cause bradycardia do not manifest themselves clinically. The clinic of AV blockade with this topography of disorders develops in cases of severe bradycardia. Due to the low heart rate and the fall in the minute output of blood by the heart during exercise, such patients experience weakness, shortness of breath, and sometimes angina attacks. Due to a decrease in cerebral blood flow, dizziness, transient feelings of confusion and fainting may occur.

With atrioventricular blockade of the II degree, patients feel the loss of a pulse wave as interruptions in the region of the heart. With type III AV blockade, Morgagni-Adams-Stokes attacks occur: a decrease in heart rate to 40 or less beats per minute, dizziness, weakness, blackout, short-term loss of consciousness, pain in the heart, cyanosis of the face, possibly convulsions. Congenital AV block in pediatric and adolescent patients may be asymptomatic.

Complications of AV blocks

Complications in atrioventricular blockade are mainly due to a pronounced slowing of the rhythm that develops against the background of organic heart damage. Most often, the course of AV blockade is accompanied by the appearance or aggravation of chronic heart failure and the development of ectopic arrhythmias, including ventricular tachycardia.

The course of a complete atrioventricular block may be complicated by the development of Morgagni-Adams-Stokes attacks associated with cerebral hypoxia as a result of bradycardia. The onset of an attack may be preceded by a feeling of heat in the head, attacks of weakness and dizziness; during an attack, the patient turns pale, then cyanosis and loss of consciousness develop. At this point, the patient may need to perform chest compressions and mechanical ventilation, since prolonged asystole or the addition of ventricular arrhythmias increases the likelihood of sudden cardiac death.

Multiple episodes of loss of consciousness in elderly patients can lead to the development or aggravation of intellectual-mnestic disorders. Less commonly, with AV blockade, the development of arrhythmogenic cardiogenic shock is possible, more often in patients with myocardial infarction.

In conditions of insufficient blood supply with AV blockade, phenomena of cardiovascular insufficiency (collapse, fainting), exacerbation of coronary heart disease, and kidney disease are sometimes observed.

Diagnosis of AV blocks

When assessing the patient's history in case of suspected atrioventricular blockade, the fact of past myocardial infarction, myocarditis, other cardiopathologies, taking drugs that disrupt atrioventricular conduction (digitalis, β-blockers, calcium channel blockers, etc.) is ascertained.

During auscultation of the heart rhythm, the correct rhythm is heard, interrupted by long pauses, indicating the loss of ventricular contractions, bradycardia, the appearance of Strazhesko cannon I tone. An increase in the pulsation of the cervical veins is determined in comparison with the carotid and radial arteries.

On the ECG, AV blockade of the 1st degree is manifested by a prolongation of the P-Q interval> 0.20 sec.; II degree - sinus rhythm with pauses, as a result of prolapse of ventricular complexes after the P wave, the appearance of Samoilov-Wenckebach complexes; III degree - a decrease in the number of ventricular complexes by 2-3 times compared with atrial ones (from 20 to 50 per minute).

Carrying out 24-hour Holter ECG monitoring in AV blockades allows comparing the subjective sensations of the patient with electrocardiographic changes (for example, syncope with severe bradycardia), assessing the degree of bradycardia and blockade, the relationship with the patient's activities, taking medications, determining whether there are indications for implantation of a pacemaker, etc.

With the help of an electrophysiological study of the heart (EPS), the topography of AV blockade is clarified and indications for its surgical correction are determined. In the presence of concomitant cardiopathology and to detect it in AV blockade, echocardiography, MSCT or MRI of the heart are performed.

Conducting additional laboratory studies in AV blockade is indicated in the presence of concomitant conditions and diseases (determination of the blood level of electrolytes in hyperkalemia, the content of antiarrhythmics in their overdose, enzyme activity in myocardial infarction).

Treatment of AV blocks

With atrioventricular blockade of the 1st degree, which occurs without clinical manifestations, only dynamic observation is possible. If AV blockade is caused by taking drugs (cardiac glycosides, antiarrhythmic drugs, β-blockers), dose adjustment or their complete cancellation is necessary.

In case of AV blockade of cardiac origin (with myocardial infarction, myocarditis, cardiosclerosis, etc.), a course of treatment with β-adrenergic stimulants (isoprenaline, orciprenaline) is performed, and implantation of a pacemaker is further indicated.

First aid drugs for stopping Morgagni-Adams-Stokes attacks are isoprenaline (sublingually), atropine (intravenously or subcutaneously). With symptoms of congestive heart failure, diuretics, cardiac glycosides (with caution), vasodilators are prescribed. As a symptomatic therapy for the chronic form of AV blockade, theophylline, belladonna extract, and nifedipine are treated.

A radical treatment for AV blockade is the installation of a pacemaker (EC), which restores normal rhythm and heart rate. Indications for implantation of an endocardial pacemaker are a history of Morgagni-Adams-Stokes attacks (even a single one); ventricular rate less than 40 per minute and periods of asystole 3 or more seconds; AV block II degree (type II according to Mobitz) or III degree; complete AV block, accompanied by angina pectoris, congestive heart failure, high arterial hypertension, etc. To decide on the operation, a consultation with a cardiac surgeon is necessary.

Prediction and prevention of AV block

The impact of the developed atrioventricular blockade on the patient's later life and work capacity is determined by a number of factors and, above all, the level and degree of blockade, the underlying disease. The most serious prognosis is in the III degree of AV blockade: patients are unable to work, the development of heart failure is noted.

The development of distal AV blockades due to the threat of complete blockade and rare ventricular rhythm, as well as their occurrence against the background of acute myocardial infarction, complicates the prognosis. Early implantation of a pacemaker can increase the life expectancy of patients with AV block and improve their quality of life. Complete congenital atrioventricular block is more favorable prognostically than acquired.

As a rule, atrioventricular blockade is caused by an underlying disease or pathological condition, therefore, its prevention is the elimination of etiological factors (treatment of cardiac pathology, exclusion of uncontrolled intake of drugs that affect the conduction of impulses, etc.). For the prevention of aggravation of the degree of AV blockade, implantation of a pacemaker is indicated.

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Treatment of heart block

The supply of oxygen to all tissues and organs occurs due to the heart, which creates pressure and pumps blood. In this case, the heart muscle should contract approximately 55 to 80 times in 60 seconds. The whole body depends on the rhythm of the heartbeat.

If the intervals between contractions are equal, then the cells regularly and continuously receive the necessary amount of oxygen and all processes in the body remain normal, but due to the slightest disturbance in the work of the cardiovascular system, tissue hypoxia occurs, turning into more problematic pathologies. Very often, the cause of a lack of oxygen in the brain and other organs is heart block.

How does pathology appear and what is it?

The origin of the impulse occurs due to the sinus node, which sets the rhythm. The impulse moves to the atria and, as a result of their contractions, is transmitted to the bundles and nodes of the system. After that, the wave moves along the smallest channels of the body and Purkinje fibers.

Interruption of this process causes a delay in the impulse in certain areas and leads to various diseases. Blockades are called pathologies that relate to heart rhythm disturbances - to arrhythmias.

Sometimes, myocardial conduction is completely isolated by the blockade. And also blockades can be combined with different types of arrhythmia or be combined with other blockades. Most often, blockades develop in older people, less at a young age.

The main danger of blockade is the delay in myocardial contractions, which can vary from a tenth of a second to a whole minute or more. Subsequently, a person may have oxygen starvation, fainting and clinical death.

Heart block symptoms and treatment - it all depends on the individual organism. The deterioration of the condition will also depend on the cause of the blockade and the place of occurrence in the conduction system. Blocking of the impulse can occur both in the atrium and in one of the ventricles.

Types of blockades

An important indicator in the diagnosis and treatment of the disease is the severity of the disturbance in the passage of excitability. According to this factor, the pathology is divided into the following types:

• blockade of the 1st degree - poor passage, but the excitation impulse is carried out;
• blockade of the 2nd degree - a complete cessation of the passage of an impulse to the ventricles, which is very dangerous and often leads to death.

Pathology is distinguished by the place of formation:

• sinotrial blockade - affects the sinus node;
• atrial blockade - a violation of the impulse in the atrium;
• interatrial - interruption of the impulse on the way to the left atrium from the sinoatrial node;
• transverse or atrioventricular - a violation during the transition of the impulse to the ventricles from the atrium;
• intraventricular - blockade of the lower part of the left or right leg of His.

In turn, intraventricular pathology is divided into the following types:

• interventricular - the ventricular septum conducting pathways are affected;
• blockade of the right ventricle - interruption of the impulse in the anterior or posterior branch of the left leg of His;
• blockade of the left ventricle - interruption of the impulse anywhere in the left leg of His;
• blockade of the left ventricle.

Types of pathology by time of appearance:

Blockade factors

Partial blockade can occur in a healthy person, while not causing any harm. For example, small anomalies of the heart can lead to a partial blockade of the right branch of His, which does not develop further and does not change position.

First-degree blockade can occur in young people due to intense sports or heavy physical work. In some cases, heart block may be congenital.

Such a pathology appears in violation of intrauterine development. In this case, there is a heart valve disease and other disorders of the cardiovascular system, which are found in the child immediately after his birth.

Causes of blockades

There are a number of main causes of pathology:

• autoimmune disease;
• thyrotoxicosis;
• diphtheria;
• myocarditis;
• vasculitis;
• acquired heart disease;
• myocardial tumor or metastasis;
• myxedema;
• sarcoidosis;
• amyloidosis;
• myocardial infarction;
• fibrosis;
• hypertension;
• violation of metabolic processes;

And also there is a possibility of blockades from taking glycosides, antiarrhythmic drugs, beta-blockers. Pathology may appear after surgery, as well as complicate various types of operations. Myocardial conduction is impaired by drugs and alcohol overdose.

Symptoms of the manifestation of pathology

In most cases, mild degrees of the disease do not cause any discomfort in a person.

Partial blockade is detected only with a cardiogram, a routine health check, or a preventive examination.

However, incomplete heart block poses a risk of possible complications. Sinoauricular blockade, when the impulse stops or slows down, the patient feels pain in the chest, suffers from shortness of breath, weakness, decreased performance and dizziness.

And in such cases, when the impulse often slows down, stops, with complete heart block, the person has a feeling of cardiac arrest, frequent dizziness, accompanied by tinnitus and passing into fainting.

Pronounced symptoms appear with complete blockade of the heart of the AV node. Such blockades are manifested by arrhythmia and bradycardia, and may also show signs of an underlying heart disease.

There are cases when, when a person feels normal, he suddenly has an arrhythmia. If the deterioration in the body lasts a long time, then the person adapts and feels good.

The patient may experience seizures against the background of blockades. They are distinguished by the level of the patient's condition:

• mild form - a person does not lose consciousness, but suffers from dizziness, feels tinnitus, limbs go numb;
• the average form of severity - the patient may lose consciousness, while there are no convulsions, urination does not occur;
• severe form - a combination of mild and moderate form of an attack. Without action, it can be fatal.

Such seizures often occur in people with atrioventricular block. The attack can be repeated, and the frequency of repetitions and the gap between them depends on the organism.

Indicators of serious conduction disorders

When the heartbeat slows down to 50 beats per minute, a person complains of dizziness. And there are other symptoms of blockades:

• a person gets tired quickly;
• physical activity is felt in a greater equivalent;
• discomfort in the chest area;
• playing sports brings pain in the chest;
• pain at rest;
• short-term cardiac arrest;
• darkening in the eyes;
• sudden weakness and dizziness;
• nausea;
• sensation of noise and ringing in the ears;
• headache, mostly in the occiput.

If a child is born with a pulse of less than 80 beats per minute, then he is given a cardiogram. The pulse in children should be higher than in adults. At the same time, a complete blockade is confirmed or refuted. Such a pathology is sometimes found in utero.

With atrioventricular block, the child is pale, has a slow heartbeat, and is developmentally retarded. It may also refuse to feed. Subsequently, insufficient blood circulation in the baby often faints, convulsions and seizures. With a prolonged attack, breath holding and cardiac arrest are possible. Congenital blockade can be the cause of death of a child in the early stages of life.

Diagnosis of the blockade

When symptoms of the disease appear, the doctor can find out about violations when deciphering the tests and examining the patient. By listening to the work of the heart, the doctor can determine disruptions in the heartbeat, as well as cardiac arrest, which is characteristic of some. Most often, the disease is diagnosed by means of electrocardiograms, thanks to which it is possible to accurately determine the type of disease.

To determine the blockade, a single electrocardiogram is not enough, the procedure may be ineffective. To obtain more accurate results, it is recommended to conduct a Holter examination.

Such a procedure is performed within a day, and the result of the procedure is information about transient blockades, problems with the rhythm of the heart. Patients are often checked for heart block on an exercise ECG, which allows you to set the level of permissible physical activity and the class of heart failure. To detect the causes of pathology, other methods of examination are also used:

Various laboratory tests and other studies may be required to obtain accurate information.

Treatment with medication

Medications can help treat heart block and restore heart rhythm. In this case, the pathology itself is affected. With partial blockade, most often the patient only needs observation and a healthy regimen.

If the pathology began as a result of an overdose or prolonged use of drugs, they must be immediately canceled. Sometimes, with myocardium caused by an autoimmune disease, it may be necessary to take antibiotics, NSAIDs, glucocorticosteroids, and statins.

Drug therapy includes taking such drugs:

• beta blockers - Betaloc;
• beta adrenostimulants - Isoprenaline or Orciprenaline;
• diuretic - Furosemide;
• vasodilator - amlodipine;
• antiarrhythmic drugs - Quinidine;
• calcium channel blocker - Corinfar and Nifedipine;
• antihypertensive substance - Perindopril and Enalapril.

Surgery for blocks

Unfortunately, unlike partial blockades, some types of blockade cannot be cured with medication. In such cases, the only way out with positive results is surgery.

When a patient has a heart attack, pacemakers are most often installed. There are also some factors that require continuous use of a pacemaker:

• a big difference in the decrease in heart rate;
• a combination of complete blockade with ectopic arrhythmia, heart failure and other heart diseases;
• impaired conduction and hemodynamics at the same time;
• asystole, which lasts up to 2 seconds.

In case of a heart attack, or other serious complications, a temporary pacemaker may be installed.

Diet during blockades

The diet and products used by the patient are of great importance for any type of blockade related to the passage of the impulse. It is recommended to use foods that contain potassium, calcium, magnesium and other minerals that nourish the myocardium. The patient's condition is positively affected by the use of products with useful minerals:

In the patient's diet, it is necessary to include more plant products, which contain more vitamins, as well as limit the intake of salty, fatty and sweet.

Prevention of pathology

Most often, first-degree heart block is a complication of an underlying heart disease. Therefore, preventive measures consist in the treatment of heart failure immediately after the detection of symptoms of pathology. At the same time, it is necessary to monitor the dosage of the medication taken to prevent overdose, as well as to abandon the use of harmful substances.

Assistance in the blockade

Blockades can develop and proceed with complications. However, the occurrence of seizures predisposes to knowledge of first aid and further actions. The patient should be put on a flat surface and put a small pillow under his head. Izadrin tablet is placed under the tongue of the patient, and in case of loss of consciousness, take measures and bring the patient to his senses.

In the absence of a pulse and respiratory arrest, perform an indirect myocardial massage and artificial respiration procedure. Providing such assistance before the ambulance arrives can save a person's life.

With elevated cholesterol levels and a tendency to be overweight, it is necessary to take measures to lose weight, since the load on the heart also depends on the weight of the human body.

With blockades of any type, smoking and alcohol abuse are prohibited. You need to lead a healthy lifestyle. The schedule of life needs to be replenished with moderate physical exercises. Children with congenital or acquired complete blocks cannot live like their peers.

They cannot serve in the army and do heavy physical work, attend sports clubs and clubs. Pregnancy during blockades needs to be planned, while doctors will decide on an individual basis whether gestation is possible.

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The cause of AV blockade can be an isolated disease of the conduction system (Lenegre's disease), myocardial infarction (blockade, as a rule, manifests itself in the first 24 hours), coronary heart disease (CHD), congenital and acquired heart defects, long-term hypertension, cardiosclerosis, some endocrinological diseases, etc. The causes of AV blockade can also be functional (taking certain types of drugs, intense sports).

Functional causes of AV blockade of the heart, such as taking β-blockers, cardiac glycosides (digitalis), antiarrhythmic drugs (quinidine), intravenous administration of drotaverine and papaverine, calcium channel blockers (diltiazem, verapamil, corinfaroma), lithium deposits, can be eliminated by refusing from taking medications. In general, the functional causes of the onset and development of AV blockade are caused by an increase in the tone of the parasympathetic nervous system.

The causes of AV blockade in children are congenital heart defects and some maternal diseases during pregnancy (for example, systemic lupus erythematosus in the mother). Often, the congenital form of atrioventricular block in children is due to the absence of sections of the conduction system (between the AV node and the ventricles, between the atrium and the AV node, between both legs of the His release).

Causes of AV blockade 1 degree

Atrioventricular blockade of the 1st and 2nd degree in isolated cases is observed in young trained people (athletes, pilots, military, etc.). The cause of AV blockade of the 1st degree in this case is the increased activity of the vagus nerve - the blockade usually manifests itself in sleep and disappears during physical activity. Such a manifestation of it is considered as a variant of the norm and does not require treatment.

The cause of the appearance of AV blockade of the 1st degree may be the use of drugs that reduce the heart rate (HR). Such drugs with the appearance of AV blockade should be taken with caution. The disease itself (deviation) can only be detected on an electrocardiogram (ECG).

Causes of AV blockade 1 tbsp. without background myocardial damage are not looked for, treatment is not prescribed, however, the patient is recommended to undergo regular medical examination, because. the disease tends to progress. In most cases, AV blockade 1 tbsp. is transient (transient), does not manifest itself clinically, and vegetative-vascular dystonia of the hypotonic type may also be its cause.

The causes of transient AV blockade are often the abuse of medications, including their incorrect combination with each other. Increased physical activity, leading to an increase in vagal activity, is also the cause of transient AV blockade during sleep.

Causes of AV blockades of the 2nd degree Mobitz I and II types

At the heart of AV blockade 2 tbsp. Mobitz types I and II often underlie organic diseases:

• IHD - during ischemia, the myocardium experiences a prolonged lack of oxygen (hypoxia), and therefore there are microscopic areas of tissue that do not conduct electrical impulses (and do not fully contract). If such foci are concentrated near the boundaries of the atria and ventricles, an obstacle appears on the path of the impulse propagation - a blockade arises and develops;
• myocardial infarction (acute and subacute) - a similar mechanism, but areas of dead tissue also appear;
• heart defects (congenital or acquired) - a serious violation of the structure of muscle fibers, leading to a structural change in the chambers of the heart, cardiomyopathies;
• arterial hypertension (long-term) - leads to hypertrophic or obstructive left ventricular cardiomyopathy.

Causes of atrioventricular blockade of the 2nd degree can also be in isolated diseases of the conduction system of the heart - Lenegra's disease and Lev's disease, calcification of valve rings, infiltrative myocardial diseases - amyloidosis, sarcoidosis, hemochromatosis. The cause of congenital AV blockade 2 tbsp. may become systemic lupus erythematosus in the mother. Congenital heart defects - an atrial septal defect of the ostium primum type and transposition of the main arteries - can also cause AV blockade of the 2nd stage. Mobitz 1 and 2 types.

Inflammatory diseases also become the causes of AV blockade of the 2nd degree: infective endocarditis, myocarditis (Lyme disease, Chagas disease, rheumatism, measles, tuberculosis, mumps). Endocrinological diseases such as diabetes mellitus (especially type 1), hypothyroidism, as well as gastric ulcer, primary adrenal insufficiency are also causes of AV blockades of the 2nd degree.

The causes of AV blockades of the 2nd degree can be: metabolic disorders - hyperkalemia, hypermagnesemia, damage to the AV node during heart surgery, cardiac catheterization, catheter destruction, mediastinal irradiation, neuromuscular diseases (for example, atrophic myotonia). The causes of AV blockades of the 2nd degree can be craniocerebral trauma, intoxication and poisoning, infectious diseases, fevers.

Tumors (mesothelioma, melanoma, lymphogranulomatosis, rhabdomyosarcoma), collagenoses (rheumatoid arthritis, systemic scleroderma, systemic lupus erythematosus, Reiter's syndrome, ankylosing spondylitis, polymyositis) can also act as causes of AV blockade of the 2nd stage. Neurogenic causes of transient and permanent 2nd-degree AV block in young and old people may be triggered by diseases such as carotid sinus syndrome or vasovagal reactions.

In general, the causes of AV blockades of the 2nd degree are the development of idiopathic fibrosis and sclerosis of the conduction system of the heart in various diseases. This includes a whole list of diseases associated with rheumatic processes in the myocardium, syphilitic heart damage, cardiosclerosis, ventricular septal infarction, diffuse connective tissue diseases.

Regardless of the causes of AV blockade of the 2nd degree, treatment, as a rule, comes down to the installation of a pacemaker. Medical treatment is not carried out independently. In rare cases, when the cause of the disease was the use of medications, the treatment is reduced to the abolition of the medication.

Causes of complete AV block (3 degrees)

The causes of 3rd degree AV block (complete block) are the same as 2nd degree. Not uncommon AV blockade 2 tbsp. goes into complete blockade. Treatment is the installation of a pacemaker.