How many live with sinoatrial blockade. Sinoauricular blockade

Pathological changes in conduction between the sinus node and the atrium can cause dangerous complications: complete sinoatrial blockade leads to disruption of heart contractions and sudden death. Mild sinoauricular conduction disturbances are usually transient, cause cardiac cycle loss, and are not life-threatening. But any pathological changes conductivity in the area sinus node(SA blockade) require a full diagnosis and effective treatment. The main goal of therapy is to restore rhythm and prevent ischemia of vital organs.

Causes of the disease

The severity of external manifestations depends on the presence and quality of the impulse: sinoatrial conduction changes occur against the background of the following factors:

1. complete absence of momentum in the node;
2. low force of impulse action;
3. limitation of conduction between the node and the atrium.

The main factors that cause conduction disturbances and episodes of loss of rhythm of the sinus node are the following conditions and diseases:

• heart pathology (, myocarditis, congenital malformations, chronic heart failure, atherosclerosis);
• negative drug effects (side effects of certain cardiovascular drugs);
• toxic damage in case of poisoning or serious illness (pronounced lack of potassium and oxygen);
• tumors in the cardiovascular system;
• neurovegetative reflex reactions;
• mechanical damage during injuries and operations.

Any type of disturbance in the conduction of impulses in the heart requires a complete diagnosis, highlighting the severity and type of cardiac pathology, which will become the basis of high-quality treatment.

Options for pathology

There are 3 levels of severity:

1. 1st degree sinoauricular block - No symptoms, extremely rare with special tests
2. Sinoauricular block 2nd degree (type 1) - Gradual increase in heart block with sudden episodes of complete loss of impulses with typical manifestations on the ECG
3. SA block 2nd degree (type 2) - Arrhythmic prolapse of cardiac complexes with episodic and temporary complete blockade of conduction
4. SA blockade 3 degrees (complete) - Complete absence of impulses from the sinus node to the atrium

With the help of electrocardiography, the doctor will be able to identify a variant of a pathological conduction disorder and distinguish the disease from other types of dangerous cardiac pathology.

Symptoms of the disease

With 1 degree of impaired sinoatrial conduction, there will be no signs, except for a moderate slowing of the heartbeat. Possible manifestations of blockade of the sinus node of the 2nd degree include:

• circulatory disorders in the central nervous system, manifested by episodes of memory loss, dizziness and headaches;
• intermittent shortness of breath;
• edema of the cardiac type;
• tendency to faint and loss of consciousness with a temporary stop of vital functions.

At grades 2-3, the risk of sudden death in patients with sinoauricular disorders is quite high, so it is necessary to make a timely and accurate diagnosis, ensuring that the necessary therapeutic measures are taken.

Diagnostic studies

In addition to the usual examination, the doctor will definitely refer you to an ECG. It is according to the results of an electrocardiographic study that one can accurately identify the presence and severity of sinoatrial blockade. At grade 1 ECG, the manifestations are minimal - sinus bradycardia, which normally occurs in many people and is not considered a pathology (we wrote more about sinus bradycardia).

The first type of 2nd degree of blockade on the cardiogram is expressed by periodic rhythmic loss of cardiac cycles (loss of P-P teeth or the whole PQRST complex). The second type is characterized by non-rhythmic and repeated loss of P-P waves, PQRST complexes, when two or more cardiac cycles disappear, forming pathological condition circulation.

Identification of typical clinical symptoms and manifestations on the electrocardiogram is a criterion for diagnosis and treatment, which is especially important in the complete absence of impulses and high risk sudden death.

Type of cardiogram with SA-blockade of the 2nd degree (type 1)

Principles of treatment

Detection of sinus bradycardia does not require therapeutic measures: it is enough to periodically see a doctor. In case of violation of conductivity of the 2nd degree, it is necessary to carry out complex therapy:

• identification and treatment of heart diseases that create conditions for the blockade of the sinus node;
• removal of toxic factors and drugs that negatively affect the cardiac conduction of impulses;
• use of symptomatic therapy;
• the use of pacing (surgical implantation of the pacemaker).

Indications for the installation of a pacemaker are:

• violation of cerebral blood flow;
• heart failure;
• decrease in heart rate below 40 beats;
• high risk of sudden death.

In grade 2-3 sinoatrial blockade, treatment is best after surgery to install a pacemaker, and drug therapy can only provide temporary improvement and relief of symptoms.

Dangerous Complications

Against the background of bradycardia and rhythm disturbances due to blocking of impulses in the sinus node, one should be wary of the formation of the following pathological conditions:

• stop or failure of the sinoatrial node;
• acute heart failure with edema, shortness of breath and a drop in vascular pressure;
• severe disorders of cerebral blood flow;
• sudden death.

Even if nothing worries, with any variant of SA blockade, it is categorically unacceptable to refuse periodic visits to the doctor and regular examinations with an ECG.

A timely identified deterioration in cardiac conduction can be corrected with a pacemaker and drug therapy, and with the development of severe complications, it is extremely difficult to restore lost heart functions and restore the previous quality of human life.

SA block (sinoatrial block) is a kind of weakness of the sinus node. In general, this is a rather rare phenomenon from the category of arrhythmias and is diagnosed mainly in men. There is no age limit for SA blockade as such. In a completely healthy heart, an impulse of electrical charge from the right atrium travels unhindered along this path, creating a muscle contraction in the heart. If during the journey through our heart, the charge stumbles upon an obstacle, then the contractions themselves automatically fail, it is these obstacles that are the blockade.

With SA-blockade, there is a violation in the creation of a charge and its subsequent distribution. Consequently - disruption of ventricular contractions. After a while, the heart begins to systematically skip contractions.

Causes

The problems that SA-blockade creates are the deformation of the node and the dysfunction of the contraction of the heart muscle. It happens that because of it, the impulse is too weak, or not generated at all.

Reasons for blockade:

1. Rheumatism of certain forms;
2. heart attack;
3. Overdose of drugs;
4. Myocarditis;
5. Ischemia;
6. Heart disease;
7. Injury to the heart tissue;
8. Intoxication with organophosphorus substances;
9. Cardiomyopathy.

SA-blockade appears when an overactive vagus nerve begins to influence the sinus node by activation. In the bulk of situations, under such conditions, a transient blockade is performed. This type of SA-blockade disappears over time on its own, without therapeutic and external intervention. Changes in the structure of the heart anatomically do not occur, which allows the likelihood of its manifestation in healthy and strong people. In very exceptional cases, SA blockade is idiomatic, the factor of its occurrence has not yet been found by scientific doctors.

Children are also susceptible to this pathology. Due to autonomic dysfunction, a child develops a transitive SA blockade from the age of seven to eight years. At the same time, it is possible to identify other arrhythmias.

Degrees of SA blockade

The degree is directly subject to the intensity of arrhythmias.

• First. At this level, impulses occur, but less frequently than in the normal state. The node is working in accordance with the norm. The problem is only in the speed of the pulse. An ECG will not show this degree;
• Second. The heart does not contract every time, the prerequisite is a periodic deficit of the impulse;
• Third. Complete SA block. There is no necessary impulse, the muscle does not contract.

The first two stages are not complete because, although it is bad, the sinus node performs its functions. With the latter, complete, the impulse does not reach the atrium in principle.

SA block and ECG

An electrocardiogram is a key way to detect blockade. The first degree is not noticeable on the ECG, but it is calculated from bradycardia. Only the second and third ECG will show the most reliable.

What will the ECG show in the second degree:

1. Longer intervals between muscle impulsive contractions (R-R);
2. Decrease in R-R in time after a pause;
3. If the intervals are large, the impulses come from a different source;
4. When several consecutive impulses and contractions fall out, the pauses P-R are long, as in the normal state.

At the third degree, any absence of electric charges is observed. It is not uncommon for a person to die in such a situation.

How SA blockade manifests itself and how to diagnose it

In the first degree, a person does not have discomfort, and there are no symptoms. The body becomes addicted to frequent bradycardia and the person does not feel changes inside himself, lives quite comfortably.

The last degrees already have symptoms that are easily recognizable. These are unpleasant sensations in the area chest, periodic noise and ringing in the ears, shortness of breath, frequent dizziness. Weakness throughout the body also occurs due to a rare rhythmic contraction. If there has been a change in the structure of the muscle, signs such as:

• bluish skin;
• Enlargement of the liver;
• puffiness;
• shortness of breath;
• Heart failure;
• Decreased work capacity.

The child has the same symptoms. We recommend that you take a closer look at the following: cyanosis of the nasolabial region, decreased performance and severe fatigue. In the event that such symptoms are noticed, go to a cardiologist for a check.

When the pause between contractions is long, paroxysms appear. Paroxysms are a process in which the brain stops receiving the right amount of arterial blood, its supply is reduced significantly. Symptoms:

1. Noise and ringing in the ears;
2. Involuntary urination and emptying;
3. Systematically loss of consciousness;
4. Spasm.

If bradycardia has begun to bother you, or if a pulse is missed on the ECG, you should undergo a full check with a cardiologist. Be sure to do daily monitoring for the cardiogram. If the ECG gave only a doubt on the SA-blockade, then the wear of the monitor is necessary for a long time. The blockade is easiest to fix during a state of complete rest, sleep, or during physical exertion.

The child should also be monitored. Bradycardia for about forty minutes, together with pauses between impulses of three seconds, are an alarming bell. It is common practice to test samples with atropine. If there are problems, the pulse instantly increases several times and just as sharply returns to the original, or lower, this is a blockade.

In order to be directly convinced of this diagnosis, it is necessary to conduct an ultrasound of the heart in order to exclude other diseases, for example, problems.

Treatment of the disease

The first degree does not require intensive treatment. It will be enough to restore the correct daily routine, if it is disturbed, to treat the main heart diseases, or to stop using heart drugs that can affect the performance of the sinus node.

Transient blockade can be treated with drugs containing atropine. They are actively used in pediatrics for vagotonia. It should be remembered that reaction therapy is transient. Metabolic treatment is more effective in SA-blockades. Riboxin, cocarboxylase and vitamin-mineral complexes are the leading fighters in the war against blockades.

If you have been given SA blockade, beta-blockers and potassium supplements are prohibited. They will aggravate the bradycardia and further complicate the functioning of the sinus nodes. When symptoms of the third stage appear, the person is strongly advised to implant a pacemaker in the heart.

SA blockade is a heart disease that is extremely life-threatening, do not forget about routine examinations by a cardiologist.

Video about heart rhythm disorders

In this video, Elena Malysheva will tell you how to treat cardiac arrhythmia:

Second-degree atrioventricular (AV) block

Second-degree atrioventricular (AV) block is characterized by impaired, delayed, or interrupted conduction of impulses through the AV node, with the exception of block. associated with premature atrial contraction. AV blockade can be permanent or temporary, depending on the features of anatomical or functional disorders in the conduction system. which are subdivided into type I blockade, or Mobitz type I and Wenckebach blockade - Mobitz type II blockade, 2: 1 blockade and complete AV blockade.

Differential diagnosis of type I and II AV blockade of the second degree is based on the data of an electrocardiographic study, and not on the anatomical location of the focus of the blockade. Type I is characterized by a progressive increase in pulse delay. Type II is characterized by episodic or recurrent sudden blockade of impulse conduction without a prior noticeable increase in conduction time. Accurate localization of the focus of the blockade within the conduction system is critical for proper treatment of individuals. with second degree AV block.

Of course, 2:1 AV block cannot be classified as either type I or II because only one PR interval is used for diagnosis. Both 2:1 block and block involving two or more sinus P waves are sometimes referred to as complete AV block, in which there is some conduction in the block, as opposed to third-degree AV block.

Pathophysiology

Type I AV block is most often the result of a conduction defect in the AV node, but can rarely be associated with infranodal block and is rarely secondary to structural anomalies of the AV node. when the QRS complex is narrow and there is no underlying heart disease. In such cases, type I AV block may be vagal-mediated and may occur in conditions accompanied by relatively high parasympathetic tone, such as in highly trained athletes, overdose of cardiac glycosides (eg, digoxin), and neurogenic (or neurotransmitter) syncope syndrome.

Vagal-mediated AV block occurs at the node when, under the influence of parasympathetic influences, a marked ECG slowdown is observed. sinus rhythm. Vagal-mediated AV block improves physical performance and occurs more frequently during sleep, when parasympathetic tone is dominant. If an increase in the tone of the sympathetic system (for example, physical exercise) initiates or exacerbates type I AV block, infranodal block may be suggested.

Cardioactive drugs are another common cause of AV block. They can have a negative (i.e. dromotropic) effect on the AV node directly, indirectly through the autonomic nervous system or in their combination. Digoxin, beta-blockers, calcium channel blockers, and some antiarrhythmic drugs have been reported to cause second-degree AV block.

Various inflammatory, infiltrative, metabolic, endocrine disorders and systemic collagenoses with vascular damage are accompanied by blockade of the AV node. Less commonly, type I blockade may be associated with a conduction disorder localized in the bundle of His, its distal sections. In this situation, the QRS complex may be wide, and the basal PR interval preceding the block is usually shorter, with reduced amplitude. The prognosis for type I infranodal block is significantly worse than for block at the level of the AV node. The location of the focus of type II blockade is most often infranodal, which determines the increased risk for the patient.

Distribution frequency in the USA

Almost 3% of patients with underlying structural heart disease develop some form of second-degree AV block.

Mortality / morbidity

The location of the focus of the blockade and its root causes determine the prognosis. Nodal-level AV block and the vast majority of type I block have a favorable prognosis, while infranodal block of both types can progress to complete block with a significantly worse prognosis. However, the symptoms of type I blockade can be very wide.

• Type I AV node block is often non-progressive and benign in terms of mortality. The risk of progression to complete heart block is significant when the block is located in the His-Purkinje system (infranodal location).
• Type II AV block often progresses to third degree block and thus has a more worrying prognosis. Type II blockade can lead to Stokes-Adams syncope.
• Vagal-mediated AV block is generally benign in terms of mortality. but can lead to dizziness and fainting.

Gender specificity

• The number of men and women among patients with AV blockade is the same.

Clinical manifestations

Symptoms associated with type I blockade vary greatly, ranging from asymptomatic course in well-trained athletes and individuals without significant structural changes in the heart, to periodic syncope, before fainting and bradycardia in patients with heart disease. AV block can cause cardiac arrest and angina pectoris.

Causes

Second-degree AV block may occur with or without structural heart disease.

• Increase in tone vagus nerve possibly due to pain, mechanical impact on the carotid sinus, or carotid sinus hypersensitivity, which may result in a slow sinus rhythm and/or AV block. Thus, vagal-mediated AV block can be confirmed by the slowing of the sinus rhythm noted by the ECG. High vagal tone can be seen in athletes and young people at rest. Type I Mobitz blockade has been described in 2-10% of distance runners observed.1
• Cardioactive drugs are another important cause of AV block. They can have a negative effect on the AV node directly, indirectly through the autonomic nervous system, or as a result of a combination of both. Digoxin, beta-blockers, calcium channel blockers, and some antiarrhythmic drugs have been seen as the cause of second-degree AV block. Some antiarrhythmic drugs can cause second-degree AV block, including sodium channel blockers such as procainamide, which are more common with distal His-Purkinje block. Sustained AV blockade has been reported following adenosine infusion during a stress test in patients taking cardioactive medications, suggesting an underlying conduction disorder in addition to drug influence as the etiology of the blockade. Toxic levels of some other pharmacological agents, such as tricyclic antidepressants and lithium salts, may be accompanied by AV blockade. Presynaptic alpha agonists, adrenergics (eg, clonidine) may also cause or exacerbate AV block.
• Various inflammatory, infiltrative, metabolic, endocrine diseases and systemic collagenoses with vascular damage, leading to blockade of the AV node are represented by the following:
• Inflammatory diseases:

• Endocarditis
• Myocarditis
• Lyme disease
• Acute rheumatic fever (ARF, rheumatic fever, Sokolsky-Bujo disease)

• Infiltrative diseases:

• Amyloidosis
• Hemochromatosis
• Sarcoidosis, and abnormal AV conduction may be the first sign of sarcoidosis.3
• Infiltrative malignancies such as Hodgkin's lymphoma, other lymphomas, and multiple myeloma 4

• Metabolic and endocrine disorders

• Hyperkalemia
• hypermagnesemia
• Addison's disease
• Hyperthyroidism
• Myxedema
• Thyrotoxic periodic paralysis 5

• Collagenosis with vascular lesions

• Ankylosing spondylitis
• Dermatomyositis
• Rheumatoid arthritis
• scleroderma
• lupus erythematosus
• Reiter's syndrome
• mixed diseases connective tissue(NWST) 6

• Other diseases accompanied by AV blockade

• Tumors of the heart
• Injuries (including those associated with catheterization, especially with an existing blockade of the left bundle branch block)
• Muscular "bridges" of the myocardium 7
• Transcoronary alcohol ablation of the interventricular septum in obstructive hypertrophic cardiomyopathy
• Transcatheter occlusion of an atrial or ventricular septal defect 8, 9
• Heart surgery for congenital malformations, especially near the septum
• Progressive (age) idiopathic fibrosis cardiac skeleton
• Valvular complications cardiovascular disease especially aortic stenosis and aortic valve replacement
• Obstructive sleep apnea associated with a range of cardiac arrhythmias, including AV block.10
• Muscular dystrophies. The development of defects in patients with muscular dystrophy is progressive, therefore, these patients should be carefully evaluated clinically and followed up even if they have a benign conduction defect, such as first-degree AV block.11
• Acute myocardial infarction (MI) can lead to second-degree AV block.
• In some patients, AV blockade may have autosomal dominant traits and show a tendency to be inherited. Several mutations in the SCN5A gene have been associated with hereditary AV block. Various mutations in another gene have been reported in other dysrhythmias such as long QT syndrome or Brugada syndrome.

If there are disturbances in the functioning of the sinus node, new sources may form in different areas of the heart muscle. They provide electrical impulses.

The presented new sources can have a negative impact on the sinus type node, competing with it or aggravating its activity.

There may be a blockage of wave propagation through the heart muscle. All the presented negative phenomena can be accompanied by arrhythmias and, in the worst case, blockades, which are called atrioventricular.

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Conduction system of the heart

Speaking of cardiac impulses, it should be noted that they are formed in the formations of the sinus node. It is located in the right atrium and is the main one.

It is the sinus node that guarantees the frequency of rhythmic contractions, which after it are transmitted to the atrioventricular node.

The latter is located in the region of the interatrial septum. The fibers that form the bundle of His lag behind it. It is located in the septum between the ventricles, from which both of its legs emerge: right and left. The presented endings branch and terminate on the myocardial cells of the ventricles.

Each of the components of the conductive system can independently create excitation, and when the operation of a certain node, which is higher, is destabilized, its functioning will replace the underlying one.

However, in such a situation, the degree of frequency of the impulse suffers, and, as a result, the rhythm, which decreases to a large extent (from 60 to 20 contractions).

Causes of pathology

Second degree heart block is formed due to the following factors:

• genetic predisposition and inherited pathologies;
• ischemic heart disease and myocardial infarction;
• , angina pectoris, myocarditis;
• the use of huge dosages of medicinal components or the use of drugs not according to medical recommendations;
• change in the thickness of the heart muscle.

The frequency of heart contractions in an adult with normal health is from 60 to 80 repetitions per 60 seconds. If within 3-5 seconds there are no heartbeats, then the person is likely to lose consciousness. Also, he may begin convulsive contractions, and in the absence of the help of specialists, death occurs.

The presented pathological phenomena are formed sometimes or can be observed constantly. identified by ECG.

Differences in heart block 2 degrees

With 2 degrees of heart block, not every impulse from the atria is conducted to the region of the ventricles, and therefore some contractions of the presented region fall out.

On the ECG, first of all, manifestations of slowing or optimal complexes are identified.

Only after that a tooth is detected, which corresponds to the contraction of the precordial region, and the contraction of the ventricles is not observed. This can happen with every fifth, fourth, third and any subsequent contraction.

Blockades that form without a previous delay in implementation can transform into a full-fledged cardiac block. Treatment upon detection of a blockade of the 2nd degree largely depends on the leading ailment.

In some cases, atropine and isadrin are used. If the heart rate is significantly reduced, then permanent electrical stimulation of the heart, namely a pacemaker, is used.

Treatment Methods

When forming a blockade on the basis of pathologies of the heart (myocarditis or acute myocardial infarction), they first of all struggle with the leading disease.

The recovery algorithm for blockages of the 2nd and 3rd degree is selected taking into account where the violation is located within the conduction:

Folk remedies

Usage folk recipes to restore health in case of heart blockade, it is also recommended to coordinate with a specialist. But first of all, it is required to follow elementary recommendations regarding lifestyle.

It is necessary to exclude the use of alcohol and cigarettes, to minimize the use of strong coffee and tea. It is undesirable to use salt, as well as fried and fatty foods.

For a speedy recovery, salty and smoked dishes are excluded from the menu, while preference is given to fruits, vegetables, meat and fish with a low percentage of fat content, as well as similar dairy-type products.

Traditional medicine can offer the following simple recipes that will help the heart muscle to function fully:

Mixing onion with an apple, for the preparation of which you need to mix 1 small head of an ordinary onion. Next, rub 1 apple on a fine grater and mix thoroughly. It is necessary to use the mixture for 2 times in between meals.

The composition of peppermint, for the preparation of which use 1 tbsp. l. finely chopped mint leaves, which are poured into 200 ml of boiling water. It is required to insist the mixture under the lid for at least 60 minutes. The broth is filtered and consumed slowly, within 24 hours.

It is required to avoid physical and emotional excessive stress, remember to observe the rest regimen and exercise physical exercises as often as possible.

Consequences

The terms at which disability occurs are directly dependent on how difficult the leading disease is.

The prognosis depends on the underlying disease and the level of blockade. A pessimistic prognosis is associated with distal blockades, because they are prone to constant development - the consequences in this case will be the most severe.

Absolute heart block of the distal type is identified by the probability of syncope formation in 70% of cases. The blockade, which develops according to the proximal algorithm, is determined by the possibility of fainting in 25% of cases.

It should be noted that:

• if there was a primary attack of Morgagni-Adams-Strokes, and the EKS was not transplanted, then life expectancy is significantly reduced, and will be no more than 2.5 years;
• the survival rate of patients increases due to permanent stimulation;
• the prognosis after transplantation is directly dependent on the nature of the leading disease.

If there was a myocardial infarction of the anterior wall, then with absolute blockade, an aggravated lesion of the septum between the ventricles is noted. This means that the prognosis is extremely unfavorable: the percentage of death from ventricular fibrillation or heart failure is identified in 90% of cases.

Second degree heart block is a dangerous pathology that can aggravate a person's life, provoking many complications. In order to avoid this, you should undergo a correct and timely course of treatment.