What it is
Arrhythmia is a violation of the regularity and sequence of heart contractions. Everything that is not a sinus rhythm is called this term and includes a variety of pathologies of impulse formation and conduction. But few of the ordinary people know this, and it is believed that if a patient said to the doctor: “I have an arrhythmia!”, Then he understood everything and immediately solve the problem by prescribing one specific medicine.
Alas, it’s not that simple.
There is more than one classification of arrhythmias, but since my task is to acquaint readers with the diversity and help them figure it out on their own, and not give a lecture for cardiologists, I will divide them into 2 groups:
- violation of the formation of an impulse - here we include extrasystoles and tachycardias;
- pathology of the same signal - blockade and bradyarrhythmias.
How does a normal heart beat? Normally, the sinus node dominates - a power plant that generates impulses and transmits them further through the inter-nodal pathways to the atrioventricular node, from which the signal goes along the His bundle, to its right and left branch, to the Purkinje fibers and to the ventricular myocardium.
Causes of arrhythmias
There are three groups of reasons:
- cardiac - when there is cardiovascular pathology: ischemic disease, hypertension, heart disease, myocarditis, pericarditis, cardiomyopathy, and so on;
- extracardiac - these include diseases of other organs and systems (chronic bronchitis, pathologies of the thyroid gland, gastrointestinal tract), taking medications (antiarrhythmics, sympathomimetics, antidepressants, diuretics, etc.) or toxic effects (smoking, alcohol, drugs), as well as electrolyte disturbances (hypo- or hyperkalemia, hypomagnesemia, etc.);
- idiopathic - when the cause of the arrhythmia could not be identified.
The mechanism of occurrence of cardiac arrhythmias
The heart has the following abilities:
- automatism - cardiomyocytes can spontaneously generate an impulse (due to this they are called "pacemakers");
- excitability - cells perceive the signal and respond to it;
- conduction - the impulse can propagate through the conducting system of the heart;
- contractility - the ability to contract in response to a stimulus.
Thus, the myocardium independently generates electrical currents that are conducted along the intracardiac pathways, excite the muscle and cause it to contract.
As noted earlier, arrhythmias occur as a result of impaired impulse formation or conduction. The main mechanisms are shown in the figure below.
A change in automatism in the sinus node is the cause of tachycardia, bradycardia (with weakness of the sinus node) and other arrhythmias. If the excitability of the underlying links of the conducting system, for example, the atrioventricular junction, increases, then it takes on the role of a pacemaker, and an ectopic accelerated rhythm arises.
Trigger activity is the formation of impulses by cardiomyocytes, which normally do not have a pacemaker (signal-forming) function. This mechanism underlies extrasystoles and tachycardia, just like the other, re-entry (in his case, the signal causes one contraction, but under certain conditions it can excite the myocardium repeatedly due to the circulation of current in a circle).
A blockade occurs when an impulse collides with tissue that is unable to respond to a signal, for example, with a post-infarction scar that has taken the place of a damaged cardiac conduction system.
Signs and symptoms: what are the complaints of patients
The palette of clinical manifestations is varied and colorful: from normal health to loss of consciousness and arrhythmogenic shock.
Depending on the type of arrhythmia, psychoemotional status and concomitant diseases, patients present with the following complaints:
- sinking of the heart;
- heart beats on the chest;
- cardiopalmus;
- dizziness, darkening in the eyes;
- shortness of breath, feeling short of breath;
- weakness, fatigue;
- loss of consciousness and so on.
These symptoms are accompanied by a feeling of dread and are not always specific. A similar picture of the disease is also described by somatically (bodily) healthy people suffering from panic attacks, neuroses or phobias. In these situations, we are talking about psychosomatics, and work with a psychotherapist is required, and not treatment with a cardiologist.
Case from practice: arrhythmia in a woman
In my practice, there was an interesting case: a middle-aged woman came to complain of episodes of loss of consciousness. They occurred during physical activity (climbing stairs, cycling), which was accompanied by severe shortness of breath, and before falling, she felt a heartbeat. Before contacting a cardiologist, the patient was examined by a neurologist, but no abnormalities were found.
During cardiac echocardiography, the following was visualized: secondary hypertrophic cardiomyopathy, which developed as a result of subvalvular aortic stenosis. Thickened left ventricular myocardium is a risk factor for the development of life-threatening tachycardia and sudden cardiac death. During 24-hour ECG monitoring, runs of ventricular arrhythmias of varying duration were recorded.
The patient is referred for surgical treatment - correction of the heart defect and ablation (cauterization) of the arrhythmia zone.
Features in men
A feature of rhythm disturbances in men is the "holiday heart syndrome". This is a condition in which arrhythmia occurs after a short-term use of large doses of alcohol (usually during feasts). Atrial fibrillation (atrial fibrillation) or ventricular arrhythmias are more common.
Clinically, this syndrome is manifested by a feeling of palpitations, a feeling of weakness, shortness of breath, chest discomfort, which can lead to arrhythmogenic death. The mechanisms of the influence of alcohol on the heart are both direct toxic effects and an increase in the activity of the sympathetic nervous system and electrolyte imbalance. In chronic alcoholism, cardiomyopathy develops, the main manifestations of which are heart failure and heart rhythm disturbances.
If you stop drinking alcohol in time, there is a chance to restore the pumping function of the heart, but where is the limit, when it is not too late, scientists have not been able to figure out. The attitude to drinking in our country is very frivolous, people believe that alcohol "cleans blood vessels" and its use is associated with health benefits. Yes, systematically drinking people rarely have heart attacks - they die from sudden arrhythmias, before they reach thrombosis.
Arrhythmia classification
Since the article is general education, I will not overload you with scientific terms, pathophysiology and other characteristics, but in general terms I will explain into which main groups arrhythmias are divided.
According to the source (topographically), they are supraventricular (everything that occurs above the atrioventricular node) and ventricular. According to the frequency of the rhythm, tachycardia is distinguished (with a heart rate of more than 90-100 per minute) and bradycardia (slowing down of the rhythm to 50-60 beats or less). Tachycardias, in turn, are subdivided into supraventricular and ventricular, paroxysmal and non-paroxysmal.
At the heart of bradycardia is a violation of impulse conduction - blockade, which can be sinoatrial, atrioventricular, interatrial and intraventricular. These are the most common arrhythmias, and such a classification gives an idea of how to treat them.
Table 1. Classification of arrhythmias.
By localization:
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By heart rate:
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Tachycardias:
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Blockades:
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Separately, I will single out extrasystole - the "queen" among arrhythmias. The overwhelming majority of patients come to me with just this problem. Extrasystoles are extraordinary contractions of the heart. They are found in everyone - both in healthy people and in people with various diseases - and often take away peace and sleep from patients because of the painful sensations they experience during rhythm interruptions.
An interesting paradox is associated with this type of rhythm disturbance: in healthy individuals, they do not pose a danger to life, despite the vivid manifestations of symptoms. In people with serious organic diseases, extrasystoles can be asymptomatic and be an accidental finding on an electrocardiogram or daily ECG monitoring.
Manifestations on the cardiogram
Consider the signs of arrhythmia on an electrocardiogram using the example of extrasystole, tachycardia and blockade of impulse conduction.
If the patient has an extrasystole, for example atrial, his ECG will look like this: against the background of a sinus regular rhythm, where there are equal intervals between the ventricular complexes, an extraordinary contraction appears, followed by a pause of varying duration depending on the type of extrasystole.
Let us analyze tachycardia using two examples: paroxysmal AV-nodal and ventricular. With the first type of arrhythmia, an episode of rhythm with a high frequency was recorded on the ECG, while it remains constant throughout the entire paroxysm. The complexes on the cardiogram are narrow and the P waves characteristic of sinus rhythm will not be visible.
With ventricular tachycardia, expanded deformed complexes are recorded, resembling blockade of the bundle of His bundle, heart rate - more than 120 beats per minute.
In the case of blockade development, for example, 1st degree AV block, on the ECG we see an extension of the PQ interval by more than 0.2 sec, which reflects a violation of the impulse conduction from the atria to the ventricles. With Mobitz II degree 2 AV block, there is a sudden collapse of the complex, while the PQ interval is either lengthened or normal.
Treatment of cardiac arrhythmias
“There is an arrhythmia - an antiarrhythmic should be prescribed” - everyone thinks logically, but this is not so.
Arrhythmia can be a SYMPTOM of a disease and not necessarily a heart one! Thyrotoxicosis is a condition caused by excessive synthesis of thyroid hormones. It is complicated by atrial fibrillation, and it is atrial fibrillation that is the first sign of thyroid dysfunction.
In women with menopause, extrasystoles occur, and they do not require treatment with antiarrhythmics, since the cause can be eliminated in another way - by the appointment of hormonal drugs.
In patients with ischemic heart disease, various arrhythmias are considered one of the symptoms of pathology - from extrasystole to ventricular tachycardia - and the first point in their treatment is the elimination of myocardial ischemia by surgery: stenting of the coronary arteries or coronary artery bypass grafting.
In patients with myocardial infarction, the arrhythmia substrate is the area on the border of the scar and healthy heart tissue. These people are advised to ablate the hearth of the rhythm disturbance or homogenize this area.
A large group of patients are people with atrial fibrillation - a violation of excitability, in which multiple impulses arise in the atrial myocardium, causing muscle contractions asynchronous with the work of the ventricles. In addition to antiarrhythmic drugs, such people are shown anticoagulants and therapy of the underlying disease (for example, ACE inhibitors for arterial hypertension), as well as surgical destruction of arrhythmogenic zones.
Paroxysm of tachycardia (ventricular, atrial fibrillation, orthodromic with the participation of DPP, etc.) can be complicated by arrhythmogenic shock with a drop in blood pressure and the absence of a peripheral pulse (on the arm). The method of choice in this situation is emergency electrical impulse therapy using a defibrillator. The electrical discharge interrupts the reentry wave and the sinus rhythm is restored.
Antiarrhythmic drugs are classified into 4 groups and are prescribed only by a doctor. Despite the fact that they are designed to treat rhythm disturbances, these drugs can lead to arrhythmias, therefore, their use requires caution and supervision of a cardiologist. Class 1 antiarrhythmics are contraindicated in patients with previous myocardial infarction, chronic heart failure and left ventricular hypertrophy of more than 14 mm.
With regard to blockades, the tactics of their conduct depends on the level of damage and degree. AV block of 3 degrees, stopping the sinus node with ventricular asystole are absolute indications for implantation of a permanent pacemaker. High-grade AV block may accompany myocardial infarction of the inferior wall of the left ventricle. Early revascularization leads to the restoration of the work of the atrioventricular node.
Doctor's advice: how to get rid of arrhythmias
The golden rule “it is easier to prevent than to cure” remains relevant in the case of arrhythmias. Exercise, a healthy balanced diet, blood pressure control, and avoiding bad habits are always at the forefront. Prevention is our everything!
Wrong rhythm of life, short sleep, alcohol abuse, caffeine-containing drinks, psychostimulants, stress are also harmful to health and can provoke rhythm and conduction disturbances, therefore, the normalization of work and rest is far from the last component of arrhythmia therapy. Patients with neuroses should be given a recommendation to seek help from a psychotherapist.
Before treating arrhythmia, you need to find out its etiology. It is pointless to eliminate the symptom if we do not know the root cause. I had a young pregnant woman at the reception with complaints of palpitations. She had no diseases of the cardiovascular system, and to clarify the diagnosis, I prescribed her a complete blood count and serum iron.
As a result, iron deficiency anemia with hemoglobin 80 mg / l was diagnosed, which was the cause of the woman's tachycardia. Appointment of etiotropic therapy - iron preparation - stopped all symptoms after a while. Beta blockers to slow the heart rate would not solve the problem, but only make it worse.
What is the danger and what are the forecasts
To determine the prognosis of the patient, the classification created by J. Bigger is used. Depending on the type of arrhythmia, the presence of cardiovascular disease, the risk of sudden cardiac death is assessed, and on this basis, the rhythm disturbance is considered benign or malignant. The more serious and dangerous the problem is, the more intensively it must be eliminated, and in patients with atrial extrasystole and without heart pathology, arrhythmia should not be artificially removed.
In the course of treatment, the possible risks and benefits of taking antiarrhythmic drugs are assessed.If there is a risk of developing undesirable consequences (proarrhythmogenic effect in the first place), then the appointment is irrational and dangerous.
In addition to arrhythmia therapy, a mandatory item is the treatment of the disease, the consequence of which it has become. A frequent cause of atrial fibrillation is arterial hypertension, and without control of systolic and diastolic pressure, changes in the heart continue to develop, and atrial fibrillation paroxysms occur more often. Also, with the aggravation of chronic obstructive pulmonary disease, bronchial asthma, the formation of cor pulmonale and a worsening of the course of arrhythmia are observed.
Catheter ablation (AV node modification in paroxysmal AV nodal tachycardia) in a small percentage of cases is complicated by the development of complete transverse blockade with the further need for pacemaker implantation. Also, the operation can be aggravated by hemopericardium, perforation of the heart chambers, but these are very rare situations. Ablation remains the main way to eliminate paroxysmal tachycardia once and for all.
In patients with WPW syndrome and rare, asymptomatic seizures, dynamic follow-up by a physician is possible. At the same time, there are not medical, but social indications for the destruction of DPP (the same ablation). This item concerns pilots, cosmonauts, professional athletes, etc. If paroxysms occur with severe symptoms that disrupt daily life, then catheter destruction is an option in any case.
