Bradycardia: causes, symptoms, treatment
Bradycardia is a condition in which the heart beats slower than normal, that is, the heart rate (HR), or pulse, is less than 60 beats per minute. Normally, a healthy person has a heart rate of 60 to 100 beats per minute.
Bradycardia is not an independent disease, but a symptom indicating violations of the heart. It can be the result of heart disease or pathologies of other organs and systems.
But bradycardia can be physiological, that is, it is a variant of the norm. As a rule, physiological bradycardia is characteristic of athletes or people engaged in heavy physical labor.
What causes bradycardia?
Pathological bradycardia is caused by the fact that the conduction of an electrical impulse to the muscles of the heart is disturbed. It is the electrical impulse produced by the sinus node, the so-called pacemaker, that causes the muscles to contract and the heart to beat, providing blood circulation in the body. This process occurs automatically and constantly. When it is broken, the heart begins to beat more slowly and bradycardia occurs. If the violation occurs during the formation of a pulse in the sinus node, they talk about sinus bradycardia, if the pulse is generated normally, but then in the process of its implementation fails, they say about heart block.
How does bradycardia manifest?
Bradycardia (both sinus and heart block) is manifested by the following symptoms:
discomfort in the heart;
feeling short of breath, shortness of breath;
dizziness and fainting;
short-term loss of vision;
These symptoms may manifest to a greater or lesser extent, and all or only some of them may be present. Often manifestations of bradycardia are taken for signs of fatigue or age. Bradycardia is diagnosed by heart rate (less than 60 beats per minute) and ECG changes.
Depending on the severity, there are three degrees of bradycardia:
light – heart rate 50–60 beats per minute;
moderate – 40–50 beats per minute;
pronounced – less than 40 beats per minute.
In mild and moderate bradycardia, symptoms are usually absent, since the blood circulation is not disturbed. But with severe bradycardia, circulatory disorders occur, which causes the above symptoms. With a heart rate of 30 to 40 beats per minute, the person feels weak, he quickly gets tired, it is difficult for him to concentrate, there is palpitations, dizziness and shortness of breath, pallor of the skin, and vision may be disturbed. With a pulse of less than 30 beats per minute, fainting or convulsions are possible. Faint with severe bradycardia is called Morgagni – Adams – Stokes syndrome. At the same time, the blood supply to the brain is disrupted, and the patient needs urgent medical care.
What are the causes of bradycardia?
Pathological bradycardia can be caused by heart disease (cardiac causes) and diseases of other organs and systems (non-cardiac causes).
Cardiac causes include: coronary heart disease, myocardial infarction, chronic heart failure, cardiomyopathy, myocarditis, endocarditis, heart defects, age-related changes in the heart. Bradycardia can also cause tumors and brain injuries, meningitis, high intracranial pressure, hypothyroidism, brain edema, influenza, hepatitis, gastric ulcer and duodenal ulcer, some tumors, etc.
Bradycardia may appear when taking certain drugs (pharmacological bradycardia): beta-blockers, cardiac glycosides, antiarrhythmic drugs, etc. In this case, after stopping the drug, bradycardia passes.
Pathological bradycardia can occur in acute or chronic form. Acute bradycardia arises suddenly, in conditions that traumatize the heart – heart attack, poisoning. Chronic bradycardia lasts for years, accompanying serious illnesses that take a long time.
What is the danger of bradycardia?
If the symptoms of bradycardia are absent, then it does not pose any health hazard, much less for life. Nevertheless, its presence may indicate that some pathological process takes place in the body. Therefore, when detecting bradycardia, it is necessary to conduct an examination and, if necessary, to treat the disease with which bradycardia is associated.
Bradycardia is very dangerous in syncope, as it can lead to cardiac arrest.
How is bradycardia treated?
If bradycardia is not accompanied by symptoms, then there is no need to treat it. In the case of low pressure, heart failure, arrhythmias, fainting, treatment is carried out, which depends on the causes of bradycardia. For heart disease, a pacemaker is indicated. If bradycardia is the result of another, non-cardiac pathology, you should start with the treatment of the underlying disease. In addition, drugs are used that increase the heart rate.