What is bradycardia and what types are there?
Normally, the rhythm is set by the sinus node in the right atrium, and the impulse travels through the conduction system to the ventricles. The resting frequency of contractions in an adult is usually 60–100 beats per minute. If the sinus node generates impulses less frequently, they speak of sinus bradycardia. If impulses are delayed or do not travel from the atria to the ventricles, atrioventricular block develops. Separately, there is sick sinus syndrome, in which a rare rhythm can alternate with attacks of rapid heartbeat. The type of disorder determines whether treatment is needed.
- Physiological - in athletes, in sleep, in young people
- Sinus bradycardia
- Sick sinus syndrome
- Atrioventricular blocks I–III degrees
- Drug-induced bradycardia
- Bradycardia in diseases of other organs
Causes and risk factors
In athletes, the heart works sparingly and pumps out more blood per contraction, so the resting pulse is low. Pathological bradycardia more often occurs in the elderly due to age-related fibrosis of the conduction system. It is caused by coronary heart disease and heart attack, myocarditis, and cardiomyopathies. Beta blockers, some antiarrhythmic drugs, and digitalis drugs can slow down the rhythm. Non-cardiac causes include hypothyroidism, increased potassium levels, hypothermia, increased intracranial pressure, and obstructive sleep apnea syndrome. Sometimes bradycardia develops during infections, such as tick-borne borreliosis.
- Age-related changes in the conduction system
- Coronary heart disease and previous heart attack
- Myocarditis, cardiomyopathies
- Medicines that slow down your heart rate
- Hypothyroidism
- Potassium disturbances
- Sleep apnea syndrome
Symptoms
Physiological bradycardia does not manifest itself in any way. With a pathological slowdown in rhythm, the heart cannot cope with the needs of the body, and the brain and muscles are the first to suffer. The person notes weakness, fatigue, decreased exercise tolerance, and shortness of breath. Characterized by dizziness, darkening of the eyes, episodes of confusion, and memory impairment. The most dangerous symptom is fainting, which occurs during a long pause in the heart. In the elderly, bradycardia can only manifest itself as falls and decreased performance, so such complaints cannot be attributed to age.
- Weakness and fatigue
- Dizziness
- Presyncope and fainting spells
- Shortness of breath on exertion
- Chest pain or discomfort
- Deterioration of memory and concentration
Diagnostics
The cardiologist asks about symptoms, physical activity, medications taken and performs an ECG, which shows the rhythm frequency and type of disorder. Since bradycardia can be episodic, Holter ECG monitoring plays an important role throughout the day and longer: it records pauses and the connection of symptoms with rhythm. Echocardiography evaluates the structure and contractility of the heart. An exercise test shows whether your heart rate increases with exercise. Tests for thyroid hormones and electrolytes help find reversible causes. For rare episodes, long-term rhythm recorders are used.
- ECG at rest
- Holter ECG monitoring
- Echocardiography
- Load test
- TSH
- Potassium, sodium
- Polysomnography for suspected sleep apnea
Treatment
Physiological bradycardia without symptoms does not require treatment; periodic monitoring is sufficient. For drug-induced bradycardia, the doctor reduces the dose or replaces the drug; You cannot stop taking medications for blood pressure and arrhythmia on your own. If the cause is hypothyroidism, electrolyte abnormalities, or sleep apnea, the underlying condition is treated and the rhythm is usually restored. In case of sick sinus syndrome and severe blockades with symptoms, the only effective method remains the implantation of a pacemaker. This is a common operation, after which most people return to their normal lives.
- Regular monitoring of pulse and well-being
- Do not take drugs that slow your heart rate without a doctor.
- Treatment of thyroid diseases
- Electrolyte correction
- Pacemaker implantation when indicated
- Routine stimulator checks after surgery