Bradyarrhythmia (BA) is a condition upon which the heart rate is slowed down to less than 50 beats per minute. Such a deceleration of rate can be observed in perfectly healthy individuals (such as athletes). However, in most patients the BA is abnormal, that is the evidence of any disease.
Classification and Causes
As regards nature of violations, 2 types of bradyarrhythmias are distinguish:
1. Sinus bradycardia (SB). It is due to a decrease in the ability of the sinus node to generate electrical impulses. Normally, it develops in the background of active physical training. Short rate decelerations are also observed in all human beings during sleep or when the body temperature is lowered.
The common reasons for abnormal SB are myocardial ischemia, hypoxia, vascular dystonia, increased intracranial pressure, hypothyroid and poisoning.
2. Atrioventricular block (AB). It is characterized by impaired impulse conduction through the atrioventricular node. It appears because of the toxic effects of drugs, upon increased tone of the parasympathetic nervous system or organic heart diseases (myocardial infarction, myocarditis and others).
Depending on the duration, bradyarrhythmias are subdivided into acute and chronic.
In some patients, BAs are asymptomatic. Others report:
- chest pain,
- shortness of breath.
Diagnosis is based on the patient's complaints, clinical examination and ECG findings. If no pulse deceleration was recorded at the time of the study, the patient is prescribed a 24h ECG monitoring.
To identify the causes of the condition, the following tests may also be carried out:
- heart ultrasound,
- heart MRI,
Asymptomatic forms of BA do not require treatment. In the presence of clinical signs and established cause of disorder, the underlying disease (myocarditis, neurosis, and so on) is treated.
BA symptoms are corrected by prescription of drugs stimulating the heart (caffeine, ginseng tincture, Siberian ginseng). Life-threatening conditions are an indication for pacemaker installation.