Bradycardia is defined as a slower than average heart rate, below 60 beats per minute. If it is very common and among top athletes, bradycardia can sometimes hide a more serious condition such as heart abnormalities or cardiovascular disease. It can also be caused by old age or certain medications such as beta blockers. Bradycardia is found when the patient's pulse is below 60 beats per minute at rest. In young children, the heart beats faster, and bradycardia thresholds are increased according to age. Bradycardia should not be confused with bradyarrhythmias that are slow but irregular heartbeats.
In suspected cases of bradycardia, the physician or cardiologist will conduct an examination based on patient and family history. He will then perform a clinical examination completed by an ECG, which will confirm bradycardia and allow him to guess the cause.
Heart rate monitoring can be done over a longer period, usually 24 hours, through the use of an external electrocardiographic recording: a Holter-ECG. Most of the time, an ECG is enough to diagnose bradycardia, but a test called an intracardiac electrophysiology study in a cardiology unit is sometimes necessary. The cause of bradycardia may be physiological in some individuals, but this disease can also result from a disorder of the electrical conduction of impulses between the atria and the ventricles, in which case an atrioventricular block forms. Some heart rhythm disorders are rarely involved.
Generally, bradycardia is a condition that is very well tolerated by patients and does not have symptoms. Nevertheless, it can be related to fatigue, excessive inactivity or discomfort. In the most severe cases, bradycardia may also occur with an unpleasant sensation that the heart will stop.
Bradycardia can be treated in different ways depending on the identified cause. The choice of treatment depends on the origin of the disease and its impact on daily life of the patient. A lack of treatment is possible in some cases such as less serious atrioventricular block. It is also possible to use certain drugs to accelerate the heart rate, such as atropine. Under certain conditions and in the event of a significant atrioventricular block, an implantable pacemaker may be needed to stimulate the heart.