Bradycardia is a general term that describes a number of conditions in which the heart beats at an unusually slow rate (fewer than 50 to 60 beats per minute). Electrical impulses travel through a complex network of cells and fibers making up the heart’s circuitry, triggering a steady heartbeat. However, these impulses may be slowed, delayed or blocked altogether, resulting in bradycardia. This may be due to aging, medications, metabolic disturbances or pre-existing heart disease.

One type of bradycardia (sinus bradycardia) may be perfectly normal, though, and occur in well–conditioned athletes or during a state of deep relaxation. Other forms of bradycardia vary in the area of the heart affected, severity of symptoms and treatment required.