An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the chest.

An abrupt loss of heart function.

Syncope is a syndrome in which loss of consciousness is of relatively sudden onset, temporary (usually less than 1 to 2 minutes), self-terminating, and of usually rapid recovery. Syncope leads to a generalized weakness of muscles with loss of postural tone, inability to stand upright, and loss of consciousness. Once the patient is in a horizontal position, blood flow to the brain is no longer hindered by gravitation and consciousness is regained. Unconsciousness usually lasts for seconds to minutes. Headache and drowsiness (which usually follow seizures) do not follow a syncopal attack. Syncope results from a sudden impairment of brain metabolism usually due to a reduction in cerebral blood flow.

Bradycardia related to a mean resting sinus rate of less than 50 beats per minute.

A disorder characterized by an electrocardiographic finding of an atypical cardiac rhythm resulting from a pathologic process in the cardiac ventricles.

Increased time between the start of the Q wave and the end of the T wave as measured by the electrocardiogram (EKG).

An anomaly of the U wave of the electrocardiogram (EKG). The U wave is a small (0.5 mm) deflection immediately following the T wave, usually in the same direction as the T wave. It is best seen in leads V2 and V3.