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

Paroxysmal chest pain that occurs with exertion or stress and is related to myocardial ischemia.

An atrial arrhythmia characterized by disorganized atrial activity without discrete P waves on the surface EKG, but instead by an undulating baseline or more sharply circumscribed atrial deflections of varying amplitude an frequency ranging from 350 to 600 per minute.

Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality.

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.

Uncontrolled contractions of muscles fibers in the left ventricle not producing contraction of the left ventricle. Ventricular fibrillation usually begins with a ventricular premature contraction and a short run of rapid ventricular tachycardia degenerating into uncoordinating ventricular fibrillations.

A conduction block of the right branch of the bundle of His. This manifests as a prolongation of the QRS complex (greater than 0.12 s) with delayed activation of the right ventricle and terminal delay on the EKG.

Hypertrophic cardiomyopathy with an symmetrical and concentric pattern of hypertrophy.

Conduction block in the anterior division of the left bundle branch of the bundle of His.

Thickening of the heart walls in both ventricles.

An electrocardiographic anomaly in which the ST segment is observed to be located inferior to the isoelectric line.

A diminution of the volumetric fraction of blood pumped out of the ventricle with each cardiac cycle.

Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.

Perceived difficulty to breathe that occurs with exercise or exertion and improves with rest.