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.

A type of atrial arrhythmia characterized by atrial rates of between 240 and 400 beats per minute and some degree of atrioventricular node conduction block. Typically, the ventricular rate is half the atrial rate. In the EKG; atrial flutter waves are observed as sawtooth-like atrial activity. Pathophysiologically, atrial flutter is a form of atrial reentry in which there is a premature electrical impulse creates a self-propagating circuit.

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.

An abrupt loss of heart function.

The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction.

Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum.

A conduction block of the left branch of the bundle of His. This manifests as a generalized disturbance of QRS morphology on EKG.

A sensation that the heart is pounding or racing, which is a non-specific sign but may be a manifestation of arrhythmia.

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 tachycardia originating in the ventricles characterized by rapid heart rate (over 100 beats per minute) and broad QRS complexes (over 120 ms).

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.

Enlargement or increased size of the heart left ventricle.

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

A localized hypertrophy of the subaortic segment of the ventricular septum has been frequently described in elderly persons, and variously termed subaortic ventricular septal bulge (VSB), sigmoid-shaped septum, localized or discrete upper septal hypertrophy.

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