An insufficiency of the aortic valve, leading to regurgitation (backward flow) of blood from the aorta into the left ventricle.

Familial dilated cardiomyopathy is a genetic form of heart disease. It occurs when heart (cardiac) muscle becomes thin and weakened in at least one chamber of the heart, causing the open area of the chamber to become enlarged (dilated). As a result, the heart is unable to pump blood as efficiently as usual. To compensate, the heart attempts to increase the amount of blood being pumped through the heart, leading to further thinning and weakening of the cardiac muscle. Over time, this condition results in heart failure.\n\nIt usually takes many years for symptoms of familial dilated cardiomyopathy to cause health problems. They typically begin in mid-adulthood, but can occur at any time from infancy to late adulthood. Signs and symptoms of familial dilated cardiomyopathy can include an irregular heartbeat (arrhythmia), shortness of breath (dyspnea), extreme tiredness (fatigue), fainting episodes (syncope), and swelling of the legs and feet. In some cases, the first sign of the disorder is sudden cardiac death. The severity of the condition varies among affected individuals, even in members of the same family.

An abnormality of the mitral valve characterized by insufficiency or incompetence of the mitral valve resulting in retrograde leaking of blood through the mitral valve upon ventricular contraction.

Episodes of ventricular tachycardia that have a sudden onset and ending.

Severely decreased cardiac output with evidence of inadequate end-organ perfusion (i.e., tissue hypoxia) in the presence of adequate intravascular volume.

A rapid heartrate that exceeds the range of the normal resting heartrate for age.

Failure of the tricuspid valve to close sufficiently upon contraction of the right ventricle, causing blood to regurgitate (flow backward) into the right atrium.

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.

Multifocal atrial tachycardia is a rare supraventricular arrhythmia in neonates and young infants that is characterized by multiple P waves with varying P wave morphology and is usually asymptomatic.

Increase in size of the left atrium.

A type of ventricular tachycardia that is characterized by uniform QRS complexes within each lead (i.e., each QRS is identical or nearly so).

Hemorrhage into the parenchyma of the brain.

A nonparallel arrangement of cardiac myocytes.

A large reduction in the fraction of blood pumped from the left ventricle with each cardiac cycle. The normal range in adults is at over 50 percent, and a severe reduction is defined as less than 30 percent.

Abnormally increased width of the Z-disk of the sarcomere, resulting from splitting or opening of the Z-disc (c.f., Figure 2 of PMID:28732005).

A disruption of the structure of the sarcomeres of cardiomyocytes. The sarcomere is the repeating unit between two Z lines comprised largely of myosin and actin that mediates contractility, and normally sarcomeres are aligned with the long axis of cells, with the Z bands being in register throughout the length of the cardiac myocytes.