Damage to the mitral valve can result from rheumatic fever, hypertrophic cardiomyopathy, mitral valve prolapse, myocardial infarction, severe left-sided heart failure, subacute or acute bacterial endocarditis, or ruptured chordae tendineae.

In older patients, mitral insufficiency may occur because the mitral annulus has become calcified. The cause is unknown, but it may be linked to a degenerative process.

Mitral insufficiency is sometimes associated with congenital anomalies such as
transposition of the great arteries. The condition has a higher incidence in females than in males.

Ventricular hypertrophy and increased end-diastolic pressure result in increased pulmonary artery pressure, eventually leading to left-and right-sided heart failure with pulmonary edema and cardiovascular collapse.

Depending on the severity of the disorder, the patient may be asymptomatic or may complain of orthopnea, exertional dyspnea, fatigue, weakness, weight loss, chest pain, and palpitations.

Inspection may reveal jugular vein distention with an abnormally prominent a wave. You may also note peripheral edema.

Auscultation may detect a soft S₁ that may be buried in the systolic murmur. A grade 3 to 6 holosystolic murmur, most characteristic of mitral insufficiency, is best heard at the apex. You’ll also hear a split S₂ and a low-pitched S₃. The S₃ may be followed by a short, rumbling diastolic murmur. An S₄ may be evident in patients with a recent onset of severe mitral insufficiency and who are in normal sinus rhythm.

Auscultation of the lungs may reveal crackles if the patient has pulmonary edema.