Mitral Regurgitation, Chronic Functional

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Major causes include ischemic heart disease and dilated cardiomyopathy

• Dyspnea or orthopnea

• Signs of left ventricular dysfunction

• Characteristic apical systolic murmur

• Doppler echocardiography shows dilated, dysfunctional left ventricle and a central regurgitant jet into the left atrium

GENERAL CONSIDERATIONS

• Functional mitral regurgitation is caused by diseases of the left ventricle or atrium, which disrupt the mitral apparatus

• Most often, the mitral regurgitation is mild to moderate and not a significant issue in overall patient management

• Occasionally, the condition is severe and alleviation or correction of the leak becomes therapeutically important

• Severe mitral regurgitation is associated with dilatation of the left heart chambers and left ventricular systolic dysfunction; it may be difficult to decide which problem occurred first

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Dyspnea on exertion, progressing to heart failure

• Fatigue

• Palpitations often from atrial fibrillation

PHYSICAL EXAM FINDINGS

• Signs of congestive heart failure

• Brisk upstroke but low-volume carotid pulse

• Enlarged apical impulse

• S₃ heart sound

• Holosystolic apical murmur that increases in intensity with hand grip exercise

DIFFERENTIAL DIAGNOSIS

• Organic mitral regurgitation

• Tricuspid regurgitation

• Aortic stenosis

• Ventricular septal defect

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Low serum sodium

• Elevated B-type natriuretic peptide

ELECTROCARDIOGRAPHY

• Atrial fibrillation may be present

• Left ventricular hypertrophy

• Left atrial abnormality if in sinus rhythm

IMAGING STUDIES

• Chest x-ray:

  • – Enlarged left heart chambers

  • – Normal-sized aorta

  • – Possible signs of pulmonary congestion and heart failure, such as pleural effusions

• Echocardiography:

  • – Evidence of left ventricular disease

  • – Hypertrophic, dilated, or ischemic cardiomyopathy

  • – Left atrial enlargement

  • – Possibly systolic anterior motion of the mitral valve

  • – Rarely mitral valve prolapse due to papillary muscle dysfunction

• Doppler echocardiography:

  • – Usually a central regurgitant jet into the left atrium during systole

  • – Estimated pulmonary artery systolic pressure from the tricuspid regurgitant velocity may be moderately elevated

  • – In severe regurgitation, pulmonary venous flow may be reversed in systole

DIAGNOSTIC PROCEDURES

• Left and right heart catheterization may be useful to confirm the magnitude of left atrial and pulmonary pressures and to determine if the pulmonary pressure elevations are likely due to the regurgitation

• Coronary angiography is useful to determine the cause of functional mitral regurgitation

• Left ventriculography may be useful to confirm the presence and severity of mitral regurgitation and the degree of left ventricular disease

TREATMENT

CARDIOLOGY REFERRAL

• Moderate to severe mitral regurgitation

• Evidence of heart failure

• Any cardiovascular symptoms

HOSPITALIZATION ...