Mitral Regurgitation, Chronic Organic

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Disease principally of the mitral valve leaflets caused by myxomatous changes, rheumatic fever, collagen vascular disease, or endocarditis

• Dyspnea or orthopnea

• Characteristic apical systolic murmur

• Doppler echocardiographic evidence of systolic regurgitation into the left atrium

GENERAL CONSIDERATIONS

• Mitral regurgitation refers to systolic leakage of blood from the left ventricle to the left atrium

• Organic mitral regurgitation refers to diseases that involve the leaflets or their immediate supporting apparatus: chordae and the mitral annulus

• Among causes of organic mitral regurgitation, mitral valve prolapse is a unique entity (covered separately)

• Causes of chronic organic mitral regurgitation:

  • – Rheumatic heart disease

  • – Infective endocarditis

  • – Collagen vascular diseases

  • – Trauma

• Mitral regurgitation of any etiology tends to worsen over time because the volume load on the left heart results in chamber dilation, which further compromises mitral competence

• Although slowly progressive, mitral regurgitation may ultimately result in a large dysfunctional left ventricle and left atrium

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• History of potential causal factors such as rheumatic fever and collagen vascular disease

• Progressive dyspnea

• Fatigue, orthopnea with heart failure

• Palpitation, usually due to atrial arrhythmias

PHYSICAL EXAM FINDINGS

• Tachycardia if heart failure or atrial fibrillation is present

• Brief low-amplitude carotid pulse

• Narrow pulse pressure due to reduced forward stroke volume

• Signs of congestive heart failure

• Enlarged apical impulse

• Auscultation:

  • – Loud P₂ if pulmonary hypertension present

  • – S₃ with or without heart failure

  • – Blowing holosystolic high-pitched murmur at the apex, radiating to the axilla

• The murmur characteristically increases in intensity with hand grip exercise but is unchanged in the beat after a premature beat with a compensatory pause

DIFFERENTIAL DIAGNOSIS

• Functional mitral regurgitation

• Aortic stenosis

• Ventricular septal defect

• Hypertrophic obstructive cardiomyopathy

• Other causes of dyspnea and orthopnea

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Specific tests for the cause of mitral valve disease such as rheumatoid factor, blood cultures

ELECTROCARDIOGRAPHY

• Left atrial abnormality

• Left ventricular hypertrophy

• Atrial arrhythmias

• In severe cases, right ventricular and right atrial hypertrophy

IMAGING STUDIES

• Chest x-ray:

  • – Cardiac enlargement, especially of the left heart chambers

  • – Pulmonary congestion if heart failure present

• Echocardiography:

  • – Left ventricular and atrial enlargement

  • – Abnormalities of the leaflets, chordae, or annulus may suggest the cause

• Doppler echocardiography:

  • – Color flow shows regurgitant jet through mitral valve in systole into the left atrium

  • – Severity of regurgitation correlates roughly with jet size

  • – Tricuspid regurgitation should be sought to estimate pulmonary pressures

  • – Regurgitant flow can be calculated as the difference between mitral flow and left ventricular outflow in ...