Review Question - QID 217140

This patient who presents with symptoms of left-sided heart failure (dyspnea on exertion, orthopnea), bibasilar crackles, and a holosystolic murmur (murmur persisting throughout the interval between S1 and S2) best heard at the apex with radiation to the axilla most likely has mitral regurgitation.

Mitral valve regurgitation (also known as mitral insufficiency) is caused by defective mitral valve leaflets that allow blood to flow from the left ventricle to the left atrium instead of into the systemic circulation during systole. It is most commonly caused by rheumatic fever or infective endocarditis. This retrograde flow can be heard as a holosystolic murmur that radiates to the axilla. Mitral regurgitation causes decreased cardiac output and increased left atrial pressure, which the body compensates for with valvular dilation and retention of additional volume. Together, these adaptations increase strain on the left ventricle and result in left-sided heart failure. Patients will therefore present with signs of cardiogenic pulmonary edema such as orthopnea, dyspnea on exertion, and paroxysmal nocturnal dyspnea. Patients may also go into atrial fibrillation given the changes in left atrial size causing disruption of the conduction system. Diagnosis can be made with an echocardiogram. Treatment consists of vasodilators, beta-blockers, and heart valve replacement for severe cases.

Kampaktsis et al. present a review of the evidence on the management of mitral regurgitation. They found that major advances have increased the prevalence of catheter-based approaches as well as edge-to-edge repair. They recommended that clinicians pay careful attention to distinguishing primary from secondary mitral regurgitation, as treatment approaches differ.

Incorrect Answers:
Answer 1: Aortic regurgitation presents with left ventricular dilation and a diastolic decrescendo murmur heard best at the right upper sternal border. Patients often report shortness of breath, fatigue, and head bobbing may be observed. Aortic regurgitation can also be caused by infective endocarditis and rheumatic heart disease.

Answer 2: Aortic stenosis would present with left ventricular dilation and a crescendo-decrescendo systolic murmur heard best at the right upper sternal border. Patients often report syncope, angina, and dyspnea. Aortic stenosis becomes more common with increasing age as calcium deposits occur on the aortic valve leaflets.

Answer 3: Mitral prolapse would present with a systolic murmur with a mid-systolic click heard at the cardiac apex. Patients often report palpitations and chest pain regardless of exertion. Causes include connective tissue disorders such as Marfan syndrome.

Answer 5: Mitral stenosis would present with a diastolic murmur with an opening snap that represents the separation of the leaflets heard at the apex. Patients often report palpitations and fatigue. Rheumatic fever can also cause mitral stenosis.

Bullet Summary:
Mitral regurgitation presents with a holosystolic murmur best heard at the apex that radiates to the axilla.