Cardiac amyloidosis presenting as severe mitral regurgitation

We report a patient with extensive infiltration of the left ventricle with amyloid who presented with severe mitral regurgitation which led to mitral valve replacement. The right ventricular biopsy showed minimal focal deposits of amyloid. A 47-year-old white woman was admitted to Loyola Medical Center after a cl-week illness consisting of progressive dyspnea and fatigue. She had had ventricular dysrhythmia during the labor of her seventh and final pregnancy 8 years before this admission which resolved spontaneously. At presentation she was acutely ill, tachypneic, tachycardic, normotensive and afebrile. Her neck veins were distended and the lungs were congested bilaterally. A loud S, gallop and a grade 3/6 holosystolic murmur were audible at the apex. The remainder of her examination was unremarkable. Her admitting chest X-ray revealed bilateral pleural effusions. The ECG showed low voltage with precordial poor R wave progression. The hemogram and blood chemistry panel were normal. Cardiac enzymes were less than 2 times elevated with cardiac fractions present. M-mode and two-dimensional echocardiogram revealed diffusely increased left ventricular wall thickness with a normal internal chamber size and wall texture but depressed left ventricular function. The valves appeared normal. Gated blood pool scan showed an ejection fraction of 47%. Transvenous endomyocardial biopsy histology showed minimal focal deposits of amyloid (Fig. la) which were confirmed by electron microscopy. As her condition deteriorated, cardiac catheterization was performed to evaluate the severity of the mitral regurgitation. The right heart pressures were moderately elevated. The mean capillary wedge pressure was 20 mm Hg with a 35 mm Hg “V” wave, and the cardiac index was 1.9 I/min per m*. The left ventricular cavity was small and diffusely hypokinetic and severe mitral regurgitation was present (Fig. 2). The coronary arteries were normal. As mitral valve replacement surgery was attempted, she suffered a cardiac arrest and was unable to be weaned from cardiopulmonary bypass even after mitral valve replacement. Post mortem examination revealed extensive amyloid infiltration of the left ventricular myocardium and mitral papillary muscles (Fig. 1 b). The mitral apparatus removed at the time of surgery was grossly normal; histologically, there were patchy globules of amyloid present in the leaflets. The right ventricle was much less involved than the left ventricle. Amyloid deposition may cause cardiovascular dysfunction in a variety of ways. Stenotic valvular lesions have been described [l-4], but severe mitral regurgitation has not been described [5]. In spite of the low ejection fraction with severe mitral regurgitation, mitral valve replacement was attempted as a life saving measure since her presentation was acute and right ventricular involvement by amyloid was minimal. These factors raised the possibility that additional processes may have been contributing to her cardiac dysfunction. The post mortem findings established that the left, ventricular dysfunction and severe mitral regurgitation were caused by extensive amyloid in the papillary muscles and anchoring myocardium. Retrospectively, since there was only one pathologic process operating in our patient, the