Clinical History An 87-year-old man with a history of coronary artery disease and previous coronary artery bypass graft (CABG) surgery was admitted to Mass General with congestive heart failure. A TTE (transthoracic echocardiogram) revealed moderate left ventricular systolic dysfunction and severe aortic stenosis. TTE also revealed a restrictive filling pattern in diastole, suggestive of an infiltrative myopathy. Prior to proceeding with high-risk repeat cardiac surgery, a cardiac MRI (CMR) was requested to further explore the possibility of infiltrative disease.
TTE revealed moderate concentric left ventricular (LV) hypertrophy with normal left ventricular chamber dimensions (Figure 1). The LV myocardium was echo bright, suggestive of an infiltrative cardiomyopathy, and the transmitral Doppler filling pattern was "restrictive," suggestive of elevated left-atrium filling pressures and/or a non-compliant LV. The estimated left ventricular ejection fraction (LVEF) was 38%. Non-specific thickening of both anterior and posterior mitral leaflets was noted, together with marked biatrial enlargement.
CMR (Figures 2 and 3) demonstrated diffuse sub-endocardial abnormal delayed enhancement involving all coronary artery territories, with relative sparing of only small portions of the mid-inferior and septal wall. The resting LVEF was confirmed to be significantly impaired at 33%. The overall findings were consistent with diffuse amyloid infiltration of the myocardium.
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Figure 1: Legend for figure 1
Figure 2:Legend for figure 2
Figure 3:Legend for figure 3
Figure 4:Legend for figure 4
Amyloidosis is a common cause of restrictive cardiomyopathy in octogenarians. It arises due to deposition of proteinaceous material in the interstitium, leading to atrophy of myocardium. The classic imaging appearance includes concentric wall thickening, reduced ejection fraction, and biatrial enlargement1-3. CMR findings include global or sub-endocardial delayed gadolinium enhancement, with heterogeneous patchy enhancement in the myocardium. When heart failure is the presenting symptom, the life expectancy is less than one year. In our patient, a subsequent myocardial biopsy confirmed the diagnosis of cardiac amyloidosis, and surgery was deferred.
Wood MJ and Picard MH. Utility of echocardiography in the evaluation of individuals with cardiomyopathy. Heart, 2004; 90: 707-712