The two familiar faces of thick hearts: hypertrophic cardiomyopathy (HCM) and cardiac amyloidosis (CA).
The two most recent triumphs of modern medicine have been the emergence of medical management of HCM and CA. In both the cases, therefore, accurate echocardiographic diagnosis is extremely important and strain imaging is mandatory, particularly for phenotyping differentiation of thick hearts. In HCM, all the three morphological distributions (sigmoid, reverse curve, apical) have distinct strain patterns, while in CA the demonstration of classic apical sparing of left ventricular longitudinal strain ( “cherry on the top”, one of the “red flags”) always necessitates referral for further investigation to confirm CA (by hematologic, scintigraphic, genetic, histologic)11.While apical strain is generally spared in CA, different regions within the apex may exhibit subtle variations in their response to pressure overload, as illustrated by differing pressure strain loops obtained by myocardial work. These variations highlight the regional differences in how these areas respond to demand of the poorly functioning heart (Figures 4,5). In case of hypertrophic cardiomyopathy, in which there clearly exists a gradient of strain within the Bull’s eye plot differentiating HCM from CA, myocardial work indices may also uncover how a poorly functioning left ventricle distorting the pressure strain curve reminiscent of a stiff chamber despite preserved LVEF ( Figure 6).