Left Ventricular Apical Hypertrophic Cardiomyopathy After Heart Transplant: Case Report.

Abstract

<h3>Background</h3> Apical hypertrophic cardiomyopathy (ApHCM) is a rare variant of HCM which predominantly involves the left ventricular apex, and therefore does not typically result in obstructive physiology. It has been infrequently reported in general, with a rarity in heart transplant patients, mostly due to a modest or delayed presentation with symptoms. We present a case of a heart transplant patient with a stable postoperative course who was incidentally found to have ApHCM during follow up non-invasive testing. <h3>Case presentation</h3> Patient is a 45-year-old gentleman with a history of cardiac transplantation in March 2013 for heart failure in the setting of arrhythmogenic right ventricular cardiomyopathy, on chronic dual immunosuppression therapy. He has maintained preserved allograft function with no treatable rejection. Mild donor-derived atherosclerotic disease was found on the first surveillance coronary angiogram with no progression over subsequent years. He has remained asymptomatic and extremely active. In September 2020, he underwent surveillance myocardial perfusion imaging, which showed a large area of moderately severe ischemia laterally extending from the mid ventricle to the apex, prompting coronary angiography which did not show significant epicardial coronary disease. A subsequent echocardiogram with contrast demonstrated normal biventricular function, with evidence of hypertrophy with classic spading of the apical myocardium, along with a corresponding reduction in longitudinal straining, consistent with ApHCM. Upon retrospective evaluation of prior echocardiograms, the finding was likely also present though less evident. Holter monitor detected no arrhythmia and treadmill exercise testing confirmed normal functional capacity, normal blood pressure response to exercise, and no arrhythmias.. Review of the details of the donor's death did not suggest cardiac etiology or arrhythmia. <h3>Conclusion</h3> In our literature search, we found only one similar presentation in a cardiac transplant patient with apical HCM. In general, familial ApHCM is known to follow an autosomal dominant inheritance, whereas sporadic forms are caused by acquired mutations of various sarcomeric and nonsarcomeric protein genes. Other associated factors include long-standing high-pressure states, as well as medications, with one case report suggesting a possible relation with tacrolimus. One literature review suggested a possible increase in mortality in ApHCM patients. Therefore, although it is usually a rare condition, pre and post transplant monitoring must take into account that this condition may clinically manifest post transplantation.