LAUSR

A 65-year-old male with no prior medical history was referred for cardiac evaluation of exertional chest pain and dyspnea. His electrocardiogram (ECG) showed deep T-wave inversions (Figure 1). Cardiovascular examination did not reveal any murmurs, but transthoracic echocardiogram showed features consistent with apical HCM (Figure 2; Supplementary Video S1). Myocardial perfusion imaging showed a filling defect at the apex consistent with apical infarct (Figure 3). However, a coronary angiography revealed intermediate coronary artery disease that was not functionally significant on fractional-flow reserve study (Supplementary Videos S2A and S2B). Cardiac magnetic resonance (CMR) imaging showed apical thinning, aneurysmal formation, and extensive fibrosis on the late gadolinium enhancement sequence (Figure 4). Apical HCM is associated with giant T-wave inversions on ECG precordial leads. Transthoracic echocardiogram is the first-line investigation for diagnosis of HCM, and CMR is recommended particularly in the evaluation of apical hypertrophy, aneurysms, and thrombi. Patients can mimic acute coronary syndrome, therefore myocardial perfusion imaging are often performed. The severity of apical filling defect is found to correlate with the degree of cavity obliteration in the apical left ventricle, which may explain the pathogenesis of apical aneurysm in this case. Apical aneurysm is seen in 15% of apical HCM, possibly secondary to apical infarction and mid-ventricular obstruction caused by increased thickness of apical wall. While apical HCM is often relatively benign, apical aneurysms represent a high-risk subgroup with increased implantable cardioverter-defibrillator activation, out-of-hospital cardiac arrest, and thromboembolic events. Multimodality imaging is useful in characterizing HCM, and patients with apical HCM and aneurysms demonstrate characteristic changes on myocardial perfusion imaging, which may supplement findings on echocardiogram and CMR.