Abstract 2162: Left Ventricular Apical Aneurysms: A Novel Under-recognized Subgroup within the Hypertrophic Cardiomyopathy Disease Spectrum
Introduction. Hypertrophic cardiomyopathy (HCM) is characterized by a diverse clinical and morphologic spectrum.
Methods. A novel and under-recognized subgroup of HCM patients, characterized by left ventricular (LV) apical aneurysms and associated with marked LV hypertrophy, were systematically analyzed in our cohort.
Results. LV apical aneurysms were present in 21 of 1,132 HCM patients (2%) from 2 centers including one set of identical twins, and were identified predominantly by cardiac magnetic resonance (CMR) imaging in 15 and by echocardiography in only 6. Patients presented at a wide range of ages, 30–79 years, but 8 (40%) were ≤ 50 years of age. Most patients (12; 57%) were asymptomatic, but 9 (43%) had moderate-severe heart failure symptoms. Septal thickness was 20 ± 7 mm. LV apical aneurysms were small in 12 patients (≤ 1 cm in diameter) and larger in 9. Each aneurysm was associated with akinetic/dyskinetic wall motion, substantial apical wall thinning and regional transmural scarring evident by post-gadolinium delayed enhanced CMR. Five patients (25%) had LV outflow obstruction of the muscular mid-ventricular type in the absence of mitral valve systolic anterior motion (gradient 88 ± 61 mm Hg). Adverse events included: sudden death/cardiac arrest (n = 4); monomorphic ventricular tachycardia (n = 10); apical thrombosis (n = 2); severe heart failure leading to transplantation (n = 2); event rate was 8%/year. Four patients had HCM-associated myofilament mutations: myosin-binding protein C (n = 2), β-myosin heavy chain (n = 1) and cardiac troponin T (n = 1).
Conclusions. LV apical aneurysms of varying size are an under-diagnosed, important abnormality within the heterogeneous HCM spectrum requiring a high index of clinical suspicion for identification. This HCM subset is caused by the same mutant sarcomeric genes known to cause the disease in other patients. LV apical aneurysms represent a potentially arrhythmogenic substrate and possibly a new risk factor for sudden death in HCM. CMR proved to be superior to echocardiography for imaging the LV apex/aneurysms and demonstrating the associated myocardial scarring, thereby providing important insights to the clinical evaluation and management of HCM.