Role of MRI in Hypertrophic Cardiomyopathy with Midventricular Obstruction and Apical Aneurysm: Uncommon High-risk Variant

Abstract

Hypertrophic cardiomyopathy (HCM) is characterized by cardiac muscle hypertrophy, unexplained by loading conditions with a nondilated left ventricle and normal or increased ejection fraction Midventricular obstruction of the left ventricle is an increasingly recognized phenotypic variant of hypertrophic cardiomyopathy due to the widespread availability of Cardiac Magnetic Resonance Imaging (CMR). Mid ventricular obstruction with apical aneurysm is a high risk variant of HCM which can lead to higher risk of arrhythmia and SCD. This variant is clinically and prognostically significant with MRI playing a major role in detection. CMR has nearly 100 % sensitivity in diagnosis and also helps in identifying other high risk features. CMR is helpful in detecting Late gadolinium enhancement (LGE) and apical aneurysm for which echocardiography is less sensitive. LGE represent area of replacement fibrosis which can act as a source for life threatening arrhythmia. Although this variant is not considered high risk feature for sudden cardiac death (SCD) in HCM cohort according to standard guideline, it is increasingly being recognized as a high risk feature by recent studies. Treatment is controversial however patients with multiple risk factors of SCD can be treated with ICD implantation to prevent catastrophic events. Herein we present a case of HCM with midventricular obstruction where MRI showed apical aneurysm with scarring and midventricular gradient. Incidence, pathophysiology, diagnosis role of CMR and treatment of this variant of HCM is discussed.