[The current and emerging role of cardiovascular magnetic resonance imaging in hypertrophic cardiomyopathy]

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy and the leading cause of sudden death in young people and a major cause of heart failure symptoms at any age. Due to its genetic etiology, there is substantial heterogeneity in the phenotypic expression and clinical course of patients with HCM. Traditionally, two-dimensional echocardiography has been the easiest and reliable technique for establishing a diagnosis of HCM. However, cardiovascular magnetic resonance (CMR) has emerged as a novel, 3-dimensional tomographic imaging technique, which provides high spatial and temporal resolution images of the heart (not limited by thoracic or pulmonary parenchyma), in any plane and without ionizing radiation. As a result, CMR is particularly well suited to provide detailed characterization of the HCM phenotype, including a precise assessment of the location and distribution of LV wall thickening (as well as other myocardial structures such as the right ventricle and papillary muscles). In this regard, CMR has been demonstrated to provide a diagnosis of HCM in cases where the echocardiogram was non-diagnostic. Furthermore, CMR provides an accurate assessment of total LV mass which is a more robust marker of hypertrophy, with potential implications for risk stratification. In addition, with the intravenous administration of gadolinium, first-pass perfusion sequences can identify myocardial perfusion abnormalities, while late gadolinium enhancement sequences can identify areas of myocardial fibrosis/scarring. Although the clinical implications of late gadolinium enhancement in HCM are still uncertain this information may, in the near-future, have important implications with regard to identifying HCM patients at high risk of sudden death and progressive heart failure, including evolution into the end-stage phase of HCM. Therefore, at present, CMR provides important information impacting on diagnosis and clinical management strategies in patients with HCM and will likely have an expanding role in the evaluation of patients with this complex disease.