Hypertrophic Cardiomyopathy Registry: The rationale and design of an international, observational study of hypertrophic cardiomyopathy

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common monogenic heart disease with a frequency as high as 1 in 200. In many cases, HCM is caused by mutations in genes encoding the different components of the sarcomere apparatus. Hypertrophic cardiomyopathy is characterized by unexplained left ventricular hypertrophy, myofibrillar disarray, and myocardial fibrosis. The phenotypic expression is quite variable. Although most patients with HCM are asymptomatic, serious consequences are experienced in a subset of affected individuals who present initially with sudden cardiac death or progress to refractory heart failure. The Hypertrophic Cardiomyopathy Registry study is a National Heart, Lung, and Blood Institute-sponsored 2,750-patient, 44-site, international registry and natural history study designed to address limitations in extant evidence to improve prognostication in HCM (NCT01915615). In addition to the collection of standard demographic, clinical, and echocardiographic variables, patients will undergo state-of-the-art cardiac magnetic resonance for assessment of left ventricular mass and volumes as well as replacement scarring and interstitial fibrosis. In addition, genetic and biomarker analyses will be performed. The Hypertrophic Cardiomyopathy Registry has the potential to change the paradigm of risk stratification in HCM, using novel markers to identify those at higher risk.

Figure 1

Diagram of the organizational structure of the HCMR study.

Figure 2

An illustration of the basic CMR outputs in HCMR study. A–C) Selected mid short-axial cine frames with cardiac delay times corresponding to A) systolic, B) mid-diastolic and C) end-diastolic frames. D) LGE image. E) Native T1 map as displayed on Siemens platform. Currently General Electric and Philips ShMOLLI acquisitions require off-line processing. F–H) Postcontrast T1 maps at specified time points.