Supplementary Material for: The Prevalence and Long-Term Outcomes of Extreme Right versus Extreme Left Ventricular Hypertrophic Cardiomyopathy

<br><strong><em>Objectives:</em></strong> Extreme left ventricular hypertrophy (LVH) is a known risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM). Extreme right ventricular hypertrophy (RVH) is rare, and whether it is linked to a poor outcome is unknown. This study was designed to investigate differences between HCM patients with extreme RVH and those with extreme LVH. <b><i>Methods:</i></b> Among 2,413 HCM patients, 31 with extreme RVH (maximum right ventricular wall thickness ≥10 mm) and 194 with extreme LVH (maximum left ventricular wall thickness ≥30 mm) were investigated. The main clinical features and natural history were compared between the 2 groups. <b><i>Results:</i></b> The prevalence of extreme RVH and extreme LVH was 1.3 and 8.0%, respectively. Patients with extreme RVH tended to be younger and female (p < 0.01). Cardiovascular-related mortality and morbidity within 10 years were significantly greater in the extreme RVH group (p < 0.05). Multivariate analysis demonstrated 3 independent predictors for cardiovascular mortality - extreme RVH, left ventricular end-diastolic dimension ≥50 mm, and age ≤18 years at baseline - and 2 for morbidity - extreme RVH and presyncope. <b><i>Conclusions:</i></b> Compared with extreme LVH, extreme RVH was quite uncommon in HCM and had a worse prognosis. A right ventricle examination should be performed in routine HCM evaluation.