Prognostic Implication of Right Ventricular Hypertrophy in Patients With Hypertrophic Cardiomyopathy

To evaluate the prognostic significance of right ventricular hypertrophy (RVH) in patients with hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance imaging (CMR) and to assess its incremental value when incorporated into the established 5-year sudden cardiac death (SCD) risk prediction model.

This retrospective study included 320 patients with HCM who underwent CMR and echocardiography between 2007 and 2019. RVH was defined as a right ventricular wall thickness of ≥5 mm. The primary event was heart failure (HF) hospitalization. The secondary events were a composite of HF hospitalization, cardiovascular death, and heart transplantation. The prognostic role of RVH was assessed using Kaplan-Meier survival analysis, Cox proportional hazards regression, and model performance metrics, including time-dependent receiver operating characteristic curve analysis for a 5-year follow-up and Harrell's C-index.

Among 320 patients (mean age 57.5 ± 12.8 years; 66.3% men), 65 (20.1%) had RVH. Over a median follow-up of 7.7 years, 28 (8.8%) patients experienced HF hospitalization, and 34 (10.6%) experienced composite adverse events. In multivariable Cox models, RVH was an independent predictor of both events: HF hospitalization (hazard ratio [HR] = 3.19, 95% confidence interval [CI] = 1.23-8.28, P = 0.017) and the composite events (HR = 2.38, 95% CI = 1.01-5.64, P = 0.048). Incorporating RVH into the 5-year SCD risk model increased the time-dependent area under the curve, though not significant, from 0.620 to 0.725 for HF hospitalization (P = 0.057) and from 0.712 to 0.848 for composite events (P = 0.062). Harrell's C-index improved significantly from 0.606 to 0.688 (P = 0.033) and from 0.641 to 0.727 (P = 0.030), respectively.

CMR-detected RVH independently predicts adverse events in patients with HCM. Incorporating RVH into a conventional risk model may enhance its predictive performance, supporting the importance of routine biventricular assessments in HCM evaluation.