P1248Characteristics and clinical significance of right ventricular involvement in patients with hypertrophic cardiomyopathy

Abstract

Background A few studies have demonstrated bi-ventricular hypertrophy in hypertrophic cardiomyopathy (HCM). However, clinical significance of HCM with right ventricular (RV) involvement has not been fully established. Therefore, we aimed to investigate the structural characteristics and clinical significance of RV hypertrophy in patients with HCM. Methods In a single center, large HCM registry, 256 patients with HCM who underwent both cardiac magnetic resonance (CMR) and transthoracic echocardiography within 6 months were retrospectively analyzed. RV involvement was defined as increased RV wall thickness >7 mm on CMR in any segments of RV free wall and apex. Patients who had evidence of significant RV pressure overload (RV systolic pressure >50mmHg) or had undergone septal myectomy were excluded. Cardiovascular outcomes were defined as the composite of cardiovascular death and hospitalization for cardiovascular disease. Results Among 256 patients, 41 (16%) showed RV involvement. During follow-up period (median 1099 days), 32 cardiovascular outcomes (3 cardiovascular death and 29 cardiovascular hospitalization) were occurred. Patients with RV involvement showed a significantly higher left ventricular (LV) thickness (23.8±5.8 vs. 21.2±5.0 mm, p=0.004), more advanced diastolic dysfunction, and larger left atrial volume index (LAVI, 48.5±20.3 vs. 40.2±14.9 mm/m2, p=0.016) compared to those without RV involvement. In multivariate cox regression analysis, presence of RV involvement (HR: 4.21, 95% CI: 1.99–8.90, p<0.001) and LV ejection fraction <50% (HR: 4.29, 95% CI: 1.37–13.43, p=0.012) were independently associated with cardiovascular outcomes. The Kapan-Meier curve showed that there was a significant decrease in probability of cardiovascular outcomes-free survival in patients with RV involvement (p=0.007) after using 1:1 propensity score matching (n=82) to adjust for age, sex, LV ejection fraction, LV maximal wall thickness, LAVI, and RV systolic pressure than patients without RV involvement (Figure 1). Figure 1 Conclusion RV involvement in patients with HCM were not rare (16%). Patients with RV involvement showed more advanced LV structure and dysfunction, suggesting an indicator of severe HCM. RV involvement in HCM has clinical significance related to cardiovascular outcomes.