Cardiac remodelling and heart failure symptoms in patients with apical hypertrophic cardiomyopathy

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Although earlier publications suggested a more benign clinical course for patients (pts) with apical hypertrophic cardiomyopathy (ApHCM), recent studies report increased morbidity and mortality, comparable to the prognosis of other HCM variants. Moreover, information regarding cardiac remodelling and its relationship with symptoms in pts with ApHCM is scarce. The aim of our study was to assess left ventricular (LV), right ventricular (RV) and left atrial (LA) remodelling in pts with ApHCM in comparison with non-apical variants of HCM (nonApHCM), and the impact of cardiac remodelling on heart failure symptoms. Methods One hundred fifty-one consecutive pts with HCM (52 ± 16 yrs, 47% men) in sinus rhythm and with preserved LV ejection fraction (16 pts with ApHCM and 135 pts with nonApHCM), were prospectively enrolled. Comprehensive echocardiography was performed in all, including the measurement of maximal LV wall thickness (LVWT), RV free wall thickness (RVWT) and maximal LA volume indexed to body surface area (LAVi). Global LV strain (ɛ), RVɛ, LAɛ and end-diastolic LA strain rate (ASr) were measured using speckle-tracking echocardiography (STE). The ratio of E to average e’ was used to estimate LV filling pressure. The degree of mitral regurgitation (1/2/3) has also been assessed. Heart failure symptoms were defined according to the New York Heart Association (NYHA) classification. Results Forty-eight pts in nonApHCM group had intraventricular obstruction. There were no significant differences between pts with and without ApHCM regarding: age (58 ± 20 vs 52 ± 16 yrs), gender distribution, RVWT, LVɛ (-14.9 ± 2.7 vs -13.9 ± 3.5 %), RVɛ (-19.6 ± 3.6 vs -10.0 ± 5.0%), LAɛ (19.2 ± 5.8 vs 16.4 ± 7.1%)(p > 0.05 for all). Pts with ApHCM had lower values for LVWT (17.2 ± 1.9 vs 21.4 ± 5.2 mm, p = 0.002), E/e’ (12.0 ± 5.8 vs 17.6 ± 8.5, p = 0.02) and LAVi (48 ± 16 vs 61 ± 25, p = 0.03) compared to pts with nonApHCM. Pts with ApHCM had slightly better LA contractile function as assessed by ASr (-1.23 ± 0.50 vs -0.97 ± 0.49 sec-1, p = 0.05). Mitral regurgitation was more often severe in nonApHCM pts (56/42/31 vs 10/4/0, p < 0.001). There was no significant difference between the percentage of symptomatic pts (NYHA class ≥2) in ApHCM vs nonApHCM group (p = 0.3). In the ApHCM group, symptomatic pts had significantly lower ASr compared to asymptomatic pts (-0.98 ± 0.35 vs -1.61 ± 0.46 sec-1, p = 0.01). Conclusions Despite of lower LVWT values, less severe MR and no obstruction, pts with apical HCM have similar prevalence of heart failure symptoms, and similar LV, RV and LA dysfunction compared to pts with non-apical HCM. Symptomatic pts with apical HCM have worse LA contractile function compared to asymptomatic pts.