Respiratory dyssynchrony is a predictor of prognosis in patients with hypertrophic non-obstructive cardiomyopathy

Abstract

BackgroundRespiratory dyssynchrony (RD) is a phenomenon that may be reflected by reduced breathing efficiency (CO2 output relative to minute ventilation, V̇E/V̇CO2 slope) or by Exercise oscillatory ventilation (EOV). Low breathing efficiency and EOV indicate a worse prognosis in chronic heart failure patients with reduced ejection fraction (HFrEF). However, only little is known about their role in other forms of structural myocardial diseases. In this study, we assessed the prognostic impact of RD in hypertrophic non-obstructive cardiomyopathy (HNCM) as a subgroup of patients with heart failure and preserved ejection fraction (HFpEF). Methods and resultsWe selected n = 132 HNCM patients (pts) who underwent cardiopulmonary exercise testing (CPET) during baseline assessment. The average follow-up was 4.3 ± 3.6 years. The primary endpoint was a composite of death, heart transplantation (HTX), and implantation of a ventricular assist device (VAD).Respiratory dyssynchrony, as measured by EOV, was recorded in 18 pts. (14%), and as measured by a V̇E/V̇CO2 relationship of higher than 34 in 34 pts. (26%).In total, 22 (16.7%) pts. met the endpoint. Multivariate COX regression Analysis were made for EOV, V̇E/V̇CO2 and the combination of EOV andV̇E/V̇CO2. All parameters correlated significantly with the endpoint: EOV (hazard ratio [HR]: 3.7; p = 0.006), V̇E/V̇CO2 > 34 (HR: 5.6; p = 0.001) and EOV andV̇E/V̇CO2: (HR: 6.1; p ≤ 0.001). ConclusionThis is the first study to demonstrate the prognostic impact of RD on pts. with HNCM, and to investigate EOV as a novel factor to aid risk stratification in HNCM.