Moderate Continuous and Modified High-Intensity Interval Training in Patients With Left Ventricular Assist Devices: The Prospective Train-the-LVAD Trial

High-intensity interval training (HIIT) of 4 minutes at 80%-90% of peak oxygen consumption (VO2peak) has been shown to be feasible in patients with left ventricular assist devices (LVADs). The effect of shorter bouts of HIIT, which reduce the anaerobic burden, has not been investigated compared to moderate continuous training (MCT).We conducted a prospective, monocentric study (NCT05121077) randomizing patients with LVADs into 20 minutes of MCT (n = 10) or short bouts (≤ 90 seconds) of HIIT (n = 10) following cardiopulmonary exercise testing at 50%-60% and 80%-90% of VO2peak. Each of the 18 supervised sessions (3×/week, t0-t1) included 10 minutes of strengthening training. The primary outcome was the increase of VO2peak in the 2 groups between t0 and t1. Secondary outcomes were changes in the 12-item Kansas City Cardiomyopathy Questionnaire, the 6-minute walk distance and the percentage of VO2peak at the first ventilatory threshold. VO2peak significantly increased with HIIT (13.0 ± 4.6mL/kg/min vs 14.6 ± 4.3mL/kg/min; P = 0.037), but not with MCT (11.8 ± 3.3mL/kg/min vs 13.1 ± 3.3mL/kg/min; P = 0.322), without between-group differences (P = 0.853). Secondary outcomes improved from t0-t1 in MCT and HIIT, without differences between the groups.Short bouts of HIIT are feasible, and they improved VO2peak and functional parameters in patients in this pilot prospective study.