High-Intensity Interval Training Induces Reverse Left Ventricular Remodeling in Patients with LVAD

Abstract

Purpose High-Intensity interval training (HIIT) has been shown to induce reverse left ventricular (LV) remodeling in patients with heart failure. We tested whether this effect could be reproduced in patients supported with long-term LVAD. Methods Chronic LVAD pts prospectively completed 15 cycle ergometer based, supervised HIIT sessions. Cardiopulmonary exercise test (CPX) with full LVAD support and resting turn-down echocardiogram (HM II speed reduced to 6000 rpm) were performed before and after training. Training intensity was based on peak power output (PPO) attained during baseline CPX. Each session lasted 30 min: 3 min warm-up (50% PPO), six 30 sec challenges (100% PPO) and six interspersed 4 min recovery periods (40% of PPO). One reader, unaware of the study intervention, interpreted the turn-down echocardiograms. Two blinded independent readers identified oxygen uptake (VO2) at ventilatory threshold (VT) and peak exercise (pVO2) in all CPXs. Results Nine subjects were enrolled (6 male, 7 NICM, 7 BTT) mean ± SD age 47±16yrs. Time from heart failure diagnosis to LVAD 60±34 mos., time on LVAD 28±16 mos. Adherence to HIIT was high; one pt withdrew due to drive line malfunction and one voluntarily withdrew. No serious adverse events occurred during exercise. All patients had ICD in place. Four were on ACE-I/ARB, 9 on Beta-blocker and 5 on loop diuretics. Two had DM2, 4 had AF, 2 had prior CVA and 3 had prior pump exchange. Seven pts completed the protocol. HIIT significantly reduced LV end-diastolic (193±90 to 183 ±89 ml; p=0.0041) and end-systolic (133±63 to 128±63; p=0.04) volumes. LV size decreased in all pts. Submaximal aerobic capacity, VO2 at VT (7.0±1.5 to 9.0±1.6 ml.kg.min-1; p=0.02) and pVO2 (11.3±2.3 to 12.2±2.4 ml.kg.min-1 p=0.02) also improved after HIIT. Conclusion A short HIIT program guided by CPX induced reverse LV remodeling and improved aerobic capacity in pts with long-term LVAD support. Addition of HIIT to established recovery protocols warrants further investigation.