Reversal of Left Ventricular Remodeling Associated with High-Intensity Interval Training Promoting Cardiorespiratory Fitness in Heart Failure Patients

This study was designed to explore the high-intensity interval training (HIIT) effects on cardiorespiratory fitness as well as the reversal of left ventricle (LV) remodeling, and association between them in heart failure (HF) patients. We included HF patients under our HF care program between 2009 and 2018. The 17 HF patients enrolled in the study were further divided into in-hospital supervised HIIT (n=8) or medical care (control) (n=9) groups according to their preference. All participants underwent cardiovascular magnetic resonance imaging (CMR) examination and a cardiopulmonary exercise test (CPET) before the exercise intervention or medical care. The HIIT participants had 36 sessions of HIIT, 2 to 3 sessions every week for 3 to 4 months, along with their current medical treatment. The HIIT involved alternating 80% and 40% peak oxygen consumption(VO_(2peak)) exercise intensity for 30 min in each session. Only medical treatment was prescribed for the control group. After completing HIIT training (i.e., 3-4 months after initial recruitment), all participants underwent CMR and CPET. HIIT significantly improved in LV ejection fraction and reduced LV end-systolic volume (LVESV) as well as LV mass (LVM), accompanied by increased cardiorespiratory fitness and cardiac output during exercise. However, these significant alterations were not observed in the control group. HIIT participants showed significantly greater reduced LVM and improved VO_(2peak) than controls. The improvement in VO_(2peak) was significantly correlated with reduced LVESV and LVM as well as increased cardiac output during exercise. Promotion of HIIT in cardiorespiratory fitness in HF patients may be associated with the reversal of LV remodeling.