High‐Intensity Interval Training Is Associated With Improved 10‐Year Survival by Mediating Left Ventricular Remodeling in Patients With Heart Failure With Reduced and Mid‐Range Ejection Fraction

Background This study aimed to assess the left ventricular (LV) remodeling response and long‐term survival after high‐intensity interval training (HIIT) in patients with various heart failure (HF) phenotypes during a 10‐year longitudinal follow‐up. Methods and Results Among 214 patients with HF receiving guideline‐directed medical therapy, those who underwent an additional 36 sessions of aerobic exercise at alternating intensities of 80% and 40% peak oxygen consumption (V̇$$ \dot{\mathrm{V}} $$O2peak) were considered HIIT participants (n=96). Patients who did not undergo HIIT were considered participants receiving guideline‐directed medical therapy (n=118). Participants with LV ejection fraction (EF)