High-intensity interval training in cardiac resynchronization therapy: a randomized control trial

AimsTo determine the effects of high-intensity interval training (HIIT) following cardiac resynchronization therapy (CRT) implantation in patients with chronic heart failure (CHF), on noninvasive estimates of systolic ventricular function, exercise performance, severity of symptoms and quality of life.MethodsCardiopulmonary exercise testing, resting transthoracic echocardiogram and health-related quality of life assessment were obtained before and at 6months after CRT implantation in 37 patients with moderate-to-severe CHF. Patients were randomized after CRT to either a 24-week HIIT group (90-95% peak heart rate, 2days per week) or to a usual care group (CON). Mixed design 2x2 repeated measures ANOVA were used to test for differences within and in-between groups.ResultsImprovements in health-related quality of life (HIIT=98.54%, CON=123.47%), NYHA class (HIIT=43.44%, CON=38.30%) HR recovery at minute 1 (HIIT=32.32%, CON=42.94%), pulse pressure at peak effort (HIIT=14.06%, CON=9.52%, LVEF (HIIT=42.17%, CON=51.10%) and LV Mass (HIIT=13.26%, CON=11.88%) were similar in both groups (p>0.05). Significant increases in CPET duration in the HIIT group(25.94%), and increases in peak VO2 (HIIT=8.64%, CON=4.85%) and percent-predicted VO2 (HIIT=10.57%, CON=4.26%) in both groups, were observed in the intention-to-treat analysis.ConclusionSix months of HIIT in patients in CRT did not further improved indices of functional capacity and health-related quality of life, and LV structure and function, compared to CRT alone. However, HIIT led to further improvements in exercise performance. It remains unclear whether HIIT benefits patients in CRT to a similar degree as more conventional forms of exercise training previously shown to maximize benefits in CRT.Clinical trial registrationhttp://www.clinicaltrials.gov. Unique identifier: NCT02413151.