Abstract 15342: Outcomes of High-Intensity Interval Training Are Superior to Moderate Exercise Training Among Post-Heart Transplant Patients

INTRODUCTION: Heart failure patients who underwent heart transplantation (Htx) need to undergo cardiac rehabilitation (CR) to regain and improve their physical ability and functional capacity. To date, there is no established exercise regimen that optimizes this recovery. This study aims to compare the outcomes of High-Intensity Interval Training (HIIT) versus Moderate Exercise Training (MT) among Htx patients.

Hypothesis: The outcomes of HIIT are superior to MT among Htx patients.

Methods: A systematic review was conducted in multiple databases including PubMed, Embase, and Google Scholar from inception to 2022 following the PRISMA guidelines to look for randomized controlled trials that directly compare clinical outcomes of HIIT versus MT. Joanna Briggs Institute (JBI) critical assessment tool was used to assess the risk of bias. A meta-analysis was performed using a random effect model to calculate mean differences with 95% confidence intervals (CI). This study is registered on Prospero (CRD42023403954).

Results: This study included four clinical trials (n=177 patients). The average age was 51 years ± 10.57, with a majority male (73%). On average, patients were overweight (BMI = 25.78 ± 4.08) with comorbidities including hypertension (81%) and diabetes (12%). Compared to baseline levels, the peak oxygen consumption (VO2 peak), maximal muscle strength extensors, maximal muscle endurance, body mass index, and FEV1 were statistically significantly increased after the intervention of either HIIT or MT. Of these, HIIT had higher percent changes in VO2 peak at 0.205 (95% CI: 0.007 to 0.417, p=0.0578), maximal muscle strength extensors at 0.100 (95% CI: 0.059 to 0.141, p<0.001), and maximal muscle endurance at 0.263 (95% CI: 0.185 to 0.341, p<0.001) compared to MT.

CONCLUSION: Both exercise CR regimens significantly improved the physical ability and functional performance of Htx patients. However, HIIT was superior to MT in terms of VO2 peak, maximal muscle strength extensors, and maximal muscle endurance, which may be associated with higher survival.