CONGRESS ABSTRACT

Background. CardiacRehabilitation (CR) is a cornerstone of secondary prevention, aimed at improving functional capacity, quality of life and reducing cardiovascular risk. Outcome measures are essential for assessing the efficacy of CR programs and quantifying individual improvements in cardiorespiratory fitness and exercise tolerance. While the Cardiopulmonary Exercise Test (CPET) remains the gold standard for assessing functional capacity, the SixMinute Walking Test (6MWT) offers a simpler and more accessible alternative becoming a pivotal tool in CR and outcome evaluation. However, the determinants of walking distance improvement remain elusive and the information on walking efficiency during 6MWT is still limited. Objective. This study aimed to evaluate the impact of an intensive CR program on functional capacity and metabolic efficiency in patients with heart disease. We focused on identifying the key variables contributing to performance improvement: enhanced cardiorespiratory capacity, greater walking efficiency, or a combination thereof. Methods.  Using a wearable metabolic cart, we analyzed changes in energy expenditure during the usual 6MWT and also performed on a treadmill before and after CR, in a cohort of 12 patients with heart disease. Participants underwent the 6MWT at baseline and post-intervention, along with maximal CPET both on a cycleergometer and treadmill to assesswalking economy and cardiorespiratory capacity. Results.  6MWT performance was significantly increased with a reduced oxygen consumption per unit of distance walked. The improvement in functional capacity is associated with enhanced metabolic walking efficiency, likely attributable to training-Induced physiological adaptations such as increased aerobic capacity, muscle strength, balance, and reduced internal energy cost. Conclusions. Our findings support the hypothesis that CR can not only improve 6MWT performance but also maximize walking energy efficiency, leading to substantial benefits in patients' quality of life and autonomy.