"Following ST-segment elevation myocardial infarction (STEMI), patients present some degree of cardiac dysfunction, which may affect the ability to perform physical activity. However, cardiac rehabilitation can improve these parameters. To evaluate the association of right ventricular function with exercise tolerance after a CR program in patients with STEMI treated with percutaneous coronary intervention. Observational, cross-sectional, analytical and retrospective study. Patients with STEMI-STEMI treated with PCI during January 2019 to January 2020 were included. Patients underwent assessment of RV function prior to a 16-session CR program and a stress test before and after the program. Demographic variables, comorbidity, infarct location and culprit artery were documented. The relationship of RV function with exercise tolerance METs before and after the CR program was also evaluated, as well as the degree of improvement in functional class (NYHA). Statistical analysis was performed in the SPSSv.22 program. A value of p<0.05 was considered significant. 109 patients were included in a 12-month period. 3.7% had RV global dysfunction, 10.1% had RV radial dysfunction, and 11% had RV longitudinal dysfunction. RV Radial dysfunction and improvement of more than 1 MET was observed with a statistically significant difference (p=0.028) as well as in patients with RV longitudinal dysfunction (p=0.008). A slight significant correlation was observed between RV longitudinal dysfunction and the results of initial MET (p=0.046), final (p=0.003) and difference of METs (p=0.009). A slight correlation was identified between global RV dysfunction and the initial METS result with significant difference (p = 0.045), as well as final METS (p = 0.012) and METS difference (p = 0.032). Longitudinal and global right ventricular dysfunction is associated with a lower capacity to tolerate exercise, however, this does not reduce the benefits obtained from a CR program."