The aim of our prospective study was to evaluate the effects of cardiac resynchronization therapy (CRT) on right ventricular function and remodeling in clinical responders and nonresponders after 3 and 15 months of CRT. 15 months after CRT we found a statistically significant improvement of right ventricular systolic function and a significant reduction of right ventricular size in responders to CRT. These changes were not observed in nonresponders