The purpose of the present study was to evaluate the effects of RF ablation on selected hemodynamic parameters of left ventricular (LV) systolic and diastolic function and exercise capacity in patients with AVNRT, AVRT and VEB. Material and methods The study population consisted of 70 patients (22M, 48F) undergoing effective RF ablation for AVNRT (Group A, 24 subjects,mean age 42.7y ) or AVRT (Group B, 24, 38.1y) or VEB (Group C, 22, 37.8y). Patients in Group A were submitted to ablation of the slow pathway, patients in Group B to ablation of accessory pathways and patients in Group C to ablation of the VEB site. Patients were evaluated with 24hr Holter monitoring TTE to evaluate LV systolic and diastolic function and dimensions of cardiac cavities, treadmill exercise test using the modified Bruce protocol before and 6 months after procedure. Results and Conclusions Ablation RF of sepcified arrhythmias affects exercise efficiency, and some hemodynamic parameters. AVNRT and VEB have the most negative effect on left ventricular systolic and diastolic function. In patients with AVNRT and VEB ablation improves left ventricular systolic and diastolic function. Elimination of AVNRT and AVRT resulted in reduction of left atrial size. After RF ablation of AVNRT right atrial dimensions decreased significantly. Exercise capacity improved significantly after RF ablation of VEB, AVNRT and ; AVRT.