Effects of catheter ablation of idiopathic ventricular ectopic beats on left ventricular function and exercise capacity.

BACKGROUND: Frequent ventricular ectopic beats (VEB) in patients without significant cardiac disease are usually classified as benign arrhythmia. However, they may alter cardiac performance. RF ablation can effectively eliminate VEB.

AIM: To evaluate the effects of RF ablation on selected haemodynamic parameters of left ventricular (LV) systolic and diastolic function and exercise capacity in patients with VEB.

METHODS: The study population consisted of 22 patients (8 males, 14 females, mean age 37.8+/-8.2 years) undergoing effective RF ablation for VEB. Those over 50 years of age, with concomitant cardiovascular disease, depressed global LV function (EF<50%) and segmental wall motion abnormalities were excluded from the study. All patients underwent at baseline and at 6 months after the procedure: physical examination, standard ECG recording, 24-hour Holter monitoring, transthoracic echocardiography to evaluate LV systolic and diastolic function, and treadmill exercise test using the modified Bruce protocol to evaluate exercise duration, peak heart rate and workload achieved.

RESULTS: NYHA functional class improved in the whole population after RF ablation. The LV end-systolic dimension (LVESD) and end-diastolic dimension (LVEDD) significantly decreased (33.1+/-4.6 vs. 29.3+/-3.4 mm and 49.0+/-5.4 vs. 44.4+/-2.8 mm, respectively; p<0.001), whereas LVEF increased (58.0+/-7.0 vs. 67.8+/-4.8%; p<0.001) along with fractional shortening (FS) improvement (34.2+/-2.4 vs. 37.6+/-1.4%; p<0.001). Parameters of LV diastolic function significantly changed: the E/A ratio, diastolic pulmonary vein flow D and LV flow propagation velocity Vp significantly increased (p<0.001), whereas systolic pulmonary venous flow S and pulmonary venous atrial reversal flow AR were significantly reduced (p<0.001). Furthermore, E wave deceleration time (EDT) and isovolumetric relaxation time (IVRT) were significantly shortened (p<0.001). The parameters of exercise capacity (exercise duration, peak heart rate and workload achieved) were increased after the procedure. The following correlation was found: the higher the number of VEB/24 h, the bigger the LVEDD and LVESD (r=-0.69 and r=-0.72, respectively), the longer EDT (r=-0.53), the larger AR (r=-0.51), the slower A and Vp waves (r=0.56 and r=0.62, respectively) and the lower EF and FS (r=0.59 and r=0.61, respectively). However, all these correlations did not reach statistical significance.

CONCLUSIONS: 1. Frequent VEB have a highly negative effect on LV systolic and diastolic function. In patients with VEB ablation improves LV systolic and diastolic function. 2. Exercise capacity improves significantly after RF ablation of VEB. 3. After the procedure NYHA functional class improves irrespective of arrhythmia type. 4. The higher the number of ventricular ectopic beats per day, the larger LV size and the more depressed its systolic and diastolic function.