Frequent isolated ventricular premature complexes (VPCs) in patients without major structural heart disease are generally associated with benign prognosis, however can lead to serious symptoms and also to the development of left ventricular dysfunction. Purpose of this study is to present mapping findings and immediate results of catheter ablation of frequent idiopathic VPCs, and evaluation of long-term clinical outcome and the role of catheter ablation in clinical practice.
Methods: Twenty-seven patients, aged 48 +/- 14 years without major structural heart disease, presenting with frequent VPCs, were investigated electrophysiologically in 28 procedures. Twenty-five patients underwent catheter ablation.
Results: In 19 patients, the ectopic focus was found in the right ventricular outflow tract (RVOT) and could be reached from the endocardial approach. In these patients, VPCs were successfully eliminated by the ablation. Comparison of 24-hour Holter ECG recordings showed complete elimination of the target VPCs in all the cases [18,483 +/- 12,790 (2,152-48,820)/17 +/- 10 (3-42) % VPCs before ablation vs. 94 +/- 219 (0-763)/0.01 +/- 0.2 (0-0.7) % VPCs after ablation]. In 5 patients, mapping revealed epicardial localization of the ectopic focus in the OT. Ablation endocardially from the RVOT failed in 2 of the patients, cryoablation epicardially from the venous system was partially successful in 1 patient, and no ablation was attempted in 2 patients. In another 3 patients, ectopic foci were found in other parts of the ventricles and ablation was completely successful in one case. During the 14 +/- 9 (1-34) month follow-up period, full elimination of the target VPCs and elimination or significant reduction of symptoms was achieved in 20 (74%) patients. The procedures were accomplished without complications and with fluoroscopy time of 8,2 +/- 5,9 minutes.
Conclusion: Catheter ablation of frequent idiopathic VPCs was performed effectively and safely, particularly, if the ectopic focus was localized on the endocardial aspect of the RVOT. Efficacy of catheter ablation ofVPCs arising from the epicardium of ventricular OT or other atypical sites is limited by inaccessibility or proximity to the conduction system. Indication to more aggressive mapping and ablation methods like intrapericardial approach or ablation from inside the venous system should be always critically considered with regard to the symptoms or other clinical risk factors.