Characteristics of Unsuccessful Catheter Ablation of Ventricular Arrhythmia

This study was to identify the electrophysiologic characteristics of unsuccessful catheter ablation (CA) of ventricular arrhythmias (VAs). Methods: Out of 302 patients undergoing CA of VAs, 43 consecutive patients (14.2%, 43±4 years) who attempted but failed to eliminate VAs with the first CA (US group). US group was compared with successful CA group (S group) to assess predictors to affect unsuccessful ablation. Results: US group included 8 patients underwent unsuccessful CA and 35 patients underwent repeated CA due to arrhythmia recurrence. Presenting VA was ventricular tachycardia (VT) in 24 patients (55.8%) but premature ventricular complex in only 13 patients (30.2%). VT was more common in US group (55.8%) than that of S group (39.0%, P=0.03). The ejection fraction of the left ventricle (LV) was lower in US group (38.0±7.2%) than in S group (43.7 ±.9%, P=0.02). The earliest activation time (EAT) prior to QRS onset in US group (29.8 ± 7.8 ms) was later than S group (37.4 ±8.4ms, P=0.04). There was a significant difference in VAs origin from-right ventricular outflow tract (RVOT) (41.8% in US group vs. 60.2% in S group, P=0.02). There were no significant differences in QRS width during VAs between two groups. Conclusions: A VT as presenting VAs, the severity of LV dysfunction, later EAT and non-RVOT origin were associated with unsuccessful CA, in whom repeated CA was often required.