Automated template matching correlates with earliest activation during mapping of idiopathic premature ventricular contractions

Ablation of premature ventricular contractions (PVC) can be challenging due to infrequent spontaneous ectopy and the limitations subjective pacemapping (PM). Activation mapping (AM) provides an objective parameter, but relies on spontaneous ectopic activity. The objective of the study was to evaluate the correlation of automated template matching (TM) with activation timing and to investigate potential implications towards ablation success. Forty patients undergoing catheter ablation of idiopathic outflow tract VT or PVC in 47 procedures were included. PVC/VT origin was determined by PM and AM. A percentage value for PM was calculated using TM software and correlated with corresponding activation timing. Overall, 126 TM and corresponding AM values were analyzed. All patients were followed (313 ± 158 days after ablation) including a 24-hour Holter ECG. A correlation between TM and activation timing (r = 0.66, P < 0.0001) could be shown. Success rate at followup was 77%. No statistically significant coherence of TM percentage and relapse was observed. Template matching correlates with activation timing in the process of mapping idiopathic focal PVC/VT. TM helps to objectify the process of PM and may therefore be helpful to guide successful ablation in the absence of spontaneous ectopy.