Simple ECG features predict successful catheter ablation of idiopathic premature ventricular contractions with an...

Numerous algorithms predict the origin of idiopathic premature ventricular contractions (PVCs) with an inferior axis using the electrocardiogram (ECG), especially trying to differentiate between PVCs from the left and right ventricular outflow tract (LVOT and RVOT). Although evaluating the PVC origin goes along with evaluating risks and benefits of catheter ablation, this approach is complex for non-electrophysiology (EP) experts and shows limited reliability. As an additional strategy to guide decision-making, we sought to find simple ECG criteria that predict outcome of catheter ablation directly rather than origin.

Patients undergoing catheter ablation of idiopathic PVCs with an inferior axis at our center between 2012 and 2020 were included. Procedural data assessed included complete suppression of the PVC at the end of the procedure, ECG analysis included assessment of Q-, R-, and S-amplitudes, -durations and derived parameters.

104 patients (54% male, 54 ± 17 years) were included. Overall ablation success was 81%. Two ECG features - a more leftward PVC axis in the limb leads and an earlier precordial transition in the chest leads - independently predicted ablation failure. Using ROC statistics, we suggest combining the following two criteria to predict ablation success with a positive predictive value of 95% with no major complications: (1) PVC axis ≥ 75° (lead III ≥ (neg) aVR) and (2) TZ-score > 2 (V2 net negative, p < 0.001). If either parameter was not met, success rate was only 60% and major complication rate was 7%. Considering the PVC origin underlying these findings, the two criteria were inversely associated with a parahisian and LV summit origin, while no differences in ablation success or procedural data were observed between RVOT and LVOT origins.

While catheter ablation of LVOT and RVOT PVCs show similarly high success rates, two simple ECG criteria based on PVC axis and precordial transition independently predict ablation outcome due to complex PVC foci. These should be considered when evaluating patients with idiopathic PVCs with an inferior axis for catheter ablation.