Mp-453083-5 prospective real-time use of forward-solution ecg mapping to facilitate focused activation mapping of unstable ventricular tachycardia: accuracy and outcomes

The efficacy of ventricular tachycardia (VT) mapping may be limited by hemodynamic instability during induced arrhythmias, reducing the ability to accurately map the critical isthmus. We developed a novel 12-lead ECG mapping algorithm using forward solution computational models to localize VT exit sites. We hypothesized that a non-invasive computational mapping system using the 12-lead ECG can help focus activation mapping of hemodynamically unstable VTs by allowing pre-induction placement of multielectrode mapping catheters near arrhythmia-sustaining substrates. Consecutive patients referred for catheter ablation of drug-refractory VT were enrolled in this IRB-approved study. In the prospective arm of this study incorporating clinical ECG mapping, VT induction was performed first. In patients with unstable VT (defined as mean arterial pressure <60mmHg during VT), cardioversion was performed and computational ECG mapping was used to localize the VT using the recorded 12-lead ECG. The multielectrode catheter was then positioned at the mapping-predicted site and limited activation mapping was attempted during VT reinduction. Ablation was then performed per standard protocol. In the retrospective arm of the study to evaluate accuracy, ECG mapping was performed on all cases in which invasive activation mapping was available. Out of 16 consecutive patients who underwent VT ablation, 7 of the 8 patients undergoing prospective ECG mapping had unstable VT. All 7 patients with unstable VT (median VT CL: 261±27ms, mean EF: 37±17%) underwent successful limited activation mapping (median LAT = -56±47ms) guided by ECG mapping. There was a 98% reduction in total VT episodes (including 69 to 2 shocks before and after ablation) during mean 4.2 month follow-up. No complications (acute heart failure, stroke, or death) occurred. For all 16 patients (mean EF: 40±20%, ICM: 50%), the mean accuracy of ECG mapping was 1.2±0.8cm when compared to invasive activation mapping. Real-time incorporation of a novel computational 12-lead ECG mapping algorithm into a VT ablation workflow appears to facilitate targeted activation mapping of hemodynamically unstable “unmappable” VT, resulting in excellent VT suppression.