Aims: Using a modified CARTO 3D mapping system, we studied if premature ventricular contractions (PVCs) cause position shifts within the 3D co-ordinate system. We quantified magnitude of the phenomenon and corrected for it, by creating both an activation map that represents the conventional local activation time (LAT) and one corrected for this position shift (hybrid LAT map).
Methods and results: We prospectively enrolled patients planned for PVC ablation. Distances between the earliest LAT, the earliest hybrid-LAT, and the best pacemap positions were calculated in a 3D model. Ablation was performed at the best hybrid-LAT location. Efficacy was evaluated by acute response to ablation as well as clinical outcome on 24-h Holter at 1 year. One hundred and twenty-seven LAT-hybrid pairs were studied in 18 patients (age 48.3 ± 18.0 years, 12 female). Baseline PVC burden was 16 ± 12%. The mean position shift between LAT-hybrid and its associated LAT position was 8.9 ± 5.5 mm. The mean position shift between best LAT-hybrid and best pacemap was 6.2 ± 5.0 mm and the mean shift between best conventional LAT and best pacemap was 13.5 ± 7.0 mm (P < 0.0001 for all pairwise comparisons). Exclusive targeting of best LAT-hybrid position resulted in acute abolition of PVC activity in all patients. After 1-year follow-up, mean PVC burden reduction was 16% (baseline) to <1%.
Conclusion: Premature ventricular contractions cause a position shift in 3D mapping systems compared with the same endocardial position in sinus rhythm. An approach to account for this phenomenon, correct it and target exclusively the adjusted 3D position is feasible and highly efficient in terms of acute and 1-year clinical outcome after radiofrequency ablation.
Keywords: 3D mapping; Premature ventricular contraction ablation; Ventricular tachycardia ablation.
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