The Empirical Evidence in the Successful Anatomical Ablation of Idiopathic LV Summit Ventricular Arrhythmias: Lessons From Endocardial Mapping.

BACKGROUND

Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) can be ablated from some endocardial sites across the left ventricular myocardium where ventricular activation is later than in the great cardiac vein (anatomical approach). Failure of ablation at the initial target site was common, however, approaches have evolved to improve the outcomes.

OBJECTIVES

The goal of this study was to explore predictors of successful anatomical ablation of LVS VAs to elucidate the ablation site selection strategy.

METHODS

Forty consecutive patients who underwent successful anatomical ablation of idiopathic LVS VAs with completed endocardial mapping were studied.

RESULTS

The earliest ventricular activation relative to the QRS onset in the endocardium and great cardiac vein was -1 millisecond (-5 to 0 milliseconds) and -24 milliseconds (-29 to -18.25 milliseconds), respectively. Endocardial radiofrequency catheter ablation (E-RFCA) was performed at the shortest distance from the epicardial earliest activation site (EAS) in 36 patients; it was successful in 20 in whom the endocardial earliest ventricular activation was also recorded at the ablation site. That approach failed in 16 patients, and E-RFCA was successful at the junction between the left and right coronary cusps in 3. In 13 of 16 patients with a failed ablation and the remaining 4 patients, E-RFCA was successful at or near the endocardial EAS. Overall, E-RFCA was successful at the endocardial EAS in 37 (93%) of 40 patients.

CONCLUSIONS

This study suggests that E-RFCA of LVS VAs through an anatomical approach should first target the endocardial EAS rather than sites anatomically closest to the epicardial EAS.