Extensive coronary venous system mapping for outflow tract ventricular arrhythmias: Utility of a dual over-the-wire...

During catheter ablation of epicardial or intramural outflow tract ventricular arrhythmia (OTVA), the presumed site of origin must often be inferred from coronary venous system (CVS) mapping, which is anatomically constrained.

This study sought to evaluate the feasibility and clinical utility of a dual over-the-wire (OTW) microelectrode catheter technique for extensive CVS mapping in OTVAs.

We prospectively enrolled 30 patients with OTVA exhibiting either a right bundle branch block or a left bundle branch block pattern with V2 or V3 transition. 2 2.7Fr OTW microelectrode catheters were routinely introduced: 1 positioned along the main CVS trunk from the great cardiac vein to the anterior interventricular vein and the other advanced into a peripheral CVS branch.

Both catheters were successfully placed in the intended vessels in 28 patients (93%). Among the 26 patients whose earliest activation site was within the CVS, the site with earlier activation within the CVS could be clearly identified in 12 patients (46%) by aligning electrograms from both catheters. Activation timing was equally early between the 2 catheters in 10 patients (39%), requiring pace map findings to delineate the area of interest. In 4 patients (15%), the earliest activation was recorded within the great cardiac vein where both catheters were positioned. The targeted OTVA was eliminated in 27 patients (90%), including 4 patients who underwent successful chemical ablation.

A dual OTW microelectrode catheter technique was feasible for extensive CVS mapping and was useful in defining the area of interest to perform anatomical approach or chemical ablation.