Abstract 2745: Electrical Coupling Index Guided Radiofrequency Ablation of the Pulmonary Veins
Introduction: Titration of radiofrequency (RF) ablation lesions has traditionally been difficult and imprecise. A novel electrical coupling index (ECI) measures the electrical coupling between the catheter tip and tissue and may aid in lesion creation efficacy. ECI guided ablation was evaluated in patients requiring pulmonary vein (PV) isolation for atrial fibrillation.
Methods: Baseline ECI in non-contact and contact locations was determined in the left atrium. An ECI threshold of 5 units above the non-contact level or 10% below the contact level was calculated. PV were randomized to ablation with or without ECI. With ECI monitoring, the catheter was initially placed in contact with the atrial endocardium such that ECI was greater than the threshold. The catheter was held in position during the ablation until ECI dropped below the threshold. If ECI was not used, standard methods (such as electrogram reduction) were used to isolate the PV. Fluoroscopy, procedure, and RF durations to initially encircle a PV and to apply additional touch-up lesions in order to achieve bi-directional block were recorded.
Results: Thirty-eight patients requiring PV isolation were studied. With ECI monitoring, isolation was achieved on initial encircling in 61% (23/38) of PV, whereas without ECI, isolation was achieved in only 29% (11/38) (p < 0.02). When touch-up lesions were required, the number of RF applications was significantly smaller with ECI monitoring than without (4.9±4.1 vs 9.0±8.6, p < 0.03). While fluoro, procedure, and RF durations to initially encircle the PV were significantly longer with ECI monitoring (9.3±4.6 min, 27±7 min, 20±5 min, respectively) than without ECI monitoring (6.7±3.3 min, 25±12 min, 18±4 min, respectively) (p < 0.03), overall procedure times with ECI monitoring (32±10 min) trended lower than without ECI monitoring (39±22 min, p = ns).
Conclusions: Monitoring ECI results in longer fluoro, procedure, and RF durations to initially encircle a PV, but decreases durations to achieve bi-directional block. Monitoring ECI reduces the need for touch-up ablations and leads to fewer gaps when touch-up is needed. Monitoring ECI may be useful in improving encircling lesion continuity, and may be useful as a new metric for creating efficacious lesions.