Favorable effect of pulmonic vein isolation by partial circumferential ablation on ostial flow velocity

OBJECTIVES The aim of this study was to determine the effect of electrical isolation of pulmonic vein (PV) on flow velocity. BACKGROUND We report our experience with electrical isolation of PV by partial circumferential ablation and its effect on ostial peak flow velocity as assessed by phased-array ultrasound catheter imaging. METHODS Sixty-two patients participated in the study. Magnetic electroanatomic mapping, ultrasound catheter imaging, and Lasso mapping catheter were used. Electrical isolation was achieved by delivering radiofrequency ablation (RFA) lesions proximal to Lasso mapping catheter bipoles showing PV entry. Following this, the number of RFA lesions/PV and their segment-wise distribution (maximum 4/PV) were assessed. RESULTS Fifty right superior, 51 left superior, 32 left inferior, and 17 right inferior PVs were isolated. RFA involved 4 segments in 42 PVs, 3 segments in 61 PVs, and less than or equal to2 segments in 47 PVs. Electrical isolation augmented ostial peak flow velocity (55 +/- 15 cm/s to 96 26 cm/s). This net increase was higher for superior versus inferior PVs (43 +/- 23 cm/s and 34 +/- 18 cm/s; P =.02). For less than or equal to2, 3, and 4 segments ablated per vein, the net increase in peak flow velocity was 33 +/- 22 cm/s, 42 +/- 23 cm/s, and 46 +/- 23 cm/s, respectively (P =.02). Over a mean follow-up of 16 +/- 7 months, freedom from atrial fibrillation (AF) or >90% reduction in AF burden, either with or without previously ineffective antiarrhythmic agents, was achieved in 54 patients (87%). CONCLUSIONS In the majority of PVs (72%), electrical isolation can be achieved by partial circumferential ablation (targeting less than or equal to3 segments/PV) with lower acute increase in ostial peak flow velocity and good AF control.