Phased-array intracardiac echocardiography to guide radiofrequency ablation in the left atrium and at the pulmonary vein ostium

Introduction: We sought to evaluate the utility of a phased-array intracardiac echocardiography (ICE) device to identify left atrial (LA) and pulmonary vein (PV) anatomy; accurately guide radiofrequency ablation (RFA) to the right or left PV ostium and LA appendage (LAA); and evaluate PV blood flow before and after RFA using Doppler parameters. Methods and Results: Twelve adult sheep were anesthetized and an Acuson 10-French, 7-MHz ICE transducer introduced via the internal jugular vein into the right atrium. The LA was imaged and PV anatomy and blood flow documented using two-dimensional and pulsed-wave Doppler. Mean LA dimensions were 4.6 ± 0.4 × 3.5 ± 0.5 cm; mean single right and left main PV ostium diameters were 1.5 ± 0.2 and 1.3 ± 0.3 cm; and mean right and left PV first-order branch diameters were 0.8 ± 0.2 and 0.6 ± 0.1 cm. Mean PV maximum inflow velocity for the right PV were 0.30 ± 0.05 m/sec and for the left PV were 0.35 ± 0.04 m/sec. The PV ostia and LAA could be targeted accurately for RFA using ICE guidance. At pathologic evaluation, the mean distance of the lesion center to the right or left PV-LA junction was 3.0 ± 2.0 mm. The mean distance of the lesion center to the posterior margin of the LAA was <4 mm in all cases. There was no significant increase in PV maximum inflow velocity or decrease in PV diameter following RFA at the PV ostium. Absence of PV obstruction was confirmed at pathology. Conclusion: Phased-array ICE allows detailed assessment of LA and PV anatomy when imaged from the right atrium; accurate guidance of RFA to the PV ostium and LAA; and immediate evaluation of PV patency after RFA.