Utilidade do ultrassom intracardíaco no isolamento de Veias Pulmonares usando cateter-balão a laser

Background: Pulmonary vein isolation (PVI) with balloon catheter has been used as the endpoint for AF ablation. Objective: To determine the usefulness of intracardiac ultrasound (ICUS) to guide PVI using laser balloon catheter. Methods: 59 PVs were ablated in 27 dogs. Doppler imaging was used to identify blood flow leaks between PV and balloon. After each energy delivery, the circular mapping catheter was repositioned to check if isolation had been achieved. The leak position was then correlated with the gap position at the pathological study. Multivariate logistic regression analysis was undertaken. Results: 59 PV were ablated. Mean burn time was 279±177 sec, mean balloon diameter was 23±3 mm, and mean balloon length was 25±4 mm. Complete isolation was achieved in 38/59 (64%) cases, and it was significantly more common when there was no leak: [30/38 (79%) versus 8/23 (35%), p<0.001]. This occurred regardless of time of laser application (302±223 sec. vs. 266±148 sec., p=ns), laser power (3.5 W/cm, 4.5 W/cm, and 5.5 W/cm), balloon diameter (24± 3 mm vs. 22± 3 mm, p=ns) and length (27±4 mm vs. 24±4mm, p=ns). The positive predictive value for predicting incomplete isolation was 65% and the negative predictive value was 83%. Conclusion: An identifiable leak between PV and the LBA device seen at the ICUS is predictive of lower PV isolation rates. ICUS may be useful for leak detection to avoid ineffective energy application during circumferential PV ablation. This could also be helpful when other types of energy are used.