Predictors of single shot pulmonary vein isolation with Heliostar radiofrequency balloon

Abstract Introduction Single shot pulmonary vein isolation techniques have emerged as an effective and safe alternative to point-by-point ablation, considerably reducing procedure times. The recent appearance on the market of the Heliostar® radiofrequency (RF) balloon offers a new option in this regard. The main predictors of single-shot isolation with this new device are unknown. Objectives Our objective was to evaluate as potential predictors of single-shot isolation the impedance drop, temperature rise and voltage reduction of the electrograms recorded by the balloon during radiofrequency application. Methods A total of 25 patients with paroxysmal (68%) or persistent (32%) symptomatic atrial fibrillation were prospectively included and underwent pulmonary vein isolation with Heliostar® RF balloon. Impedance and temperature parameters were collected from each of the applications performed in all veins. The voltage of the electrograms recorded by the Heliostar® RF balloon immediately before and after initiating the RF application in each vein was collected. The number of applications per vein was recorded and the single shot criterion was discriminated in each vein. A total of 92 veins were included for impedance and temperature analysis, and 59 veins for electrogram analysis (excluding veins in which the RF application was performed in atrial fibrillation). Impedance drop, temperature increase and electrogram voltage decrease during each application were analysed by logistic regression to correlate these parameters as potential predictors of single shot isolation. Results Single shot isolation was obtained in 64.1% of the veins. Applications that obtained persistent single shot isolation showed a higher impedance drop [22.5 ± 6.3 Ω vs 19 ± 5.3 Ω, p = 0.005] and a higher temperature rise [12.5 ± 4.4 ºC vs 10.3 ± 3.5 ºC, p = 0.008]. The voltage reduction of the electrograms collected by the balloon, on the other hand, did not differ significantly between the two groups [2.3 mV in single shot vs 2.2 mV in non-single shot applications, p = 0.4]. Univariate analysis by logistic regression showed impedance drop [OR per 1 Ω increase, 1.11, 95% CI 1.02-1.21, p = 0.007] and temperature increase [OR per 1°C increase, 1.15, 95% CI 1.02-1.3, p = 0.01] as significant predictors of single shot isolation. Conclusions Impedance drop and temperature rise during application were significant predictors of single shot isolation with Heliostar® RF balloon. The voltage reduction of the electrograms recorded by the balloon was not a predictor of single shot application.