Background

Atrial fibrillation (AF) is the most frequent arrhythmia in developed countries with increasing prevalence in the next years. Hence, efficient ablation technologies are required to fulfil the upcoming need of catheter-based AF treatment. Beside 3D mapping systems in combination with single-tip catheter radiofrequency (RF) energy, various balloon-based ablation system for pulmonary vein isolation (PVI) have been introduced in the last decade into the market. However, the optimal technical approach especially for durable pulmonary vein isolation (PVI) is still under debate. We here present our first experiences with the novel RF balloon catheter (Heliostar), which combines the advantages of a single-shot-device with the strengths of irrigated RF energy and 3D mapping, for PVI in patients with paroxysmal or persistent AF undergoing PVI.

Methods and Results

We included 10 patients with either paroxysmal or persistent AF in this prospective single center study (ATRIUM, DRKS-ID: DRKS00013013), which were treated with the RF balloon HelioStar. 7/10 patients were male and had paroxysmal AF. Mean CHA²DS²-VasC-Score was 2.8 ±0.3 with arterial hypertension as the most frequent comorbidity (8/10 patients). Electroanatomical mapping (EAM) was performed before and after PVI. Irrigated RF energy (20 watts) was applied for 60 seconds by 10 electrodes, each with 4 irrigation holes. RF ablation time was limited to 20 seconds for posterior orientated electrodes (figure 1). Mean procedure duration was 85 ±17min with an average fluoroscopy time of 18 ±9 min. 38/39 PV (97.4%) were successfully isolated with the RF balloon with a mean time-to-PV-isolation (TTI) of 17 ±8 seconds. PV isolation with the first energy application was realized at 25/39 PV (64%). RF energy application was interrupted in 2 patients due to increased esophageal temperature (>38°C) and in 1 patient due to reduced phrenic nerve activity, which resolved immediately after energy interruption. Severe bleeding, groin complications, stroke or pericardial effusions were not registered in our study cohort. 1/10 patients were rehospitalized 16 days after index procedure with an AF episode which was self-limiting during an overnight hospital stay.  

Conclusion

The novel RF balloon catheter HelioStar is a promising tool allowing effective and safe pulmonary vein isolation in our study cohort. Remarkably, circumferential RF energy applied by the HelioStar balloon leads to immediate PV isolation as indicated by a very short TTI. However, further procedural and clinical data have to be collected to evaluate the clinical benefit of this RF balloon catheter.





Figure 1: RF balloon HelioStar during energy application (max. 20 Watts, yellow bars) for pulmonary vein isolation of the left superior pulmonary vein. Significant local impdeance drop at electrode 2-8 (green bars) indicating effective tissue damage. Maximum temperatur (red bars) was 39.2C° at electrode 5. Posterior electrode (1, 9 and 10) were switched of after 20 seconds according to official product manual.