Background: Cryoballoon ablation (Arctic Front, Cryocath) represents a novel technology for pulmonary vein isolation (PVI). The initial phase of a freeze is crucial for cryolesion formation which is determined by local temperature depending on blood flow. We investigated the impact of right ventricular rapid pacing (RVRP) on temperature kinetics in patients (pts) with paroxysmal atrial fibrillation (PAF).
Methods and results: Right ventricular rapid pacing was performed from the RV apex. Absolute minimal temperature (MT, degrees C), temperature slopes [time (s) to 80% MT; dT/dt), area under the curve (AUC) and arterial blood pressure (ABP, mmHg) were compared (group I: with RVRP vs. group II: without RVRP). RVRP (mean duration 55 +/- 7 s) was performed in 11 consecutive PAF pts (41 PVs, age 58 +/- 9 years, LA size 44 +/- 6 mm, normal ejection fraction). Only freezes with identical balloon positions were analyzed (11/41 PVs). RVRP (cycle length 333 +/- 3 ms) induced a significant drop in ABP (group I: 45 +/- 3 mmHg vs. group II: 100 +/- 18 mmHg, p < 0.001). MT was not different between group I and group II (-45.0 +/- 4.4 vs. -44.3 +/- 3.4 degrees C, p = 0.46), whereas slope (38.0 +/- 4.6 s vs. 51.6 +/- 14.4 s, p = 0.0034) and AUC (1090 +/- 4.6 vs. 1181 +/- 111.2, p = 0.02) was significantly changed. In one pt, a ventricular tachycardia was induced. PVI was achieved in 41/41 PVs.
Conclusion: Right ventricular rapid pacing significantly accelerates cryoballoon cooling during the initial phase of a freeze possibly suggesting improved cryolesions.