Two Versus One Repeat Freeze–Thaw Cycle(s) After Cryoballoon Pulmonary Vein Isolation: The ALSTER EXTRA Pilot Study

BACKGROUND: Repeated freezing (bonus applications) during cryoballoon pulmonary vein isolation (PVI) has been suggested to improve lesion durability. However, the long-term clinical effects of repeated freezing have not been investigated. METHODS AND RESULTS: A total of 51 patients (pts) with paroxysmal atrial fibrillation (AF) underwent PVI using the single big (28 mm) cryoballoon technique. One (27 pts, group I) or 2 bonus applications (24 pts, group II) were performed at all PVs subsequent to PVI. Clinical follow-up consisted of continuous rhythm monitoring by an implantable cardiac monitor (ICM, 24 pts) and serial 7-day Holter-ECG recording (7DH, 27 pts). The primary endpoint was defined as recurrent AF or atrial tachycardia. Acute PVI of all PVs was obtained in 50/51 pts (98%). The median (Q1;Q3) follow-up duration in this study was 384 (213;638) days. The primary endpoint occurred in 48% (group I, 15 pts ICM, 12 pts 7DH) and 46% (group II, 9 pts ICM, 15 pts 7DH), P = 0.84. Procedure- and fluoroscopy-time for group I versus group II was 193 ± 56 minutes versus 207 ± 27 and 33 ± 13 minutes versus 34 ± 11 minutes, respectively. Right phrenic nerve palsy (PNP) occurred in 3 pts (all group II, time to resolution: 128 ± 112 days). In 2 of these pts, PNP occurred during the second bonus application. CONCLUSION: Application of 2 when compared to 1 freeze-thaw cycle(s) following cryoballoon PVI did not result in improved clinical success but was associated with a higher complication rate.