Received: 3 April 2020 Revised: 26 July 2020 Accepted: 6 September 2020 DOI: 10.1111/pace.14062 ELECTROPHYSIOLOGY Shorter RSPV cryoapplications result in less phrenic nerve injury and similar 1-year freedom from atrial fibrillation Marleen M.D. Molenaar MSc 1, 2 Tim Hesselink MD 1 Rachel M.A. ter Bekke MD, PhD 3 Marcoen F. Scholten MD, PhD 1 Randy Manusama MD, PhD 3 Laurent Pison MD, PhD 4 Marjolein Brusse-Keizer PhD 1 Karin Kraaier MD, PhD 5 Bernard ten Haken PhD 2 Jan G. Grandjean MD, PhD 1 Carl C. Timmermans MD, PhD 3 Jurren M. van Opstal MD, PhD 1 1 Medisch Spectrum Twente, Enschede, The Netherlands 2 Universiteit Twente, Enschede, The Netherlands 3 Maastricht University Medical Centre, Maastricht, The Netherlands 4 Ziekenhuis Oost-Limburg, Genk, Belgium 5 Medisch Centrum Leeuwarden, Leeuwarden, The Netherlands Correspondence Marleen Molenaar, Thorax Centre Twente, Medisch Spectrum Twente, Koningsplein 1, 7512 KZ Enschede, The Netherlands. Email: mmdmolenaar@gmail.com Abstract Background: In the 123-study, we prospectively assessed, in a randomized fashion, the minimal cryoballoon application time necessary to achieve pulmonary vein (PV) iso- lation (PVI) in patients with paroxysmal atrial fibrillation (AF) with the aim to reduce complications by shortening the application duration. The first results of this study demonstrated that shortened cryoballoon applications (<2 minutes) resulted in less phrenic nerve injury (PNI) without compromising acute isolation efficacy for the right PVs. We now report the 1-year follow-up results regarding safety and efficacy of shorter cryoballoon applications. Methods: A total of 222 patients with AF were randomized to two applications of 1 min “short,” 2 min “medium,” or 3 min “long” duration, 74 per group. Recurrence of AF and PV reconduction at 1-year follow-up were assessed. Results: The overall 1-year freedom from AF was 79% and did not differ significantly between the short, medium, and long application groups (77%, 74%, and 85% for short, medium, and long application groups, respectively; P = 0.07). In 30 patients, a redo PVI procedure was performed. For all four PVs, there was no significant difference in recon- duction between the three groups. Reconduction was most common in the left superior PV (57%). The right superior PV (RSPV) showed significantly less reconduction (17%) compared to the other PVs. Conclusions: Shortening cryoballoon applications of the RSPV to <2 minutes results in less PNI, while acute success and 1-year freedom from AF are not compromised. There- fore, shorter cryoballoon applications (especially) in the RSPV could be used to reduce PNI. KEYWORDS atrial fibrillation, cryoballoon, phrenic nerve injury, pulmonary vein isolation, safety This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2020 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals LLC Pacing Clin Electrophysiol. 2020;43:1173–1179. wileyonlinelibrary.com/journal/pace 1173