Verification of a novel atrial fibrillation cryoablation dosing algorithm guided by time-to-pulmonary vein isolation: Results from the Cryo-DOSING Study (Cryoballoon-ablation DOSING Based on the Assessment of Time-to-Effect and Pulmonary Vein Isolation Guidance)

• Published in: Heart rhythm Vol. 14; no. 9; pp. 1319 - 1325
• Main Authors: Aryana, Arash, Kenigsberg, David N., Kowalski, Marcin, Koo, Charles H., Lim, Hae W., O'Neill, Padraig Gearoid, Bowers, Mark R., Hokanson, Robert B., Ellenbogen, Kenneth A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2017
• Subjects: Algorithm; Algorithms; Atrial fibrillation; Atrial Fibrillation - diagnosis; Atrial Fibrillation - physiopathology; Atrial Fibrillation - surgery; Cardiac Catheterization; Cardiovascular; Catheter ablation; Catheter Ablation - methods; Cryoablation; Cryoballoon; Cryosurgery - instrumentation; dosing; Equipment Design; Female; Fluoroscopy - methods; Follow-Up Studies; Heart Conduction System - physiopathology; Heart Conduction System - surgery; Humans; Male; Middle Aged; Pulmonary Veins - surgery; Recurrence; Retrospective Studies; Surgery, Computer-Assisted - methods; Tachycardia, Paroxysmal - diagnosis; Tachycardia, Paroxysmal - physiopathology; Tachycardia, Paroxysmal - surgery; Time Factors; RF; AF; Atrial fibrillation; Catheter ablation; PV; Cryoablation; TT-PVI; Cryo-AF; dosing; Algorithm; Cryoballoon; atrial fibrillation; catheter ablation; cryoablation; cryoballoon; algorithm
• ISSN: 1547-5271; 1556-3871; 1556-3871
• DOI: 10.1016/j.hrthm.2017.06.020

There are no recommendations on the optimal dosing for cryoablation of atrial fibrillation (Cryo-AF). The purpose of this study was to develop and prospectively test a Cryo-AF dosing protocol guided exclusively by time-to-pulmonary vein (PV) isolation (TT-PVI) in patients undergoing a first-time Cryo-AF. In this multicenter study, we examined the acute/long-term safety/efficacy of Cryo-AF using the proposed dosing algorithm (Cryo-AFDosing; n = 355) against a conventional, nonstandardized approach (Cryo-AFConventional; n = 400) in a nonrandomized fashion. Acute PV isolation was achieved in 98.9% of patients in Cryo-AFDosing (TT-PVI = 48 ± 16 seconds) vs 97.2% in Cryo-AFConventional (P = .18). Cryo-AFDosing was associated with shorter (149 ± 34 seconds vs 226 ± 46 seconds; P <.001) and fewer (1.7 ± 0.8 vs 2.9 ± 0.8; P <.001) cryoapplications, reduced overall ablation (16 ± 5 minutes vs 40 ± 14 minutes; P <.001), fluoroscopy time (13 ± 6 minutes vs 29 ± 13 minutes; P <.001), left atrial dwell time (51 ± 14 minutes vs 118 ± 25 minutes; P <.001), and total procedure time (84 ± 23 minutes vs 145 ± 49 minutes; P <.001) but similar nadir balloon temperature (–47°C ± 8°C vs –48°C ± 6°C; P = .41) and total thaw time (43 ± 27 seconds vs 45 ± 19 seconds; P = .09) as compared to Cryo-AFConventional. Adverse events (2.0% vs 2.7%; P = .48), including persistent phrenic nerve palsy (0.6% vs 1.2%; P = .33) and 12-month freedom from all atrial arrhythmias (82.5% vs 78.3%; P = .14), were similar between Cryo-AFDosing and Cryo-AFConventional. However, Cryo-AFDosing was specifically associated with fewer atypical atrial flutters/tachycardias during long-term follow-up (8.5% vs 13.5%; P = .02) as well as fewer late PV reconnections at redo procedures (5.0% vs 18.5%; P <.001). A novel Cryo-AF dosing algorithm guided by TT-PVI can help individualize the ablation strategy and yield improved procedural endpoints and efficiency as compared to a conventional, nonstandardized approach.