From the Department of Cardiology, Arrhythmia Unit, INCLIVA Foundation, Hospital Clínico Universitario, Valencia, Spain (A.F.-d.-L.-O., M.I.-d.-F, A.M., P.L.-M., C.N., L.B.-S., J.M.S.-G., F.J.C.-G., R.R.-G.); Department of Cardiology, Arrhythmia Unit, Hospital General Universitario, Valencia, Spain (A.G.-F., A.I.-C., M.A.-F., J.G.M.-M.); and Department of Cardiology, Arrhythmia Unit, Hospital Universitario de San Juan, Alicante, Spain (J.C.-C., J.M.-A., V.B.-G.).
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BackgroundThe optimal dosage of cryotherapy during cryoballoon ablation of pulmonary veins is still unclear. This trial tested the noninferiority of a novel, individualized, cryotherapy-dosing strategy for each vein.Methods and ResultsThis prospective, randomized, multicenter, noninferiority study included 140 patients with paroxysmal atrial fibrillation, which was refractory to antiarrhythmic drugs. Patients were randomly assigned to a conventional strategy of 180-second cryoballoon applications per vein with a bonus freeze (control group, n=70) or to a shorter-time application protocol, with 1 application that lasted the time required for electric block time to effect plus 60- and a 120-second freeze bonus (study group, n=70). Patients were followed with a long-term monitoring system of 30 days. At 1-year follow-up, no difference was observed in terms of free atrial fibrillation-recurrence rates: 79.4% in control versus 78.3% in study group (Δ=1.15%; 90% confidence interval, −10.33% to 12.63%; P=0.869). Time to effect was detected in 72.1% of veins. The control and study groups had similar mean number of applications per patient (9.6±2 versus 9.9±2.4; P=0.76). Compared with controls, the study group had a significantly shorter cryotherapy time (28.3±7 versus 19.4±4.3 minutes; P<0.001), left atrium time (104±25 versus 92±23 minutes; P<0.01), and total procedure time (135±35 versus 119±31 minutes; P<0.01). No differences were observed in complications or acute reconnections.ConclusionsThe new time-to-effect–based cryotherapy dosage protocol led to shorter cryotherapy and procedure times, with equal safety, and similar acute and 1-year follow-up results, compared with the conventional approach.Clinical Trial RegistrationURL: https://clinicaltrials.gov. Unique identifier: NCT02789358.