Shortening of freezing cycles provides equal outcome to standard ablation procedure using second-generation 28 mm cryoballoon after 15-month follow-up

Aims Complications such as thermal oesophageal lesions, phrenic nerve injury, and pulmonary haemorrhage were found in cryoballoon (CB) ablation. Whether shortening of freezing times translates into equal efficacy rate and outcome is unknown. The aim of this study was to test the hypothesis that a single freeze cycle per pulmonary vein (PV) without dormant conduction during adenosine infusion is equally effective to standard CB procedure with a bonus freeze after documented PV isolation (PVI). Methods and results In 53 patients with drug-refractory atrial fibrillation (AF) demonstrating PVI after a single 240 s freeze cycle without PV activity during adenosine no additional bonus freeze was applied (study group). In 139 patients, PVI was performed using a bonus freeze (240 s) after documented PVI (control group). Primary endpoint was recurrence of AF. Secondary endpoint was the assessment of quality of life (QoL-score from 1 to 6, being 1 the best and 6 the worst). Follow-up (FU) was performed at 3, 6, and 12 months. Freedom from symptomatic AF during a mean FU of 458 +/- 107 days was achieved in 43 (81%) patients in the study group and in 110 (79%) control patients (P = ns). The QoL-score improved equally in both groups (4.8 +/- 0.9 to 2.1 +/- 0.7, P < 0.05 and 4.7 +/- 0.6 to 2.2 +/- 0.6, P < 0.05). Procedure duration (79 +/- 14 vs. 98 +/- 16 min, P < 0.01) was shorter in the study group. Complication rate was similar in both groups. Conclusion Shortening of freezing times to 4 min per PV without residual dormant PV conduction after adenosine provocation is equally effective to the standard CB ablation protocol using a bonus freeze.