We analyzed the medium-term follow-up of cryoballoon ablation (CBA) for atrial fibrillation (AF) and the clinical risk factors predicting outcome.

AF patients treated for the first time with CBA in a 4.5-year period were studied retrospectively. Pulmonary vein isolation (PVI) was achieved via a single cryoballoon with diameter of 28 mm. Left atrial diameter (LAD) was measured by transthoracic echocardiography. Failure of cryoablation treatment was defined as detection of an episode of AF, atrial flutter, or atrial tachycardia lasting more than 30 s during the 3-month follow-up.

A total of 212 patients were enrolled and in 87.7 % patients PVI was achieved by CBA. The complication rate was 2.83 %. The mean follow-up was 28 ± 15 months; in 166 patients follow-up was complete. The rate of successful treatment for primary CBA was 45.8 %. The percentage of patients who experienced atrial arrhythmia recurrence in the first 12 months was 84.44 %. Patients in whom treatment failed had a larger LAD (47 ± 6 mm vs. 43 ± 5 mm, p < 0.0001). The Kaplan–Meier curve showed that the patients with LAD < 45 mm had a higher success rate than patients with LAD ≥ 45 mm [57.9 % (44/76) vs. 35.6 % (32/90), log rank = 5.492, p = 0.019]. The LAD [odds ratio, OR = − 0.1053(0.303, 12.2040), p = 0.0005] was shown in logistic regression analysis to be independently predictive of CBA treatment failure.

The CBA procedure for AF patients is safe and effective. Most atrial arrhythmia recurrences occurred during the first 12 months after CBA. The LAD can independently predict failure of CBA treatment.