| Objectives: To investigate the learning curve, operation experience, efficacy and safety of pulmonary vein isolation(PVI) using cryoballoon catheter ablation(CBCA) technique for atrial fibrillation(AF) in single-center.Methods: This study was carried out in a consecutive series of 39 patients who underwent PVI for AF using the CBCA approach performed by a single operator in Shenyang Military General Hospital. The patients were arbitrarily divided into three groups according to the chronological order, and each group(named Group A, B and C,respectively) had 13 patients. Differences of procedural time, fluoroscopic time,cryoablation time and amount of X-ray exposure using CBCA between the three groups were compared. The immediately success rates, complications and the results of mid-term follow-up between the three groups were compared, too.Results: In the 39 patients, there were 28 males(71.8%) and 11 females(28.2%); the mean age was(57.3 ± 9.70) years, and the mean body weight was(75.1 ± 9.8) kg.Hypertension occurred in 19 patients(48.7%), diabetes in 3 patients(7.7%), smoking in15 patients(38.46%), and alcohol drinking in 13 patients(33.33%). The mean left atrial diameter was(34.5 ± 5.9) mm, the mean left ventricular end diastolic diameter was(44.8± 4.1) mm, and the mean left ventricular ejection fraction(EF) was(0.66 ± 0.05). InGroup A, B and C, the mean operation time was [(146.9 ± 40.7) min vs.(105.2 ± 24.5)and(103.5±23.1) min, P = 0.001], which had a statistically significant difference. There was no statistical difference between Group B and C in the mean operative time(P=0.88).In group A, B and C, the cryoablation time was [(43.7±8.8)min vs.(35.9±7.6)min and(33.6±8.4) min; P=0.02 between Group A and B, P=0.004 between Group A and C]. The cryoablation time between Group B and C had no statistical significance(P=0.49). When three groups were compared, the mean freezing times, fluoroscopic time and amount of exposure had no statistical significance. Following the experience of cryoballoon operation increasing, the operation time and cryoablation time in both Group B and C decreased significantly compared with group A. With more than 10 cases of operation,the operation time and cryoablation time tended to be stable. The immediate PVI success rates achieved by only using the CBCA among Groups A, B and C were 69.2%,84.6% and 84.6%, respectively; however, there were no statistically significant between Groups A, B and C(P >0.05, although the success rate seemed lower in Group A).Among the 39 patients, phrenic nerve palsy occurred in 1 patient(2.5%) during operation,and severe vagal reaction occurred in one patient(2.5%). The mean follow-up time during postoperative period was 8 months, and 37 of 39 patients completed the follow-up(2 patients lost the follow-up),. Atrial fibrillation, atrial tachycardia and atrial flutter episodes did not occur in 35 patients after three months follow-up and the success rate of the operation was 94.5%. There were two cases of recurrence after three months of follow-up(5.4%). The incidence of the complications of atrioesophageal fistula and pulmonary vein stenosis between CBCA and radiofrequency ablation is similar. However,compared with radiofrequency ablation, the incidence of phrenic nerve palsy(PNP),which is a major complication in CBCA, was higher. Usually, the phrenic nerve function can recover by itself within 12 months after cryoablation, and permanent PNP would happen rarely. Severe vagal reaction could occur in the operation occasionally, and carefully monitoring of vital signs(such as blood pressure, heart rate and so on) should be done for early discovery and early treatment.Conclusions: CBCA for AF is safe and efficient with a short learning curve, and the success rate is pretty high during a midterm of follow-up. To the operators who had relatively experienced technique of radiofrequency catheter ablation of AF, the learning curve for CBCA was relatively shorter comparing with radiofrequency catheter ablation.. |
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