P03 : Structural heart disease predicts success rates of pulmonary vein isolation with the cryoballoon catheter

Aim To retrospectively evaluate clinical predictors of successful ablation of atrial fibrillation following pulmonary vein isolation using the Medtronic Arctic Front Cryoballoon catheter. Background Cryoablation is an effective technique for the treatment of AF. Long-term data measuring the rates of recurrence and symptom reduction is lacking. Methods 73 patients undergoing cryoablation for symptomatic paroxysmal or persistent AF using the Arctic Front Cardiac CryoAblation balloon catheter (Medtronic, Inc.) were retrospectively examined. One patient had a repeat procedure for a total of 74. Patient characteristics, AF type, recurrence of AF, symptomatic reduction, and the presence of structural heart disease was recorded. Recurrence of AF was measured at 6 and 12 months. Methods of monitoring included EKG, mobile cardiac telemetry (MCT), holter monitor, and implantable devices such as internal loop recorders, pacemakers, and implantable cardioverter–defibrillators. The presence of structural heart disease was defined as a left atrial diameter >4.0 cm and/or ejection fraction (EF) Results A total of 74 procedures were performed from October 2011 through April 2013. Diaphragmatic palsy occurred in 1 patient, leading to an incomplete ablation procedure with immediate failure. At 6 months 84.2% of patients were free of recurrent atrial fibrillation. At 12 months, 65.2% of patients were free of recurrent atrial fibrillation. There was no difference in success rates between men and women. The presence of structural heart disease was a significant predictor of long-term success. In patients with structurally normal hearts, success rates were 93.3% and 77.8% at 6 and 12 months. In patients with structural heart disease, success rates at 6 and 12 months were 70.6% and 45.5%, respectively. Patients with structural heart disease had a mean left atrial diameter of 4.79 cm with an EF of 38.8%. Patients without structural heart disease had a mean left atrial diameter of 3.36 cm with an EF of 57.2%. The type of AF also influenced outcomes at the 6-month follow-up, with procedural success in 90% of those with paroxysmal AF and 62.5% of those with persistent AF. This pattern was not seen at 12-month follow-up, with success rates of 64.7% and 66.7% in those with paroxysmal and persistent AF, respectively. Conclusion Cryoablation serves as an alternative approach for the treatment of drug-refractory atrial fibrillation with high rates of immediate success and low rates of recurrence. Success rates are highest in those with paroxysmal AF without a history of structural heart disease.