On the Quest for the Best Freeze

The second-generation cryoballoon is effective in achieving acute pulmonary vein isolation (PVI) and favorable clinical outcome. To date, no data are available on factors affecting late PV reconnection after second-generation cryoballoon ablation.A total of 29 consecutive patients (25 male, 86.2%; mean age 57.8±13.8 years) underwent a repeat procedure, after a mean 11.6±4.5 months (range, 3.5-19.7 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electroanatomical mapping system. Among all 115 PVs, including 1 left common ostiums (LCOs), 25 (21.7%) showed a PV reconnection in 20 patients (1.25 per patient). Persistent PVI could be documented in 90 of 115 PVs (78.2%). In 9 of 29 patients (31%), all PVs were electrically isolated. In the multivariable analysis, time to PVI (P=0.03) and failure to achieve -40°C within 60 s (P=0.05) independently predicted late PV reconnection. At receiver-operator curve analysis, time to PVI <60 s identified the absence of PV reconduction (sensitivity, 86.7%; specificity, 86.2%; positive predictive value, 59.1%; and negative predictive value, 96.4%; area under the curve, 0.85; confidence interval, 0.73-0.97; P<0.001).The rate of late PV reconnection after second-generation cryoballoon ablation is low (1.25 PVs/patient). Faster time to isolation and achievement of -40°C within 60 s independently predict durable PVI. In addition, 60-s cut-off for time to PVI indicates persistent isolation with 96.4% negative predictive value. These parameters might guide the operator whether to perform further applications to ensure a long-lasting PVI.