Cryoablation in Patients With Atrial Flutter

After double transseptal puncture, selective PV angiography was performed to identify the PV ostia in 2 projections (right anterior oblique 30º, left anterior oblique 40 º). Baseline potentials of all PVs were recorded with a Lasso catheter (Biosense Webster, Inc., Diamond Bar, California). To assess the exact position of the inflated balloon in relation to the left atrial (LA)-PV junction, contrast medium was injected from the distal lumen of the cryoballon catheter . CBA was performed for a target time of 300 seconds. The right phrenic nerve was constantly paced from the superior caval vein during freezing at the septal PVs. After each freeze, PV conduction was revaluated by the Lasso catheter.

The RevealXT was implanted in the parasternal area of the chest. The requirement for defining the exact final position was an R-wave amplitude ≥0.4 mV assessed through the Vector Check. Patients were provided with the Patient Assistant, a toolthat allows each patient to store the ECG through the implanted device during symptoms: datawere collected in order to analyze heart rhythm during symptomatic events

Externally-irrigated tip (5-mm tip, Celsius Thermo-Cool, Biosense Webster, Diamond Bar, CA, USA). Temperature-controlled RF delivery was performed with a maximum power output of 50 W and temperature limit of 50 C. The catheter was irrigated using 0.9% saline infusion at a flow rate of 20-40 mL/min during RF delivery and 2 mL/min between applications using a commercially available pump (Cool Flow, Biosense Webster).