Carto 3

In absence of contraindications, a contrast-enhanced multi-detector cardiac tomography (MDCT) will be obtained using a 64 or 128 slice CT scanner, with ECG gating set between 50 and 100% of cardiac cycle. The exam will be performed after hospital admission or in an outpatient setting. Anatomical data obtained from such exam will be used for clinical management purposes and, after post-elaboration with ADAS 3D software, integrated within the spatial reference coordinates of the EAM system (CARTO 3 Biosense Webster, Diamond Bar, CA, USA), alongside data derived from LGE-CMR.

Ablation procedure was performed under deep sedation as previously reported [12 (link)]. Esophageal temperature was monitored throughout the procedure; temperature limit was set to 41 ^°C. The procedure was performed during AF. Only radiofrequency ablation was used for PVI. No additional linear ablation in the LA was performed; only cavotricuspid isthmus ablation was permitted for documented typical atrial flutter.
PVI was achieved using a focal “point-by-point” catheter approach, delivering radiofrequency energy to the cardiac tissue with irrigation tip catheters (THERMOCOOL SMARTTOUCH® SF™, Biosense Webster, Diamond Bar, CA, USA [target contact force: 10-20 g, RF time: 30–60 s, irrigation flow rate: 8 ml/min for ≤ 30 W, 15 ml/min for > 30 W, power control mode] or FlexAbility™, Abbott, St. Paul, MN, USA [RF time: 30–60 s, irrigation flow rate: 10 ml/min for < 38 ^°C, 13 ml/min for ≥ 38 ^°C, temperature control mode]). RFCA lesion sets encircled the PV antra using electro-anatomical mapping (CARTO3, Biosense Webster, Diamond Bar, CA, USA or EnSite NavX, Abbott, St. Paul, MN, USA) and fluoroscopy guidance.
Activated clotting time (ACT) was measured every 20 min after the first heparin shot and additional heparin boluses were given to maintain the ACT ≥ 300 s.

All patients underwent a preablation angiographic CT examination (Optima CT660, GE Healthcare, Milwaukee, WI, USA) within 2 days before the procedure to assess LA and PV anatomy. Angiographic CT images were integrated in the electroanatomical mapping system CARTO 3 (Biosense Webster, Diamond Bar, CA, USA) using the “image integration” software, resulting in 3-dimensional reconstructed images. LA volume was quantitively calculated from the 3-dimenstional reconstructed images and further indexed to the body surface area. All measurements were performed by a blinded investigator with no knowledge of the patient history.
Typical PVs anatomy was defined as two left and two right. Atypical anatomy was determined by the presence of a common trunk or an additional pulmonary vein. The left common trunk (LCT) was defined when the left superior and left inferior PVs joined at least 5 mm before entering the LA, resulting in a single atriopulmonary venous junction [7 (link)]. An accessory PV was defined as a supranumerary vein that has its own independent atriopulmonary venous junction separated from the typical superior and inferior PVs and is named for the pulmonary segment that it drains.

All operations were performed under local anesthesia. Before surgery, all patients (excluding patients with LA thrombosis) underwent TEE, and the LAAEV was recorded. Under the guidance of the CARTO 3 (Biosense Webster, USA) system, a Thermocool SmartTouch catheter (Biosense Webster, USA) was used to isolate the pulmonary veins, and a Lasso catheter (Biosense Webster, USA) was used to verify the bidirectional isolation of all pulmonary veins. No additional ablation lines were performed in this study. The sinus rhythm of all patients was recovered through ablation, medication, or electrical cardioversion. After ablation, blocking was conducted according to routine procedure. Watchman devices (Boston Scientific, Marlborough, Massachusetts, USA) were used as implanted occluders, and the PASS principle was followed to release the occluders.

A total of 60 consecutive patients undergoing their first PVI for persistent AF were included in this prospective study. After completion of the first recruitment phase involving 30 patients, the derivation cohort, an interim analysis was performed. Subsequently, the validation cohort (n = 30) was enrolled. All patients underwent electrical cardioversion 4–6 weeks prior to PVI. In case of AF recurrence, patients were again electrically cardioverted in the early morning at admission. Subsequently, a TTE (GE ultrasound system E95, M5Sc probe, GE Healthcare, Solingen, Germany) was performed in sinus rhythm in the late afternoon one day prior to PVI in all patients. The following day, high-density voltage maps were acquired in sinus rhythm using an endocardial contact mapping system (CARTO-3, Biosense Webster, Irvine, CA, USA) prior to PVI. All patients underwent follow-up visits 6 and 12 months after PVI to assess arrhythmia recurrence. The study was approved by the institutional ethics committee and all patients provided written informed consent prior to enrollment.

All but one patient underwent cardiac imaging prior to the ablation procedure, either by contrast-enhanced computed tomography (CT) scan or by noncontrast cardiac magnetic resonance (CMR) imaging as it is a standard at our institution. For CMR, a free-breathing, diaphragm-navigated, balanced steady-state free precession sequence with 3D reconstruction was performed to image the whole heart [7 (link)]. All preacquired 3D imaging data were processed to obtain individual 3D reconstructions of all cardiac chambers and vessels to be fused with the EAM 3D maps (POLARIS software, Biosense Webster, Brussels, Belgium).
The electroanatomical mapping system CARTO3 (Biosense Webster, Brussels, Belgium) was used in all but two procedures, which were performed with the Rhythmia (Boston Scientific, Marlborough, MA) 3D mapping system. For 3 procedures (#19, #28, and #41) in patients with complex congenital heart disease, the remote magnetic navigation system (NiobeII, Stereotaxis Inc., St. Louis, MS) was used in combination with CARTO [8 (link)].