The LSI can be used to predict gaps/DC during the PVI procedure. An LSI of 5.2 may be a suitable target for effective lesion formation. An LSI of 4.0 may be acceptable in the posterior wall, especially in areas adjacent to the esophagus.

Compared to conscious sedation (CS), the use of general anesthesia (GA) in pulmonary vein isolation (PVI) is associated with a lower recurrence rate of atrial fibrillation (AF). GA may improve catheter stability and mapping system accuracy compared to CS, but its influence on contact force (CF) parameters during ipsilateral PVI has not previously been investigated. The study population comprised 176 consecutive patients (107 in GA group and 69 in CS group) with AF who underwent their first PVI procedure. We retrospectively assessed CF parameters, force-time integral (FTI), FTI/wall thickness during anatomical ipsilateral PVI and long-term outcome after ablation. Complete PVI with single continuous circular lesions around the ipsilateral PVs was achieved in 54 patients (50.5%) in the GA group but only 24 patients (34.8%) in the CS group (P = 0.04). The distribution of gaps did not differ between the groups. All CF parameters were significantly higher in the GA group than in the CS group (average CF: 19.4 ± 8.7 vs. 16.7 ± 7.7 g, P < 0.0001; FTI: 399.0 ± 262.5 vs. 293.9 ± 193.4 gs, P < 0.0001; FTI/wall thickness: 155.5 ± 106.1 vs. 115.7 ± 85.5 gs, P < 0.0001). GA was associated with lower AF recurrence rate in patients with paroxysmal AF but not with persistent AF. Compared with CS, GA improves CF parameters, FTI and FTI/wall thickness, and reduced gap formation after ipsilateral PVI.

Background--Low contact force and force-time integral (FTI) during catheter ablation are associated with ineffective lesion formation, whereas excessively high contact force and FTI may increase the risk of complications. We sought to evaluate the optimal FTI for pulmonary vein (PV) isolation based on atrial wall thickness under the ablation line.

Introduction Pulmonary vein isolation (PVI) affects the ganglionated plexi (GP) around the atrium leading to a modification of intrinsic cardiac autonomic system (ANS). In animal models, GP ablation has the potential risk of QT prolongation and ventricular arrhythmias. However, the impact of PVI on QT intervals in human remains unclear. Methods and Results We analyzed electrocardiograms of 117 consecutive patients with paroxysmal atrial fibrillation (AF) who underwent their first PVI procedures and maintained sinus rhythm without antiarrhythmic drugs at all evaluation points (4 h, 1 day, 1 month, and 3 months after PVI). Heart rate significantly increased at 4 h, 1 day, and 1 month. Raw QT interval prolonged at 4 h (417.1 ± 41.6 ms, p < .001) but shortened at 1 day (376.4 ± 34.1 ms, p < .001), 1 month (382.2 ± 31.5 ms, p < 0.001), and 3 months (385.1 ± 32.8 ms, p < 0.001) compared with baseline (391.6 ± 31.4 ms). Bazett‐corrected QTc intervals were significantly prolonged at 4 h (430.8 ± 27.9 ms, p < .001), 1 day (434.8 ± 22.3 ms, p < .001), 1 month (434.8 ± 22.3 ms, p < .001), and 3 months (420.1 ± 21.8 ms, p < .001) compared with baseline (404.9 ± 25.2 ms). Framingham‐corrected QTc intervals significantly prolonged at 4 h (424.1 ± 26.6 ms, p < .001) and 1 day (412.3 ± 29.3 ms, p < .01) compared with baseline (399.2 ± 22.7 ms). Multiple regression analysis revealed that female sex is a significant predictor of raw QT and QTc interval increase at 4 h after PVI. Conclusion Raw QT and QTc were prolonged after PVI, especially in the acute phase. Female sex is a risk factor for QT increase.

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Introduction: Optimal radiofrequency-generated thermal energy applications have not been established for hot balloon ablation (HBA) systems. We investigated the feasibility of real-time monitoring of pulmonary vein (PV) potentials and optimal timeto-isolation (TTI)-guided application strategies in HBAs. Methods and Results:Real-time monitoring of PV potentials was performed using a four-electrode unidirectional catheter in 34 consecutive patients. Acute isolation was achieved when PV potentials disappeared during HBAs and were undetected by highresolution mapping. The TTI, the difference between TTI and the time to reach target temperature (TTRT), and ablation time after isolation were examined for 177 applications in 136 PVs. Real-time monitoring of PV activity was obtained in 167 out of 177 applications (94.3%) and acute isolation was achieved in 97 out of 177 (54.8%) applications. TTI-TTRT was significantly shorter, and ablation times after isolation were significantly longer in the acute isolation group than in the other groups.TTI-TTRT <4.5 seconds and TTIs <33.5 seconds predicted acute isolation (sensitivity 74.2%, specificity 88.4%; sensitivity 76.3%, specificity 76.7%, respectively). Ablation time after isolation >148.5 seconds (sensitivity 93.6%, specificity 51.7%) and >120.5 seconds (sensitivity 84.0%, specificity 78.6%) predicted acute isolation in superior PVs and inferior PVs, respectively. Conclusions:Real-time assessment of PV isolation can be achieved during HBAs with single-shot techniques. (TTI-TTRT)s <4.5 seconds and TTIs <33.5 seconds predicted for acute isolation. Ablation time after isolation >148.5 seconds in superior PVs and >120.5 seconds in inferior PVs were effective application durations. K E Y W O R D S application duration, hot balloon ablation, real-time pulmonary vein monitoring, time to isolation

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