Introduction: Some patients with cardiac implantable electronic devices (CIEDs) require atrial fibrillation (AF) ablation, and the superior vena cava (SVC) has been identified as one of the most common non-pulmonary vein foci of AF. This study aimed to investigate the interaction between SVC isolation (SVCI) and CIED leads implanted through the SVC. Methods and Results: We studied 34 patients with CIEDs who had undergone SVCI as part of AF ablation (CIED group), involving a total of 71 CIED leads. A similar number of age-, sex-, and AF type-matched patients without CIEDs formed a control group (non-CIED group). Patients’ background and procedural characteristics were compared between the groups. In the CIED group, lead parameters before and after AF ablation were compared, and lead failure after AF ablation was also examined in detail. Procedural characteristics other than fluoroscopic time were similar in both groups. The success rate of SVCI after the final ablation procedure was 91.2% in the CIED group and 100% in the non-CIED group; however, these differences were not statistically significant. Lead parameters before and after the AF ablation did not significantly differ between the 2 groups. Lead failure was observed in 3 patients, with a sensing noise in 1 patient and an impedance increase in 2 patients after SVCI. Conclusions: SVCI was achievable without lead failure and significant change in lead parameters in most patients with CIEDs; however, the 8.8% incidence of lead failure observed after SVCI should be noted.

Introduction: Acute pulmonary vein reconnection (PVR) is associated with longer procedure time and radiofrequency time during pulmonary vein isolation (PVI). However, determinants of acute PVR after high-power, short-duration PVI (HPSD-PVI) in the guidance with unipolar signal modification (USM) remain unclear. Methods and Results: We evaluated 62 patients (age, 62±12 y; 45 men) with paroxysmal atrial fibrillation undergoing USM-guided HPSD-PVI. A 50-W radiofrequency (RF) was applied for 3–5 s after unipolar signal modification. In the segments adjacent to the esophagus (SAE), RF time was limited to 5 s. Each circle was subdivided into 12 segments. For each radiofrequency tag within the circle, possible predictors of acute PVR, including minimum contact force, minimum force-time integral, minimum ablation index (AImin), minimum impedance drop (Imp-min), and maximum inter-lesion distance (ILDmax) were assessed. Acute PVR was observed in 43 (7%) SAE and 21 (17%) other segments (p = 0.001). RF energy, RF application time and bilateral isolation time were 28±8 kJ, 10±3 min, and 27±11 min, respectively. Imp-min and ILDmax had the highest area under the curve (0.69 and 0.68) and of all indices, and were the sole independent predictors of acute PVR in segments other than the SAE and SAE, respectively, after adjusting for other cofounders (odds ratio [OR]: 0.90 [0.85–0.95], p = 0.0003; and OR: 1.39 [1.11–1.74], p=0.005). Conclusions: In HPSD-PVI, a non-negligible amount of acute PVR was still observed, which was possibly dealt with an optimal target value of impedance drop and lesion distance.