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An 80‐year‐old man underwent catheter ablation for atrial tachycardia (AT), which developed after catheter ablation for atrial fibrillation. The AT was diagnosed as dual‐loop tachycardia, which included peri‐mitral and roof‐dependent ATs. An ethanol infusion into the vein of Marshall resulted in left phrenic nerve paralysis. During the procedure, the phrenic nerve paralysis was completely relieved. [ABSTRACT FROM AUTHOR]

A 77‐year‐old man underwent catheter ablation of an atrial tachycardia (AT) after a pulmonary vein (PV) isolation of atrial fibrillation. The AT appeared to be a figure‐of‐eight reentrant AT by high‐resolution mapping: one reentrant circuit rotated clockwise within the right PV (RPV) carina and the other rotated counterclockwise via two conduction gaps along the previous RPV isolation line. However, entrainment pacing from the carina and conduction gaps suggested that the AT was an intra‐carina localized reentrant AT with a passive loop around the anterior RPV isolation line via those gaps. A radiofrequency application at the RPV carina terminated the AT. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the impact of the size of the isolated surface area and non-ablated left atrial posterior area after extensive encircling pulmonary vein isolation (EEPVI) for non-paroxysmal atrial fibrillation (AF) on arrhythmia recurrence. This study included 132 consecutive persistent AF patients who underwent EEPVI guided by Ablation Index (AI). The isolated antral surface area (IASA) excluding the pulmonary veins, the non-ablated left atrial (LA) posterior wall surface area (PWSA), the ratio of IASA to LA surface area (IASA/LA ratio), and the ratio of PWSA to LA surface area (PWSA/LA ratio) were assessed using CARTO3 and the association with AF and atrial tachycardia (AT) recurrence was examined. At a mean follow-up of 13.2 ± 7.3 months, sinus rhythm was maintained in 115 (87%) patients. In the univariate Cox regression analysis, the factors that significantly predicted AT/AF recurrence were a history of heart failure, a higher CHA2DS2-VASc score, a larger LA diameter, and a larger PWSA/LA ratio. Multivariate Cox regression analysis revealed that the independent predictors of AT/AF recurrence were LA diameter [hazard ratio (HR) 1.120 per 1 mm increase; 95% confidence interval (CI) 1.006–1.247; P = 0.039] and PWSA/LA ratio (HR 1.218 per 1% increase; 95% CI 1.041–1.425; P = 0.014). Receiver operating characteristics curve analysis yielded an optimal cut-off value of 8% for the PWSA/LA ratio. The Kaplan–Meier survival curve showed that patients with a larger PWSA/LA ratio had poorer clinical outcomes (Log-rank P = 0.001). A larger PWSA/LA ratio was associated with a high AT/AF recurrence rate in patients with non-paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Introduction: Local impedance (LI) drops during radiofrequency ablation can predict lesion formation. Some conduction gaps during pulmonary vein isolation (PVI) can be associated with nonendocardial connections. This study aimed to investigate the incidence, characteristics, and predictors of endocardial and nonendocardial conduction gaps during an LI‐guided PVI. Methods and Results: We prospectively enrolled 157 consecutive patients undergoing an initial LI‐guided extensive PVI of atrial fibrillation (AF). After the first‐pass encirclement, the residual conduction gaps and reconnected gaps were mapped using Rhythmia (Boston Scientific) and a mini‐basket catheter. Right and left PV (RPV/LPV) gaps were observed in 22.3% and 18.5% of the patients, respectively: 27 endocardial and 49 nonendocardial gaps. The carina regions were common sites for the gaps (51 carina‐related vs. 25 noncarina‐related). The carina‐related gaps consisted of more nonendocardial gaps than endocardial gaps (RPVs: 90.0% vs. 10.0%, p =.001; LPVs: 76.2% vs. 23.8%, p <.001). A univariate analysis revealed that paroxysmal AF and the left atrial (LA) volume index for RPV endocardial gaps (odds ratio [OR]: 8.640 and 0.946; p =.043 and 0.009), minor right inferior PV diameter for RPV nonendocardial gaps (OR: 1.165; p =.028), and major left inferior PV diameter for LPV endocardial gaps (OR: 1.233; p =.028) were significant predictors. Conclusions: During the LI‐guided PVI, approximately two‐thirds of the conduction gaps were nonendocardial. The carina regions had more conduction gaps than noncarina regions, which was due to the presence of nonendocardial connections. Paroxysmal AF, a lower LA volume index, and larger inferior PV diameters may increase the risk of conduction gaps. [ABSTRACT FROM AUTHOR]