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Background There have been an increasing number of atrial fibrillation (AF) patients with Watchman® left atrial appendage occlusion (LAAO) device, requiring catheter ablation (CA) for maintenance of normal sinus rhythm. In this study, we describe our experience with the feasibility and safety of CA in patients with a preexisting Watchman LAAO device. Methods This was a retrospective multicenter AF registry of 60 patients with Watchman® LAAO device who underwent CA for AF. Baseline clinical and procedural characteristics of the included subjects were retrieved from review of medical records and were analyzed. Results The mean age was 72.7±4.9 years and the mean CHADS2 score was 2.3±0.6. All patients had successful pulmonary vein isolation (PVI). The left atrial appendage (LAA) was electrically active in 34 (56%) while reentrant tachycardia and AF triggers were seen in 17 (28%) patients. Electrical isolation was attempted in these 17 patients with only 10 achieving complete LAA isolation. Repeat imaging showed new peri-device leaks in 30% (12/40) patients, while new significant peri-device leaks (≥5 mm) were noted in 10% (10/40) of patients after RFA, respectively, requiring continuation of oral anticoagulation. There were a higher proportion of patients with severe peri-device leaks (≥5 mm) after LAA isolation. However, >50% of those leaks sealed off on follow-up TEE. Conclusion AF ablation is a feasible and safe in patients with preexisting Watchman LAAO device. Electrical isolation of the LAA could be difficult and when attempted can result in increased risk of short-term peri device leak and recurrence of AT/AF in almost all patients. This article is protected by copyright. All rights reserved

Pleural Effusions After the Lariat Procedure Background The Lariat procedure is increasingly used for the exclusion of the left atrial appendage (LAA) in atrial fibrillation (AF) patients. There are anecdotal reports of pleural effusions after the Lariat procedure. However, the incidence, demographics, and pathophysiology of these effusions are largely unknown. Objective Characterization of pleural effusions in patients who underwent LAA exclusion using the Lariat procedure. Methods We report the incidence, demographics, and clinical and laboratory characteristics of patients from a multicenter prospective registry who underwent the Lariat procedure and subsequently developed pleural effusions. Results A total of 10 out of 310 (3.2%) patients developed significant pleural effusions after the Lariat procedure. The mean age of these patients was 67 ± 9, ranging from 52 to 78 years and included 5 (50%) males. Nine patients had persistent AF with median CHADS2 score of 2.7 ± 1.2. The LAA was successfully ligated in all these patients. Post-Lariat procedure, 6 patients developed bilateral and 4 patients developed left-sided pleural effusions. Pleural tap revealed transudative in 2 and exudative in 6 patients. The remaining 2 patients responded to active diuresis and behaved clinically like transudative effusions. There is a statistically significant difference between the onset of pleural effusion after the Lariat procedure between tPLE versus ePLE groups (14 ± 1.2 vs. 6 ± 6, P = 0.05). Conclusion Incidence of clinically significant pleural effusion is uncommon after the Lariat procedure and can be either exudative or transudative in nature depending on the underlying mechanisms. More prospective studies are needed to study the pathophysiologic basis of development of pleural effusions after the Lariat procedure.

AF Ablation in Pulmonary Vein Stumps Background Pulmonary vein isolation (PVI) of the remnant pulmonary vein (PV) stumps in pneumonectomy patients has not been well characterized. Methods This is a multicenter observational study of patients with a remnant PV stump after pneumonectomy. Consecutive patients with a history of pneumonectomy and who had undergone RF ablation for drug refractory AF were identified from the AF database at the participating institutions. Results There were 15 patients in whom pneumonectomy was performed, for resection of tumors in 10, infection in 4, and bullae in 1 patient and who underwent RF ablation for AF. The mean age was 63 ± 7 years. The stumps were from the right lower PV in 5, left upper PV in 5, left lower PV in 3, and right upper PV in 2 patients. All the PV stumps were electrically active with PV potentials and 9 (60%) of them had triggered activity. PVI was performed in 14 and focal isolation in 1 patient. At 1-year follow-up, 80% were free of AF, off of antiarrhythmic medications. Conclusion PV stumps in AF patients with previous pneumonectomy are electrically active and are frequently the sites of active firing. Isolation of these PV stumps can be accomplished safely and effectively using catheter ablation with no practical concern for PV stenosis or compromising PV stump integrity.

RF Ablation of VT in Chronic Cocaine Users Background Cocaine use is a known but rare cause of cardiac arrhythmias. Ventricular arrhythmias related to cocaine may not respond to antiarrhythmic drugs and may need treatment with radiofrequency ablation. Objectives We describe the clinical and electrophysiological characteristics of cocaine-related ventricular tachycardia (VT) from a multicenter registry. Methods Subjects presenting with VT related to cocaine use and being considered for radiofrequency ablation have been included in the study. Patients who were refractory to maximal medical therapy underwent radiofrequency ablation of the VT. Clinical, procedural variables, efficacy, and safety outcomes were assessed. Results A total of 14 subjects met study criteria (age 44 ± 13, range 18- to 68-year-old with 79% male, 71% Caucasian). MRI showed evidence of scar only in 43% of patients (6/14). The mechanism of VT was focal in 50% (n = 7) and scar related reentry in 50% (n = 7) based on 3D mapping. The mean VT cycle length was 429 ± 96 milliseconds. The site of origin was epicardial in 16% (3/18) of VTs. Most clinical VTs were hemodynamically stable (75%). Mean ejection fraction at the time of admission was 44 ± 14%. Duration of procedure was 289 ± 50 minutes. One subject developed pericardial tamponade requiring drainage. At 18 ± 11 months follow-up, freedom from arrhythmia was seen in 86% (1 case lost to follow-up and 2 died). Conclusion Radiofrequency ablation is not only feasible but also safe and effective in patients who have drug refractory VT related to chronic cocaine use. © 2014 Wiley Periodicals, Inc.

Fluctuation of impedance on defibrillator leads is highly suggestive of lead failure. A drop in impedance is associated with insulation defects while high impedance is suggestive of lead fracture. In this case report, we described a patient where electromagnetic interference from radiofrequency ablation near the site of superior vena cava coil caused the sensed impedance to fluctuate without uneventful outcomes and we discussed the possible mechanism. Both electromagnetic interference and defibrillator lead insulation defect can result in low threshold and inappropriate shocks. Sometimes electromagnetic interference may result in physical damage of the implanted system and may result in subsequent fluctuations in impedance. Awareness of electromagnetic interference that can cause fluctuating impedance without structural damage can help in making appropriate diagnosis and may avoid unnecessary procedures. (PACE 2012; 35:e163–e166)