Faculty Bibliography

OBJECTIVES/OBJECTIVE:This study aimed to evaluate the cumulative effect of treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) on atrial fibrillation (AF) recurrence. BACKGROUND:OSA is a known predictor for onset and recurrence of AF. The effect of treatment with CPAP on AF recurrence has been evaluated in small studies with varied outcomes. METHODS:We searched MEDLINE, EMBASE, CINAHL, Google Scholar, Cochrane Database of Systematic Reviews, and Cochrane Trials Register for relevant studies. Evaluation of AF recurrence in CPAP users and nonusers in patients with OSA was the primary outcome evaluated in this study. The secondary outcome was evaluation of AF recurrence in CPAP users and nonusers after pulmonary vein isolation (PVI). RESULTS: = 0%). The beneficial effect of CPAP use was statistically significant in both groups of patients: those who underwent catheter ablation with PVI and those who did not undergo ablation and were managed medically. No other study covariates had any significant association with these outcomes of AF reduction. CONCLUSIONS:The use of CPAP is associated with significant reduction in recurrence of AF in patients with OSA. This effect remains consistent and similar across patient populations irrespective of whether they undergo PVI.

SCN5A encodes the alpha subunit of the major cardiac sodium channel NaV1.5. Mutations in SCN5A are associated with conduction disease and ventricular fibrillation (VF); however, the mechanisms that link loss of sodium channel function to arrhythmic instability remain unresolved. Here, we generated a large-animal model of a human cardiac sodium channelopathy in pigs, which have cardiac structure and function similar to humans, to better define the arrhythmic substrate. We introduced a nonsense mutation originally identified in a child with Brugada syndrome into the orthologous position (E558X) in the pig SCN5A gene. SCN5AE558X/+ pigs exhibited conduction abnormalities in the absence of cardiac structural defects. Sudden cardiac death was not observed in young pigs; however, Langendorff-perfused SCN5AE558X/+ hearts had an increased propensity for pacing-induced or spontaneous VF initiated by short-coupled ventricular premature beats. Optical mapping during VF showed that activity often began as an organized focal source or broad wavefront on the right ventricular (RV) free wall. Together, the results from this study demonstrate that the SCN5AE558X/+ pig model accurately phenocopies many aspects of human cardiac sodium channelopathy, including conduction slowing and increased susceptibility to ventricular arrhythmias.

New devices designed for minimally invasive closure of the left atrial appendage (LAA) may be a viable alternative for patients in whom anticoagulation is considered high risk. The Lariat (Sentreheart, Redwood City, CA), which is currently FDA-approved for percutaneous closure of tissue, requires both trans-septal puncture and epicardial access. However it requires no anticoagulation after the procedure. Here we describe a case of effusion and tamponade during a Lariat procedure with successful completion of the case and resolution of the effusion.

PURPOSE: Transesophageal echocardiography (TEE) is routinely used to assess for thrombus in the left atrium (LA) and left atrial appendage (LAA) in patients undergoing atrial fibrillation (AF) ablation. However, little is known about the outcome of AF ablation in patients with documented LAA sludge. We hypothesize that AF ablation can be performed safely in a proportion of patients with sludge in the LAA and may have a significant benefit for these patients. METHODS: We performed a retrospective analysis of all patients undergoing AF ablation at New York University Langone Medical Center (NYULMC) from January 1st 2011 to June 30, 2013. Patients with sludge found on their TEE immediately prior to AF ablation were identified and followed for stroke, AF recurrence, procedural complications, major bleeding, or death. RESULTS: Among 1,076 patients who underwent AF ablation, 8 patients (mean age 69 +/- 13 years; 75 % men) with sludge were identified. Patients with sludge in their LAA had no incidence of early or late occurrence of stroke during mean follow-up of 10 months. One patient had a left groin hematoma, and two patients had atrial tachycardias that needed a repeat ablation. TEE at the time of repeat ablation demonstrated the presence of spontaneous echo contrast (smoke) and resolution of sludge. There were no deaths. CONCLUSION: In a cohort of eight patients with LAA sludge who underwent AF ablation, no significant thromboembolic events occurred during or after the procedure. AF ablation can be performed safely and may be beneficial in these patients. Larger studies are warranted to better determine the most appropriate management route.

BACKGROUND: Venous occlusion is not uncommon and total venous obstruction with more proximal patency may occur in as many as 10% of previous implants. Many techniques are available to obtain ipsilateral access; however, most require special equipment or skills. We describe a technique of infraclavicular cannulation of the brachiocephalic vein ipsilateral to the occlusion that is safe and feasible for most implanters. METHODS: Fourteen patients with subclavian/axillary occlusions ipsilateral to the implanted device and requiring revision or upgrade of their system or venous occlusion with contraindication to implant on the contralateral side underwent lead addition/placement via a brachiocephalic approach. Following venography, an 18-gauge needle was used to gain brachiocephalic access. The needle was initially positioned in a lateral infraclavicular location. The needle was then advanced under the clavicle in a horizontal plane and advanced toward the sternal notch under fluoroscopic guidance. RESULTS: Fourteen patients underwent an attempt at brachiocephalic access. Cannulation of the brachiocephalic was possible in all 14 and lead(s) were successfully implanted in all. There were no complications with the procedure, specifically no pneumothoraces. In follow-up (mean 36 months, range 1-86 months), all implanted leads function well, with no evidence of lead failure or impedance changes. CONCLUSION: A lateral infraclavicular approach is a safe and effective technique for obtaining brachiocephalic access when the subclavian/axillary vein is occluded. This technique is easy to learn and may be useful for implanters without the equipment or skills needed for lead extraction or microdissection or in cases where patients refuse these procedures.

Atrial fibrillation (AF), the most common cardiac arrhythmia, is a significant cause of embolic stroke. Although systemic anticoagulation is the primary strategy for preventing the thromboembolic complications of AF, anticoagulants carry major bleeding risks, and many patients have contraindications to their use. Because thromboembolism typically arises from a clot in the left atrial appendage (LAA), local therapeutic alternatives to systemic anticoagulation involving surgical or percutaneous exclusion of the LAA have been developed. Surgical exclusion of the LAA is typically performed only as an adjunct to other cardiac surgeries, thus limiting the number of eligible patients. Furthermore, surgical exclusion of the LAA is frequently incomplete, and thromboembolism may still occur. Percutaneous LAA exclusion includes two approaches: transseptal delivery of an occlusion device to the LAA and epicardial suture ligation of the LAA, the LARIAT procedure. In the LARIAT procedure, a pretied snare is placed around the epicardial surface of the LAA orifice via pericardial access. Proper snare placement is achieved with epicardial and endocardial magnet-tipped guidewires. The endocardial wire is advanced transvenously to the LAA apex after transseptal puncture. The epicardial wire, introduced into the pericardial space, achieves end-to-end union with the endocardial wire at the LAA apex. The snare is then placed over the LAA, tightened, and sutured. On the basis of early clinical experience, the LARIAT procedure has a high success rate of LAA exclusion with low risk for complications. The authors describe the indispensable role of real-time transesophageal echocardiography in the guidance of LAA epicardial suture ligation with the LARIAT device.

BACKGROUND: Data on relative safety, efficacy, and role of different percutaneous left ventricular assist devices for hemodynamic support during the ventricular tachycardia (VT) ablation procedure are limited. METHODS AND RESULTS: We performed a multicenter, observational study from a prospective registry including all consecutive patients (N=66) undergoing VT ablation with a percutaneous left ventricular assist devices in 6 centers in the United States. Patients with intra-aortic balloon pump (IABP group; N=22) were compared with patients with either an Impella or a TandemHeart device (non-IABP group; N=44). There were no significant differences in the baseline characteristics between both the groups. In non-IABP group (1) more patients could undergo entrainment/activation mapping (82% versus 59%; P=0.046), (2) more number of unstable VTs could be mapped and ablated per patient (1.05+/-0.78 versus 0.32+/-0.48; P<0.001), (3) more number of VTs could be terminated by ablation (1.59+/-1.0 versus 0.91+/-0.81; P=0.007), and (4) fewer VTs were terminated with rescue shocks (1.9+/-2.2 versus 3.0+/-1.5; P=0.049) when compared with IABP group. Complications of the procedure trended to be more in the non-IABP group when compared with those in the IABP group (32% versus 14%; P=0.143). Intermediate term outcomes (mortality and VT recurrence) during 12+/-5-month follow-up were not different between both groups. Left ventricular ejection fraction