Faculty Bibliography

Introduction: Large clinical trials have recently demonstrated stepwise linear ablation for non-paroxysmal atrial fibrillation (NPAF) to be inferior to pulmonary vein isolation alone. It is unknown whether the unfavorable outcomes observed in these trials can be attributed to the pro-arrhythmic effects of incomplete ablation lines. We hypothesized that improved lesion quality related to use of contact-force sensing (CFS) ablation catheters would improve procedural outcomes. Methods: We prospectively analyzed procedural outcomes of 74 consecutive patients with NPAF undergoing first-time radiofrequency catheter ablation with a CFS catheter (Smart Touch, Biosense Webster) using a step-wise approach (Group 1). The clinical outcomes of these patients were compared with 74 consecutive patients with NPAF who underwent catheter ablation between September 2013 and June 2014 with a non-contact force sense radiofrequency ablation catheter (Group 2) at a single tertiary care medical center. Arrhythmia recurrence was assessed using 2-week event monitors at 3-month intervals following index ablation. Results: Baseline characteristics of Group 1 and Group 2 were similar, although in Group 1 there was a greater prevalence of patients with persistent NPAF lasting for 6-months or longer prior to initial ablation (43% vs 21%, p=0.071). The recurrence rate at 1 year as estimated by the Kaplan-Meier method was not significantly different between Group 1 and Group 2 (25.7% vs 29.7%, p=0.582). The presenting recurrent arrhythmia was most frequently atrial tachycardia (AT) in both groups (Group 1: n=19, AT 68.4% and AF 31.6% vs Group 2: n=22, AT 59.1% and AF 40.9%). A similar proportion of patients in both groups underwent repeat ablation (Group 1: 17.6% vs Group 2: 13.5%, p=0.496). Conclusions: Utilization of a CFS ablation catheter was not associated with improved clinical outcomes for stepwise catheter ablation for NPAF. The optimal strategy for NPAF ablation using a contact-force sensing catheter remains undefined

Introduction: Transcatheter aortic valve replacement (TAVR) is becoming a widely accepted alternative treatment for patients with symptomatic aortic stenosis who are at high risk for surgical aortic valve replacement. A common complication of the procedure is the development of conduction defects requiring permanent pacemaker (PPM) implantation. It has been noted that in some patients, the conduction block is not permanent. Determine the incidence and predictors of resuming intrinsic conduction in patients that receive PPM implantation after TAVR. Methods: A retrospective chart review of patients undergoing TAVR at New York University Langone Medical Center was undertaken. Extracted data included patient demographics, pre-TAVR electrocardiogram, procedural, echocardiographic, catheterization, and device interrogation data. Evaluation of device interrogations done at one month follow-up or earlier to look for resumption of intrinsic conduction. Results: There were a total number of 451 patients who were status-post TAVR in our registry at NYU. Of the 451, 45 patients received a permanent pacemaker placement for complete heart block; 9.9% 45/451. The majority of patients were implanted within 48hrs post TAVR. Device follow-up information at 1 month or earlier was available for 33 of the 45 patients who received PPM. 5 patients who were recently implanted are still pending follow-up. 3 patients expired after implantation and 4 were lost to follow-up. Of the 33 patients, 14 (42%) patients had resumption of AV nodal conduction at 1 month follow-up. 19 patients (57%) remained dependent. Conclusions: 42% of patients who received a permanent pacemaker for complete heart block after TAVR had resumption of conduction. This suggests that many patients may not require long term PPM post TAVR. Patients that remained dependent had a higher incidence of preexisting RBBB and LAFB, however a lack thereof does not preclude an increased risk. These data suggest that waiting longer than 48 hours for resumption of AV nodal conduction would avoid unnecessary implantation in patients who develop complete heart block post TAVR

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: Spinal cord stimulation (SCS) has been shown to modulate atrial electrophysiology and confer protection against ischemia and ventricular arrhythmias in animal models. OBJECTIVE: To determine whether SCS reduces the susceptibility to atrial fibrillation (AF) induced by tachypacing (TP). METHODS: In 21 canines, upper thoracic SCS systems and custom cardiac pacing systems were implanted. Right atrial and left atrial effective refractory periods were measured at baseline and after 15 minutes of SCS. Following recovery in a subset of canines, pacemakers were turned on to induce AF by alternately delivering TP and searching for AF. Canines were randomized to no SCS therapy (CTL) or intermittent SCS therapy on the initiation of TP (EARLY) or after 8 weeks of TP (LATE). AF burden (percent AF relative to total sense time) and AF inducibility (percentage of TP periods resulting in AF) were monitored weekly. After 15 weeks, echocardiography and histology were performed. RESULTS: Effective refractory periods increased by 21 +/- 14 ms (P = .001) in the left atrium and 29 +/- 12 ms (P = .002) in the right atrium after acute SCS. AF burden was reduced for 11 weeks in EARLY compared with CTL (P <.05) animals. AF inducibility remained lower by week 15 in EARLY compared with CTL animals (32% +/- 10% vs 91% +/- 6%; P <.05). AF burden and inducibility were not significantly different between LATE and CTL animals. There were no structural differences among any groups. CONCLUSIONS: SCS prolonged atrial effective refractory periods and reduced AF burden and inducibility in a canine AF model induced by TP. These data suggest that SCS may represent a treatment option for AF.