Faculty Bibliography

Introduction: LA ablation for persistent AF that achieves organization to atrial tachycardia (AT) or sinus rhythm (SR) predicts greater long term ablation success. However, extensive LA ablation increases the risks of recurrent AT, adverse atrial remodeling and procedural complications. Preclinical and observational studies suggest that right atrial ablation may reduce AF risk. We hypothesized that CTI ablation may reduce the extent of LA ablation required to achieve organization of persistent AF. Methods: Persistent AF patients (n=107) were randomized to two arms (CTI-first or CTI-last) in a single center, prospective, single blind study. Excluding the CTI ablation, stepwise linear LA ablation was performed in a prespecified order. The primary endpoint was the percentage of patients who organized to AT or SR. The secondary endpoint was number of steps to organization. Results: CTI ablation first versus last during AF ablation did not significantly alter the percentage of patients who organized (Table). Among those who organized, the number of steps to organization did not differ between the two arms. No significant differences were found when patients were stratified by LA size or AF duration. Conclusions: CTI ablation does not alter the extent of LA ablation needed to achieve organization of AF. The utility of right atrial ablation for persistent AF ablation remains unclear. (Table presented)

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

Congenital absence of left atrial appendage (LAA) is an extremely rare condition and its physiological consequences are unknown. We present two cases of incidental finding of a congenitally absent LAA in a 79-year-old male who presented for routine transesophageal echocardiogram (TEE) to rule out intracardiac thrombus prior to placement of biventricular implantable cardioverter-defibrillator and a 54-year old female who presented for TEE prior to radiofrequency ablation of atrial fibrillation. Characterization of patients with such an absence is important because congenitally absent LAA may be confused with flush thrombotic occlusion of the appendage. There are very few published reports of congenital absence of LAA. To our knowledge, our report is the first to demonstrate the congenital absence of LAA by 3D transesophageal echocardiography.

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.