Exclusion of electrical and mechanical function of the left atrial appendage in patients with persistent atrial fibrillation: differences in efficacy and safety between endocardial ablation vs epicardial LARIAT ligation (the EXCLUDE LAA study).

BACKGROUND: Electrical isolation of the left atrial appendage (LAA) may provide incremental benefits for arrhythmia management in patients undergoing radiofrequency ablation (RFA) for persistent atrial fibrillation (AF). OBJECTIVE: The aim of this study was to compare efficacy and safety of endocardial ablation and LAA exclusion with LARIAT device for electrical and mechanical exclusion of LAA. METHODS: We compared patients who underwent endocardial LAA isolation during index RFA for persistent AF and underwent a repeat RFA to patients who underwent LAA exclusion with LARIAT device followed by RFA for AF in this multicenter registry. Efficacy of electrical and mechanical isolation of LAA was assessed. RESULTS: We included 182 patients of which 91 patients underwent endocardial LAA isolation during RFA for AF, and 91 patients underwent LAA exclusion with LARIAT device followed by RFA for AF. Baseline characteristics were similar except for higher CHA2DS2-VASc score, coronary artery disease, and prior stroke rate in LARIAT arm. Persistence of electrical isolation (measured at beginning of second procedure) after LARIAT procedure was higher than one-time AF-RFA (96.7% vs 52.8%, p < 0.01). Acute pulmonary vein isolation rates were similar in both arms. AF recurrence rate after second isolation attempts at 1 year was similar in both arms. No difference in major complications was noted between both arms. CONCLUSIONS: LAA exclusion with LARIAT device appears to be more efficacious as compared to one-time endocardial ablation, but not compared to repeat isolation, in achieving complete electrical isolation of LAA for persistent AF.

Myocarditis Causing Premature Ventricular Contractions: Insights From the MAVERIC Registry.

BACKGROUND: Premature ventricular contractions are a common clinical presentation that drives further diagnostic workup. We hypothesize the presence of underlying inflammation is often unrecognized in these patients with a potential for continued disease progression if not diagnosed and treated early in the disease course. METHODS: This is a single-center, prospective study including 107 patients with frequent symptomatic premature ventricular contractions (>5000/24 h) and no known ischemic heart disease. Patients underwent a combination of laboratory testing, 18F-fluorodeoxyglucose positron emission tomography scan, cardiac magnetic resonance imaging, and biopsy. Patients were diagnosed with myocarditis based on a multidisciplinary approach and treated with immunosuppressive therapy. RESULTS: The mean age of the cohort was 57±15 years, 41% were males, and left ventricular ejection fraction was 47±11.8%. Positive positron emission tomography scan was seen in 51% (55/107), of which 51% (28/55) had preserved left ventricle function. Based on clinical profile, 18F-fluorodeoxyglucose-positron emission tomography imaging, cardiac magnetic resonance, and histological data 58% patients (32/55) received immunosuppressive therapy alone and 25.4% (14/55) received immunosuppressive therapy and catheter ablation. Optimal response was seen in 67% (31/46) over a mean follow-up of 6±3 months. In patients with left ventricle systolic dysfunction, 37% (10/27) showed an improvement in mean left ventricular ejection fraction of 13±6%. CONCLUSIONS: Approximately 51% of patients presenting with frequent premature ventricular contractions have underlying myocardial inflammation in this cohort. 18F-fluorodeoxyglucose-positron emission tomography scan can be a useful modality for early diagnosis and treatment with immunosuppressive therapy in selected patients can improve clinical outcomes.

Safety of rapid switching from amiodarone to dofetilide in atrial fibrillation patients with an implantable cardioverter-defibrillator.

BACKGROUND: Dofetilide is a class III antiarrhythmic drug commonly used for treatment of atrial fibrillation. Drug guidelines mandate a 3-month waiting period before initiating dofetilide after amiodarone use. Whether patients with an implantable cardioverter-defibrillator (ICD) can be rapidly switched from amiodarone to dofetilide is not known. OBJECTIVE: The purpose of this study was to evaluate whether rapid switching from amiodarone to dofetilide is safe in atrial fibrillation patients with an ICD. METHODS: In this retrospective observational study, we assessed the feasibility and the short- and long-term safety of rapid switching from amiodarone to dofetilide in hospitalized atrial fibrillation with an ICD. RESULTS: The study included a total of 179 patients who were followed for 12.6 ± 2.2 months. All patients had drug initiation during hospitalization. Dofetilide resulted in successful cardioversion in 66% (118/179). Twenty percent of patients (36/179) required dofetilide dose adjustments in the initiation phase because of QT prolongation and decreased creatinine clearance. A total of 6.1% of patients (11/179) required drug discontinuation. The incidence of torsades de pointes was 1.1% (2/179) during initiation. One patient (0.5%) had self-terminating ventricular tachycardia at follow-up. No other significant adverse events were noted during follow-up. CONCLUSION: Atrial fibrillation patients with an ICD can be rapidly switched to dofetilide after 7 days of discontinuation of amiodarone without significant arrhythmia-related complications. Prospective studies with large sample sizes, especially of women, should be performed to further validate these findings.