Focal Left Atrial Tachycardias Not Associated with Prior Catheter Ablation for Atrial Fibrillation: Clinical and Electrophysiological Characteristics ANGELO B. BIVIANO, M.D.,* WILLIAM BAIN, B.A., WILLIAM WHANG, M.D.,* JOSHUA LEITNER, M.D.,† JOS ´ E DIZON, M.D.,* KATHLEEN HICKEY, A.P.R.N., ED.D.,* and HASAN GARAN, M.D.* From the *Departments of Medicine, Cardiology Divisions, Columbia University College of Physicians and Surgeons, New York, New York; and †Warren Alpert Medical School of Brown University, Providence, Rhode Island Background: The clinical features and electrophysiological characteristics of patients with focal left atrial tachycardias (LATs) are not well characterized. This study reports the experience of a single center in catheter mapping and radiofrequency ablation of focal LAT not associated with prior atrial fibrillation (AF) ablation, including in cardiac sarcoidosis and transplant patients. Methods: Patients with focal LAT without a history of AF ablation were included in this retrospective analysis. Results: A total of 24 focal LATs were documented in 20 patients. Two patients were subsequently diagnosed with cardiac sarcoidosis. Two patients were status post a thoracic transplant. The mean initial cycle length of the focal LATs was 347.4 ± 96.2 ms (range 190–510 ms). Patients with a pulmonary vein (PV) ostium focus (n = 6) demonstrated a shorter cycle length than patients with other LA foci (259.2 ± 56.4 ms vs 371.9 ± 91.1 ms, P = 0.02), as well as a trend for a history of AF (67% vs 21%, P = NS). Catheter ablation was immediately successful for 19 of 22 focal LATs. Conclusions: Focal LATs not associated with prior AF ablation can originate in a variety of LA locations and clinical settings. Focal LAT arising in the PV ostia is associated with a history of AF and demonstrates a faster tachycardia rate. We also report focal LAT in cardiac sarcoidosis patients and in the donor heart of an orthotopic heart transplant recipient. Radiofrequency ablation is a successful treatment for focal LAT not associated with prior ablation, including those refractory to medical therapy. (PACE 2012; 35:17–27) focal left atrial tachycardia, catheter ablation, transplant , sarcoidosis Introduction Focal atrial tachycardias (ATs) form a small subset of supraventricular tachycardias (SVT), arising not only in patients who have un- dergone cardiac interventions such as catheter ablations, congenital cardiac defect repairs, or valve replacements, but also in patients free of structural heart disease. 1,2 Morbidities associated with AT include symptoms such as palpitations, but also tachycardia-mediated cardiomyopathy and a potential to cause atrial fibrillation (AF). 3,4 Targeted radiofrequency (RF) catheter ablation is generally recognized as an effective therapy for focal AT. 2 Focal tachycardias originating in the left atrium (LAT) form a small subset of all ATs, Financial Support: WB was supported by a 2009 NIH Summer Research Fellowship. Address for reprints: Angelo Biviano, M.D., M.P.H., Columbia University Medical Center, 177 Fort Washington Avenue, Milstein 5-435F, New York, NY 10032. Fax: 212-342-3591; e-mail: ab542@columbia.edu Received March 9, 2011; revised July 3, 2011; accepted August 1, 2011. doi: 10.1111/j.1540-8159.2011.03227.x reportedly constituting 9% to 37% of all focal AT. 5,6 While a few reports detail the anatomic distribution of focal LAT, 7,8 characteristics of patients with focal LAT, particularly LAT not associated with prior catheter ablations for AF, are not well characterized. 9 This study reports the clinical features and electrophysiological characteristics of focal LATs not associated with prior AF ablation, including reports of focal LAT in two cardiac sarcoidosis patients and in the donor heart of a patient who had undergone cardiac transplantation. Methods Patient Population This is a retrospective study of all patients without prior AF ablation diagnosed with focal left AT during a cardiac electrophysiology (EP) study in the Columbia University Medical Center Electrophysiology Laboratory between September 2001 and May 2009. These patients were referred to our center for EP study and catheter ablation of clinically documented symptomatic AT. Patients underwent an initial evaluation that included history, physical examination, electrocardiogram (ECG), and echocardiogram. C 2011, The Authors. Journal compilation C 2011 Wiley Periodicals, Inc. PACE, Vol. 35 January 2012 17