756 Routine Transthoracic Echocardiography to Assess Pericardial Collections in Patients After Extensive Left Atrial Catheter Ablation: A Prospective Study MANISH KALLA, M.R.C.P., KIM RAJAPPAN, M.D., M.R.C.P., SUNDEEP KALRA, M.R.C.P., GLYN THOMAS, Ph.D., M.R.C.P., CALUM REDPATH, M.R.C.P., MARK J. EARLEY, M.R.C.P., SIMON C. SPORTON, M.D., M.R.C.P., and RICHARD J. SCHILLING, M.D., F.R.C.P. From the Department of Cardiology, St Bartholomew’s Hospital and Queen Mary College, University of London, London, UK. TTE after AF Ablation. Introduction: Little is known about the incidence and timing of reactive pericardial collections developing after left atrial catheter ablation (LACA), and when and if transthoracic echocardiography (TTE) should be performed routinely in these patients postprocedure. Methods and Results: Two hundred consecutive LACA patients for persistent atrial fibrillation (AF) (107), paroxysmal AF (75) or atrial tachycardia (AT) (18) underwent on-table TTE at the end of the procedure, and the next day prior to discharge. One patient developed tamponade at the time of transseptal puncture. Thirty-three percent of the remaining 199 who underwent on-table TTE, had a pericardial collection. On next day TTE, there were significantly more pericardial collections (53%, P < 0.0001). Persistent rather than paroxysmal arrhythmia at the time of the procedure was the only predictor of a pericardial collection, either on-table (χ 2 = 9.64; P = 0.002) or next day (χ 2 = 5.95; P = 0.02). Eight patients had collections on next day TTE ≥ 1.5 cm. One needed drainage because of clinical tamponade. Repeated TTEs in the other 7 patients demonstrated resolution of collections over 1–2 weeks. Conclusion: Pericardial collections are common in LACA patients. Almost all are not associated with clinical compromise. The only predictor of collection size is arrhythmia type at ablation, which may correspond to ablation at sites specific to persistent rather than paroxysmal arrhythmias. Performing on-table TTE routinely may help guide immediate anticoagulation protocols, but even larger on-table collections are not associated with tamponade and resolve spontaneously. TTE does not need to be performed routinely unless there are clinical signs of tamponade. (J Cardiovasc Electrophysiol, Vol. 22, pp. 756-760, July 2011) atrial fibrillation, catheter ablation, echocardiography, pericardial effusion, pericardial tamponade Introduction Catheter ablation for atrial fibrillation (AF) is a highly successful and increasingly common procedure but is lim- ited by the need for repeated procedures 1,2 and the signifi- cant complication rates. 3−5 One of these is the occurrence of pericardial effusions resulting in tamponade, requiring inter- vention either in the form of percutaneous pericardiocentesis or cardiac surgery. 6 For those patients in whom the problem occurs acutely at the time of the procedure, the hemodynamic consequences often make this immediately apparent. How- ever, there is a proportion that may develop a problem with pericardial collections after the procedure, and the current practice to shorten hospital stays after left atrial (LA) abla- tion means that this can be a significant clinical issue. There is limited literature on postprocedural occurrence of effu- sions after radiofrequency ablation in general 7,8 and only 1 in patients with AF. 9 None of these have addressed evolution No disclosures. Address for correspondence: Richard J. Schilling, M.D., F.R.C.P., St Bartholomew’s Hospital, London EC1A 7BE, U K. Fax: 44-20-7601-8627; Email: r.schilling@qmul.ac.uk Manuscript received 6 September 2010; Revised manuscript received 21 November 2010; Accepted for publication 29 November 2010. doi: 10.1111/j.1540-8167.2010.02008.x of effusions and the value of routine postprocedure transtho- racic echocardiography (TTE) remains unclear. We therefore prospectively studied the use of routine postprocedure TTE in patients specifically after extensive LA ablation to identify the frequency of pericardial collections, their clinical impor- tance, and the implications for service provision with regard to echocardiography. Methods Study Population Two hundred patients who underwent catheter ablation for either AF or atrial tachycardia (AT) were included in this study. All patients had symptomatic documented AF/AT and had failed or been intolerant of at least 1 antiarrhythmic drug. Electrophysiological Study and Radiofrequency Ablation The procedure was performed in the postabsorptive state under conscious sedation and transesophageal echocardiog- raphy (TOE) was performed within 24 hours of the procedure to exclude LA thrombus. At this time the presence of any pericardial collection was also noted. Ablation procedures were performed using electroanatomic mapping (CARTO, Biosense Webster Inc., Diamond Bar, CA, USA) with or without CT integration (Cartomerge TM , Biosense Webster Inc.) to guide catheter ablation. This has been previously