P3-120

S218 P3-120 WIDE COMPLEX TACHYCARDIA IN A PATIENT WITH EBSTEIN’S ANOMALY Rupa Bala, MD and Edward P. Gerstenfeld, MD. University of Pennsylvania, Philadelphia, PA. Background: Patients with Ebstein’s anomaly are susceptible to multiple atrial arrhythmias, but rarely, ventricular tachycardia(VT). We report a unique case of wide complex tachycardia in a patient with Ebstein’s anomaly. Case: A 29 year old female with a history of Ebstein’s anomaly experienced palpitations and presyncope. Her ECG demonstrated a wide complex tachycardia. She was placed on amiodarone and sotalol and referred to our institution. The 12-lead ECG during tachycardia demonstrated a left bundle branch (LB) morphology with late precordial transition and evidence of AV dissociation. A sinus rhythm voltage map revealed normal voltage throughout the right ventricle. Anterograde and retrograde AV nodal conduction was concentric and decremental. Programmed ventricular stimulation induced only isolated PVCs. Burst pacing on 2mcg of isuprel induced sustained LB superior axis VT at 330ms, identical to the clinical tachycardia. Pacing from the right ventricular (RV) apical catheter at progressively shorter cycle-lengths resulted in a RV paced morphology, with no evidence of progressive fusion. The tachycardia could not be reset with single extrastimuli. Activation mapping localized the VT to the basal RV free wall (Figure1). Radiofrequency (RF) application at the site of earliest activation terminated the tachycardia after 14 seconds. Pace mapping at this site yielded an identical 12-lead match to the clinical VT. After ablation, burst pacing on isuprel failed to initiate VT. The patient has done well with no VT recurrence. Conclusion: This case demonstrates a rare case of catecholamine sensitive VT occurring in a patient with Ebstein’s anomaly. We were able to localize the VT to the basal RV free wall. The response to pacing maneuvers and isuprel suggests a non-reentrant mechanism, possibly triggered activity. VT should be considered in patients with Ebstein’s anomaly and palpitations or syncope.

Heart Rhythm, Vol 3, No 5, May Supplement 2006 normal coronary arteries with normal LV function, & dextrocardia with situs inversus. Procedure: A preop TEE & a chest CT scan with angiography were performed. CS cannulation with an internal defibrillation catheter was obtained via the left internal jugular vein. A 10 Fr intracardiac echo (ICE)catheter (Acuson, Siemens, Inc.) was advanced to the right atrium for visualization of the left atrium (LA) and PV ostium. A temperature probe was placed in the esophagus at the level of the LA. Fluoroscopy demonstrated severe rightward rotation of the cardiac structures with the right ventricle central in the cardiac silhouette. A right-sided aortic arch was present. Transseptal catheterization to the LA was performed with the guidance of ICE. A three dimensional LA activation map was created with a 4mm tip Biosense Webster catheter (Johnson & Johnson) & registered to the LA/PV CT scan image. PVI of the left common, right upper, & right inferior PV was successfully performed with the aid of a circumferential mapping catheter. Positioning of the circumferential mapping catheter was easily navigated to the ostium of all PVs. Radiofrequency (RF) energy was delivered at 35W & 55o C with no increase in the esophageal temperature. Post RFA, no AF was induced on high dose isoprel & complete PVI remained. No complications occurred. Conclusion: PVI can be successfully and safely performed in AF patients with dextrocardia & situs inversus. Intracardiac ultrasound is critical for visualization of the foramen ovale, guidance of transseptal catheterization, & identification of the PV ostium.

POSTER SESSION 4 Friday, May 19, 2006 Session Time: 9:00 a.m.–12:00 p.m. Presenter Available: 9:30 a.m.–10:30 a.m. Location: Exhibit Hall P4-1 TRAFFICKING PROBLEMS ASSOCIATED WITH A NOVEL MUTATION (P1008S) IN THE HUMAN SCN5A GENE CONTRIBUTE TO THE DEVELOPMENT OF CARDIAC CONDUCTION DEFECTS Dan Hu, MD, PhD, Jonathan M. Cordeiro, PhD, Ryan Pfeiffer, Anne Curtis, MD, Kui Hong, MD, PhD, Ramon Brugada, MD, Alejandra Guerchicoff, PhD, Guido D. Pollevick, PhD and Charles Antzelevitch, PhD. Masonic Medical Research Laboratory, Utica, NY and University of South Florida, Tampa, FL. P3-121 PULMONARY VEIN ISOLATION IN A PATIENT WITH DEXTROCARDIA AND SITUS INVERSUS Gery F. Tomassoni, MD, Julie Griffin, PA, Greg McLoney, PA, Aaron Hesselson, MD and Peter Gallagher, MD. Lexington Cardiology Consultants, Lexington, KY. Pulmonary vein isolation (PVI) is an effective treatment of atrial fibrillation (AF). We report a case in which PVI was successfully performed in a patient with both dextrocardia & situs inversus. History: A 48 year old man was evaluated for paroxysmal AF resistant to multiple medications. His past history was remarkable for hypertension,

Introduction: Inherited loss of function mutations in SCN5A, the gene that encodes the ␣-subunit of the human cardiac sodium channel (hNav1.5), have been linked to cardiac conduction defects as well as to the development of life-threatening arrhythmias associated with the Brugada syndrome. The mechanism underlying the development of conduction defects is not well understood. Methods: PCR-based sequencing analysis was performed in a family with cardiac conduction disease. WT and mutant SCN5A genes were co-expressed with the ␤1-subunit (SCN1B) in TSA201 cells. Whole-cell patch clamp experiments were conducted to assess functional expression. Confocal microscopy was used to determine the spatial distribution of WT and mutant channels.