Pulmonary vein isolation is always associated with Troponin elevation

Poster 6 line, but other criteria were not satisfied. Persistent conduction was defined as visualization of activation through a break in the line. Along the roof, definite block was achieved in 16 pts, indeterminate block in 9, and no block in 7. For the MI, definite block was achieved in 6 patients, indeterminate block in 14, and no block in 12. To achieve definite block, noncontact mapping correctly identified gaps guiding lesion placement in 13/16 roof lines, and 5/6 MI lines. Over mean follow-up of 8.1 months (range 3-28), 13/16 (81%) pts with definite roof block, 7/9 (78%) with indeterminate block, and 6/7 (86%) with persistent conduction were free of AF on or off antiarrhythmic drugs (p⫽NS). 5/12 (42%) pts with persistent conduction through the MI recurred in atypical flutter, compared to only 1/20 (5%) with definite or indeterminate block (p⫽0.01).Noncontact mapping may be helpful in identifying gaps in linear lesions facilitating creation of conduction block in the left atrium. Persistent conduction visualized with noncontact mapping across the MI may be a predictor of recurrent atrial flutter. P6-62 PULMONARY VEIN ISOLATION IS ALWAYS ASSOCIATED WITH TROPONIN ELEVATION Emily Kotschet, FRACP, David Adam, MBBS, *Richard Leather, MD, FRCP and *Laurence Sterns, MD, FRCP. Royal Jubilee Hospital, Victoria, British Columbia, Canada. Background: Small elevations in Troponin levels have been shown with limited radiofrequency (RF) ablation procedures for SVT, usually to levels below the threshold for ischaemia or infarction. Left atrial curative AF ablation procedures use far more RF energy, therefore could be expected to have greater elevation. We determined Troponin levels before and after ablation in these patients to evaluate the amount of rise with this ablation. Methods: All patients undergoing PVI from May 2004 to October 2004 had Troponin levels measured four hours following completion of the procedure. The first 30 patients also had a Troponin level measured one hour prior to PVI, to establish a baseline reference. Results: Sixty patients were studied, with 81.7% males and a mean age of 54.6 ⫾ 9.9 yrs. No patient had underlying structural heart disease. The baseline Troponin level was normal (⬍0.01 ␮g/dl) in all 30 patients. Post procedure Troponin levels were elevated in all 60 patients compared to baseline (p⬍0.05), with a mean level 0.85 ␮g/dl and range 0.26-1.57 ␮g/dl after an average RF ablation time of 56 ⫾ 15 minutes. All levels were above the reference range for diagnosis of acute myocardial infarction (⬎0.15 ␮g/dl). Troponin elevation was not related to the number of RF lesions, RF time, procedure time or associated external cardioversion. Discussion: Troponin elevations occurred in all patients undergoing PVI, to levels at least 20 times the normal concentration, into the range for diagnosis of acute myocardial infarction. Troponin would not be specific for ischaemia, should a patient experience chest pain following PVI. P6-63 INITIAL EXPERIENCE WITH PULMONARY VEIN (PV) ISOLATION (I) USING A HIGH INTENSITY FOCUSED ULTRASOUND (HIFU) BALLOON CATHETER Kai U. Markus, MD, Anil M. Sinha, MD, Doris Karla, MS, Peter Hanrath, MD and Christoph Stellbrink, MD. Cardologic Department, Aachen, Germany. PV-I from the left atrium (LA) using radiofrequency current ablation (RFCA) is being increasingly used as a curative approach for the treatment of atrial fibrillation (AF). As multiple PV-LA connections are frequently present, circular lesions around the PV ostia are usually required which is hard to achieve with RFCA and may increase the risk of PV stenosis (S). We investigated a new catheter system for PV-I applying circular ultrasound lesions around the PV ostia. Methods: The catheter consists of a balloon (diameter 24-32 mm) with an ultrasound generator placed at the PV antrum over a guide wire via a transseptal puncture. A parabolic reflector (CO2/H2O interface) focuses the ultrasound for a circular lesion around the PV ostium. We performed PV-I

S313 using the HIFU system in 5 Patients (pts) (1f, 61⫾4 yrs.) with paroxysmal (n⫽4) or persistent AF (n⫽1) and without structural heart disease. Success was determined by pt diaries and 24h Holter ECG recordings (HOL) after 1 and 3 months. Transesophageal echocardiography after 1 and 3 months and magnetic resonance imaging after 3 months were performed to exclude PV stenosis. Results: 14 of 15 targeted veins were successfully isolated (the right lower PV was not targeted) with 3.3⫾1.6 (median 3) HIFU applications. In one pt with a big common right-sided PV only incomplete I of the common ostium could be achieved. Mean procedure time was 301⫾117min in total and 129⫾44min for the ablation procedure. One pt. developed a pericardial effusion (not related to HIFU) which required pericardiocentesis. No PV-S was observed during follow-up. In the 4 pts with paroxysmal AF, mean duration of AF associated symptoms decreased from 113⫾75 (52-219h/month) to 0.2⫾0.3 h/month (0-0.7 h/month). In HOL after 1 month, the AF burden decreased from 668⫾592 min/24h (0-1440 min/24h) to 0⫾0 min/24h. However, the 1 pt presenting with persistent AF had a relapse after 10 days and is scheduled for re-ablation. Conclusion: HIFU is a promising new technique for PV-I in pts with paroxysmal AF. Its efficacy in pts with persistent AF remains to be determined. Further refinements of the catheter design will simplify the use of this catheter. P6-64 CATHETER ABLATION OF PERMANENT ATRIAL FIBRILLATION IN THE ELDERLY *Li-Fern Hsu, MRCP, *Pierre Jaı¨s, MD, PhD, *Prashanthan Sanders, MBBS, *Me´le`ze Hocini, MD, Fre´de´ric Sacher, MD, Yoshihide Takahashi, MD, Martin Rotter, MD, Thomas Rostock, MD, Jacques Cle´menty, MD and *Michel Haı¨ssaguerre, MD. Hoˆpital Cardiologique du Haut Le´ve`que, Bordeaux-Pessac, France. Background: Though catheter ablation for atrial fibrillation (AF) has been shown to be feasible and safe in the elderly, presently available studies have included predominantly patients with paroxysmal AF. The impact of age on ablation of permanent AF has not been specifically evaluated. Methods: 83 consecutive patients (56⫾11 years, 64 male) with permanent AF of 71⫾35 months’ duration who were symptomatic despite a trial of 3⫾1 antiarrhythmic drugs, were studied. Ablation comprising pulmonary vein isolation with individualized left atrial (LA) linear lesions was performed. The patients were divided into 3 groups based on age: ⬍45 years, 45-64 years, and ⱖ65 years, and the outcomes compared. Results: Patients aged ⱖ65 years (range 65-80) included more females and were in AF for a longer duration before ablation. Procedural parameters were similar in all 3 groups, though all those aged ⱖ65 years required LA linear lesions. Overall, 60 patients (72%) were in sinus rhythm (53 patients, 64% without antiarrhythmic drugs) over 15⫾9 months of follow-up, and outcomes were similar in all 3 age groups (Table).