Identication and Catheter Ablation of Extracardiac and Intracardiac Components of Ligament of Marshall Tissue for Treatment of Paroxysmal Atrial Fibrillation DEMOSTHENES KATRITSIS, M.D., PH.D., JOHN P.A. IOANNIDIS, M.D.,‡ CONSTANTINE E. ANAGNOSTOPOULOS, M.D.,* GEORGE E. SARRIS, M.D.,† ELEFTHERIOS GIAZITZOGLOU, M.D., SOCRATES KOROVESIS, M.D., and A. JOHN CAMM, M.D.§ From the Department of Cardiology, Athens Euroclinic, Athens, Greece; the *Department of Cardiothoracic Surgery, Columbia University at SLRHC, New York, New York; the †Department of Pediatric Cardiac Surgery, Onassis Cardiac Surgery Center, Athens, Greece; the ‡Department of Hygiene and Epidemiology, University of Ioannina, Ioannina, Greece; and the §Department of Cardiological Sciences, St. George’s Hospital Medical School, London, United Kingdom Catheter Ablation of Ligament of Marshall Tissue. Introduction: The ligament of Marshall is a left atrial neuromuscular bundle with sympathetic innervation that may be a source of atrial brillation (AF)-inducing automatic activity. Methods and Results: Twenty-four patients with paroxysmal AF (including 18 with adrenergic AF) and 25 with other arrhythmias underwent catheter mapping. In cases of adrenergic AF, radiofrequency ablation was attempted when Marshall potentials were recorded. Patients were followed for 2 months before and 11.2 6 4.2 months after the procedure. Catheterization of the distal superoposterior coronary sinus was feasible in 14 patients with AF (10 with adrenergic AF) and 12 patients without AF. A discrete Marshall potential was recorded in 12 patients with AF versus 3 patients without AF (P 5 0.004). In 10 patients with adrenergic AF, this potential followed the atrial electrogram during sinus rhythm by 26 6 5 msec on left atrial recordings and 24 6 4 msec on coronary sinus recordings, and preceded it during atrial ectopy by 29 6 5 msec and 26 6 5 msec, respectively. It was abolished by epicardial (n 5 1), endocardial (n 5 4), or combined epicardial and endocardial ablation (n 5 5). Seven patients with ablation showed signicant reductions in adrenergic AF, whereas no signicant change was seen in 8 adrenergic AF patients not undergoing ablation (P 5 0.004). No improvement was seen in 3 of 4 patients with only endocardial ablation, whereas all 6 patients with epicardial ablation improved (P 5 0.033). Conclusion: Recording of Marshall potential is feasible in patients with paroxysmal AF. Combined epicardial and endocardial catheter ablation of ligament of Marshall tissue may reduce the paroxysms of adrenergic AF. (J Cardiovasc Electrophysiol, Vol. 12, pp. 750-758, July 2001) atrial brillation, electrophysiologic study, ablation, ligament of Marshall, coronary sinus Introduction Atrial brillation (AF) is the most common arrhythmia, found in 3% of asymptomatic persons .60 years and up to 11% of asymptomatic persons .70 years. 1 Its establishment is associated with doubling of cardiac and overall mortal- ity. 2 Despite its clinical importance, AF remains one of the few arrhythmias for which catheter ablation therapy is not feasible in most cases. The ligament of Marshall is a left atrial epicardial neu- romuscular bundle that has been associated with the genesis of atrial tachyarrhythmias and AF. 3-6 The ligament of Mar- shall is rich in sympathetic innervation. Isoproterenol infu- sion may induce automatic activity that may be responsible for induction of adrenergic AF. 4,5 Epicardial ablation of the ligament of Marshall in canines can terminate such sponta- neous activity and prevent AF, 4 whereas in humans, endo- cardial ablation at the insertion site of the Marshall bundle may terminate AF. 5 According to observations in our lab- oratory, ligament of Marshall tissue also can be identied and ablated in man through the coronary sinus and left atrial endocardium. 7 In the present study, we hypothesized that in patients with adrenergic paroxysmal AF, electrical activity of tissue surrounding the ligament of Marshall may be identied by simultaneous epicardial and endocardial recording of dis- crete potentials. We investigated whether ablation through the coronary sinus or left atrial endocardium is feasible and can abolish this electrical activity, and whether recurrences of the arrhythmia can be reduced or eliminated by catheter ablation. Methods Patients The study population consisted of 24 patients (21 men and 3 women; age 50.2 6 9.6 years, range 40 to 71) who presented with drug-refractory prolonged episodes of par- oxysmal AF (group A, with AF) and agreed to participate in the study, and 25 patients (15 men and 10 women; age 34.1 6 4.5 years) with other supraventricular arrhythmias Address for correspondence: Demosthenes Katritsis, M.D., Ph.D., Athens Euroclinic, 9 Athanassiadou Street, Athens 11521, Greece. Fax: 301- 6416555; E-mail: dkatrits@otenet.gr Manuscript received 24 October 2000; Accepted for publication 27 March 2001. 750 Reprinted with permission from JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Volume 12, No. 7, July 2001 Copyright ©2001 by Futura Publishing Company, Inc., Armonk, NY 10504-0418