Low energy synchronous transcatheter cardioversion of atrial flutter/fibrillation in the dog

Department of Internal Medicine, School of Medicine, Fukuoka University, Fukuoka, Japan.

The feasibility and effectiveness of low energy synchronous transcatheter cardioversion of atrial flutter and fibrillation were examined in dogs with talc-induced pericarditis. A conventional electrode catheter was positioned transvenously in the right atrial appendage. Atrial flutter/fibrillation was induced by using the train pulse method, and the tachyarrhythmia-inducing threshold was determined. The minimal effective cardioversion energy levels were compared in three different cardioversion methods: method A = delivery of shock between the proximal electrode (cathode) and the backplate (anode), method B = delivery between the proximal electrode (cathode) and the distal electrode (anode) and method C = conventional external cardioversion. In both methods A and B, all 149 cardioversion attempts were successful with shocks of less than or equal to 5 J. Shocks of less than or equal to 1 J resulted in successful cardioversion in 57 (70%) of 81 attempts, 50 (74%) of 68 attempts and 5 (12%) of 41 attempts with methods A, B and C, respectively. The mean minimal effective cardioversion energy levels were not significantly different between methods A and B (0.62 +/- 0.67 versus 0.58 +/- 0.71 J). Transcatheter cardioversion decreased the defibrillation threshold 3- to 75-fold (mean 6- to 7-fold) from that of transthoracic cardioversion. The defibrillation threshold was not influenced by the inducibility of atrial flutter/fibrillation. There were no complications of heart block, ventricular fibrillation or pathologic evidence of severe shock-induced atrial injury. Thus, low energy synchronous transcatheter cardioversion of atrial flutter/fibrillation is considered feasible and effective. This technique may also be useful in managing the atrial flutter/fibrillation that can occur during electrophysiologic studies.

This article has been cited by other articles:

				G. Manoharan, N. Evans, B. Kidwai, D. Allen, J. Anderson, and J. Adgey Novel Passive Implantable Atrial Defibrillator Using Transcutaneous Radiofrequency Energy Transmission Successfully Cardioverts Atrial Fibrillation Circulation, September 16, 2003; 108(11): 1382 - 1388. [Abstract] [Full Text] [PDF]

				A. L. Waldo Mechanisms of atrial flutter and atrial fibrillation: distinct entities or two sides of a coin? Cardiovasc Res, May 1, 2002; 54(2): 217 - 229. [Full Text] [PDF]

				A. L. Waldo Low-Energy Atrial Defibrillation : A Promising New Technique Circulation, September 1, 1998; 98(9): 833 - 834. [Full Text] [PDF]

				A. C. Skanes, R. A. Gray, C. L. Zuur, and J. Jalife Effects of Postshock Atrial Pacing on Atrial Defibrillation Outcome in the Isolated Sheep Heart Circulation, July 7, 1998; 98(1): 64 - 72. [Abstract] [Full Text] [PDF]

				R. A. Gray and J. Jalife Effects of Atrial Defibrillation Shocks on the Ventricles in Isolated Sheep Hearts Circulation, April 28, 1998; 97(16): 1613 - 1622. [Abstract] [Full Text] [PDF]

				E Alt, R Ammer, G Lehmann, C Schmitt, J Pasquantonio, and A Schömig Efficacy of a new balloon catheter for internal cardioversion of chronic atrial fibrillation without anaesthesia Heart, February 1, 1998; 79(2): 128 - 132. [Abstract] [Full Text]

				E. T. Keelan, D. Krum, J. Hare, K. Mughal, H. Li, M. Akhtar, and M. R. Jazayeri Safety of Atrial Defibrillation Shocks Synchronized to Narrow and Wide QRS Complexes During Atrial Pacing Protocols Simulating Atrial Fibrillation in Dogs Circulation, September 16, 1997; 96(6): 2022 - 2030. [Abstract] [Full Text]

				M. C. Sokoloski, G. M. Ayers, K. Kumagai, C. M. Khrestian, S. Niwano, and A. L. Waldo Safety of Transvenous Atrial Defibrillation : Studies in the Canine Sterile Pericarditis Model Circulation, August 19, 1997; 96(4): 1343 - 1350. [Abstract] [Full Text]

				R. A. Gray, G. Ayers, and J. Jalife Video Imaging of Atrial Defibrillation in the Sheep Heart Circulation, February 18, 1997; 95(4): 1038 - 1047. [Abstract] [Full Text]