Effect of direct current shocks on left atrial mechanical function in patients with structural heart disease

Department of Cardiology, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia.

OBJECTIVES: This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease. BACKGROUND: DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial "stunning" and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear. METHODS: Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock. RESULTS: There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks. CONCLUSIONS: Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.

This article has been cited by other articles:

				V. P. Nikolski and I. R. Efimov Electroporation of the heart Europace, January 1, 2005; 7(s2): S146 - S154. [Abstract] [Full Text] [PDF]

				G. Lehmann, J. Horcher, K. Dennig, A. Plewan, K. Ulm, and E. Alt Atrial Mechanical Performance After Internal and External Cardioversion of Atrial Fibrillation : An Echocardiographic Study Chest, January 1, 2002; 121(1): 13 - 18. [Abstract] [Full Text] [PDF]

				C. Stefanadis, J. Dernellis, and P. Toutouzas A clinical appraisal of left atrial function Eur. Heart J., January 1, 2001; 22(1): 22 - 36. [PDF]

				A. Al-Khadra, V. Nikolski, and I. R. Efimov The Role of Electroporation in Defibrillation Circ. Res., October 27, 2000; 87(9): 797 - 804. [Abstract] [Full Text] [PDF]

				A Roijer, J Eskilsson, and B Olsson Transoesophageal echocardiography-guided cardioversion of atrial fibrillation or flutter. Selection of a low-risk group for immediate cardioversion Eur. Heart J., May 2, 2000; 21(10): 837 - 847. [Abstract] [PDF]

				Y. Agmon, B. K. Khandheria, F. Gentile, and J. B. Seward Echocardiographic assessment of the left atrial appendage J. Am. Coll. Cardiol., December 1, 1999; 34(7): 1867 - 1877. [Abstract] [Full Text] [PDF]

				P. B. Sparks, S. Jayaprakash, H. G. Mond, J. K. Vohra, L. E. Grigg, and J. M. Kalman Left atrial mechanical function after brief duration atrial fibrillation J. Am. Coll. Cardiol., February 1, 1999; 33(2): 342 - 349. [Abstract] [Full Text] [PDF]

				P. B. Sparks, S. Jayaprakash, J. K. Vohra, H. G. Mond, A. G. Yapanis, L. E. Grigg, and J. M. Kalman Left atrial "stunning" following radiofrequency catheter ablation of chronic atrial flutter J. Am. Coll. Cardiol., August 1, 1998; 32(2): 468 - 475. [Abstract] [Full Text] [PDF]