Modification of Atrioventricular Conduction by Selective AV Nodal Artery Catheterization PAUL J. WANG, FREDERICK J. SCHOEN, KATHLEEN REAGAN. HUSSEIN HASAN RIZK HASAN, HONG SHENG GUO, and PETER L. FRIEDMAN From the Clinical Electrophysiology Laboratory, Brigham and Women's Hospital and the Department of Medicine, Harvard Medical School. Boston, Massachusetts WANG, P. J., ET AL.: Modification of Alrioventricular Conduction by Selective AV Nodal Artery Cathe- terization. The effects of selective AV nodal artery embolization on AV nodal function was investigated in six closed-chest adult dogs. Programmed atrial stimulation was performed to determine control values for AV nodal effective refractory period (AVN-ERP} and the paced cycle length at which AV nodal Wenckebach conduction occurred (WCL). Using standard percutaneous/emoraJ techniques of coronary artery catheter- ization. a flexible infusion caiheteru'as positioned selectively in (he AVnodaJ artery. Proper positioning of the catheter was confirmed angiographical/y and by seJective acefylchoiine (ACH) infusion into the AV nodal artery, which caused transient complete AV nodaJ block in three dogs, and for the group, caused lengthening of both AVN-EHP and WCL. Following cessation of ACH infusion and autonomic blockade with atropine 0.04 mg/kg and propranohi 0.2 mg/kg, denervated recontrol values for AVN-ERP and WCL were 192 msec and 243 msec, respectively. The AV nodal artery was then embolized vvith a suspension of cross-linked collagen fibrils in either normal saline or absolute ethanol. Successful embolization of the AV nodal artery, confirmed ungiographically, caused an acute increase in AVN-ERP (243 msec, P < 0.05 compared to denervated control) and WCL (287 msec, P - 0.058 compared to denervated control]. How- ever, at a mean follow-up of 37 days, only one animal exhibited a chronic increase in AVN-ERP and WCL. Selective AV nodaJ artery cathelerization can be performed using standard percutaneous catheterization techniques. Selective administration of agents with direct cida] effects on the AV node using this technique may provide an alternative to conventional methods of catheter ablation of AV conduction in patients with drug-resistant supraventricular arrhythmias. (PACE, Vol. 13, /anuary 1990) supraventricular tachycardia, catheter ablation, atrioventricuiar node, AV nodal artery Introduction In most patients with supraventricular tachy- arrhythmias, antiarrhythmic drug therapy is ef- fective in preventing paroxysms of arrhythmia or satisfactorily controlling ventricular rate during such paroxysms. However, for those patients in whom drug therapy is either ineffective or poorly tolerated because of drug-related side effects, ab- lation of atrioventricular conduction has emerged Address for reprints: Pnter L. Friedman, M.D., Ph.D.. Cardio- vascular Division, Brigham and Women's Hospital, 75 Francis Street, Boston. MA 02115. Received July 5, 1989; revision August 11, 1989; accepted Au- gust 14. 1989. as an acceptable therapeutic option. By its very nature abiation of AV conduction, whether achieved surgically or by presently available catheter techniques, usually results in high grade or even complete AV block.^""^ As a consequence, prophylactic permanent pacemakers are required in all patients undergoing such procedures.'^ De- velopment of a catheter technique to modify AV conduction without risk of progression to high grade AV block, thereby obviating the need for surgery as well as for a permanent pacemaker, would represent a considerable advance in tbe management of patients with refractory supra- ventricular arrbytbmias, Inoue et al. have advanced the hypothesis January 1990 PACE, Vol. 13