Modification of Late Potentials by Intracoronary Ethanol Infusion SHARON M. DAILEY, G. NEAL KAY, ANDREW E. EPSTEIN, and VANCE J. PLUMB From the Division of Cardiovascular Disease, The University of Alahama at Birmingham, Birmingham. Alahama DAILEY, S.M., ETAL.: Modification of Late Potentials by Intracoronary Ethanol Infusion. Antiarrhythmic drugs have no consistent effects on the signal-averaged electrocardiogram (ECGJ while successful surgical abJotion o/ventricular tachycardia is known to abolish Jate potentials. Ten patienis with prior myocardial infarction had successful ablation of recurrent sustained ventricular tachycardia by selective ethanol infusion into a small coronary vessel supplying the tachycardia origin. Signal-averaged ECGs were per- formed before and after initially successful ahlation in patients without pacemaker dependence or intra- ventricular conduction delay to assess the effects on late potentials and to determine if the signal-aver- aged ECG could predict ventricular tachycardia recurrence. Only four of ten patients were eligible for study and all four had late potentials prior to ethanol ablation. Late potentials were abolished in one patient who has not had an arrhythmia recurrence in 25 months. One patient ivith sudden death and another patient with ventricular tachycardia recurrence had persistent late potentials post procedure that were modified by a reduction in terminal voltage and lengthening of terminal low amplitude signal. The fourth patient who receives chronic amiodarone had no arrhythmia recurrence in spite of persistent but modified late potentials. Thus, the abolition of late potentials after ethanol ablation may predict freedom from arrhythmia recurrence. (PACE, Vol. 15, November, Part I 1992) ventricular tachycardia, late potentials, ethanol ablation, electrophysiology Introduction Late potentials are high frequency, low ampli- tude signals seen in the terminal QRS and can be recorded from the body surface using signal-aver- aged electrocardiography in most patients with ventricular tachycardia after myocardial infarc- tion.^"^ Because of the apparent relationship of late potentials to fragmented ventricular elec- trograms that are thought to represent the substrate for reentrant ventricular arrhythmias/'"^ signal- averaged electrocardiography holds promise for observing changes in the arrhythmia substrate after antiarrhvthmic interventions. The use of Address for reprints: Sharon M, Dailey. M.D., 321B Tinsley Harrison Tower, University of Alabama at Birmingham, Bir- mingham, AL 35294. Fax: (205) 934-1279. Received April 28, 1992; revision July 1, 1992; accepted July 16, 1992. such a noninvasive approach that might obviate repeated invasive electrophysiological studies is appealing. While successful surgical treatment of ventricular tachycardia correlates well with aboli- tion of late potentials,^"^^ successful pharmaco- logical treatment and catheter ablation have largely unpredictable effects on the signal-aver- aged electrocardiogram (ECG),""^'^ Late potential changes can predict tachycardia cycle length pro- longation by certain drugs.^•* Selective intracoronary ethanol infusion has been described as a technique for ablation of inces- sant ventricular tachycardia.'^ More recently, our group has reported a prospective evaluation of in- tracoronary ethanol ablations of paroxysmal ven- tricular tachycardia,^^ Since ethanol is a cytotoxin producing tissue necrosis,^ ^ the present study was designed to determine if ethanol infused at the presumed site of arrhythmia origin would abolish late potentials in a manner similar to surgical re- section or destruction. 1646 November, Part I 1992 PACE, Vol, 15