Mapping-guided surgical therapy of refractory ventricular tachycardia (VT) due to coronary artery disease

MAPPING-GUIDED SURGICAL THERAPY OF REFRACTORY VENTRICULAR TACHYCARDIA (VT) DUE TO CORONARY ARTERY DISEASE. Jay W. Mason MD, FACC, Edward B. Stinson MD, FACC, Philip E. Oyer IID, PhD, FACC, Roger A. Winkle MD, FACC and Gerry C. Derby, RN. Stanford University, Stanford, California Electrical activation sequence mapping was used to guide surgical therapy in 50 patients with medically refractory VT due to prior myocardial infarction. Age of the 45 men and 5 women was 59 f 9 (SD, range 36 to 73) years. The primary procedure was endomyocardial excision in 31, cryothermal ablation in 13 and transmural or endoventriculotomy in 6. Concomitant coronary grafting was done in 24 and mitral valve replacement in 3. Mean follow-up is 268 (range 1 to 768) days. Fifteen patients (30%) have died. Death resulted from left ventricular (LV) failure in 8, a stroke in 1, and exsanguination in 1. Three died of documented arrhythmia recurrence at 1, 6 and 24 days and two had sudden, presummed arrhythmic, deaths at 75 and 157 days. By actuarial analysis 79 ? 6 (SEM)% at 1 month, 69 ? 7% at 6 months, and 66 f 7% at 11 through 25 months survived. A total of 11 (22%) have had documented or suspected post-operative VT recurrence. Six additional patients (12%) had inducible VT before discharge but have not had spontaneous recurrence; 4 of them are receiving antiarrhythmics. Actuarial analysis shows 87 ? 5% at 1 month, 75 2 7% at 5 months and 71 2 8% at 10 through 25 months to be free of VT recurrence. Of the 13 patients who underwent cryoablation, only 1 died of LV failure; one died suddenly and 1 died with refractory ventricular tachycardia. We conclude: (1) Mapping-guided surgical therapy of medically refractory VT is associated with compromise of LV function in some patients. (2) Mapping-guided surgery provides long-term arrhythmia prophylaxis in most patients.. (3) Cryothermal ablation is probably as effective and may be less damaging to the LV than endocardial incision or excision. REGIO'IAL ELECTROPHYSIOLOGIC AHD WEOLOGIC EFFECTS OF EHWCARDIAL CRYOABLATIOH Ross M. Ungerleider , MD; David Calcagno, BS; Masatoshi Ikeshita. MD: Lillian L. Holnan. MD: J. Mark IJilliams. MD: Peter K.'Smith, MD; Gary K. Lofland; MD; James L. Cox; ::Di Dept. of Surgery, Duke University, Durham, !Iorth Carolina Cryoablation of the ventricular endocardiun (CAVE) has been introduced recently as a method for treating refractory ventricular tachycardia. This study was designed to determine the effects of CAVE on local electrophysiology and regional myocardial blood flow (T!?gF). Ten dogs underwent cardiopulnonery bypass and multiple epicardial, intranural, and endocardial electrodes were positioned in the left ventricular free-wall. FMBF was determined using 8~ radioactive tracer microspheres. Four-5 cm2 of the endocardium was cryoablated at -50°C for 2 minutes. Interelectrode conduction time was increased by 20% (p<O.O08) within the cryolesion,(CL) and by 24% (p<O.OOOl) across its borders, while conduction in adjacent normal myocardium remained unchanged. Total electrical activity was ablated in 39% (12/31) of subendocardial electrograms within the CL but not in the overlying subepicardium. Subendocardial ?MBF within the CL decreased by 84% but remained unchanged in adjacent subepicardiun. Endocardial cryoablation results in local electrophysiologic changes similar to those produced by an encircling endocardial ventriculotomy (REV), with the advantage of sparing the RMBF to adjacent myocardium. Although the long-term effectiveness of endocardial cryoablation for the treatment of refractory ventricular tachycardia remains to be determined, it is safer, more rapid, and less destructive than other currently employed surgical procedures. TUESDAY, APRIL 27, 1982