ABSTRACTS

IMPORTANCE OF ASYNERGY IN THE EXERCISE ELECTRCCARDIQGBAPHIC RESPONSE OF PATIENTS WITH ANGINA PECTORIS AND CORONARY DISEASE Michael D. Busky, MD; Michael S. Feldman, MD, FACC; Monty M. Bodenheimer, MD, FACC; Vidya S. Banka, MD; Richard H. Helfant, MD, FACC, Presbyterian-University of Pennsylvania Medical Center, Philadelphia, Pennsylvania.

The diffuseness and severity of coronary obstructive dis- ease has been shown to significantly affect the appear- ance and severity of exercise induced ST segment depres- sion. However, little is known of the relationship between the ST segment response to exercise and ventricu- lar performance. Thus, 55 patients with angina and coro- nary artery disease (L75% obstruction of one or more major vessels) underwent maximal treadmill stress, and the re- lationship between ST depression with exercise (positive ST), asynergy and the number of involved vessels was eval- uated. None had clinical heart failure. Thirty-six had positive and 19 negative ST responses. Twenty-one of the 25 patients with 3 vessel disease had positive ST's while 13 of 19 with 2 vessel and one of 11 with 1 vessel disease had positive ST's (pCOO1). However, of those with 3 ves- sel disease, 20 of 21 with positive ST's had asynergy while 1 of the 4 with negative ST's had asynergy (pCO25). In the 2 vessel disease group, all 13 with positive ST's had asynergy while 4 of the 6 with negative ST's had no asynergy (pi.001). When asynergy was evaluated independ- ently, only 5 of the 18 (27%) with no asynergy had posi- tive ST's while 28 of 37 (76%) with asynergy had positive ST's (p<.OOl). Of the 13 with no asynergy and negative ST's, 6 had 1 vessel, 3 had 2 vessel and 4 had 3 vessel disease. Conversely, of the 33 with both 2 or 3 vessel involvement and asynergy, only 3 had negative ST's. Thus, in addition to the number of obstructed vessels, asynergy appears to be an important additional factor in the ST segment response to exercise.

EXERCISE-INDUCED REDUCTION IN MYOCARDIAL INFARCT SIZE AFTER CORONARY ARTERY OCCLUSION IN THE PAT. A PRELIMINARY REPORT. Caryl L. McElroy; Sally A. Gissen, BS; Michael C. Fishbein, MD, Dept. of Pathology, Peter Bent Brigham Hospital and the Harvard Medical School, Boston, MA.

Chronic exercise(E) has been thought to be beneficial to the cardiovascular system by increasing energy production and utilization, improving myocardial contractility and increasing myocardial vascularity; whether or not any of these effects are beneficial to ischemic myocardium is uncertain. In this study, rats were forced to swim 1 hr/ day, 5 days/wk for 5 wks. They were sacrificed and the myocardial capillary bed was perfused with carbon black. Using a calibrated eyepiece grid, histologic sections of heart were examined to determine capillary/fiber ratios (C/F) and myocardial fiber diameter. C/F was increased by 30% in E rats [0.87?0.06(mean?S.E.)(n=4 rats)] when com- pared with sedentary controls(C) [0.67+0.04(n=4 rats),p< 0.051. This training effect occurred in the absence of hypertrophy since there were no differences in ventricu- lar weight (1.21+0.04mgs in E rats vs 1.1640.03mgs in C rats,NS) or in fiber diameter (13.0+0.2n in E rats vs 13.1 20.2~ in C rats,E;S) in the 2 groups. An additional 27 E rats and 25 C rats underwent left coronary artery occlu- sion and were sacrificed 48 hrs later. Myocardial infarct size was measured by planimetry of histologic sections of serial slices of left ventricle(LV). In the 27 E rats, 21.5+1.9% of the LV was infarcted compared with 31.3*-7.6% in the 25 C rats(pc0.005). Thus, infarct size was reduced by 30% in E rats. In the rat, exercise results in a reduction of myocardial infarct size after coronary artery occlusion which, at least in part, may be related to increased myocardial vascularity.

EXERCISE TRAINING SOON AFTER MYOCARDIAL INFARCTION. Nancy Houston RN, William Haskell PhD, Robert DeBusk MD FACC, Cardiology Div., Stanford Medical School, Stanford, CA. Gary Fry MD, YMCArdiac Therapy Program, Palo Alto, CA.

To assess the effect of exercise training (ET) on func- tional capacity (FC) soon after myocardial infarction (MI) 34 patients (pts) mean age 52, matched for clinical seve- rity of MI and post-MI physical activity level, were ran- domly assigned to control group, home ET or gym ET. No significant intergroup differences in age or severity of infarction were noted. Training heart rates for pts re- ceiving home or gym ET were 60-80% of' peak values record- ed during symptom-limited treadmill tests at 3 weeks post MI. Both exercise groups performed 3 l-hour ET sessions per week for 8 weeks. Pts performing home ET used heart rate monitors to regulate the level of effort during sta- tionary cycling and to transmit electrocardiograms via telephone during ET sessions. Treadmill tests were re- peated on all pts at 11 weeks post-Ml. FC was expressed as multiples of resting oxygen consumption (estimated) or METS. RESULTS:

3 weeks 11 weeks Max HR Max METS Max HR Max METS AMETS

Control n=13 134+-17 7.1f1.4 150+20 9.9i1.6 2.8* Home ET n=7 151+19 7.6t1.3 156+24 10.2r1.8 2.6* Gym ET n=14 139+23 7.3t2.1 149?22 10.5i2.1 3.2* Intergroup NS NS NS NS *3vsll wk

differences P< 0.01

CONCLUSIONS: 1) Individualized physical exercise training commencing as soon as 3 weeks post-MI appears to be safe in well selected and monitored patients. 2) A substantial increase in FC noted between 3-11 weeks post-MI was not further augmented by exercise training within this population.

PREDICTIVE VALUE AND SAFETY OF LOW LEVEL EXERCISE TOLER- ANCE TESTING EARLY AFTER ACUTE MYOCARDIAL INFARCTION Pierre ThCroux, MD; Christine Halphen, MD; David D.Waters, MD, FACC; Henry F. Misgala, MD, FACC, Montreal Heart Institute, Montreal, Quebec Exercise testing is highly predictive of subsequent cor-

onary events and mortality in most populations. According- ly, graded exercise tests (ETs) were done in 125 consecu- tive pts (mean age 52) 12 days (7-24) after acute myocar- dial infarction to determine in this setting its safety and prognostic value. Pts with a physical handicap, overt heart failure, angina within 72 hours or aged >70 years were excluded. End-points were 70% of the maximal age pre- dicted heart rate, 5 metabolic equivalents, ST depression b1.5 mm, typical angina, incapacitating fatigue or the ap- pearance of a serious arrhythmia. The development of 1.5 mm of horizontal or downsloping ST depression or typical angina were criteria for a positive test (+ET). Resting ECG and CPK-MB done before and at 6 and 12 hours after ET were unchanged. One pt had severe chest pain 24 hours post ET without objective evidence of re-infarction.

22 pts had ventricular extrasystoles and an additional 2 had salvos. 46% of pts with ventricular arrhythmias (VAs) had ST depression but only 19% of those without VAs had ST depression (pcO.02). Overall 46 pts had +ETs and 69 -ETs. During the next 3 to 16 (mean 10) months, coronary events occurred in 25 pts, 13 of whom had had -ETs (NS). These events were unstable angina in 6 (1 with+ET), re-infarc- tion in 14 (5 with+ETs) and death in 10 (3 with+ETs). 56% of pts with +ETs had subsequent angina at 3 months com- pared to 31% of those with -ETs (pcO.02). We conclude that low level ET soon after myocardial in-

farction appears safe. VAs correlate with ST depression in this setting, suggesting that both may be caused by ische- mia. +ETs predict subsequent angina but not early coronary events or death.

February 1979 The American Journal of CARDIOLOGY Volume 41 431