ABSTRACTS

PREDICTIVE ACCURACY OF CORONARY ARTERY CALCIFICATION AND POSITIVE EXERCISE TEST IN ASYMPTOMATIC NON-HYPERLIPIDEMlC MEN FOR CORONARY ARTERY DISEASE. Rene A. Langou, MD, FACC; Michael J. Kelley, MD, FACC; Edwin K. Huang, MD; Lawrence S. Cohen, MO., FACC, Yale University School of Medicine, New Haven, CT.

To determine the predictive accuracy (PA) of fluoro- scopically detected coronary artery calcification (CAC) and a positive submaximal exercise test (ET), 129 asymptomatic men were screened and 13 had both CAC and positive ET (>1.5 mm ST segment depression). These 13 men were studied at coronary arteriography (ART). They had a mean age of 44 years (range 41 to 56 years); 3 had hyperlipidemia, none had history or symptoms of heart disease and all had normal resting ECG's at entry.

CAC was detected in 1 artery in 10, in 2 arteries in 2, and in 3 arteries in 1 man. Coronary artery disease (CAD) was considered clinically significant if there was >50% narrowing in any major coronary branch. ART re- vealed 12 men with clinically significant CAD (single CAD in 4, double in 5 and triple in 3 men) and 1 with minor CAD (single CAD). The PA was 100% for minor CAD, 92% for clinically significant CAD. Correlation was found between the location of CAC and CAD but the ab- sence of CAC did not rule out the presence of CAD at ART. Furthermore, CAC did not indicate the location of the highest stenotic lesions seen at ART. Followup for the 13 pts was 40 mos.; 3 pts developed typical angina and 1 pt developed a transmural myocardial infarction.

Thus, this study suggests that 1) the PA of CAC and a positive ET, in the middle aged non-hyperlipidemic asymptomatic male, is very high; 100% for CAD and 92% for clinicaliy significant CAD; 2) that CAC and a posi- tive ET, predicts an early appearance of symptoms; angina or myocardial infarction, in previously asympto- matic men.

REPRODUCIBILITY OF EXERCISE TESTING AT TWO AND SIX WEEKS POST MYOCARDIAL INFARCTION Mark Starlinq, MD; Gemma Kennedy, RN; Michael Crawford, MD, FACC; Robert O'Rourke, MD, FACC, University of Texas Health Science Center and Veterans Administration Hospi- tal, San Antonio, Texas.

Although the safety of pre-discharge (DC) ECG exercise testing in post myocardial infarction (pM1) patients (pts) and the grave prognostic significance of exercise ST seg- ment depression (ST+) has been demonstrated, little evi- dence exists concerning the reproducibility of abnor- malities detected pre-DC compared to exercise testing done post-DC. Therefore, we studied 46 pM1 pts by a modified Naughton treadmill exercise test (TT) prior to hospital DC and at 6 wks p!lI. ST+ during TT occurred in 12 pts pre-DC and in 11 of them at 6 wks. In these 11 pts, there was no difference between 2 and 6 wks in maximum heart rate

F 114216 (SD) vs 117212 beats/min , rate pressure product RPP, ? 18.3t3.8 vs 18.Oi3.7 X IO3 and the duration of TT (5.713.9 vs 5.5r2.5 min). The 1 pt without ST+ at 6 wks was put on propranolol after his 2 wk TT. Also, 2 addi- tional pts had new ST+ on TT at 6 wks. ST segment eleva- tion (ST+) on TT was seen in 17 pts pre-DC but at 6 wks was no longer present in 9 of these pts. No new pts showed ST+ at 6 wks. Angina pectoris (AP) was provoked on TT in 8 pts pre-DC and reoccurred in 5 of them at 6wks. Additionally, 6 pts had new,AP on TT at 6 wks. In these 6 pts there was no change in the duration of TT at 2 and 6 wks, however, heart rate (12Oi19 vs 125214 beats/min) and RPP (18.1r4.3 vs 20.5r9.8 X 103) tended to increase at 6 wks. No abnormality was detected in 13 pts pre-DC and 11 of them continued to have a normal TT at 6 wks. In com- paring pre-DC to 6 wks pMI, we conclude: 1) ST4 is a relatively consistent and reproducible finding at 2 and 6 wks gMI; 2) ST+ often disappears by 6 wks pM1; and 3) more pts with angina pectoris are identified at 6 wks.

DOES LOCATIO:J OR LATE DISAPPEARAUCE OF q WAVES AFTER ~OCARDIAL INFARCTION AFFECT PROGNOSIS? Jorge C. Rios, M.D., Alan G. Wasserman, \l.D., George B. Bren, M.D., Alla" M. Ross, M.D., FACC, for the Aspirin Myocardial Infarction Research Group, George tiashington University Medical Center, iqashington, D.C. Absence or disappearance of diagnostic (7 waves following a myocardial infarction (MI) and the location of the infarction by Q wave distribution have been thought to carry prognostic implications. To test that hypothesis we examined the records of all patients participating in a clinical trial (Aspirin Myocardial Infarction Study: AMIS), ages 30-69 years (m=52.7) who had a myocardial infarction within 1 year preceeding entry into the study. There were 1464 such patients which constitutes this study group. Follow up was 28-42 months (m=32) during which time 120 (8.2%) patients had died. Thus the annualized mortality is 3.1% (treatment and control groups pooled). Total mortality in patients with a single electrocardio- graphically defined infarct location was: Antero-lateral 7/73 (9.6% total, annualized to 3.6% per year); Inferior 371517 (7.2% total, 2.7% per year; and Antero-septal 131189 (6.9% total, 2.6% per year). There was no sig- nificant difference in mortality rate between any of these groups. When patients with residual Q waves at randomization (1200) were compared to those whose Q waves completely resolved (264) there was no significant mortality dif- ference after 32 months (102/1200 "s 18/264). Yearly mortality 3.2% vs 2.5% respectively (p>O.O5). CoNCLUSION: ?leither loss of Q wave nor location of MI by Q wave distribution influences the annualized mortality (3.1%) for patients having survived the acute phase of a myocardial infarction.

AN IMPROVED, RAPID RADIOIMMUNOASSAY FOR INDIVIDUAL HUMAN CK ISOENZYMES Robert Roberts, MD, FACC; Ceil Herman PhD, Washington University, St. Louis, Missouri

The radioimmunoassay (RIA) we previously developed for MB CK employed an antibody to BB CK which cross-reacts with MB and required 6 hr of incubation for sample analysis. MB CK antiserum would have been preferable but purifica- tion of MB free of albumin was not then achievable. In this study, we developed a new procedure that permits assay of MB CK within minutes based on the use of purified MB rather than BB as the inhibiting moiety. MB CK was isolated from human myocardium by homogenization (Tris HCL, 50 mM, pH 7.4), and ethanol extraction (50 and 70%) and separated from MM CK by anion-exchange chromatography on Sephadex DEAE A-SO. Albumin was removed by affinity chromatography (affigel-blue) with 250 mM NaCl elution (PH 8.0). The purified MB CK migrated as a single protein band on SDS gel and did not react to albumin antiserwn. MB CK antiserum raised in rabbits exhibited a titre of 1:10,000. With the use of MB CK antiserum and the use of zn;e;z;;dapz5body technique, rather than (NH4)zS04, free

I-CK can be separated within 10 minutes. MM CK present in SOO-fold excess of MB exhibited no inhi- bition. Plasma MB CK activity in normal subjects (n=ZOO) detectable with the new assay ranged from .S to 6.5 IU/L with similar values in patients with angina without in- farction (n=120) of .2 to 6 IU/L. In contrast, patients with myocardial infarction (n=230) exhibited mean peak plasma MB CK of 230 ? 172 IU/L with initial elevations occurring 2-4 hr after onset of symptoms. Thus, the assay of MB CK employing purified MB CK and MB CK anti- serum is sensitive, specific and more rapid than the previously available procedure.

400 February 1980 The American Journal of CARDIOLOGY Volume 45