EXTENT OF CARDIAC ANTONOMIC DENERVATION IN RELATION TO ANGINA ON EXERCISE TEST IN PATIENTS WITH RECENT ACUTE MYOCARDIAL-INFARCTION

According to the current concept, anginal pain results from stimulatio n of sympathetic nerves within the heart. In this study, we evaluated the role of cardiac adreneric denervation in exercise-induced angina p ectoris in 15 men with recent acute myocardial infarction. Before disc harge from the hospital, the patients were subjected to a symptom-limi ted exercise test. Three months after the infarction, cardiac scintigr aphic studies using 1-123 metaiodobenzylguanidine no (MIBG), 1-123 par aphenylpentadecanoic acid (pPPA), and Tc-99m sestamibi (MIBI) were per formed in order to determine the extent of denervated myocardium, the size of infarction, and myocardium with reduced perfusion, respective ly. MIBG defect (17.2 +/- 7.6% of left ventricular mass) (defect defin ed as an activity distribution less than or equal to 30% of the maxima l myocardial activity) was larger than pPPA defect (8.3 +/- 8.8%, p < 0.001) in all patients, which indicates that the area of myocardial ne crosis was surrounded by viable myocardium with sympathetic denervatio n. The extent of viable but denervated myocardium was significantly gr eater in patients who developed angina pectoris than in patients witho ut angina pectoris during the early exercise test (13.3 +/- 4.4% vs 5. 0 +/- 2.4%, p < 0.001). In addition, patients with silent ischemia ten ded to have smaller areas of viable but denervated myocardium than pat ients with painful ischemia (5.7 +/- 3.8% vs 13.8 +/- 5.1%, p = 0.07). Thus, contrary to expectations, the extent of viable but denervated m yocardium seems to be associated with increased pain sensitivity in pa tients with recent myocardial infarction.