Myocardial infarct with normal coronary vessels: an association with dysfunction of the coronary microcirculation

The association of acute myocardial infarction (AMI) with normal coronary arteries was analyzed prospectively. A series of 128 consecutive patients underwent coronary angiography within 1 week from AMI. Seven patients, all females, had no coronary artery lesions and were considered eligible for the study. All 7 patients underwent atrial pacing (10 g/min increments every 2 min), ergonovine testing (E; total dose 0.650 mg i.v.). Great cardiac vein flow (GCVF; thermodilution technique), mean aortic pressure (MAP), anterior coronary resistance (ACR) and myocardial lactate extraction [(Lac art-Lac gcv)/Lac art] were measured at baseline and during testing. Pacing-induced typical chest pain occurred in 5 patients: 4 of them showed concurrent significant (> or = 0.15 mV) ST downsloping. At peak pacing, GCVF increased only by < 50%, or even decreased, in all patients. Baseline lactate extraction (0.13 +/- 0.11) changed to lactate production (-0.15 +/- 0.10) in 7/7 patients. None of the patients showed focal epicardial coronary artery spasm following E. During testing, however, all 7 patients showed decrease in GCVF (110 +/- 47 versus 74 +/- 21; p < 0.005), increase in ACR (0.92 +/- 0.29 versus 1.43 +/- 0.20; p < 0.001), and significant coronary lactate production (-0.18 +/- 0.12). Six patients referred slight to moderate chest pain, which was accompanied by ST downsloping in 4.(ABSTRACT TRUNCATED AT 250 WORDS)