Multiparametric Approach to Diagnosis of Non-Q-Wave Acute Myocardial Infarction Clara Carpeggiani, MD, Antonio L’Abbate, MD, Paolo Marzullo, MD, Giuseppe Buzzigoli, Oberdan Parodi, MD, Gianmario Sambuceti, MD, Claudio Marcassa, MD, ClaudioBoni, Elena Moscarelli, MD, and Alessandro Distante, MD The present study investigated whether the lack of enzyme increase is reason enough to exclude ne- crosis in patients with ischemic heart disease who develop electrocardiographic sustained ST-T changes in the absence of Q waves. In 15 consecu- tive patients with angina who developed sustained ST-T changes during hospitalization, the presence of myocardial necrosis was investigated by a pro- spective multiparametric approach. Serum enzymes and myoglobin, pyrophosphate uptake, P-dimen- sional echocardiography, perfusion scintigraphy, left ventriculography and coronary angiography were evaluated. According to creatine kinase and creatine kinase-MB peak at twice the upper normal value, the diagnosis of acute myocardial infarction applied only to 40% of patients. However, myoglo- bin was positive in 80% and a perfusion defect could be documented by an electrocardiographic gated microsphere technique in 100% of patients. The positivity of myoglobin increased to 100% and of creatine kinase and creatine kinase-MB to 87 and 60%, respectively, when a peak value twice the individual Jowest value was considered for posi- tivity. The 100% presence of perfusion defects as- sociated with the high prevalence of both positive pyrophosphate uptake (87%) and regional dyssyn- ergies (87 and 73%, respectively, by left ventric- ulography and echocardiography) strongly suggest that sustained (27 days) ST-T changes in this pop- ulation were indicative of myocardial necrosis. Thus, by conventional enzymatic approach, diagno- sis of non-Q-wave infarction can be missed in a sizable number of patients and present important clinical implications. (Am J Cardiol 1989;63:404-408) From the Institute of Clinical Physiology, National Research Council, and the Institute of Special Medical Pathology, Pisa University, Pisa, Italy. This study was supported in part by the Ministry of Public Instruction and by contract n.86.00446.04 with the Cardiorespiratory Group of the National Research Council, Pisa, Italy. Manuscript re- ceived July 22,1988; revised manuscript received and accepted October 31, 1988. Address for reprints: Antonio L’Abbate, MD, Institute of Clinical Physiology, CNR Institute of Clinical Physiology, Via Savi 8, 56100 Pisa, Italy. 404 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 63 T ransient ST-segment and T-wave changes are highly specific electrocardiac markers of acute myocardial ischemia.1,2 Conversely,the signifi- cance of sustained ST-T changes after angina in pa- tients with ischemic heart disease is still controversial.3,4 In the presence of a significant increase in myocardial serum enzymes, these abnormalities are definitely as- cribed to myocardial necrosis.5 In this instance the ab- sence of Q waves is generally attributedto the limited infarct size or to its subendocardial localization6 Thus, the terms of non-Q-wavesubendocardial or nontrans- mural infarction are currently appliedto this condition, although scintigraphic and pathologic evidenceexists against a consistent relation between type of electrocar- diographic alterationsand transmural extension of ne- crosis.7,8 In the absence of both significant enzymerelease and Q-wave formation9 the interpretation of sustained ST-T changes after angina becomes controversial. The aim of the present study was to determine whether the lack of enzyme release is reason enough to exclude car- diac necrosis or, alternatively,whether the criteria in use for enzyme assessment are adequate to this purpose. To reach this goal, the significance of postischemic sus- tained ST-segment depression or T-wave inversion (ST- T) was evaluated by a prospective multiparametric ap- proach in a series of consecutive patients observed from the very beginning of the electrocardiographic changes. Possible necrosis was investigated by cardiac enzymes and serum myoglobin, pyrophosphate uptake,2-dimen- sional echocardiography, microsphere perfusionscintig- raphy, left ventriculography and coronary angiography. METHODS Patient population: Fifteen consecutive patients ad- mitted to our coronary care unit were selected for the study (14 men, 1 woman, ages 33 to 69 years). The only criterion for entering the study was the development of ST-T persistingat least 48 hours on the standard elec- trocardiogram.Three patients with previous myocardial infarction (MI), by history and Q wave on the electro- cardiogram, were allowed to enter the study because sustainedST-T occurred in leads different from those showing Q waves (i.e., anterior vs inferior leads). The clinical characteristics of the patients are listed in Table I. Electrocardiogram: The electrocardiographic crite- ria for entering the study included (1) newly developed and sustained (>48 hours) horizontal or downsloping