The effects of the association of Isosorbide Dinitrate (ISDN) and Intra-Aortic Balloon Counterpulsation (IABCP) on ECGphic signs (in 24-lead precordial maps) of myocardial damage were studied in 7 patients (pts) with anterior acute myocardial infarction (AMI) without cardiogenic shock and/or pulmonary congestion, admitted to the CCU within 6 hours (hrs) since the chest pain. Matched control group consisted of 7 pts treated with ISDN alone. Analysis of variance showed that the association of IABCP and ISDN influenced favourably (p less than 0.01) the trend of the sigma ST (in all leads and in those with ST segment elevation greater than 0.2 mV), of the ST and of NST. The trend of sigma R was similar in the two groups. sigma Q was influenced either by time and by therapy; NQ was significantly lower (p less than 0.01) in pts treated with ISDN and IABCP. These findings seem to give evidence that the association of ISDN and IABCP may really be effective in reducing and stabilizing the ECG extent of ischemic myocardial injury in pts with transmural AMI without left ventricular failure; however this aggressive therapy cannot have a widespread indication until more reliable criteria for evaluating infarct size are available and larger randomized clinical trials performed.