Reduction of Myocardial Ischemic Injury with Sublingual Isosorbide Dinitrate

Twenty-one patients with acute anterior myocardial infarction had precordial ST segment mapping, using a system of 42 leads, at 0, 2, 4, 8, 24, and 48 hours (control group). Eleven patients (treatment group) had maps on admission and after 30-45 minutes; then serial maps were performed at similar intervals after 5-10 mg of isosorbide dinitrate (ISD). There were no significant differences in age, sex, functional class, mean time elapsed between onset of chest pain and admission, and inhospital mortality between the groups. Controls had a higher incidence of recurrent MI (6 patients vs 2) compared with the ISD group (P less than 0.05).The sum of ST segment elevations in all leads (ΣST) was similar in both groups on admission and remained at the same level in controls for 48 hours. One hour after ISD the blood pressure decreased significantly; ΣST and the number of leads with more than 1 mm ST elevation (NST) decreased significantly (62±10 to 31±4 / 26±1 to 19±2) (P less than 0.01). In the ISD group serial ST maps showed significant decreases (52±5 vs 28±4; 44±4 vs 26±2; 45±4 vs 29±3; 51±5 vs 28±3, 52±8 vs 28±2, respectively at 2, 4, 8, 24 and 48 hours), suggesting reduction of ischemic injury by ISD.Estimation of infarct size (in units from R wave height and Q and S wave depths in leads I, AVL and V(1)-V(6)) indicated a reduction in the ISD group on days one, two and seven. Total CPK, SGOT and LDH levels were similar on admission; at 24 and 48 hours after admission CPK values were not significantly different but SGOT and LDH were lower in the treated group.