Beneficial effect of intravenous nitroglycerin in patients with non-Q myocardial infarction.

In 129 patients with acute myocardial infarction (MI) there was ST segment elevation on admission but no Q wave in the infarcted area: they were randomly divided into 2 groups. In a single blind study 62 patients received intravenous nitroglycerin, while another 67 patients were given placebo. The average time which elapsed since the beginning of symptoms to start of treatment was 157 +/- 82.17 min in nitroglycerin group and 169 +/- 66.9 min in placebo group (NS). The beneficial effect of nitroglycerin on mortality, extension of MI or occurrence of left ventricular failure (LVF) could be seen only if these conditions were combined. No significant difference could be detected if these conditions were analyzed individually. The size of MI assessed by peak of creatine kinase (CK) was similar in both groups. However, if Q and non Q MI were separately analyzed, the peak CK was significantly lower in non Q MI patients receiving nitroglycerin (523 +/- 161 IU/l compared to 1049 +/- 583 IU/l for placebo, p = 0.002) while the same beneficial effect could not be seen in Q MI. Although there was no difference in the final occurrence of Q MI and Q MI in both groups taking nitroglycerin or placebo, we found that non Q MI patients had significantly lower peak CK than Q MI patients (770 +/- 491.9 to 2783 +/- 1720.9, p = 0.001) and this peak CK was observed earlier for non Q MI patients (16.2 +/- 5.41 hours compared to 22.6 +/- 6.86 hours for Q MI patients, p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)