RESUMO
The effects of i.v. nitroglycerin were studied by ECG and enzymatically in 16 patients (mean age 57.9 +/- 1.4 years) (NTG) in comparison with a control lot (c) of 17 patients (mean age 62.7 +/- 2.1 years) treated with dipyridamole and/or nifedipine (N), admitted in the first 4-10 hours after the onset of the first symptoms. The patients with heart failure and those with Q waves and CPK or LDH values greater than 2 x n were not admitted. NTG was administered in doses of 20 micrograms--60 microgram/hour for 24-96 hours and systolic AT (s) was kept under 10% of the basic values but not under 100 mmHg. Myocardial infarction appeared in 9 N-treated patients (54.86%) and 11 controls (58.25%) (p = 0.07). The size of myocardial necrosis was reduced in the N-treated patients. Peak serum CPK levels had considerably less increases in N (from 72.9 U to 73.4 U) (p greater than 00.5) versus C from 34.2 U to 364.5 U) (p less than 0.001). The sum of segmentary depression failed from 9.13 mm to 3.19 mm (p less than 0.05) in N, whereas in C the decrease was not significant (6.12 mm as against 9.38 mm; p greater than 0.05). The evolution was severe in C, as the angina crises (14 cases versus 2 cases, p less than 0.01) and the extension of the infarction (8 cases versus, 0; p 0.05) less than 0.05) appeared more frequently than in N. Only two patients in C died (p less than 0.05). Therefore, i.v. NTG administration in small doses in acute myocardial infarction leads to immediate disappearance of the anginal pain, lowers the extent of the myocardial necrosis and improves the clinical evolution.