Blood volume and right heart haemodynamics in abrupt hypotension following sublingual isosorbide dinitrate in acute myocardial infarction.

Abstract

Arterial blood pressure and heart rate were measured in 43 patients with acute myocardial infarction and a systolic blood pressure greater than or equal to 120 mmHg during sublingual administration of 5 mg of isosorbide dinitrate. In 25 of them right heart haemodynamics were also measured. Severe (greater than or equal to 25%) hypotension developed in 12 patients (Group 1, systolic blood pressure 158 +/- 28 to 78 +/- 17 mmHg, mean +/- SD) but not in the remaining 31 (Group 2) and was accompanied by a fall in heart rate (82 +/- 20 to 70 +/- 22 beats min-1, P less than 0.05), in cardiac output (4.3 +/- 0.3 to 3.2 +/- 0.41 min-1, P less than 0.02, n = 5) and in systemic vascular resistances (2326 +/- 463 to 1532 +/- 442 dynes sec-1 cm.5, P less than 0.02) not present in Group 2. The reduction in right (Group 1, 8 +/- 3 to 3 +/- 1, vs. Group 2, 10 +/- 3 to 6 +/- 3 mmHg, P less than 0.005) and in left ventricular filling pressures (Group 1, 15 +/- 4 to 8 +/- 2, vs. Group 2, 18 +/- 6 to 13 +/- 5 mmHg, P less than 0.001) was more remarkable in Group 1. In this group there was also a high incidence of anterior infarction (9/12, 75%).(ABSTRACT TRUNCATED AT 250 WORDS)