Abstract

It is a documented fact that nitrates have a positive effect on the regression of symptoms of angina pectoris. There are discrepant findings concerning the changes in stroke volume and cardiac index after the administration of a single small dose of isosorbide dinitrate (ISDN) spray. There are still too few data on haemodynamic effects of nitrates of short-term activity in patients on chronic therapy with nitrates of prolonged activity. The aim of the present work was a non-invasive evaluation of the effect of a single dose of ISDN spray (1.25 mg) on haemodynamic indices in patients with stable angina pectoris. The study included 15 men aged 52±8 years, with body mass 82±12 kg, with the symptoms of stable coronary disease confirmed by coronarography. The average of 3 atherosclerotic stenoses exceeding 75% of coronary artery lumen were observed. EF ranged from 38% to 55%. 9 patients displayed arterial hypertension, 7 subjects experienced transmural myocardial infarction. All the patients received nitrates of prolonged activity. In order to stop the attacks of angina pectoris, the patients used nitrates of short-term effect. 15-minute record of changes in preload, stroke volume, cardiac index, heart rate were performed with the use of digital analysis of impedance cardiogram and ECG. In 3rd minute, the patients received 1.25 mg ISDN spray. Arterial blood pressure was measured according to Korotkow method. Changes in systemic vascular resistance were calculated. After the administration of 1.25 mg ISDN spray, preload decreased and reached the level of statistical significance in 9th minute (p<0.05). Stroke volume dropped from 100.04 ml to 90.07 ml in 7th minute after ISDN administration. Cardiac index changed from 3200 ml/m2 to 2950 ml/m2 (p<0.01). Heart rate increased from 62.8±8 / min to 65.8±9 / min (p<0.05). Systolic, diastolic and mean blood pressure decreased (from 131.2±18 mm Hg to 121.5±18 mm Hg; from 81.9±11 mm Hg to 78.2±9 mm Hg; from 98.3±13 mm Hg to 92.6±11 mm Hg, respectively). Systemic vascular resistance changed in 3rd minute after ISDN administration (p<0.05). In five patients, a significant change in stroke volume was observed as early as in 57±14.7 second after the administration of 1.25 mg ISDN spray.

Keywords: HAEMODYNAMICS, impedance cardiography, Nitrates, therapy, Coronary Disease