Antianginal drugs and relationship between epicardial ST segment depression and moderate regional myocardial blood flow reduction in experimental partial coronary artery occlusion

Cardiovascular Research
G B TimogiannakisP K Toutouzas

Abstract

The aim of the study was to determine whether moderate reduction in regional myocardial blood flow is related to epicardial ST segment depression and to the changes in grade and extent induced in this variable by antianginal drugs. Blood flow through the anterior descending coronary artery was reduced to 25-30% of control in open chest dogs, using a cuff flow meter as a monitor, and glyceryl trinitrate, propranolol and nifedipine were infused 60 min later. Regional left ventricular blood flow was measured with 15 mu radioactive microspheres and electrocardiograms were recorded from the epicardial surface of the anterior left ventricular wall before and after administration of the drugs. 20 adult male greyhounds were used, weighing 19-24 kg. Under control conditions there was a poor correlation between ST segment depression and regional flow. Neither glyceryl trinitrate nor nifedipine had any significant effect on ST segment depression in sites overlying zones with a flow range of 80-105% of normal flow. On the other hand, glyceryl trinitrate, but not nifedipine, decreased ST segment depression in sites overlying the central ischaemic zone (35-80% of control posterior wall flow). With propranolol, mean ST depression was decrease...Continue Reading

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