[The effect of single doses of antianginal preparations on the correlation of the time of the onset of typical pain and the electrocardiographic signs of myocardial ischemia in patients with stenocardia of effort].

Altogether 359 paired bicycle ergometries coupled with administration of single doses of antianginal drugs were carried out in 62 men suffering from angina pectoris of effort, functional classes II and III. A study was made of the indicator characterizing the time that elapsed since the onset of a typical angina pectoris attack till the appearance of the signs of ischemia on the ECG. Administration of effective single doses of antianginal drugs raised the time elapsed since the pain onset till the appearance of the ST segment greater than or equal to 1.0 mm fall during the exercise. Administration of ineffective doses of nitrates, calcium antagonists and placebo entailed a decline of that indicator, a rise of the number of cases where the segment ST greater than or equal to 1.0 mm fall was recordable before the onset of painful sensations. Administration of propranolol in ineffective single doses failed to provoke a decrease of the time elapsed since the typical pain onset till the appearance of the ST segment greater than or equal to 1.0 mm fall. Intake of ineffective single doses of nitrates, calcium antagonists and placebo may deprive certain patients of early signalization and appearance of the ECG signs of myocardial ischemia.