The change in coronary blood flow in pacing induced angina pectoris and its relationship to anginal pain and ischemic ST depression (author's transl)

Abstract

The relationship between the changes in coronary sinus blood flow (CSF) and the anginal pain and ischemic ST depression has been studied in 16 cases of effort angina, in which the attack was induced by coronary sinus pacing, aiming at a target heart rate previously determined by the treadmill test. CSF was measured by the thermodilution method. Ischemic ST depression appeared in 11 cases, of which 7 cases were accompanied by anginal pain. The pacing period was divided into two stages: Stage I (period of 80% of the target heart rate) and Stage II (period of appearance of ischemic ST depression and/or anginal pain or attainment of target heart rate). At Stage I, CSF was significantly larger in cases with ST depression than in those without ST depression. CSF at Stage II decreased significantly more than at Stage I. On the contrary in all cases without ST depression, CSF increased at Stage significantly more than at Stage I. There was a significant correlation between CSF and the degree of ST depression. No significant difference in CSF was seen between anginal and nonanginal groups.Myocardial lactate extraction ratio in the anginal group decreased significantly after pacing off, while no change was seen in the non-anginal group. No significant difference was observed in myocardial lactate extraction ratio between cases with and without ST depression.At Stage II no significant change in left ventricular enddiastolic pressure (LVEDP) was seen, but it was significantly higher 2 or 3 heart beats after pacing off than at Stage II and 5min. after pacing in cases with ST depression, but such a difference was not seen in cases without ST depression.There were no differences in LVSP, LV max dp/dt, and double product between cases with and without ST depression and between anginal and non-anginal groups.Niludipine (a new Ca-antagonist) of 0.25mg was given intravenously in 9 cases. Significant increase in HR and CSF and significant decrease in LVSP were seen before pacing. At Stage II the degree of ST depression and decrease in LVSP and double product were observed to be suppressed. Increase in LVEDP immediately after pacing off was also suppressed. These findings indicate that niludipine partly shares pharmacological effect on effort angina with nitroglycerin and nifedipine.