Extent of ischemic stimulus and plasma beta-endorphin levels in silent myocardial ischemia.
BACKGROUND
Beta-endorphin has been reported to play a role in the mechanism of silent myocardial ischemia.


OBJECTIVE
Plasma beta-endorphin levels during coronary angioplasty-induced silent and symptomatic myocardial ischemia were compared with those during exercise-induced silent ischemia.


RESULTS
The study population consisted of 40 nondiabetic patients with angioplasty-indicated coronary artery disease. All patients underwent exercise treadmill testing 2 to 4 days before angioplasty. Patients were divided into three groups: group 1, 10 patients with silent ischemia during exercise and angioplasty; group 2, 15 patients with silent ischemia during exercise and symptomatic ischemia during angioplasty; and group 3, 15 patients with symptomatic ischemia during both exercise and angioplasty. In group 1, plasma beta-endorphin levels during balloon inflation were significantly higher than in groups 2 and 3 and also significantly higher than during exercise. In group 2, plasma beta-endorphin levels were significantly elevated at exercise-induced silent myocardial ischemia and balloon-induced symptomatic myocardial ischemia, but the levels between exercise and balloon inflation were not significantly different.


CONCLUSIONS
For "silent" myocardial ischemia, it may be necessary for beta-endorphin levels to increase to sufficiently high levels to suppress anginal symptoms in response to the degree of ischemic stimuli.
Hikita
H
H
First Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Etsuda
H
H
Takase
B
B
Satomura
K
K
Kurita
A
A
Nakamura
H
H
D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D003327:Coronary Disease / Q000097:blood / Q000628:therapy; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000175:diagnosis*; D011379:Prognosis; D001615:beta-Endorphin / Q000097:blood*
D001615:beta-Endorphin