Differences in plasma beta-endorphin and bradykinin levels between patients with painless or with painful myocardial ischemia.
To verify whether plasma beta-endorphin and bradykinin affects the pathophysiology of myocardial ischemia and the perception of cardiac pain, 35 patients with coronary artery disease were subjected to treadmill testing and 48-hour Holter ECG monitoring to measure their pain thresholds. Patients were divided into two groups during exercise testing: group 1 (N = 19) who had ST segment depression, and group 2 (N = 16), who had chest pain. Both groups were then compared with 12 age-matched control subjects. Pain thresholds were measured after Holter ECG monitoring, and blood samples were drawn before and immediately after exercise. No statistical differences were noted between groups 1 and 2 with regard to the severity of myocardial ischemia as assessed by ST segment depression or exercise tolerance time. The frequency of the episodes of silent myocardial ischemia in group 1 was found to be significantly (p less than 0.05) higher than that in group 2. The duration of the episodes of silent myocardial ischemia in group 1 was 41.9 minutes (range 3 to 343 minutes), which was significantly (p less than 0.05) longer than that in group 2 (11.5 minutes; range 0 to 74). The pain threshold in group 1 was a statistically (p less than 0.05) higher value than that in group 2. Although the resting plasma beta-endorphin level in group 1 was not statistically significantly different from values in either group 2 or the control group, during exercise the plasma beta-endorphin levels in both group 1 and the control group were significantly (p less than 0.05) elevated in comparison with their resting levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Kurita
A
A
Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Takase
B
B
Uehata
A
A
Sugahara
H
H
Nishioka
T
T
Maruyama
T
T
Satomura
K
K
Mizuno
K
K
Nakamura
H
H
D001920:Bradykinin / Q000097:blood*; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010465:Perception / Q000502:physiology; D012307:Risk Factors; D012684:Sensory Thresholds / Q000502:physiology; D001615:beta-Endorphin / Q000097:blood*
D001615:beta-Endorphin; D001920:Bradykinin