Elevated plasma beta-endorphin levels in patients with congestive heart failure
S Kawashima,
N Fukutake,
K Nishian,
S Asakuma,
and
T Iwasaki
First Department of Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
Recent experimental studies show that the opioid system is important to the pathophysiology of cardiovascular impairment in congestive heart failure. Plasma beta-endorphin levels were measured in 37 patients with congestive heart failure and compared with those of 21 age- and gender-matched normal subjects. The relation of plasma beta-endorphin levels and cardiac function at rest and exercise capacity was assessed in 17 of the patients with dilated cardiomyopathy. Exercise capacity was determined by symptom-limited maximal treadmill exercise with expired gas analysis. Plasma beta-endorphin levels were elevated and correlated with the patients' New York Heart Association functional cardiac status (control: 14.0 +/- 4.4 pg/ml; class II: 17.9 +/- 3.6 pg/ml; class III: 28.3 +/- 8.8 pg/ml; class IV: 46.7 +/- 14.6 pg/ml, mean +/- SD). No relation was found between plasma beta-endorphin levels and left ventricular systolic performance as assessed by M-mode and Doppler echocardiography. Plasma beta-endorphin levels were negatively correlated with cardiac output determined by Doppler echocardiography and positively correlated with systemic vascular resistance (r = -0.733, r = 0.747, respectively, both p less than 0.001), but not correlated with calf blood flow as measured by a plethysmography. A good correlation was found between plasma beta-endorphin levels at rest and exercise capacity. The correlations with peak oxygen consumption, anaerobic threshold, and peak rate-pressure product were r = -0.721, -0.672, and -0.674, respectively (p less than 0.01). The data show that plasma beta-endorphin levels are elevated in patients with congestive heart failure and reflect, to some degree, the severity of the disease.
