Hormone and Haemodynamic Effects of Angiotensin II Infusion during Captopril Treatment for Heart Failure

Summary

Withdrawal of captopril therapy for cardiac failure results in increments in plasma cortisol, noradrenaline and heart rate. To determine whether these changes related to the concomitant rise in circulating angiotensin II, we infused angiotensin II at 0.5, 2, 4 and 8 ng/kg/minute, each infusion lasting for 1 hour, in 4 patients during maintenance captopril therapy for heart failure. A control solution of 5% dextrose was infused over a similar time interval on a separate day. The study was performed under metabolic balance conditions, with constant body posture and continuous haemodynamic monitoring.

Angiotensin II induced the expected rise in arterial pressure and in plasma aldosterone. In contrast the diurnal decline in plasma ACTH and cortisol was not altered, and no changes in noradrenaline or heart rate were observed.

Plasma angiotensin II appears to have little or no effect on ACTH, cortisol, noradrenaline and heart rate under the conditions of this study.

Key-Words:

Heart Failure - Angiotensin II - Captopril - Cortisol - Aldosterone - Noradrenaline