Some adverse cardiodynamic effects of prostaglandin E₂ in congestive heart failure

The cardiodynamic effects of prostaglandin E₂ (PGE₂) were studied in both healthy sheep and in animals with congestive heart failure (CHF). Merino ewes were equipped surgically with high fidelity micromanometers and left ventricular pressures measured. Heart rate, left ventricular systolic and end-diastolic pressures, +dP/dt and T(In) were calculated on a computer from the recorded pressure curves. The paired t-test was used to determine the statistical significance of the differences. PGE₂ (25 μg/kg) significantly improved the cardiac contractility and relaxation rate of healthy sheep and significantly reduced the heart rate, while the loading conditions under which the heart operates were not significantly affected. In contrast to healthy sheep, PGE₂ significantly reduced the contractility and relaxation rate of sheep with congestive heart failure and significantly increased the preload while heart rate and afterload were significantly reduced. The study suggests that despite the promising vasodilatory, positive inotropic and relaxation rate actions of PGE₂ in normal hearts, PGE₂ might not be a suitable therapeutic agent for CHF, because of the worsening effect it has on the cardiodynamics and loading conditions of the failing heart.