[The hypertensive heart. VI. Ventricular function and coronary artery haemodynamics as influnced by digitalis glycosides (author's transl)].

The effect of intravenous digoxin (0.01 mg/kg) on ventricular function, coronary arterial haemodynamics and myocardial oxygen uptake was studied in 12 patients with essential hypertension but no heart failure, significant left ventricular hypertrophy and normal coronary arteriogram. There was a definite, velocity-related increase in the inotropic function of the left ventricle, by 19.4%, 50 min after digoxin injection, while ventricular pumping function decreased by between 6.5 and 11.2%. Coronary blood flow through the left ventricle decreased by 8.8%. On the other hand, coronary vascular resistance and coronary arteriovenous oxygen difference increased by 11 and 5.9%, respectively. Oxygen uptake remained essentially unchanged (-2.1%). These results indicate that the increase in inotropism caused by intravenous digoxin in essential hypertension without heart failure produces not only no therapeutically useful improvement in left ventricular pumping function: there is also a coronary constrictor and ischaemia-inducing effect on the coronary arterial system.