Role of the sympathetic nervous system in supporting cardiac function in essential arterial hypertension.

Treatment of hypertension with sympathetic blocking agents may convert latent cardiac failure into overt failure. Detection of early cardiac insufficiency is desirable. Thirty patients with essential hypertension without history or symptoms of circulatory decompensation were investigated. According to the changes induced by digitalis on the left ventricular mean rates of systolic ejection and isovolumic pressure development, they were divided into 2 groups: group I (non-responders), and group II (responders to digitalis). Seventeen (II randomly selected from group I, and 6 from group II) had treatment with reserpine and guanethidine. Despite the hypotensive response, allfrom group II developed, in about two weeks, obvious clinical and haemodynamic signs of left ventricular impairment, while the iI from group I maintained unchanged cardiac performance. Some of the patients were treated with a diuretic as well as the antihypertensives. The response of mean systolic ejection rates and isovolumic pressure development to digitalis seems a reliable test in estimating the degree of cardiac reserve and in predicting whether the antiadrenergic therapy is liable to induce decompensation. No signs offailure appeared in the patients (ii from group I and 2 from group II) who were treated with the diuretic combined with antiadrenergic drugs. This combination restored to pretreatment levels the parameters of myocardial function which were disturbed by the administration of the antiadrenergic drugs alone. The different effects of chronic and acute administration of antiadrenergic agents on the function of the failing hypertensive heart, and the favourable action of the diuretic, are discussed.