Comparison of the Hemodynamic Effects of Mercurial Diuretics and Digitalis in Congestive Heart Failure

Abstract

The non-xanthine-containing mercurial diuretic mercaptomerin (Thiomerin), a noncardiotonic agent, was given repeatedly to 14 patients with congestive heart failure until all edema fluid had been eliminated. There resulted relief of subjective symptoms and removal of the characteristic physical signs of circulatory congestion to the point where subjects were considered in "cardiac compensation"; reduction of the elevated intracardiac pressures, in the right atrium, right ventricle, and pulmonary artery; variable changes in cardiac function (cardiac output) and cardiocirculatory (arterial-mixed venous oxygen difference) function, with improvement toward normal in half of the patients and no change in the other half. In subjects in whom full mercurial diuresis alone improved the cardiac and cardiocirculatory functions, subsequent digitalization produced no further improvement in these functions. These patients were in a first or second episode of cardiac decompensation. In subjects in whom full diuresis alone did not alter the cardiac and cardiocirculatory dynamics, subsequent digitalization produced an increase in cardiac output and a decrease in A-V oxygen difference toward normal values. These subjects usually had had one or several previous episodes of congestive failure. When there was persistent chronic congestive heart failure, neither mercurial diuretic nor digitalis therapy altered the low cardiac output or the high A-V oxygen difference. Removal of the edema and vascular congestion by diuresis alone nevertheless produced subjective improvement. In those patients in whom an increase in cardiac output occurred as the mercurial diuretic eliminated edema and lowered the elevated intracardiac pressures, the response may be considered consistent with Starling's law of the heart in man in congestive heart failure. The data clearly make the point that it is the circulatory congestion that produces the symptoms and the physical signs traditionally considered characteristic of congestive heart failure. Removal of the circulatory congestion, however accomplished, relieves the symptoms and physical signs of congestive heart failure, regardless of whether or not cardiac function is improved toward the normal. Circulatory congestion does not necessarily indicate, nor correlate with, the status of cardiac function.