Studies on the Effect of the Action of Digitalis on the Output of Blood From the Heart. Iii. 12

Studies on Digitalis. Ii. Extracardiac Effects on Venous Return and on the Capacity of the Peripheral Vascular Bed

“…The decline in cardiac output following the administration of digitalis to experimental animals (1)(2)(3)(4)(5) and to normal human subjects (6)(7)(8)(9)(10) would appear to be inconsistent with the well known positive inotropic action of this drug. The latter has been further confirmed by direct measurement of myocardial contractile force in both man and dog in the absence of heart failure ( 5,11,12).…”

Studies on Digitalis. Ix. Effects of Ouabain on the Nonfailing Human Heart

“…The applicability of these observations to the normal heart in intact human subjects is limited because the possibility cannot be excluded that depression of myocardial contractility by the anesthetic agents and the surgical exposure of the heart modified the response to the digitalis glycoside in the animal experiments. Hemodynamic studies in subjects with normal hearts and in patients with heart disease without congestive heart failure have suggested that digitalis does not improve myocardial contractility, and may even have a depressing effect, since its administration results either in no change in the cardiac output, or in a decline (5)(6)(7)(8)(9). It is now clear that measurement of the cardiac output alone does not necessarily provide an assessment of ventricular contractility (10).…”