Effects of Acute Digitalization

Basic hemodynamic data and the pulmonary blood volume (PBV) were determined in 23 patients before and after intravenous administration of acetyl strophanthidin during right and left heart catheterization. These patients were divided into two groups depending upon whether or not digitalization produced a significant fall in left ventricular end-diastolic pressure (LVD). Group I consisted of 11 patients who manifested a significant decrease in LVD, while in group II no change was noted after digitalization. In both groups, a significant rise in LV stroke volume, stroke work, and maximal rate of rise of LV systolic pressure (dp/dt) was recorded. In group I, a significant decrease in the pulmonary vascular distending pressure (Pd) was accompanied by a decrease in PBV. In contrast, no change in Pd or PBV was noted in the patients in group II. Changes in pulmonary vascular resistance (PVR) were inconsistent. It is concluded that: (1) in patients of group I the concordant decrease in Pd and PBV represented a passive effect on the pulmonary vascular bed mediated by improved LV performance and decrease in LVD; (2) in patients of group II, despite evidence of significant positive inotropic effects on the left ventricle, the failure of LVD to fall prevented a decrease in Pd and PBV; (3) no evidence of active vasomotor effects of acetyl strophanthidin in the lung could be demonstrated. Changes in PVR