Inotropic effect of enoximone in patients with severe heart failure: demonstration by left ventricular end-systolic pressure-volume analysis.
Left ventricular end-systolic pressure-volume analysis was employed to assess the inotropic effect of the phosphodiesterase inhibitor enoximone (formerly MDL-17,043) in nine patients with severe heart failure (New York Heart Association class IV symptoms, mean ejection fraction = 0.22). Left ventricular pressure-volume loops were constructed using high fidelity left ventricular pressure measured with micromanometer-tipped catheters and simultaneous left ventricular volume obtained by gated blood pool imaging. Afterload was reduced with the vasodilator nitroprusside to generate the baseline left ventricular end-systolic pressure-volume relation, a relatively load-independent measure of contractile function. The intravenous administration of enoximone (mean dose 75 mg) shifted the end-systolic pressure-volume point upward and leftward from the baseline pressure-volume relation in eight of the nine patients, demonstrating a positive inotropic effect of this agent. The maximal rate of left ventricular pressure development (peak positive dP/dt) increased from 1,030 +/- 142 to 1,381 +/- 219 mm Hg/s (p less than 0.01) on enoximone despite a significant decrease in preload (as assessed by left ventricular end-diastolic pressure and volume) and a small, insignificant decrease in mean arterial pressure. Two patients developed angina after enoximone administration; both patients had coronary artery disease and experienced a greater than 30% increase in heart rate-systolic blood pressure product. Thus, enoximone has a significant inotropic effect in patients with severe heart failure. Like other inotropic drugs, it has the potential to increase myocardial oxygen demand and thereby precipitate ischemia.
D001794:Blood Pressure; D001810:Blood Volume; D017335:Enoximone; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology; D006352:Heart Ventricles; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D009599:Nitroprusside / Q000627:therapeutic use; D013599:Systole
D007093:Imidazoles; D009599:Nitroprusside; D017335:Enoximone