1031-37 Does ACE Inhibition Affect the Response to IV Digoxin?

The efficacy of digoxin (dig) in heart failure patients with normal sinus rhythm is related to a fall in systemic vascular resistance (SVR) caused directly a indirectly by decreased neurohormonal activation. To determine if prior ACE inhibition (ACE-I) limits the hemodynamic effects of IV dig, we compared the response of 26 pts receiving ACE-I to 7 pts not exposed to ACE-I. Mean daily ACE-I doses were enalapril 21 mg or captopril 94 mg. Mean arterial, pulmonary capillary wedge a right atrial pressures (MAP, PCW a RAP mmHg), systemic vascular resistance (SVR, d-s-cl. cardiac index (CI, I/min/M 2 ) heart rate (HR, min -1 ) and ejection fraction (EF, %) were assessed at baseline. Pts were severely ill, with no differences between groups: EF PCW CI MAP HR RAP SVR ACE-I 22 23 1.6 93 91 12 2126 No ACE-I 21 24 1.8 94 97 11 1921 Pts were then given two 0.5 mg doses of dig, 2 hrs apart. Change (Δ) in hemodynamic parameters from before drug administration to 2 hours after the second dose of dig are shown for all pts (ALL) and for pts receiving and not receiving ACE-I, with *  = p l 0.05 v. baseline. ACE-I and No ACE-I pts were compared, with differences between groups shown as †  = p l 0.05 v. ACE-I: ΔPCW ΔCI ΔMAP ΔHR ΔRAP ΔSVR ALL -4 * +0.4 * +7 * -5 * -5 * -218 * ACE-I -3 * +0.4 * +8 * -4 * -4 * -186 No ACE-I -8 * , † +0.5 * +5 -9 * -6 * -335 * p l 005 v. baseline † p l 0.05 v. ACE-I Dig caused a marked hemodynamic response in all pts. However, PCW, RAP. SVR, and HR decreased less in ACE-I pts. Similarly, MAP tended to increase more in pts receiving ACE-I. Conclusion IV dig exerts a marked hemodynamic response in severely ill CHF pts receiving ACE-I. However, ACE-I limits the extent of vasodilation caused by acute digoxin administration.