EFFICACY OF DIGOXIN ADMINISTRATION IN DOGS WITH IDIOPATHIC CONGESTIVE CARDIOMYOPATHY

  • 1 January 1985
    • journal article
    • research article
    • Vol. 186  (2) , 162-165
Abstract
Digoxin administration (0.22 mg/m2 of body surface BID [twice daily]) to 10 large-breed dogs with congestive cardiomyopathy increased shortening fraction > 5.5% in 4 of the dogs. This group of dogs lived longer than the group that did not have a positive inotropic response to digoxin. Heart rate decreased in both groups of dogs. Base-line jugular PvO2 [mixed venous O2 partial pressure] were low in all dogs. Jugular PvO2 decreased significantly in the group that did not respond to digoxin, presumably because of decreased cardiac output. Jugular PvO2 consistently increased in dogs that had a positive inotropic response to digoxin. Base-line shortening fraction, heart rate and PvO2 did not predict which dogs would respond to digoxin. Serum digoxin concentrations were consistently between 1.5 and 2.5 ng/ml. Digoxin administration evidently is not efficacious in all dogs with congestive cardiomyopathy. The positive inotropic response is not predicted by base-line shortening fraction, heart rate or jugular PvO2. Dogs that do respond to digoxin usually live longer than those that do not. Jugular PvO2 can be used to separate dogs that do respond from dogs that do not respond to digoxin as long as the base-line PvO2 is low. The negative chronotropic effects of digoxin may be detrimental to dogs that do not have a positive inotropic effect from digoxin.