to evaluate the mechanism of the effect of the interaction of digoxin and quinidine on myocardial contractility , ferret right ventricular papillary muscles were isolated and the effects of digoxin , 4 x 10 ( -7 ) m , quinidine , 1 x 10 ( 5 ) m and atropine , 1.5 x 10 ( -6 ) m , on peak developed force , peak rate of development of force ( df/dt ) and time to peak tension were determined .
C0027061
myocardial
C0030352
papillary