The effect of the partial beta-1-adrenoceptor agonist xamoterol on hemodynamics and myocardial energetics in patients with idiopathic dilated cardiomyopathy.
Xamoterol, a new partial beta 1-adrenoceptor agonist, was evaluated in respect to its hemodynamic and energetic effects when given acutely i.v. (0.2 mg/kg body weight) to 10 patients with idiopathic dilated cardiomyopathy. Hemodynamically, a small drop in left ventricular end-systolic volume index (from 105 +/- 38 to 91 +/- 48 ml/m2; p less than 0.05) and end-diastolic volume index (from 168 +/- 44 to 152 +/- 41 ml/m2; p less than 0.05) and an increase in maximum rate of left ventricular pressure rise (from 1,003 +/- 358 to 1,283 +/- 398 mm Hg/s; p less than 0.001) was observed. The systolic stress-time integral was only slightly reduced after injection of xamoterol, from 107 +/- 28 to 94 +/- 35 x 10(3) dyn.s/cm2 (NS). Other conventional hemodynamic variables did not change significantly. Myocardial oxygen consumption per beat increased from 125 +/- 39 microliters/beat/100 g to 153 +/- 62 microliters/beat/100 g (p less than 0.05). The ratio of myocardial oxygen consumption per beat and stress-time integral--as an inverse measure of left ventricular contraction economy--increased significantly, from 132 +/- 62 to 192 +/- 115 microliters/beat/10(3) dyn.s/cm2 (p less than 0.02) after injection of xamoterol, whereas left ventricular efficiency decreased from 17.6 +/- 7.8 to 13.8 +/- 6.5% (p less than 0.05). Thus, in idiopathic dilated cardiomyopathy, xamoterol exhibited only minor hemodynamic effects whereas myocardial contraction economy and efficiency were significantly reduced.
Thierfelder
L
L
Department of Medicine, Cardiology, University of Freiburg, Germany.
Holubarsch
C
C
Hasenfuss
G
G
Heiss
H W
HW
Just
H
H
D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000378:metabolism; D003326:Coronary Circulation; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D006321:Heart / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology*; D017307:Xamoterol
D011412:Propanolamines; D017307:Xamoterol