Xamoterol in hypertrophic cardiomyopathy: effects on diastolic function and heart rate.
The aims of this study were to determine the effects of the partial beta 1-adrenergic agonist, xamoterol, on diastolic function and ambulatory heart rate in hypertrophic cardiomyopathy. Eleven patients with non-obstructive hypertrophic cardiomyopathy were studied with cross-sectional and Doppler echocardiography and 24-h Holter monitoring before and after a single intravenous dose of xamoterol. Resting heart rate (mean +/- SD) increased from 76 +/- 16 before, to 83 +/- 15 beats/min 15 min after xamoterol, p = 0.03. In the 4-h period after xamoterol, maximum heart rate was reduced (127 +/- 21 to 112 +/- 19, p = 0.01) and minimum heart increased (60 +/- 16 to 67 +/- 17, p = 0.04) compared to the same 4-h period of the previous day. There were no significant changes in cross-sectional or Doppler echocardiographic measurements of left ventricular function following xamoterol. Xamoterol stabilises the heart rate in hypertrophic cardiomyopathy. The absence of a significant effect on Doppler measurements does not preclude a beneficial effect on diastolic function. This initial study suggests that xamoterol should be further investigated as a new medical therapy for hypertrophic cardiomyopathy.
Department of Medicine (Clinical Cardiology), Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
D M
DM
Gilligan
R
R
Stewart
W L
WL
Chan
C M
CM
Oakley
D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000188:drug therapy*; D003971:Diastole / Q000187:drug effects*; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011412:Propanolamines / Q000494:pharmacology / Q000627:therapeutic use*; D017307:Xamoterol
D000318:Adrenergic beta-Agonists; D011412:Propanolamines; D017307:Xamoterol