The effects of the partial beta 1-agonist xamoterol on heart rate and ventricular arrhythmias in patients with mild to moderate heart failure.
A major concern with the use of oral inotropes in chronic heart failure is their propensity to exacerbate cardiac arrhythmias. In a double-blind randomized placebo-controlled crossover study of xamoterol, a novel beta 1-partial agonist, 24 h ambulatory electrocardiograms were obtained in 26 patients prior to and at the end of 13-week treatment periods. During treatment with xamoterol there was no significant change in mean hourly number of ventricular extrasystoles compared with baseline and placebo (30 +/- 17 vs 56 +/- 42 and 18 +/- 7, respectively), or in the number of patients showing complex forms (multiform VEs, pairs, ventricular tachycardia) (20/26 vs 19/26 and 19/26, respectively), or ventricular tachycardia alone (5/26 vs 4/26 and 6/26, respectively). Xamoterol therapy also stabilized heart rate variability over the 24 h period.
Virk
S J
SJ
Department of Cardiovascular Medicine, University of Birmingham, East Birmingham Hospital, U.K.
Anfilogoff
N H
NH
Lawson
N
N
Qiang
F
F
Murray
R G
RG
Littler
W A
WA
Davies
M K
MK
D000318:Adrenergic beta-Agonists / Q000494:pharmacology* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D002940:Circadian Rhythm / Q000502:physiology; D004311:Double-Blind Method; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test / Q000187:drug effects; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011412:Propanolamines / Q000494:pharmacology* / Q000627:therapeutic use; D012044:Regression Analysis; D017307:Xamoterol
D000318:Adrenergic beta-Agonists; D011412:Propanolamines; D017307:Xamoterol; D009638:Norepinephrine