Effects of low dose transdermal scopolamine on heart rate variability in acute myocardial infarction.
OBJECTIVE
We hypothesized that by enhancing parasympathetic activity, low dose transdermal scopolamine would increase heart rate variability after myocardial infarction.


BACKGROUND
Low heart rate variability is associated with increased mortality after acute myocardial infarction.


METHODS
Conventional time domain heart rate variability was measured from 24-h Holter recordings of 61 consecutive male patients (mean age 58 +/- 10 years, left ventricular ejection fraction 44.7 +/- 15.5%) 6 days (median) after acute myocardial infarction. Patients were then randomly assigned to wear one patch of transdermal scopolamine or a matching placebo patch for 24 h, during which their 24-h heart rate variability was remeasured.


RESULTS
Compared with placebo, transdermal scopolamine caused a significant increase in time domain measures of 24-h heart rate variability by 26% to 35% above baseline. Transdermal scopolamine was well tolerated.


CONCLUSIONS
Low dose transdermal scopolamine safely increases cardiac parasympathetic activity and short-term heart rate variability after acute myocardial infarction. Whether the effect of transdermal scopolamine on heart rate variability is a reasonable surrogate for improvement of long-term morbidity and mortality requires an appropriate designed investigation.
Vybiral
T
T
Department of Medicine, Baylor College of Medicine, Houston, Texas.
Glaeser
D H
DH
Morris
G
G
Hess
K R
KR
Yang
K
K
Francis
M
M
Pratt
C M
CM
D000279:Administration, Cutaneous; D000368:Aged; D004311:Double-Blind Method; D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology*; D010275:Parasympathetic Nervous System / Q000187:drug effects; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D013268:Stimulation, Chemical; D013318:Stroke Volume; D013997:Time Factors
D012601:Scopolamine