Atrioventricular block after administration of atropine in patients following cardiac transplantation.
BACKGROUND
Atropine is widely used as a parasympatholytic agent during diagnostic and therapeutic procedures. We observed an unexpected paradoxical response to atropine after cardiac transplantation.


METHODS
In a study investigating the occurrence of autonomic reinnervation after cardiac transplantation, atropine, at 0.015 mg/kg body weight, was given intravenously to 23 patients (mean age, 56+/-8 years) 98 days to 6.4 years after transplantation.


RESULTS
Two patients experienced a witnessed syncope 40 and 150 min after administration of atropine. Second-degree atrioventricular (AV) block was documented in the first patient immediately afterward, and third-degree AV block was seen on 24-hr electrocardiogram monitoring in the second patient. A third patient developed documented AV block 15 min after atropine but experienced no sequelae because of a previously implanted pacemaker.


CONCLUSIONS
Although the underlying mechanism is not clear, these findings suggest that atropine may paradoxically cause high-degree AV block in patients after transplantation. Accordingly, it should be used with caution and appropriate monitoring in these patients.
Brunner-La Rocca
H P
HP
Division of Cardiology, University Hospital Zurich, Switzerland.
Kiowski
W
W
Bracht
C
C
Weilenmann
D
D
Follath
F
F
D000328:Adult; D001285:Atropine / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000139:chemically induced*; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010276:Parasympatholytics / Q000009:adverse effects*
D010276:Parasympatholytics; D001285:Atropine