Theophylline for the treatment of atrioventricular block after myocardial infarction.
OBJECTIVE
To show that second- or third-degree atrioventricular block occurring as an early complication of acute inferior myocardial infarction is mediated by adenosine.


METHODS
Cardiac care unit.


METHODS
Uncontrolled, observational, hypothesis-driven study.


METHODS
Patients who developed clinically significant atrioventricular nodal blockade within 4 hours of admission for acute inferior myocardial infarction.


METHODS
Theophylline, 100 mg/min intravenously to a maximum of 250 mg.


METHODS
Continuous multilead electrocardiographic monitoring before and after administration of theophylline.


RESULTS
During a 6-month period, eight men who had had acute inferior myocardial infarction developed clinically significant atrioventricular block. Three had third-degree block, and five had high-grade second-degree block. In all patients, 1:1 atrioventricular nodal conduction was restored and normal sinus rhythm reappeared within 3 minutes of the administration of theophylline. All patients remained free of arrhythmia for at least 24 hours.


CONCLUSIONS
Adenosine produced by the ischemic myocardium may induce atrioventricular nodal block. In our patients, atrioventricular nodal block was resistant to conventional therapy such as atropine, but it responded to the adenosine antagonist theophylline.
Bertolet
B D
BD
University of Florida Health Sciences Center, USA.
McMurtrie
E B
EB
Hill
J A
JA
Belardinelli
L
L
D000241:Adenosine / Q000037:antagonists & inhibitors* / Q000502:physiology; D000328:Adult; D000368:Aged; D004562:Electrocardiography; D006327:Heart Block / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009203:Myocardial Infarction / Q000150:complications*; D013806:Theophylline / Q000627:therapeutic use*
D013806:Theophylline; D000241:Adenosine