[Metoprolol prevents myocardial ischemia during endoscopic retrograde cholangiopancreatography]

The aim of our study was to evaluate the effect of metoprolol on the occurrence of myocardial ischaemia during endoscopic cholangiopancreatography. Thirty-eight (2 x 19) patients scheduled for endoscopic cholangiopancreatography received either metoprolol 100 mg or placebo two hours before endoscopy. During endoscopy, arterial oxygen saturation was measured by continuous pulse oximetry, and the electrocardiogram was monitored continuously with a Holter tape recorder. Myocardial ischaemia was defined as an ST segment deviation > 1 mV from baseline. Heart rate during endoscopy was significantly lower in the metoprolol group compared with the placebo group (p = 0.0002). Twenty-one patients (16 placebo versus five metoprolol, p = 0.0008) developed tachycardia (heart rate > 100/min) during the procedure. A total of eleven patients (ten placebo versus one metoprolol, p = 0.003) developed myocardial ischaemia during the procedure, and myocardial ischaemia was always related to increases in heart rate. In conclusion, metoprolol prevented myocardial ischaemia during endoscopic cholangiopancreatography, probably through a heart rate lowering effect. Thus, tachycardia seems to be a key pathogenic factor in the development of myocardial ischaemia during endoscopy.