Cardiac dysrhythmias associated with intravenous lorazepam, diazepam, and midazolam during oral surgery.

The incidence and nature of cardiac dysrhythmias occurring during intravenous sedation with lorazepam, diazepam, and midazolam for oral surgery were studied. Sixty American Society of Anesthesiologists (ASA) I patients of both sexes between the ages 17 and 32 years were randomly allocated to three groups. Groups received either intravenous lorazepam (.05 mg/kg), diazepam (.25 mg/kg), or midazolam (.1 mg/kg) prior to the oral surgical procedure. Electrocardiograms were made before medication and thereafter throughout the entire procedure. Of the 60 patients studied, 16 (26.7%) exhibited dysrhythmias during the surgical procedure. If sinus dysrhythmias were excluded as a cause of abnormal rhythms, only six patients (10%) exhibited dysrhythmias during surgery. No atrial or ventricular premature beats were recorded for the lorazepam group. In the diazepam group five of the patients (25%) exhibited dysrhythmias; 15% were mainly unifocal ventricular premature beats. Only one patient in the midazolam group exhibited unifocal ventricular premature beats.