Diazepam or midazolam for external DC cardioversion (the DORM Study)

To compare the clinical efficacy and tolerability of two intravenous sedatives for physician-led DC cardioversion of atrial arrhythmias.

One hundred and forty-one patients attending for elective DC cardioversion of atrial arrhythmias were randomized to intravenous midazolam or diazepam. Sedation was administered using titration protocols. Procedure times, operator satisfaction scores and adverse events were documented. The patients immediate, 24- and 48-h recall and awareness of after-effects were obtained from questionnaires. Seventy-one patients received midazolam (mean 12.5 mg) and 70 patients received diazepam (mean 28.1 mg). There were 16 minor adverse events with midazolam (20% hypotension, 3% oxygen desaturation) and nine with diazepam (7% hypotension, 6% required additional analgesia), P = 0.14. There were no major adverse events. Sedation time was 5.0 +/- 3.4 min for midazolam and 6.5 +/- 3.4 min for diazepam (P = 0.0016). Patients awoke 77 +/- 46 min post-sedation with midazolam and 39 +/- 24 min with diazepam (P < 0.0001). There was no recall of the procedure at 48 h and no difference in awareness of after-effects between the two groups at 24 or 48 h, P = ns.

Physician-led cardioversion of atrial arrhythmias using intravenous sedation is effective and well tolerated. Sedation with diazepam was associated with fewer minor adverse events and a quicker recovery time than midazolam.