Study Question: Is IV metoprolol or IV diltiazem better able to achieve hemodynamically stable rate control in noncardiac, nonthoracic (NCNT) surgical patients with postoperative atrial fibrillation (POAF)?
Study Description: This was a retrospective cohort study of adult NCNT surgical patients with POAF who received initial therapy with either IV metoprolol or IV diltiazem. Exclusion criteria included pacemaker presence, direct current cardioversion or new rate or rhythm control interventions within one hour of study drug initiation. The primary endpoint was achievement of hemodynamically stable rate control (HR < 110 bpm and SBP > 90 mmHg maintained for ≥ 6 hours) after the patient’s initial POAF episode.
Results: The baseline characteristics between the metoprolol (n = 66) and diltiazem (n = 55) cohorts were similar across all recorded parameters including surgical procedure, rate control regimens prior to admission, and vital signs. Significantly more patients receiving diltiazem achieved hemodynamically stable rate control than those receiving metoprolol (76% vs. 53%, p = 0.005). Electrolyte balance in addition to necessity of fluid boluses or new vasopressors for hemodynamic support were comparable between groups. No patients were readmitted to the ICU for recurrent AF.
Conclusion(s): NCNT surgical patients treated with IV diltiazem monotherapy for POAF achieved hemodynamically stable rate control more often than those receiving IV metoprolol.
Perspective: It is important to note that of the 524 POAF patients screened, 233 (44%) required multiple new interventions for treatment of PAOF. A smaller portion (n = 121, 23%) of patients received monotherapy with either IV metoprolol or IV diltiazem. Thus, both agents may have a place in therapy; however, when using a single agent, patients receiving IV diltiazem may have a better hemodynamic response. The dosing strategies utilized are also essential considerations as a majority (n = 45, 82%) of the IV diltiazem patients received a bolus dose prior to the start of a continuous infusion. Dose escalation in both groups occurred in initial therapy non-responders.