Arrhythmias associated with intermittent outpatient dobutamine infusion.

The use of intermittent outpatient dobutamine infusion has recently been studied as an alternative therapy modality for patients with refractory congestive heart failure. We studied the arrhythmogenic effects of intermittent outpatient dobutamine infusion in two patients with NYHA class IV heart failure. The patients received dobutamine at 5mcg./kg./min. for four hours per day for an eight week period. Ambulatory Holter monitoring was obtained during the infusion periods and compared to infusion-free periods. A significant increase of complex ventricular arrhythmias, including multifocal PVC's and ventricular tachycardias, was observed during the infusion period. The incidence of complex ventricular ectopy was dose related and could be suppressed to baseline levels with appropriate antiarrhythmic therapy. We concluded that dobutamine is extremely arrhythmogenic when used in patients with heart failure and that this effect was controllable with antiarrhythmics. Extreme caution and careful monitoring is required for this new therapeutic modality in the treatment of refractory heart failure.