Oral versus intravenous amiodarone

AV: atrioventricular; A-H interval: time from initial rapid deflection of the atrial wave to the initial rapid deflection of the His bundle potential; H-V interval: time from initial deflection of the His bundle potential to the onset of ventricular activity; +: yes or present; -: no or absent; ↑ : increase; ↓: decrease.
Comparison of the electropharmacologic effects of oral and intravenous amiodarone. Compared with oral amiodarone, the intravenous preparation produces a much lesser increase in the action potential duration in atrial and ventricular myocardium and a minimal increase in the atrial and ventricular refractory periods. As a result, there is little or no increase in QRS duration and the QT interval, respectively. Intravenous amiodarone also has little effect on sinus cycle length and has vasodilator activity that triggers an increase in sympathetic activity; both of these effects result in little or no slowing of the sinus rate. Lastly, the intravenous preparation may have more potent and more rapid antiadrenergic activity.