RAPID INTRAVENOUS-INFUSION OF D-1 SOTALOL - TIME TO ONSET OF EFFECTS ON VENTRICULAR REFRACTORINESS, AND SAFETY

d-1 sotalol is one of the most effective antiarrhythmic agents current ly available for ventricular tachyarrhythmias, but the recommended inf usion rate of 10-20 min is too slow for rapid pharmacological terminat ion of sustained ventricular tachycardia (VT) or for use during cardia c arrest. The safety of the drug and time lag from its rapid administr ation to onset of significant effects on ventricular refractoriness is unknown. One hundred and nine patients with a history of spontaneous and inducible sustained ventricular tachyarrhythmias were studied. d-1 sotalol (1.5 mg. kg(-1)) was infused over 5 min in the first 57 patie nts (mean age 61 +/- 13 years, mean ejection fraction 37 +/- 15%, rang e 15-70%). d-1 sotalol was then given over 1 min in the next 52 patien ts (mean age 61 +/- 12 years, mean ejection fraction 35 +/- 11%, range 18-58%). The time course of change in right ventricular effective ref ractory period (RVERP) was measured in 15 consecutive patients followi ng the 5 min infusion and in all 52 patients following the bolus injec tion. Following the 5 min infusion, RVERP increased rapidly from a bas eline of 231 +/- 17 ms, reaching a plateau of 268 +/- 23 ms at 10 min. Following the 1 min injection, RVERP increased virtually immediately from a baseline of 237 +/- 25 ms to reach a plateau of 271 +/- 31 ms a t 5 min. Two patients (one in each group) developed symptomatic hypote nsion; both responded to volume replacement. Rapid intravenous infusio n of d-1 sotalol has a rapid onset of electrophysiological effects and a low incidence of adverse effects, even in patients with poor left v entricular function.