Induction of Paroxysmal Supraventricular Tachycardia

mg, mean ± SD) of disopyramide for three to five doses over 24 hours and were then restudied. All patients had inducible, sustained PSVT during the control study. After disopyramide, PSVT was noninducible in eight patients (50%), including six of nine with atrioventricular nodal reentrance and two of seven with atrioventricular reentrance; inducible but nonsustained in two (12.5%) (both with atrioventricular reentrance); and inducible and sustained in six (37.5%). The benefit of disopyramide seemed predominantly to reflect depression of conduction in the retrograde limb of the circus movements, aIthough effects upon the antegrade limb were also observed. In the eight patients with inducible PSVT before and after disopyramide, tachycardia cycle length increased from 348 ± 33 to 404 ± 29 msec (mean i SEM) (p < 0.001). These results suggest that disopyramide would be effective in preventing recurrence of clinical PSVT in selected patients.