Our purpose was to evaluate the efficacy of antiarrhythmic drugs (AADs) in recurrent
ventricular fibrillation (VF) associated with inferolateral early repolarization pattern
on the electrocardiogram.
Although an implantable cardioverter-defibrillator is the treatment of choice, additional
AADs may be necessary to prevent frequent episodes of VF and reduce implantable cardioverter-defibrillator
shock burden or as a lifesaving therapy in electrical storms.
From a multicenter cohort of 122 patients (90 male subjects, age 37 +/- 12 years)
with idiopathic VF and early repolarization abnormality in the inferolateral leads,
we selected all patients with more than 3 episodes of VF (multiple) including those
with electrical storms (> or =3 VF in 24 h). The choice of AAD was decided by individual
physicians. Follow-up data were obtained for all patients using monitoring with implantable
defibrillator. Successful oral AAD was defined as elimination of all recurrences of
VF with a minimal follow-up period of 12 months.
Multiple episodes of VF were observed in 33 (27%) patients. Electrical storms (34
+/- 47 episodes) occurred in 16 and were unresponsive to beta-blockers (11 of 11),
lidocaine/mexiletine (9 of 9), and verapamil (3 of 3), while amiodarone was partially
effective (3 of 10). In contrast, isoproterenol infusion immediately suppressed electrical
storms in 7 of 7 patients. Over a follow-up of 69 +/- 58 months, oral AADs were poorly
effective in preventing recurrent VF: beta-blockers (2 of 16), verapamil (0 of 4),
mexiletine (0 of 4), amiodarone (1 of 7), and class 1C AADs (2 of 9). Quinidine was
successful in 9 of 9 patients, decreasing recurrent VF from 33 +/- 35 episodes to
nil for 25 +/- 18 months. In addition, quinidine restored a normal electrocardiogram.
Multiple recurrences of VF occurred in 27% of patients with early repolarization abnormality
and may be life threatening. Isoproterenol in acute cases and quinidine in chronic
cases are effective AADs.