Long-term prognosis of inducible ventricular flutter: Not an innocent finding

Background The prognostic significance of ventricular flutter (VFL) induced during programmed electrical stimulation (PES) is currently unknown. Methods This study examined patients who had PES-induced VFL and assessed their long-term prognosis compared with patients who had inducible sustained monomorphic ventricular tachycardia (SMVT). Results Of 3414 patients undergoing PES, 74 (2%) had sustained VFL. They were compared with a group of 71 patients undergoing PES in the same time frame who had inducible SMVT. Patients with inducible VFL had a higher ejection fraction than patients with SMVT (0.39 vs 0.33; P = .05). More aggressive pacing was required for arrhythmia induction in patients with VFL, with more stimuli (2.7 ± 0.5 vs 2.2 ± 0.6; P <.01) and tighter S₂, S₃, and S₄ intervals. After a mean follow-up of 30 ± 31 months, the mortality rate was 34% in patients with VFL and 30% in patients with SMVT (P = .41). No difference in the 2 groups in overall survival or a combined end point of sudden death or appropriate implantable cardioverter defibrillator shock was revealed with Kaplan-Meier analysis. Conclusion The long-term prognosis of patients with inducible VFL is similar to that of patients with inducible SMVT, even when VFL is induced with a relatively aggressive protocol.