Significance of inducible ventricular flutter/fibrillation in risk stratification in patients with coronary artery disease

Background: Although inducible ventricular fibrillation (VF) has been used as an indication for prophylactic implantation of cardioverter-defibrillators (ICDs) in patients with coronary artery disease (CAD), the significance of inducible VF remains controversial. Methods: Among 364 CAD patients who underwent electrophysiologic (EP) study for risk stratification, 23 patients, 12 without any history of VF or cardiac arrest (group A) and 11 with previously documented VF or cardiac arrest (group B), exhibited inducible ventricular flutter (VFL) or VF and subsequently underwent ICD implantation. Additionally, 11 CAD patients without previous VF or cardiac arrest, who had no inducible ventricular tachyarrhythmias but received an ICD, were included for comparison (group C). Results: During 2 years of follow-up, 1 (8%), 5 (45%), and 1 (9%) patients had appropriate ICD shocks in groups A, B, and C, respectively. The survival free from appropriate ICD shocks was significantly lower in group B compared to groups A and C (p<0.05). There were no significant differences in age, sex, ejection fraction (EF), or induction protocol between groups A and B or between groups A and C. Conclusions: In CAD patients with inducible VFL/VF, patients without any history of VF or cardiac arrest had significantly lower incidence of appropriate ICD shocks when compared to those with such clinical events. Conversely, in CAD patients without any history of VF or cardiac arrest, incidence of appropriate ICD shocks was similar regardless of inducible VFL/VF. Inducible VFL/VF is therefore not useful as an indication for prophylactic ICD implantation in this patient population.