Induction of ventricular fibrillation rather than ventricular tachycardia predicts tachyarrhythmia recurrences in patients with idiopathic dilated cardiomyopathy and implantable cardioverter defibrillator for secondary prophylaxis.

AIMS: We sought to investigate the association of inducibility of polymorphic ventricular tachycardia or ventricular fibrillation (PVT/VF) or sustained monomorphic ventricular tachycardia (SMVT) at standardized programmed ventricular stimulation (PVS) with the long-term likelihood of sudden death and/or fast VT in a large cohort of patients with idiopathic non-ischaemic dilated cardiomyopathy (DCM) and implantable cardioverter defibrillator (ICD) for secondary prophylaxis. METHODS AND
RESULTS: Between 1994 and 2007, 160 consecutive patients with DCM and spontaneous sustained VT/VF or cardiac arrest underwent PVS prior to ICD implantation. Outcome data, particularly probability of survival without (sudden) death or appropriate ICD therapies for fast VT, were assessed during long-term follow-up. PVT/VF was induced in 50 (31%) and SMVT in 30 (19%) patients. During a mean follow-up of 53 +/- 15 months, we observed 19/50 (38%), 10/30 (33%), and 14/80 (18%) deaths in the PVT/VF, SMVT, and non-inducible group, respectively. These deaths were sudden in 7/50 (14%), 2/30 (7%), and 0/80 (0%) of patients, respectively. At least one fast VT was treated by the ICD in 26/50 (52%), 6/30 (20%), and 22/80 (28%) patients, respectively. PVT/VF but not SMVT-inducible patients had a significantly worse overall survival (log-rank P = 0.013), survival without sudden cardiac death (P < 0.01), or survival without fast VT (P < 0.01) according to Kaplan-Meier method than non-inducible patients. Additionally, survival free of fast VT was significantly worse in PVT/VF vs. SMVT-inducible patients (P < 0.01).
CONCLUSION: Inducibility of PVT/VF is a much stronger predictor of recurrences of fast VT as opposed to SMVT induction in DCM patients with ICD for secondary prevention.