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Prognostic usefulness of programmed ventricular stimulation in idiopathic dilated cardiomyopathy without symptomatic
Insights
Programmed electrical stimulation can induce ventricular arrhythmias in about 40% of dilated cardiomyopathy patients. Inducible polymorphic ventricular tachycardia or fibrillation doesn't predict sudden death, but unimorphic VT may indicate future events.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure
Background:
- Idiopathic dilated cardiomyopathy (DC) is a significant cause of heart failure.
- Risk stratification for sudden cardiac death in DC patients is crucial.
- Predictive markers for ventricular arrhythmias in asymptomatic DC patients are needed.
Purpose of the Study:
- To evaluate the inducibility of ventricular arrhythmias (VA) via programmed electrical stimulation in patients with idiopathic DC.
- To determine if inducible VA correlates with clinical, hemodynamic, or prognostic factors.
- To assess the predictive value of inducible VA for future cardiac events, including sudden death.
Main Methods:
- Twenty-four patients with idiopathic DC and no history of symptomatic ventricular arrhythmias underwent right ventricular programmed stimulation.
- Stimulation protocols included up to three extrastimuli.
- Patients were followed for a mean of 12 months for clinical outcomes.
Main Results:
- Ventricular tachycardia (VT) was induced in 8 patients (33%), and ventricular fibrillation (VF) in 2 (8%).
- Polymorphic VT or VF was induced in 6 and 2 patients, respectively; unimorphic VT in 2.
- No significant differences in baseline characteristics were observed between inducible and non-inducible groups.
- Four deaths occurred during follow-up (3 sudden, 1 heart failure); only 1 sudden death patient had inducible VT.
- One patient with induced sustained unimorphic VT later experienced spontaneous sustained VT.
Conclusions:
- Ventricular tachycardia or fibrillation can be induced in approximately 40% of idiopathic DC patients without prior symptomatic arrhythmias.
- Inducibility of polymorphic VT/VF does not correlate with clinical/hemodynamic variables or sudden death risk.
- Induction of unimorphic VT may predict the future occurrence of spontaneous unimorphic VT in DC patients.
Abstract:
Twenty-four patients, mean age 42 years, with idiopathic dilated cardiomyopathy (DC) and no history of symptomatic ventricular arrhythmias underwent right ventricular programmed stimulation with up to 3 extrastimuli. Ventricular tachycardia (VT) was induced in 8 patients and ventricular fibrillation (VF) in 2. The VT was unimorphic in 2 and polymorphic in 6. No significant differences were noted between patients in whom arrhythmias were inducible and and those in whom they were not with regard to age, symptomatic class, arrhythmia severity or hemodynamic indexes. Over a mean follow-up of 12 months, 4 patients died, 3 suddenly and 1 with progressive heart failure. Only 1 of the 3 who died suddenly had inducible VT. One other patient with induced sustained unimorphic VT later presented with spontaneous sustained VT similar in rate and configuration to induced VT. In conclusion, VT or VF may be induced in approximately 40% of patients with DC and no history of symptomatic VT or VF. Inducibility of polymorphic VT or VF does not correlate with clinical or hemodynamic variables or with the risk of sudden death. However, induction of unimorphic VT may predict later occurrence of spontaneous unimorphic VT.