Defibrillation test in paediatric patients: should be done?

Abstract Funding Acknowledgements Type of funding sources: None. The defibrillation test (DFT) of an implantable cardioverter-defibrillator (ICD) is performed to evaluate ventricular fibrillation detection and termination. In adults, routine defibrillation testing for transvenous ICD is less usually done as some studies found no advantages but some potentially risks associated with. On the other hand, implantation of ICDs in paediatric patients has different characteristics than in adults. The position of the defibrillation coil will change with the body’s growth and could reflect changes in the defibrillation vector. Also, the reasons of implantation of an ICD are different (ventricular arrhythmias frequently associated with adult’s myocardial infarction vs channelopathies, non-ischemic myocardiopathies and congenital heart defects in children and young). There is still lack of information about the utility of the DFT in paediatric patients. Objective To describe the characteristics of paediatric patients who underwent implantation of an ICD , results of DFT and follow-up. Methodology Retrospective cohort study of patients less than 21 years old who underwent implantation of an ICD in the lasts 10 years at a reference paediatric hospital. In DFT, VF was induced by T wave shock, fast burst pacing or continuous direct current. Response of ICD to VF was evaluated. Patients with failure to terminate VF by ICD were defibrillated with external defibrillator. Results 68 patients with 73 ICD implantations (five replacements). Median age was 13 years old. The youngest patient was 2 years old and the oldest 21 years old. 72.6% (53/73) of patients underwent DFT. In 90.6% (48/53) of them, a VF was induced. In two patients (4%, 2/48) the ICD did not terminate the VF. One of these patients had Danon syndrome and the VF did not terminate despite of maximum energy discharged and changes in the vector of defibrillation; the problem was fixed with replacement of the single coil lead by a dual coil system. The other patient had arrhythmogenic cardiomyopathy and the ICD did not detect the VF. During the follow up, there were 20 shocks in 13 patients. 13 shocks were appropriate (and successful). One patient died because of non-arrhythmic illness. Conclusions In paediatric patients, the defibrillation test is useful to ensure both adequate detection of malignant ventricular arrhythmias, as well as their ability to reverse them. Its lack of performance could affect 4% of the implants. Therefore, its performance in paediatric patients is recommended. There could be greater utility in patients with hypertrophic cardiomyopathy.