Supraventricular arrhythmias in children and young adults with implantablecardioverter defibrillators

SVT in Pediatric ICD Recipients. Introduction: Rapidly conducted supraventr icular tachycardias (SVTs) can lead to inappropriate device therapy in impl antable cardioverter defibrillator (ICD) patients. We sought to determine t he incidence of SVTs and the occurrence of inappropriate ICD therapy due to SVT in a pediatric and young adult population. Methods and Results: We undertook a retrospective review of clinical course , Holter monitoring, and ICD interrogations of patients receiving ICD follo w-up at our institution between March 1992 and December 1999. Of 81 new ICD implantations, 54 eligible patients (median age 16.5 years, range 1 to 48) were identified. Implantation indications included syncope and/or spontane ous/inducible ventricular arrhythmia with congenital heart disease (30), lo ng QT syndrome (9), structurally normal heart (ventricular tachycardia/vent ricular fibrillation [VT/VF]) (7), and cardiomyopathies (7). Sixteen patien ts (30%) received a dual-chamber ICD. SVT was recognized in 16 patients, wi th 12 of 16 having inducible or spontaneous atrial tachycardias. Eighteen p atients (33%) received greater than or equal to1 appropriate shock(s) for V TNF; 8 patients (15%) received inappropriate therapy for SVT. Therapies wer e altered after an inappropriate shock by increasing the detection time or rate and/or increasing beta-blocker dosage. No single-chamber ICD was initi ally programmed with detection enhancements, such as sudden onset, rate sta bility, or QRS discriminators. Only one dual-chamber defibrillator was prog rammed with an atrial discrimination algorithm. Appropriate ICD therapy was not withheld due to detection parameters or SVT discrimination programming . Conclusion: SVT in children and young adults with ICDs is common. Inappropr iate shocks due to SVT can be curtailed even without dual-chamber devices o r specific SVT discrimination algorithms.