ABSTRACT
PURPOSE: Implantable cardioverter defibrillators (ICDs) can treat life-threatening tachyarrhythmia with high-voltage shocks. The aims were to compare the efficacy of single and dual coil shock vectors in modern ICDs and to identify predictors of shock failure. METHODS: This is a single-center paired randomized study including 216 patients with mixed indications and ICDs from four manufacturers. All patients underwent two implant defibrillation tests using single and dual coil vectors with the test order randomized. Tested shock energy differed slightly between manufacturers because of differences in device programmability: first shock approximately 15 J below maximal output-if failed, second shock approximately 10 J below maximal output-if failed, third shock at maximal output. RESULTS: First shock success rate was 399/432 (92.4%). Comparing single and dual coil vectors, no differences were seen in first shock efficacy (91.7% vs. 93.1%, P = 0.629) or lowest tested succesfully stored energy (27.2 J vs. 27.1 J, P = 0.620). All successive internal shocks failed in 4/432 (0.9%) of inductions requiring external rescue shocks to restore circulation. Multivariate predictors of first shock failure were QRS duration (relative risk 0.81 per 10 ms, P = 0.001), amiodarone treatment (relative risk 3.30, P = 0.003), and body height (relative risk 1.70 per 10 cm, P = 0.019). CONCLUSIONS: Implant defibrillation testing of modern intravenous ICD systems demonstrates high shock efficacy with no difference between single and dual coil vectors.
Subject(s)
Defibrillators, Implantable , Electric Countershock/instrumentation , Equipment Design , Tachycardia/therapy , Aged , Denmark , Electric Countershock/methods , Female , Follow-Up Studies , Humans , Male , Middle Aged , Multivariate Analysis , Poisson Distribution , Predictive Value of Tests , Recurrence , Risk Assessment , Tachycardia/diagnostic imaging , Treatment Outcome , Ventricular Fibrillation/diagnostic imaging , Ventricular Fibrillation/therapyABSTRACT
Sudden death involving athletes is always tragic and receives widespread public attention. The European Society of Cardiology has proposed cardiovascular screening of young competitive athletes. A report from the Danish Society of Cardiology recently concluded that screening cannot be recommended in Denmark at present. This conclusion was based mainly on inadequate documentation of the effect of screening and on considerations regarding cost-effectiveness. We recommend other prophylactic measures and further research on this issue.
