Transvenous ICD lead systems for single and dual chamber ICDs: actual and future developments

Implantable Cardioverter-Defibrillators (ICDs) nowadays provide a high degree of safety and efficacy for the detection and termination of tachyarrhythmias. These benefits are strongly correlated to the implemented algorithms as well as to the electrical properties of the implanted transvenous ICD lead systems. This study comprises the clinical experiences on 516 patients with single chamber ICDs (Phylax 06, Biotronik) and 9 patients with dual chamber ICDs (Phylax AV, Biotronik). World-wide statistics of the single chamber ICD reflect coronary artery disease with about 60 % as the most important primary cardiac disease. The occurrence of supraventricular tachyarrhythmias and their discrimination necessitates the implantation of a dual chamber ICD with additional atrial leads. Single chamber systems with transvenous leads on average show a ventricular Defibrillation Threshold (DFT) of 9.49 +/- 5.1 J. From dual chamber devices the atrial Defibrillation Threshold (aDFT) depends on the electrode configuration and has been determined to be 1.2 +/- 0.3 Joules and 4.6 +/- 2.8 Joules, respectively.