DYSFUNCTIONS IN NONTHORACOTOMY CARDIOVERTER DEFIBRILLATOR LEAD SYSTEMS - CLINICAL IMPORTANCE OF DEVICE IMPLEMENTED DIAGNOSTIC AND MEASUREMENT FUNCTIONS/

The aim of this study is the analysis of electrical failures in transv enous cardioverter/defibrillator (ICD) lead systems with regard to the importance of device implemented diagnostic and measurement functions and the potential role of an automated device-control in the detectio n of lead failures. Methods: All consecutive ICD patients at our insti tution were enrolled in this retrospective investigation. The routine follow-up controls consisted in a complete evaluation of all diagnosti c and measurement ICD features and additional controls in case of spon taneous arrhythmia episodes. Results: Two hundred thirty patients, 193 male and 37 female, were enrolled in this study (mean age: 61.5 +/- 1 0.2 years; mean LVEF 32 +/- 9 %). During a mean follow-up period of 29 .5 +/- 18.4 (6-76) months, lead failure occurred in 19 patients (8 %). 16 patients were implanted with an ICD, capable of diagnostic and mea surement functions. All nonadequate device discharges could be classif ied as sensing-failure by stored electrograms. Device implemented meas urement features revealed clinical important information in 13/16 pati ents (81 %). In 14/16 patients, the lead defect could not be detected during routine follow-up. At the time of documented lead failure the s afety of the implanted devices was already lost in 6/16 patients (38 % ). Conclusions: Device implemented diagnostic and measurement options are of great importance in the early detection of ICD lead failures. T he implementation of automated measurements of lead related parameters in connection with a patient alert function may contribute to a furth er increase in the safety of ICD therapy.