Inappropriate implantable defibrillator discharge caused by a retained pacemaker lead fragment

Introduction: Inappropriate discharge is still a major issue of implantable cardioverter defibrillator therapy. The diagnostic options of modern devic es facilitate classification of the underlying abnormality. Methods and Results: A 65-year-old woman with depressed left ventricular pe rformance received spurious shocks from an ICD, implanted for ventricular t achycardia. A lead fragment of an explanted VVI pacemaker system could be i dentified as cause of erroneous ventricular fibrillation detection by the I CD. The electrical noise caused by interaction between the lead remnant and the ICD lead was detectable even on the surface ECG. Conclusion: Based on our findings, removal of fragmented lead material shou ld be considered prior to ICD implantation, to avoid potentially adverse an d harmful interactions with ICD systems.