Mode of detection of transvenous defibrillation lead malfunction in implantable defibrillators

ABSTRACT

To assess the clinical presentation and mode of detection of transvenous defibrillation lead failure and therefore enhance earlier diagnosis and prevent subsequent complications. Retrospective study. Electrophysiology outpatient clinic, Cardiology Division, Kuwait Heart Center Subjects: Four hundred and ninety-three patients who underwent first implantation of an implantable cardioverter-defibrllator [ICD] were enrolled and followed-up in the clinic. Intervention Implantation of ICD Main Outcome Measures: ICD lead malfunction could be readily diagnosed by clinical presentation and device evaluation on an outpatient basis. Eight patients demonstrated clinical defibrillation lead failure on follow-up. It was diagnosed at a mean follow-up of 47.1 +/- 29.1 months after device implantation. Four patients presented with inappropriate shocks due to noise oversensing with an average of 4 +/- 6 shocks per patient. Lead malfunction was discovered during routine device follow-up in the remaining patients who were asymptomatic and ICD interrogation showed lead impedance out of normal range, increased chronic pacing threshold and /or sensing failure evidenced by drop in ventricular signal to less than two millivolts. All patients who sustained ICD lead failure had a new lead implanted. ICD lead malfunction requiring new lead implantation is not uncommon during long term follow-up and urge for continued close routine follow-up. Both old and new leads of different models are liable for malfunction. In asymptomatic patients lead failure can be readily diagnosed in most cases on an outpatient basis by finding abnormal measures of sensing / pacing parameters, lead impedance, stored electrograms and possibly radiographic data