Patient Alert to detect ICD lead failure: efficacy, limitations, and implications for future algorithms.

Aims An algorithm that alerts implantable cardioverter-defibrillator (ICD) patients, in case of abnormal lead impedance (Patient Alert™, Medtronic), may help to recognize lead dysfunction. We aimed to determine the utility of Patient Alert for ICD lead-failure detection in a prospective study. Methods and results Three hundred and sixty ICD patients were followed for 22±14 months. Patient Alert was active for pacing impedance 2000–3000 Ω, and high-voltage conductor impedance 200 Ω. Ten alert events and a total of 29 severe system complications occurred. Patient Alert detected three of 10 ICD lead failures, with a positive predictive value (PPV) of 77.8% for any severe system complication. R…