Analysis of pacing/defibrillator lead failure using device diagnostics and pacing maneuvers

Patients with Medtronic Sprint Fidelis (Medtronic Inc., Minneapolis, MN, USA) lead failures present with oversensing, resulting in pacing inhibition and inappropriate shocks. We present a case of lead noise from the right ventricular (RV) ring conductor, resulting in multiple inappropriate shocks with subsequent pacing inhibition and syncope. RV pacing lead impedance at no point exceeded 1,000 ohms. We found that increased noise and oversensing was more likely to be induced when pacing at higher pulse widths. RV pacing outputs at lower pulse widths may decrease susceptibility to noise generation and prove an effective temporizing measure in pacing-dependent patients.