Self-inhibition of an AV sequential demand (DVI) pulse generator due to polyurethane lead insulation disruption

Self-inhibition of bipolar DVI AV-sequential pacemakers has been attributed to electrode malposition, although the potential for self-inhibition due to current leakage has been recognized. Previous cases of current leakages due to insulation defects in bipolar VVI ventricular demand systems have usually presented as abnormal sensing or pacing function without a change to actual unipolar sensing and pacing. This article describes a case of disruption of the insulation of polyurethane bipolar atrial and ventricular leads by silk ligatures, resulting in unipolar atrial and ventricular pacing and self-inhibition of ventricular output of a DVI pulse generator. This case emphasizes the importance of avoiding any application of suture material directly to polyurethane leads. This case also emphasizes the importance of monitoring pacemaker artifact amplitude and axis in patient follow-up.