Undersensing as a consequence of lead incompatibility: case report and a plea for universality.

Implantation of a single chamber bipolar pulse generator was complicated by transient loss of ventricular sensing, caused by mechanical damage to the unipolar lead connected to the system. A perforation of the insulating sheath was found at the site of the proximal connector block, and undersensing resolved after restoring its integrity with silicone adhesive. The ability to attach an unprotected unipolar lead to a bipolar connector, shared by the Voluntary (VS-1) and International (IS-1) designs, invites the possibility of injury to the insulating sheath by accidental tightening of the proximal screw. There is thus an urgent need for the development and universal adoption of a robust interface standard in lead connector design.