Pacemaker and defibrillator lead entrapment: case studies.

Cadavers and cineradiographic analysis have been used to document the effects of the medial subclavicular musculotendinous complex (MSMC) upon lead function. Four cadavers with pacemakers were dissected and photographed to demonstrate the course a lead takes as it passes through the costoclavicular region. One lead had been placed into the cephalic vein. In the other three cadavers, leads placed by currently accepted techniques of subclavian venipuncture were all found to pass through the soft tissues of the subclavicular region before entering the venous system. Cineradiographic results from a patient with a defibrillator, taken before and after replacement of a broken lead, show the effect of clavicular motion on a lead that passes through the MSMC. Furthermore, cineradiography makes it possible to identify the point where the lead entered the vein, and whether or not it escaped being caught up in the soft tissues of the MSMC.