Cardiac Conduction Devices

Cardiac conduction devices (CCDs) include pacemakers and implantable cardioverter defibrillators (ICDs) and are used for permanent management of cardiac conduction abnormalities. Most CCDs consist of a generator which houses the battery and computer. They gather electronic information and send electric pulses through their attached leads. Typically, the leads are placed via transvenous approach into the right atrial appendage, right ventricle, or coronary sinus, depending on the purpose. A single chamber pacer may be utilized to manage SA nodal disease, with a lead in the right ventricle. Dual-chamber pacers are often used for AV nodal disease, and have leads in the right atrium and right ventricle. Biventricular pacing may be used to improve synchronized right and left ventricular function, with the additional lead positioned in the coronary sinus to stimulate the left ventricle. The presence of a thick “shock coil” confirms the defibrillator capability of the device (ICD). Radiographic evaluation following CCD placement should ensure proper lead placement, and exclude pneumothorax, hemothorax, and/or hemopericardium. Subsequent imaging should exclude Twiddler’s syndrome (change in generator position) and lead fracture. Temporary pacing devices may also be used in emergent and postoperative settings, and typically consist of epicardial leads that can be easily removed.