Radiography of Cardiac Conduction Devices: A Comprehensive Review

Abstract

Radiology plays a crucial role in initial assessment and follow-up of cardiac conduction devices (CCDs). At least 1 million patients in the United States have permanent CCDs, which comprise pacemakers and implantable cardioverter-defibrillators. Chest radiography is unique because it is the only imaging modality that allows evaluation of the physical integrity of CCD leads. As a result, a basic knowledge of the normal and abnormal radiographic appearances of these devices and their various components is important. Radiologists should have a working knowledge of CCD anatomy as well as appropriate positioning and appearance of CCD leads and generators. Acute complications of CCD implantation include dysrhythmia, pneumothorax, perforation of the heart muscle or a vein, heart valve damage, lead damage, inadequate seating of the terminal connector pin, and presence of an air pocket. Chronic complications include twiddler syndrome, lead fracture, damage to the lead insulation, and lead displacement. Radiologists play an important role in management of patients with CCDs by providing vital information about the device, starting immediately after implantation and continuing throughout its duration in the patient. To fulfill this role, radiologists must have a firm understanding of CCDs and their evolving technology.

Cardiac Implantable Electronic Devices and Magnetic Resonance Imaging

“…1) [8,15]. The CIED pulse generator is placed on the chest wall under the skin, and consists primarily of the battery and capacitors.…”

“…The main components of an ICD are a pulse generator and leads that use a right ventricular short coil as a ring electrode. The ICD has a high-voltage coil electrode which appears as a thick band on chest radiography [15]. The CRT device is a special cardiac PM that specifically aims to improve effective coordination of cardiac systole [18].…”

Mechanism and Management of Pacing Lead Related Cardiac Perforation

“…On a frontal radiograph, the tip of the right ventricular lead should be seen to the left of the spine. On the lateral view, it should traverse anteriorly towards the RV [23]. However, in some centers leads are preferentially positioned in RV outflow tract (free wall or septal aspect).…”

“…In the case of a perforation, the lead electrodes can extend outside of the cardiac silhouette and not move with the contraction of the heart [22]. Further clues to the early detection of a cardiac perforation include: an unexplained decrease in blood pressure; a decreased pulsatility of the cardiac silhouette; an increase in the size of the cardiac silhouette; and, an abnormal position of lead relative to pericardial outline [23].…”

“…Recent studies have reported a surprisingly high incidence of cardiac perforation with small body (7F) active fixation defibrillator leads (Riata) as compared to Sprint Fidelis leads (3.8% vs. 0%) [23]. The reasons for higher perforation rate are largely unknown but may include lead design and breeches in structural integrity [26].…”