Cardiac conduction devices
Citation, DOI, disclosures and article data
At the time the article was created The Radswiki had no recorded disclosures.View The Radswiki's current disclosures
At the time the article was last revised Henry Knipe had the following disclosures:
- Integral Diagnostics, Shareholder (ongoing)
- Micro-X Ltd, Shareholder (ongoing)
These were assessed during peer review and were determined to not be relevant to the changes that were made.View Henry Knipe's current disclosures
Implantable cardiac conduction devices (also known as cardiac implantable electronic devices or CIEDs) are a very common medical device of the thorax, with over one million implanted in the United States of America alone.
There are two major types of cardiac conduction devices: pacemakers and automatic implantable cardioverter-defibrillators (AICD/ICD), and these may be co-implanted as an ICD-pacemaker combination. Both have two major components:
pulse generator (battery pack and control unit): most commonly placed subcutaneously in the infraclavicular area
lead wires with electrodes for contact with the endocardium or myocardium
Some models have an antenna to transmit data wirelessly, this should not be confused with a lead disconnection or fracture 8.
Cardiac pacemakers may be temporary or permanent, with the latter commonly known by the acronym PPM (permanent pacemaker).
Categorization depends on the number of electrodes and location of pacing 7:
single chamber cardiac pacers: lead terminates in the right ventricle
dual chamber cardiac pacers: leads terminate in the right atrial appendage and right ventricular apex
biventricular pacers: also known as cardiac resynchronisation therapy, a normal dual chamber system with an additional lead that is introduced along the coronary sinus and wedged in a left ventricular cardiac vein overlying the left ventricle
epicardial biventricular pacers: epicardial wires are usually placed during cardiac surgery and tend to be placed over the left ventricular apex, right atrial appendage, and right ventricular apex
leadless cardiac pacers: implanted into the right ventricle with no leads, introduced in 2015 (should not be mistaken for loop recorders)
Automatic implantable cardioverter defibrillators
AICDs are common cardiac devices designed for both patient monitoring and therapy in case of ventricular tachycardia or fibrillation. AICDs consist of various combinations of sensing and shocking electrodes. They are frequently combined with a pacemaker as a bundled system for the patient, treating both the patient’s established arrhythmia and also acting as a fail-safe system should ventricular fibrillation or ventricular tachycardia occur.
Some types of AICD have leads that are implanted in the subcutaneous soft tissues (i.e. outside the thoracic cavity) 5.
Complications can be early or late, and procedure-related or device-related 6.
Early or late
pneumothorax: one of the more common early complications, particularly when subclavian access is used (incidence of ~2% 6)
"subclavian crush" syndrome
pectoral muscle, intercostal, or diaphragm stimulation
thrombosis: within access vein, inferior vena cava, right atrium
- 1. Hunter T, Taljanovic M, Tsau P, Berger W, Standen J. Medical Devices of the Chest. Radiographics. 2004;24(6):1725-46. doi:10.1148/rg.246045031 - Pubmed
- 2. Steiner R, Tegtmeyer C, Morse D et al. The Radiology of Cardiac Pacemakers. Radiographics. 1986;6(3):373-99. doi:10.1148/radiographics.6.3.3317544 - Pubmed
- 3. Jannette Collins, Eric J. Stern. Chest Radiology. (2008) ISBN: 9780781763141 - Google Books
- 4. Aguilera A, Volokhina Y, Fisher K. Radiography of Cardiac Conduction Devices: A Comprehensive Review. Radiographics. 2011;31(6):1669-82. doi:10.1148/rg.316115529 - Pubmed
- 5. Chang P, Doshi R, Saxon L. Subcutaneous Implantable Cardioverter-Defibrillator. Circulation. 2014;129(23):e644-6. doi:10.1161/CIRCULATIONAHA.113.006645 - Pubmed
- 6. Kotsakou M, Kioumis I, Lazaridis G et al. Pacemaker Insertion. Ann Transl Med. 2015;3(3):42. doi:10.3978/j.issn.2305-5839.2015.02.06 - Pubmed
- 7. Raj V, DG S, Tobias R. Uncommon Iatrogenic Devices Seen on Chest Radiographs. Indian Journal of Radiology and Imaging. 2021;31(1):172-84. doi:10.1055/s-0041-1729487 - Pubmed
- 8. Saleh A, Japas D, Rhee S, Yi A, Lo R. Pacemaker Bluetooth Antenna Misinterpreted as Fractured Wire. Radiology: Cardiothoracic Imaging. 2020;2(1):e190085. doi:10.1148/ryct.2020190085 - Pubmed