This document discusses pacemakers and implantable cardioverter defibrillators (ICDs). It provides an overview of the indications for cardiac pacing and ICD placement. It then presents several cases showing normal anatomy and positioning of single chamber pacemakers, dual chamber pacemakers, single chamber ICDs, dual chamber ICD-pacemaker devices, and subcutaneous ICDs on chest x-rays. Readers are invited to test their knowledge of device identification on several example cases. The document promotes mastery of cardiac device imaging interpretation and ongoing medical education.

1. Imaging Of Medical Devices
Matthew Cravens, MD, Project Lead Author
Department of Emergency Medicine
Brian Powell, MD & Lora Raines PA, Guest Authors
Sanger Heart & Vascular Institute
Michael Gibbs, MD, Faculty Editor
Pacemakers & Internal Cardiac Defibrillators (ICDs)

2. Disclosures
 This ongoing imaging interpretation series is proudly sponsored by the
Emergency Medicine Residency Program at Carolinas Medical Center.
 Sanger Heart & Vascular clinicians provide expert Cardiology input.
 The goal is to promote widespread mastery of imaging interpretation.
 There is no personal health information [PHI] within, and all ages have
been changed to protect patient confidentiality.

3. Visit Our Website
www.EMGuidewire.com
For A Complete Archive Of Imaging Presentations And Much More!

4. Airway
Bones
Cardiac
Diaphragm
Effusion
Foreign body
Gastric
Hilum

5. It’s All About The Anatomy!

6. Pacemakers and ICDs
Cases From Carolinas Medical Center

7. This Month We Will Focus On Traditional Pacemakers
and ICDs. Next Month We Will Discuss Biventricular
And Leadlless Pacemakers.

9. Single Chamber Pacemaker: The right ventricular lead (arrowhead) should cross the spine on the
anterior projection, and on the lateral projection it courses towards the ventricular apex.

11. Dual Chamber Pacemaker: The right atrial lead (arrow) assumes a “J-shape” that curves upwards
towards the right atrial appendage. The RV lead (arrowhead) should cross the spine on the anterior
projection, and on the lateral projection it courses towards the RV septum or apex.

13. Single Chamber ICD: Note the dense shock coil (arrow), making this an ICD lead. Similar to a single
chamber pacemaker, the RV lead should cross the spine on the anterior projection, and on the lateral
projection it courses towards the ventricular apex.

15. Dual Chamber Pacemaker-ICD: The RA pacemaker lead (arrow) assumes a “J-shape” that curves
upwards towards the RAA. The RV ICD lead (arrowhead) crosses the spine on the anterior projection.

17. Dual Chamber Pacemaker-ICD: The RA pacemaker lead (arrow) assumes a “J-shape” that curves
upwards towards the RAA. This ICD lead has two coils (arrowheads), one in the SVC and the second in
the RV. Of note, this patient has known situs inversus, and surgical clips are also seen.

19. Subcutaneous ICD1: The single subcutaneous ICD lead (arrow) runs vertically just left of the sternum
and is connected to a subcutaneous generator (arrowhead).
1Subcutaneous ICDs do not provide pacemaker support

20. Test yourself!
Cases From Carolinas Medical Center

22. Dual Chamber Pacemaker

24. Single Chamber ICD

26. Dual Chamber Pacemaker

28. Subcutaneous ICD

30. Single Chamber ICD

32. Dual Chamber ICD

34. Dual Chamber Pacemaker: RA lead (arrow), RV lead (arrowhead). This patient also has a mechanical
valve replacement (star). Sternal wires and an additional metallic circular object are also seen.

36. Single chamber ICD: RV lead (arrowhead) along sensing leads in the RA
(arrow). This patient also has a left ventricular assist device (LVAD; star).

38. Subcutaneous + Single lead ICD: Single lead ICD
(arrow) and subcutaneous ICD (arrowhead).

41. Cardiac Pacing – Summary Indications
• Symptomatic sinus node dysfunction
• Acquired atrioventricular block
• Chronic bifascicular block with syncope
• Neurocardiogenic syncope refractory to medical therapy
AHA/ACC 2018 Guidelines

42. • Ventricular tachycardia without
a reversible cause
• Cardiac arrest secondary to
ventricular arrhythmia
• NYHA class II-III heart failure
with LV EF <35%
• Hypertrophic cardiomyopathy
with high-risk features
• Cardiac resynchronization therapy
defibrillator, and:
• NYHA III-IV heart failure
• QRS> 130msec
• On optimal medical therapy ≥3 months
AHA/ACC 2018 Guidelines
ICD Placement – Summary Indications

43. A. Conduction begins in the SA node. Impulse propagation through the atria gives rise the P-wave. The impulse
then delays in the AV node to allow blood to flow to the ventricles. The wave front then pass through the His-
Purkinje system to rapidly activate the ventricular myocardium, giving risk to the large amplitude QRS complex.

44. B. An anatomic specimen showing the locations of the key conduction system elements. A view SA node in the
epicardium at the juncture of the SVC and right atrium is indicated. The structure itself is not visible to the
naked eye. The right atrial and ventricular free walls have been removed to reveal the position of the AV node.
AV=atrioventricular, CS=coronary sinus, FO=fossa ovalis, IVC=inferior vena cava, RAA=right atrial appendage,
SA=sinoatrial, SVC=superior vena cava, TV=tricuspid valve.

57. Selected Embedded References:
Mulpuru SK. Cardiac Pacemakers: Function Troubleshooting and Management.
Journal of the American College of Cardiology. 2017; 69:189-210.
Madhavan M. Advances and Future Directions In Cardiac Pacemakers. Journal of the
American College of Cardiology. 2017; 211-235.

58. If You Have Interesting Cases Demonstrating Pacemakers And AICDs We Invite
You To Send A Set Of Digital PDF Images And A Brief Clinical History To:
michael.gibbs@atriumhealth.org
Your De-Identified Case(s) Will Be Posted On Our Education Website And You
And Your Institution Will Be Recognized!

59. See You Next Month!