Pacemakers and Defibrillators – CXR

Table of Contents

Table of Contents

June 2022

Samantha King, MD1, Tami Bang, MD2
Section Editor: Markus Wu3

1. Chief Resident, Internal Medicine Residency, University of Colorado, 2. Assistant Professor, Cardiothoracic Diagnostic Radiology, University of Colorado and National Jewish, 3. Assistant Professor, Cardiothoracic Diagnostic Radiology, University of Colorado 


  1. Differentiate between a pacemaker and ICD on a chest radiograph.
  2. Identify the location of cardiac device leads on a chest radiograph.
  3. Describe the indications and benefits of a CRT-D.

Teaching Instructions

Plan to spend 5-10 minutes familiarizing yourself with the animations of the PowerPoint and the key findings of this chest X-ray.

Present the image either by expanding the window (bottom right) in a browser or downloading the PowerPoint file (downloading is recommended).  Have the image pulled up in presenter mode before learners look at the screen to avoid revealing the diagnosis.  Ask a learner to provide an overall interpretation.  Then advance through the animations to prompt learners with key questions and reveal the findings, diagnosis, and teaching points.

Instructions: Ask a leaner to provide an overall interpretation.  Advance using the arrows or scroll wheel on the mouse reveal subsequent questions with answers and graphics.  You can go back to prior graphics and questions by using the back arrow or scrolling back on the mouse wheel. 

Official CXR Read:. Enlarged cardiac contour. Pacing device in place. No focal consolidation. No pleural effusions.

Clinical Diagnosis:. Cardiogenic shock due to non-ischemic cardiomyopathy

Teaching: This is usually 2-4 sentences of expanded explanations for major teaching points (usually Q2).  Include references if quoting rules or specific numbers. 

This patient has a cardiac resynchronization therapy – defibrillator (CRT-D). This device contains three leads. The leads are introduced into the subclavian vein. One lead terminates in the right atrium and senses electrical activity. The next lead terminates in the right ventricle, where it can pace. The final lead courses from the right atrium into the coronary sinus (which drains the cardiac veins) and abuts the left ventricle, where it can pace this chamber. Simultaneous pacing of the right and left ventricle (resynchronization therapy) can improve ejection fraction, NYHA classification, reduce hospitalizations and mortality in patients with severe heart failure who have a prolonged QRS (>150ms or LBBB and >130ms). Most patients with an indication for CRT have a concomitant indication for an ICD as primary prevention of SCD. (1, 2)  However, a CRT-D comes with limitations and risks including higher costs, higher infection risk, greater likelihood of recall and less reliable pacing. (3)

Presentation Board

Take Home Point

  1. A thick charge coil seen on an intracardiac device lead is for defibrillation
  2. Cardiac resynchronization therapy with bi-V pacing is indicated for LVEF <35% and a QRS >120ms to improve EF, HF symptoms, hospitalizations and all-cause mortality.


  1. Russo A, Stainback R, Bailey S, et al. ACCF/HRS/AHA/ASE/HFSA/SCAI/SCCT/SCMR 2013 Appropriate Use Criteria for Implantable Cardioverter-Defibrillators and Cardiac Resynchronization Therapy. J Am Coll Cardiol2013 Mar, 61 (12) 1318–1368.
  2. Tang AS, Wells GA, Talajic M, Arnold MO, Sheldon R, Connolly S, Hohnloser SH, Nichol G, Birnie DH, Sapp JL, Yee R, Healey JS, Rouleau JL; Resynchronization-Defibrillation for Ambulatory Heart Failure Trial Investigators. Cardiac-resynchronization therapy for mild-to-moderate heart failure. N Engl J Med. 2010 Dec 16;363(25):2385-95. doi: 10.1056/NEJMoa1009540. Epub 2010 Nov 14. PMID: 21073365.
  3. Providência R, Kramer DB, Pimenta D, Babu GG, Hatfield LA, Ioannou A, Novak J, Hauser RG, Lambiase PD. Transvenous Implantable Cardioverter-Defibrillator (ICD) Lead Performance: A Meta-Analysis of Observational Studies. J Am Heart Assoc. 2015 Oct 30;4(11):e002418. doi: 10.1161/JAHA.115.002418. PMID: 26518666; PMCID: PMC4845221.
Brandon Fainstad


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