CXR III



Fig. 46.1 Anterior posterior chest x-ray showing a cardiac device
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A 65-year-old female after a motor vehicle collision requires emergency surgery for an open lower extremity fracture; the patient tells you she has a “bad heart,” she has no history in your institution, and no signs of heart failure. An EKG shows wide QRS with dual-chamber pacing. A CXR on admission show (See Fig. 46.1).




  1. 1.


    What type of device is shown in the image?

     

  2. 2.


    What are the indications for cardiac implantable electronic device placement?

     

  3. 3.


    What is the effect of placing a magnet over the device (pacemaker and/or ICD)?

     

  4. 4.


    In the OR, you place a magnet over the device. The patient goes pulseless after prolonged use of electrocautery. What is your diagnosis?

     

  5. 5.


    What are the effects of electrocautery, radiation therapy, and radiofrequency on a pacemaker and an ICD?

     

  6. 6.


    What measures can you take to ensure proper intraoperative device functioning?

     



Answers


  1. 1.


    This patient has an implantable biventricular cardio-defibrillator (BiV ICD) [1].

     






  • A371567_1_En_46_Fig2_HTML.gif



    Fig. 46.2 Anterior posterior chest x-ray showing a pacemaker




    1. (a)


      The radiographic image of a pacemaker would show (See Fig. 46.2):



      • Smaller generator


      • Discreet right ventricular lead (stable diameter)


      • With or without right atrial lead or coronary sinus lead

       




  • A371567_1_En_46_Fig3_HTML.jpg



    Fig. 46.3 Anterior posterior and lateral chest x-ray showing an ICD




    1. (b)


      The radiographic image of an ICD would show (See Fig. 46.3):



      • Larger generator.


      • Prominent right ventricular lead, otherwise known as shock coils. They appear as two metallic segments along the length of the ICD lead.

       




  • A371567_1_En_46_Fig4_HTML.gif



    Fig. 46.4 Anterior posterior and lateral chest x-ray showing a BiV ICD




    1. (c)


      The radiographic image of a BiV ICD would show (See Fig. 46.4):



      • Larger generator


      • Prominent right ventricular lead (shock coils)


      • Right atrium lead


      • Coronary sinus lead

       




  • A371567_1_En_46_Fig5_HTML.gif



    Fig. 46.5 Magnified view of a chest x-ray showing manufacturer ID of a cardiac implantable electronic device




  • Manufacturer ID can be seen in the CXR as well (See Fig. 46.5).



  1. 2.


    Indications for cardiac implantable electronic device placement [2]:


    1. (a)


      Pacemaker:



      • Patients with symptomatic sinus node dysfunction and bradycardia


      • Patients with complete AV block (symptoms less relevant)


      • Hypersensitive carotid sinus syndrome and neurocardiogenic syncope

       

    2. (b)


      ICD:



      • Patients at risk of sudden cardiac death: Prior ventricular tachycardia or fibrillation, low ejection fraction [3]


      • Long QT syndrome


      • Hypertrophic cardiomyopathy


      • Arrhythmogenic right ventricular dysplasia


      • Cardiac transplantation


      • Primary electrical disease: idiopathic ventricular fibrillation, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia

       

    3. (c)


      BiV ICD:



      • Treatment of left ventricular dysfunction and heart failure, with prolonged ventricular conduction and heart failure symptoms.


      • Required ventricular pacing and low EF:



        • RV pacing in patients with low EF increases CHF admissions and mortality.


      • Cardiac resynchronization therapy [4]:



        • Improved exercise tolerance and mortality.


        • Continuous pacing provides better hemodynamic stability.

       

     

  2. 3.


    Effect of a magnet on a device [5]:


    1. (a)


      Pacemaker:

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Sep 23, 2017 | Posted by in Uncategorized | Comments Off on CXR III

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