Pacemaker Malfunction Workup

Updated: Sep 19, 2016
  • Author: Chakri Yarlagadda, MD, FACC, FSCAI, FASNC, CCDS; Chief Editor: Jeffrey N Rottman, MD  more...
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Workup

Laboratory Studies

The following laboratory studies may be useful in cases of pacemaker malfunction:

  • Creatine kinase (CK) and isoenzymes - Elevated in myocardial injury and cardiac trauma
  • Coagulation panel - Required to prevent bleeding complications during invasive procedures
  • Electrolytes - To exclude electrolyte abnormalities that may affect pacing thresholds
  • Drug levels - For drugs, such as digoxin and antiarrhythmics (particularly flecainide), that may alter pacing thresholds
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Imaging Studies

The following imaging studies may be considered in cases of pacemaker malfunction:

  • Chest radiography: Overpenetrated film helps to evaluate lead position, fracture, and the set-screws. Specific markers on pulse generator are useful for identification.
  • Fluoroscopy: To evaluate common sites of lead fracture such as an area of acute angulation or compression by real-time imaging while applying gentle traction on the lead.
  • Echocardiogram: It has limited use in the diagnosis of pacing system malfunction. Inappropriate lead position (ie, left ventricle, left atrium, or pericardial space), pericardial effusion/tamponade, or lead fracture may be observed on 2-dimensional echocardiogram.
  • Computed tomography: CT scanning of the chest helps to evaluate lead position, especially in patients with suboptimal radiograph and echocardiogram results. Preprocedural ECG-gated multidetector CT scanning may aid clinicians in identifying patients at high risk for mechanical complications and significant perforation during lead extraction for lead malfunction, class I lead advisories, and infection. [5]
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Other Tests

Several other studies may be indicated in cases of pacemaker malfunction. Consider the following:

  • Pacemaker interrogation: Evaluation of thresholds, lead impedance, and battery voltage, as well as review of histograms, mode switch episodes, and stored electrograms.
  • Magnet application: After magnet application, pacemaker goes to asynchronous pacing mode at a programmed rate that is unique to that model. This is helpful in the diagnosis of loss of capture and battery depletion.
  • 12-lead electrocardiogram: This simple bedside test is useful to diagnose undersensing, oversensing, and capture loss.
  • Telemetry monitoring: This is useful in early recognition of loss of sensing and capture from lead dislodgement in the immediate postimplant period.
  • Holter monitoring: This 24-48-hour simple test is helpful in the diagnosis of atrial and ventricular arrhythmias and abnormal sensing or capture. Sometimes an event monitoring may be required to diagnose intermittent pacemaker dysfunction.
  • Transtelephonic monitoring: Periodic transtelephonic monitoring is very useful in early recognition of battery depletion based on the magnet rate, which is unique to each pacemaker model.
  • Fluoroscopy is useful to evaluate lead fracture, especially during provocative maneuvers.
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