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Chapter 18. Pacemakers

Sanford M. Littwin, MD

  • In the United States >500,000 pacemakers are implanted each year, with more than 6 million patients today having a pulse generator device
  • Almost 100% of pacemakers are placed for a specific disease process rather than prophylactically
  • Most patients have concomitant diseases: HTN, CAD, DM, pulmonary disease

  • Symptomatic SA node dysfunction:
    • Bradycardia, pauses
  • Symptomatic AV node dysfunction:
    • Third-degree (complete) heart block
    • Second-degree heart block:
      • With symptomatic bradycardia
      • After AV node resection or following valve surgery
      • Secondary to muscular disease
  • Post-MI heart block (≥Mobitz II)
  • Sick sinus syndrome
  • Long QT syndrome
  • Biventricular pacing for resynchronization in CHF

  • All implanted devises (pacemakers) are contraindicated in MRI suite
  • Possible other causes of interference:
    • Electrocautery (Bovie)
    • RF ablation
    • Lithotripsy
    • Electrolyte/acid–base abnormalities
    • Medications:
      • Succinylcholine (fasciculations can inhibit PM; not an absolute contraindication)
      • Cardiac medications modifying detection or stimulation thresholds (e.g., sotalol, verapamil)
    • Rare: orthopedic saw, telemetric devices, mechanical ventilators

  • Determine type of pacemaker:
    • Manufacturer’s identification card or ID bracelet
  • Obtain EKG, and if needed CXR
  • Determine if patient is pacer dependent:
    • Patient history
    • Postablative procedures
    • Rhythm strip with no spontaneous ventricular activity
  • Determine when PM last interrogated and battery life
  • Have available:
    • External defibrillator/transcutaneous pacer, transvenous pacer
    • Magnet
    • Isoprenaline and/or dopamine
  • Make preparations to have pacemaker company representative available (or other qualified personnel):
    • Interrogation of device in holding area (or in OR if necessary to change device settings only after patient is anesthetized):
      • Turn PM to asynchronous mode (DOO or VOO)
      • Turn off any other option (rate-adaptive, antitachycardia, etc.)
    • If not possible (or if PM inappropriately inhibited by cautery), place magnet over device (must be kept in place for length of procedure); magnets will typically change pacing into asynchronous mode at a preprogrammed rate
  • Minimize electromagnetic interference(s):
    • Place grounding pad away from pacer, and in such a position that the current from the cautery to the pad will not flow through the pacemaker or the heart
    • Use bipolar cautery if possible
    • If monopolar needed, advise surgeon to use short (<1 second) bursts
  • Avoid dysrhythmia-triggering situations:
    • Electrolyte imbalance
    • Ischemia
    • Hypovolemia

  • Intraoperative monitoring:
    • Special attention to EKG (capable of detecting pacer-generated spikes)
  • Applicable alternatives to intrinsic (pacer): external pacer pads, defibrillator, and transvenous pacer
  • Avoid inserting PAC if PM in place <4 weeks (risk of dislodgement)
  • If PM malfunction:
    • Stop any electrical device in use (especially cautery)
    • Evaluate clinical impact
    • If poorly tolerated bradycardia:
      • Apply magnet
      • If ineffective, start isoprenaline/dopamine infusion; use transcutaneous and/or transvenous pacer
    • If cardiac arrest, initiate CPR; use transcutaneous and/or transvenous pacer
    • If tachycardia and DDD pacer, apply magnet; otherwise, treat as appropriate (see chapter 16 on tachyarrhythmias)

  • Reevaluation (by qualified personnel) of pacer
  • Restore preoperative settings
  • Removal of magnet:
    • Pacer should return to normally functioning mode
    • Interrogation of device by qualified personnel and/or admittance for observation until proper function can be determined

Table 18-1 Generic Pacemaker Code (NGB) for All Companies Manufacturing Pulse Generators
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