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Protocol: Temporary Pacemaker Verification and Troubleshooting

Friday, August 28, 2015

Determining the Stimulation Threshold

  • NOTE: a paced rhythm must be present and patient stable
  • From 100% pacing, gradually decrease output for A or V, while watching monitor until you lose capture
  • Now gradually increase output until 1:1 capture returns – this is the stimulation threshold
  • This is the lowest amount of energy that will reliably capture the heart and pace
  • Set mA 1.5-3 times above this threshold value for safety
  • Repeat for other circuit (A or V)
  • Note: the stimulation threshold should be checked DAILY by the MD/NP when pacing is in use; in the event 
the threshold value is rising, discuss with surgeon to determine if alternative pacing system is needed

Determining the Sensing Threshold

  • Note: the patient must have an underlying rhythm and tolerate a brief period without pacing to perform
  • Set RATE at least 10 bpm below patient’s intrinsic heart rate (to allow sensing)
  • Set OUTPUT at 0.1 mA (to avoid competitive pacing when device is made asynchronous briefly)
  • Highlight SENSITIVITY (under Menu 1)
  • Decrease SENSITIVITY: Slowly turn dial counter-clockwise until pace indicator flashes regularly (asynchronously)
  • Increase SENSITIVITY: Slowly turn dial clockwise until sense indicator flashes again (when sensing resumes, this is the sensing threshold – the smallest complex that is reliably recognized, thus inhibiting the device)
  • Set SENSITIVITY < half this threshold value for safety
  • Repeat for other circuit (A or V)
  • Restore previous rate and output values

Rapid Atrial (Overdrive) Pacing – PERFORMED BY MD/NP/CNS ONLY

  • Used to “overdrive pace” and terminate some atrial reentrant tachyarrhythmias, especially atrial flutter
  • ALWAYS VERIFY correct wire connections to avoid stimulating the ventricles at a rapid rate!
  • Set maximal atrial output to promote capture (20 mA)
  • Go to RAP menu (press MENU button three times)
  • Dial in RAP rate 10-40 bpm above intrinsic atrial rate (default = 320)
  • From RAP menu: press and hold SELECT button
  • Rapid pacing will be delivered via atrial circuit
  • Assess monitor for atrial “capture” at rapid rate
  • Abruptly discontinue pacing by releasing SELECT button
  • Examine rhythm and repeat if unsuccessful, consider: increasing rate and/or duration of stimulus, or gradually reducing pacing rate while holding SELECT

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