Management of Cardiac Pacemakers and ICDs

Pacemaker & ICD Fundamentals - Electric Heart Helpers

• Pacemakers (PPM): Correct slow heart rhythms (bradyarrhythmias).
  • Indications: Symptomatic bradycardia, high-grade AV block (Mobitz II, 3rd degree), sick sinus syndrome.
  • NBG Code: Describes pacing mode (e.g., VVI, DDD). 📌 Position I: Chamber Paced, II: Chamber Sensed, III: Response to sensing.
• Implantable Cardioverter-Defibrillators (ICDs): Prevent sudden cardiac death (SCD) from fast, life-threatening rhythms (VT/VF).
  • Functions: Anti-tachycardia pacing (ATP), high-energy shocks. Can also provide bradycardia pacing.
  • Indications: Secondary prevention (post-SCD/VT/VF); Primary prevention (e.g., LVEF ≤35% post-MI, certain cardiomyopathies).
• Cardiac Resynchronization Therapy (CRT): For heart failure with ventricular dyssynchrony.
  • Types: CRT-P (pacemaker) or CRT-D (defibrillator).
  • Indications: LVEF ≤35%, NYHA Class II-IV symptoms, LBBB with QRS duration ≥150ms.

⭐ ICDs are proven to reduce mortality in selected patients at high risk for sudden cardiac death, significantly more than antiarrhythmic drugs alone for secondary prevention of SCD due to VT/VF.

Pre-op Prep - Device Detective Work

• Identify Device: Pacemaker (PPM) vs. Implantable Cardioverter-Defibrillator (ICD).
• Device Interrogation Report: Essential.
  • Manufacturer, model, serial No.
  • Implant date, last check, battery status (ERI?).
  • Programmed mode (e.g., AAI, VVI, DDD).
  • Pacing thresholds, lead impedance.
  • ICD: Tachyarrhythmia detection/therapy settings (ATP, shocks).
• Patient Assessment:
  • Underlying rhythm, device indication.
  • Pacemaker dependent? (Intrinsic rhythm < 30-40 bpm or paced > 50%).
  • Comorbidities.
• Consult Cardiology/EP team.
• Plan: Tailor to device, dependency, EMI risk from surgery.

⭐ Magnet application over most ICDs suspends tachyarrhythmia detection and therapies, but pacing function is generally unaffected or converts to asynchronous mode. Always verify specific device response!

Intra-op Vigilance - EMI & Magnet Magic

• EMI Sources & Effects:
  • EMI: Monopolar cautery (main), RFA, MRI.
  • Pacemaker effects: Oversensing (asystole), undersensing (R-on-T), mode switch.
  • ICD effects: Inappropriate shocks, inhibited therapy.
• EMI Management:
  • Prefer bipolar cautery/ultrasonic scalpel.
  • Monopolar: short bursts, low power; current path away from device.
  • Grounding pad distant from generator.
  • Monitor ECG, pulse. Pacing/defib ready.
• Magnet Application:
  • Pacemaker: Magnet → asynchronous mode (VOO, DOO). Rate may indicate battery.
    • 📌 MOP = Mode Of Pacing (Asynchronous).
  • ICD: Magnet → suspends anti-tachy therapies (shocks, ATP). Pacing usually unaffected/basic async.
    • Audible tone may confirm.
  • ⚠️ Magnet temporary; remove to restore settings.

⭐ For ICDs, magnet application typically suspends tachyarrhythmia detection and therapies, but pacing functions (if active) usually continue as programmed or switch to a basic asynchronous mode.

Post-op & Problems - Aftercare & Alerts

• Immediate Aftercare:
  • Continuous ECG monitoring.
  • Device interrogation: Verify settings, thresholds, battery.
  • CXR: Check lead position, rule out pneumothorax.
  • Wound care: Monitor hematoma, infection.
  • Analgesia.
  • Arm immobilisation (sling) 24-48h; limit lifting > 5 lbs.
• Common Problems & Alerts:
  • Lead issues: Dislodgement (common early), fracture.
  • Malfunction: Failure to capture (FOC), sense (FOS).
  • Site issues: Infection, hematoma, erosion.
  • Thoracic: Pneumothorax, hemothorax.
  • ICD-specific: Inappropriate shocks, electrical storm.
  • Pacemaker syndrome, Twiddler's syndrome.
  • ⚠️ Report: Dizziness, syncope, palpitations, hiccoughs, twitching, infection signs.

⭐ Post-operative device interrogation is crucial to verify CIED function, restore settings, and detect complications like lead displacement or threshold changes.

High‑Yield Points - ⚡ Biggest Takeaways

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