Rapid Review of Pacemakers in Anaesthesia

Pre-operative Assessment

Essential Information to Obtain:

  • Pacemaker type and manufacturer (check pacemaker card or interrogation report)

  • Indication for pacemaker (complete heart block, sick sinus syndrome, etc.)

  • Underlying rhythm and pacemaker dependency

  • Date of last interrogation and battery status

  • Current pacing parameters (rate, mode, thresholds)

  • Patient's intrinsic heart rate if pacemaker turned off

Key Questions:

  • Is the patient pacemaker-dependent? (Will they have adequate cardiac output without pacing?)

  • What is their underlying rhythm and rate?

  • Any recent symptoms suggesting pacemaker malfunction?

  • Is electrocautery planned for the procedure?

Pacemaker Codes & Common Types

NASPE/BPEG Code (First 3 Letters Most Important):

  • 1st letter: Chamber paced (A=Atrium, V=Ventricle, D=Dual)

  • 2nd letter: Chamber sensed (A=Atrium, V=Ventricle, D=Dual, O=None)

  • 3rd letter: Response to sensing (I=Inhibited, T=Triggered, D=Dual, O=None)

Common Modes:

  • VVI: Ventricular paced, ventricular sensed, inhibited response (most common)

  • DDD: Dual chamber pacing with physiologic AV synchrony

  • AAI: Atrial paced, atrial sensed, inhibited (sick sinus syndrome)

Electromagnetic Interference (EMI) Concerns

High-Risk Equipment:

  • Electrocautery (monopolar > bipolar risk)

  • MRI (absolute contraindication for most older devices)

  • Radiofrequency ablation

  • Lithotripsy

  • Transcutaneous electrical nerve stimulation (TENS)

Electrocautery Management:

  • Use bipolar cautery when possible (minimal EMI)

  • If monopolar cautery required:

    • Place grounding pad as far from pacemaker as possible

    • Use short bursts at lowest effective power

    • Have temporary pacing available if patient is pacemaker-dependent

  • Consider magnet application for pacemaker-dependent patients (converts to asynchronous pacing)

Monitoring & Equipment Setup

Essential Monitoring:

  • Continuous ECG with ability to identify paced beats

  • Arterial line if major surgery or pacemaker-dependent patient

  • Pulse oximetry (backup for pulse detection if EMI interferes with ECG)

  • Defibrillator/external pacer immediately available

Rural Hospital Preparation:

  • Ensure magnet is available and functioning

  • Check defibrillator has external pacing capability

  • Have transcutaneous pacing pads ready for pacemaker-dependent patients

  • Atropine, isoprenaline, and adrenaline immediately available

Anesthetic Considerations

Drugs to Avoid/Use Cautiously:

  • Avoid: Suxamethonium in hyperkalemic patients (can cause pacemaker inhibition)

  • Caution: Beta-blockers, calcium channel blockers (may worsen underlying bradycardia)

  • Safe: Most anesthetic agents have minimal direct effect on pacemakers

Regional vs General Anesthesia:

  • Regional preferred when appropriate (neuraxial, peripheral nerve blocks)

  • Avoids EMI from cautery, maintains hemodynamic stability

  • High spinal/epidural: Risk of sympathetic blockade causing hypotension in pacemaker-dependent patients

General Anesthesia:

  • Standard induction agents generally safe

  • Maintain adequate anesthetic depth to prevent awareness during EMI

  • Positive pressure ventilation may affect venous return and pacing thresholds

Intraoperative Management

EMI Response Protocol:

  1. If EMI suspected (loss of paced rhythm, inappropriate heart rate):

    • Stop electrocautery immediately

    • Check pulse and blood pressure

    • Switch to bipolar cautery or use short bursts only

  2. For Pacemaker-Dependent Patients:

    • Apply magnet to convert to asynchronous pacing (DOO/VOO mode)

    • Caution: Magnet may not work on all devices or if battery low

    • Have external pacing ready as backup

  3. Emergency Situations:

    • If hemodynamic compromise: external cardiac massage, atropine, isoprenaline

    • Transcutaneous pacing if available

    • Consider stopping surgery if life-threatening arrhythmias

Specific Rural Hospital Challenges

Limited Resources:

  • No on-site cardiology or pacemaker technician

  • Basic monitoring equipment only

  • Limited emergency cardiac drugs

  • Potential need for transfer to tertiary center

Risk Mitigation:

  • Avoid elective surgery in pacemaker-dependent patients without cardiology backup

  • Day surgery preferred for stable patients with non-dependent pacemakers

  • Have transfer protocol ready for complications

Post-operative Care

Immediate Recovery:

  • Continuous cardiac monitoring until stable

  • Check pacemaker function (regular paced rhythm if dependent)

  • Document any intraoperative EMI episodes

  • Monitor for delayed pacemaker dysfunction (rare but possible)

Before Discharge:

  • Normal paced rhythm demonstrated

  • No symptoms of pacemaker malfunction

  • Plan for pacemaker check within 2-4 weeks if EMI exposure occurred

  • Patient education about signs of pacemaker problems

Emergency Contacts & Resources

Essential Phone Numbers:

  • Cardiology consultant for advice

  • Pacemaker manufacturer technical support (24-hour hotlines available)

  • Tertiary center for urgent transfer

  • Local ambulance service for transport capability

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