Temporary Epicardial Pacing After Cardiac Surgery
Evidence, risk stratification and practice across New Zealand cardiac centres
25 November 2025
Dr Michael Gillham, Cardiovascular Anaesthetist & Intensivist, CVICU Auckland
Dr Thomas Barr, Cardiothoracic Anaesthesia Fellow, Wellington
OVERVIEW
Temporary epicardial pacing wires are placed routinely after cardiac surgery to protect against post-operative bradycardia and heart block. Despite being a near-universal practice, the management of these systems is poorly guided by evidence or consensus guidelines. This meeting explored the clinical risks from two complementary perspectives: a case-based deep dive into over a decade of adverse event experience at Auckland’s CVICU, and the first national New Zealand observational study quantifying how pacing is managed across our five public cardiac centres.
Part 1: What are we trying to do? (Dr Mike Gillham)
Mike’s talk included:
A review of six real cases, each illustrating a specific failure mode and the clinical decisions required to manage it:
Failure to capture
Failure to sense
R-on-T causing VF
Pacemaker-mediated tachycardia
Lead dislodgement
Haemorrhage at removal
A review of the evidence base: pacing thresholds, sensing parameters, and the rationale for dual-chamber vs single-chamber configurations were covered in detail.
A practical framework for risk-stratifying patients prior to lead removal.
Part 2: What do we actually seem to be doing? (Dr Tom Barr)
Tom has collaborated with Mike and colleagues in Auckland and Wellington on New Zealand’s first multicentre observational study of temporary epicardial pacing practice. He presented some of the key findings at the meeting. The results have been submitted for publication, so we did not record Tom’s talk. Keep a look out for their paper!
Part 3: Fun Quiz and Q&A
Mike closed the meeting with an interactive ten-question ECG quiz, run via a live polling platform. Give it a go.
KEY LEARNING POINTS
Surgery
Check pacing wire function in the operating room — before and after chest closure — as a routine step, not just when problems are suspected.
Operations at highest risk of requiring permanent pacing: double/triple valve surgery (up to 15%), septal myomectomy, aortic valve replacement with root involvement, and procedures performed in the setting of endocarditis.
The evidence consistently favours bipolar over unipolar wires for sensing and capture reliability. A Brompton study (2001) and a PES study (2016) both demonstrated significantly better performance with bipolar wires beyond the first 12–24 hours.
Consider whether patients with a very high capture threshold at wire insertion in a high-risk operation warrant a second wire placement before sternal closure.
Connecting cable quality matters. Cables should be tracked for sterilisation cycles (manufacturer limit: 25). Cables that are overused develop microfractures causing over-sensing. Single-use disposable cables are an effective solution.
Anaesthesia
Document the pacing capture threshold at handover to ICU. This establishes a baseline and allows deterioration to be tracked.
Do not use DDD pacing mode for ward-level care unless absolutely required. Poor atrial sensing in DDD mode can trigger polymorphic VT via the ventricular blanking phenomenon. VVI backup is the appropriate default on the ward.
When giving bradycardic drugs (amiodarone, metoprolol, digoxin) to treat post-operative AF, ensure the VVI backup pacing system is active and functioning well — reversion pauses after cardioversion can be prolonged and life-threatening without pacing protection.
The first step in performing a pacing check (sensing threshold assessment) is always to reduce the pacing output to 0.1 mA before adjusting sensitivity. This prevents asynchronous pacing and arrhythmia induction.
Language precision matters when teaching pacing: distinguish ‘sensing threshold’ (the amplitude of signal detected, in mV) from ‘sensitivity setting’ (the dial value, in mV). A lower sensitivity setting means the pacemaker detects smaller signals, increasing sensitivity. ‘Increase the sensitivity’ is ambiguous; ‘decrease the sensitivity setting’ is not.
ICU
Risk-stratify patients for minimum pacing protection period:
Low risk (isolated CABG, no block, young, no renal failure): brief initial monitoring, can consider early disconnection if pacing not required.
Moderate risk (single valve replacement, pre-existing high/low grade block): minimum 48 hours of VVI backup, if sensing adequate.
High risk (double or triple valve, septal myomectomy, or valve + existing block): minimum 72 hours.
These minimum periods assume the pacing system is sensing adequately. If it is not, the patient’s risk profile needs reassessment — they may need a transvenous wire or earlier permanent system implantation.
Capture thresholds deteriorate over time. Tracking the threshold serially allows early identification of failing wires and timely escalation to cardiology for permanent system planning. The European guidelines recommend waiting at least 5 days before implanting a permanent system; a Polish cohort study (Biz et al.) suggested that implanting at day 7 balances both the risk of unnecessary permanent pacing and the complications of prolonged temporary wire use.
Chronotropic agents (commonly dopamine) can mask bradycardia tendency. When dopamine is weaned on day two, bradycardic problems may emerge for the first time. Be vigilant at this transition.
Monitoring system reliability — technology AND staffing — must be understood for each environment where paced patients are nursed. A central station without a dedicated observer, or a bedside monitor connected via a worn LAN cable, is not equivalent to continuous monitoring.
Nursing
Pacing checks should be performed at least once per nursing shift. The ventricular capture threshold should be formally checked and documented every time — not just verbal handover.
A cognitive aid (bedside reference card) for how to perform a pacing check correctly reduces harm. If staff have been away from pacing-intensive environments, returning from leave is a high-risk period for errors during pacing checks.
Nursing staff often have more structured credentialing for pacing management than medical staff. If a junior doctor is hesitant or uncertain about pacing management, nurses can and should raise safety concerns.
Physical arrangement of pacing cables matters: overly long cables get coiled on the patient’s abdomen, developing microfractures. Cables should not be reused beyond the manufacturer’s recommended sterilisation limit.
Trainees
Pacing knowledge is often acquired by ‘osmosis’ during training rather than systematic teaching. The concepts are examinable and clinically important.
The ECG quiz covered ten high-yield clinical scenarios.
Tom’s work shows how practice research can be conducted in a small national community.
Dr Michael Gillham
Mike is a cardiovascular anaesthetist and intensivist at Auckland City Hospital’s CVICU, with a particular interest in patient safety and cardiac post-operative care. Over the past decade he has led a systematic review of adverse events related to temporary epicardial pacing at his centre, developing protocols, cognitive aids, and educational resources to reduce pacing-related harm.
Dr Thomas Barr
Tom is a provisional fellow in cardiothoracic anaesthesia at Wellington Hospital (now a Fellow in CVICU). His interest in temporary pacing began during his ICU training, where he found that applying pacing concepts in clinical practice required knowledge that was difficult to acquire systematically. Tom is pursuing further research in this area and is interested in developing standardised educational resources for the management of temporary pacing systems.
References
Magnusson P et al. Risk of permanent pacemaker after cardiac surgery. Eur J Cardiothorac Surg. 2022. Swedish registry (n=~84,000): CABG ~1%, single valve ~5%, double/triple valve up to ~15% require permanent pacing.
Biz D et al. Timing of permanent pacemaker implantation after cardiac surgery. Polish single-centre cohort. Day 7 implantation recommended to balance risk of unnecessary permanent pacing against complications of prolonged temporary wire use.
Brompton Hospital study (2001). Unipolar vs bipolar wires: bipolar wires demonstrated significantly better capture and sensing to day 5 post-operatively.
PES study (2016). Patients received both unipolar and bipolar ventricular wires simultaneously; confirmed bipolar superiority beyond 24 hours.
Resources
Auckland CVICU Pacemaker Check Cognitive Aid — bedside reference card. [TO ADD — request from Dr Gillham]
Auckland CVICU Day-1 Ward Risk Stratification Guide — guidance on pacing protection vs disconnection for post-operative patients. [TO ADD — request from Dr Gillham]
Slides [TO ADD — contact Dr Gillham]