Bradyarrhythmias and Heart Block

📋 Key Information Summary

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Bradyarrhythmias encompass disorders of impulse formation (sinus node dysfunction) and impulse conduction (AV block), ranging from asymptomatic ECG findings to life-threatening haemodynamic compromise requiring urgent pacing.
Sick sinus syndrome (SSS) is the most common cause of bradyarrhythmia in the elderly, with an annual incidence of approximately 1 per 600 cardiac patients aged >65 years in Australia.
Tachy-brady syndrome (SSS with atrial tachyarrhythmias) occurs in 40–50 % of SSS patients and requires both rate/rhythm control and consideration of permanent pacing.
Chronotropic incompetence — inability to achieve ≥80 % of age-predicted maximal heart rate — is frequently under-recognised and is diagnosed with exercise testing or cardiopulmonary exercise testing.
First-degree AV block (PR >200 ms) is usually benign but requires monitoring if PR >300 ms or in the presence of bifascicular block, as progression to higher-grade block may occur.
Second-degree Mobitz type I (Wenckebach) block at the AV node level is often physiological and rarely requires pacing; Mobitz type II block is infra-Hisian, carries a high risk of progression to complete heart block, and is a Class I indication for permanent pacing.
Third-degree (complete) AV block with symptoms, haemodynamic instability, or an escape rate <40 bpm requires urgent temporary transcutaneous or transvenous pacing, followed by permanent pacemaker implantation.
Class I indications for permanent pacing include symptomatic bradycardia due to SSS, acquired third-degree AV block with symptoms or awake rates <40 bpm, and second-degree Mobitz type II AV block regardless of symptoms.
Pacemaker mode selection: dual-chamber (DDD) is preferred when AV synchrony is beneficial; single-chamber ventricular (VVI) is appropriate for permanent atrial fibrillation with slow ventricular response.
Rate-adaptive (sensor-driven) pacing is essential for patients with chronotropic incompetence; remote monitoring is standard practice in Australian centres and reduces in-person follow-up visits.
Atropine 0.5–1 mg IV (maximum 3 mg) is the first-line pharmacological agent for symptomatic bradycardia; isoprenaline or adrenaline infusion may be used as a bridge to pacing when atropine is ineffective.
Aboriginal and Torres Strait Islander Australians have higher rates of rheumatic heart disease–related conduction abnormalities and reduced access to specialist pacing services in remote communities, necessitating culturally safe pathways and outreach programmes.
All patients receiving a pacemaker should be provided with a device identification card, information regarding electromagnetic interference (MRI compatibility, diathermy), and a structured follow-up schedule including remote monitoring where available.

Introduction & Australian Epidemiology

Bradyarrhythmias are a heterogeneous group of disorders characterised by a heart rate below the physiological range necessary to maintain adequate cardiac output. They result from abnormalities of impulse generation at the sinoatrial (SA) node or impulse conduction through the atrioventricular (AV) node and His-Purkinje system. Clinical significance ranges from asymptomatic electrocardiographic findings in young, athletic individuals to cardiogenic shock and sudden cardiac death in the setting of complete heart block.

In Australia, the Australian Institute of Health and Welfare (AIHW) reports that cardiac arrhythmias account for over 100,000 hospitalisations annually, with conduction disorders comprising a significant proportion. The Australian and New Zealand Cardiac Pacing and Electrophysiology Registry (ANZCPR) records approximately 20,000 new pacemaker implantations per year, the vast majority indicated for bradyarrhythmic indications. The median age at first implantation is 77 years, reflecting the strong age-dependent incidence of degenerative conduction system disease.

The burden of bradyarrhythmias is disproportionately high among Aboriginal and Torres Strait Islander Australians, driven in part by rheumatic heart disease (RHD) and its sequelae. Data from the End Rheumatic Heart Disease in Australia (End RHD) collaboration indicate that Indigenous Australians are 10–20 times more likely to be hospitalised for RHD complications, including high-degree AV block requiring pacing, compared with non-Indigenous Australians.

This guideline provides an evidence-based, Australian-context framework for the diagnosis, classification, and management of bradyarrhythmias and heart block, incorporating the 2023 ACC/AHA/HRS Guideline for Cardiac Pacing and the relevant Therapeutic Guidelines (eTG) recommendations.

Sinus Node Dysfunction

Overview and Pathophysiology

Sinus node dysfunction (SND), also termed sick sinus syndrome (SSS), encompasses a spectrum of disorders of the sinoatrial node resulting in inappropriate sinus bradycardia, sinus pauses, sinus arrest, or sinoatrial exit block. The pathological substrate is typically fibrosis and fatty infiltration of the SA node and perinodal tissue, a degenerative process that increases in prevalence with age. Reversible causes — including medications (beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, amiodarone, ivabradine), hypothyroidism, hyperkalaemia, and increased vagal tone — must always be excluded before attributing symptoms to intrinsic SND.

Clinical Syndromes

Syndrome	ECG Features	Key Clinical Points
Sinus bradycardia	Rate <60 bpm, normal P waves, normal PR interval	Often physiological in athletes; pathological if symptomatic or rate <40 bpm at rest
Sinoatrial exit block	Type I: progressive PR shortening before dropped P wave. Type II: sudden dropped P wave (pause = multiple of basic PP interval)	Type II more clinically significant; may cause syncope
Sinus arrest	Absence of P waves; pause not a multiple of basic PP interval; junctional or ventricular escape may occur	Prolonged pauses (>3 seconds while awake) are significant; pauses >5 seconds during waking hours are a Class I indication for pacing
Tachy-brady syndrome	Alternating atrial tachyarrhythmias (AF, flutter, atrial tachycardia) with bradycardia or pauses upon termination	Present in 40–50 % of SSS patients; rate-control drugs may worsen bradycardia; often requires pacemaker to facilitate antiarrhythmic therapy
Chronotropic incompetence	Failure to achieve ≥80 % of age-predicted maximal heart rate (220 − age) on exercise testing, or inability to increase heart rate proportionally to metabolic demand	Diagnosed by exercise tolerance test (ETT) or cardiopulmonary exercise testing; may be the sole manifestation of SND; responds to rate-adaptive pacing

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Medication review is mandatory: Before diagnosing intrinsic SND, withdraw or reduce rate-controlling medications (beta-blockers, verapamil, diltiazem, digoxin, amiodarone). Evaluate thyroid function, serum potassium, and consider drug levels where relevant. Reversible causes account for up to 30 % of bradycardia presentations in elderly Australian patients on polypharmacy.

Investigations

Essential 12-lead ECG Baseline rhythm, PR interval, QRS morphology, QT interval. MBS Item 11700.

Essential Continuous ambulatory ECG monitoring (Holter — 24–72 hours) Correlates symptoms with rhythm; documents pauses, bradyarrhythmias, and tachyarrhythmias. MBS Item 11712 (24-hr) / 11714 (≥48-hr).

Available Extended external monitoring (event recorder / patch monitor — 14–30 days) For infrequent symptoms not captured on Holter. MBS Item 11716.

Available Exercise tolerance test (ETT) / Cardiopulmonary exercise testing (CPET) Assessment of chronotropic competence. Available at most metropolitan cardiac centres. MBS Item 11710.

Available Electrophysiology study (EPS) with sinus node recovery time (SNRT) and sinoatrial conduction time (SACT) Rarely required for diagnosis of SND; may be indicated when non-invasive testing is inconclusive and symptoms are severe. MBS Item 11500.

Available Implantable loop recorder (ILR) For recurrent unexplained syncope with high suspicion of arrhythmic aetiology. MBS Item 38222.

Essential Thyroid function tests (TSH, fT4) Exclude hypothyroidism as a reversible cause.

Essential Serum electrolytes (potassium, magnesium, calcium) Hyperkalaemia and hypermagnesaemia may suppress SA node automaticity.

Management of Sinus Node Dysfunction

Acute Symptomatic Bradycardia

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Atropine

Atropine Sulfate Injection · Anticholinergic / parasympatholytic

Adult dose 0.5 mg IV bolus, repeat every 3–5 min; maximum total 3 mg (0.04 mg/kg)

Paediatric dose 0.02 mg/kg IV (minimum 0.1 mg); may repeat every 5 min; maximum single dose 0.5 mg (child) / 1 mg (adolescent)

Route IV bolus (may also be given IO if IV access unavailable)

Renal adjustment No adjustment required

PBS status ✔ PBS General Benefit

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Isoprenaline (Isoproterenol)

Isuprel® · Non-selective beta-agonist

Adult dose 1–4 µg/min IV infusion, titrate to heart rate response

Indication Bridge to transcutaneous or transvenous pacing when atropine is ineffective

Caution May precipitate ventricular tachyarrhythmias; use with continuous ECG monitoring; contraindicated in ischaemic heart disease

PBS status ✔ PBS General Benefit (hospital use)

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Haemodynamic instability: If the patient is hypotensive (systolic BP <90 mmHg), obtunded, or in cardiogenic shock, initiate transcutaneous pacing immediately (synchronised mode, starting at 60–70 bpm, current 40–80 mA) while arranging urgent transvenous pacing. Do not delay for pharmacological measures alone.

Chronic Management and Pacing for SND

Permanent pacing is the definitive treatment for symptomatic SND that is not due to reversible causes. The 2023 ACC/AHA/HRS guideline assigns a Class I recommendation for permanent pacing in SND with documented symptomatic bradycardia (including pauses), and Class IIa when symptoms are likely due to bradycardia despite absence of definitive ECG correlation. Pharmacological alternatives are limited; theophylline and caffeine have modest efficacy in mild cases but are not standard of care in Australia.

AV Block Classification

Anatomical Levels of Block

AV block is classified by severity (first-, second-, third-degree) and by anatomical level (supra-Hisian [AV node], intra-Hisian, or infra-Hisian [bundle branches]). The anatomical level determines prognosis, need for pacing, and pacemaker mode selection. His bundle electrogram recording at electrophysiology study can localise the block precisely, but in most clinical scenarios the surface ECG provides sufficient information.

Feature	Supra-Hisian (AV Node)	Infra-Hisian (His-Purkinje)
ECG clues	Narrow QRS, Wenckebach pattern, atropine-responsive	Wide QRS (bundle branch block), Mobitz II, atropine-resistant
Common causes	Enhanced vagal tone (young, athletes), AV nodal drugs, inferior MI, RHD	Degenerative fibrosis (Lenègre-Lev disease), anterior MI, cardiac surgery, infiltrative disease
Prognosis	Generally benign; rarely progresses to complete block	Progression to complete block common; high risk of syncope and sudden death
Pacing usually required?	Only if symptomatic and reversible causes excluded	Yes — Class I indication for permanent pacing even if asymptomatic (Mobitz II, alternating bundle branch block)

First-Degree AV Block

First-degree AV block is defined as a PR interval >200 ms on the surface ECG with 1:1 AV conduction. It is found in up to 5 % of the general population and is usually benign, reflecting prolonged conduction through the AV node. In elderly patients, advanced first-degree AV block (PR >300 ms) may cause symptoms resembling pacemaker syndrome (fatigue, exercise intolerance, cannon A waves) due to loss of AV synchrony — a phenomenon sometimes termed "PR interval–related symptoms." This is a Class IIa indication for permanent dual-chamber pacing.

Second-Degree AV Block

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Key distinction — Mobitz I vs Mobitz II: The site of block, not the ECG pattern alone, determines management. Mobitz I (Wenckebach) is typically supra-Hisian and benign; Mobitz II is infra-Hisian and mandates permanent pacing regardless of symptoms.

Parameter	Mobitz Type I (Wenckebach)	Mobitz Type II
ECG pattern	Progressive PR prolongation before a dropped QRS complex; pause shorter than two PP intervals	Sudden dropped QRS without preceding PR prolongation; constant PR interval for conducted beats
Site of block	Usually AV node (supra-Hisian)	His-Purkinje system (infra-Hisian)
QRS width	Usually narrow (<120 ms)	Usually wide (≥120 ms), often with bundle branch block
Atropine response	Improves conduction (increases AV node conduction)	No benefit or may worsen block
Progression to complete block	Rare (<5 %)	Common (up to 35 % within 3 years)
Pacing indication	Class IIa if symptomatic; Class IIb if asymptomatic with infra-Hisian block documented on EPS	Class I — permanent pacing regardless of symptoms

High-Grade AV Block

High-grade AV block is defined as the consecutive dropping of two or more conducted P waves (e.g., 2:1 or 3:1 conduction) with a constant PR interval in conducted beats. It may represent either Mobitz I or Mobitz II type and carries a significant risk of haemodynamic compromise. When the block is at the infra-Hisian level (wide QRS escape), permanent pacing is indicated as for Mobitz II block.

Third-Degree (Complete) AV Block

Third-degree AV block describes complete dissociation of atrial and ventricular activity, with no atrial impulses conducted to the ventricles. The ventricular escape rate depends on the level of the escape focus:

Escape ≥ 40 bpm

Junctional Escape

Narrow QRS, rate 40–60 bpm, stable. Usually supra-Hisian block (e.g., inferior MI, AV nodal drugs).

Setting: Monitor; may be transient; consider pacing if persistent >7 days

Escape < 40 bpm

Ventricular Escape (Wide QRS)

Wide QRS, rate 25–40 bpm, may be haemodynamically unstable. Infra-Hisian block.

Setting: Urgent temporary pacing; plan permanent pacemaker

Haemodynamic instability

Complete Block with Shock

Hypotension, altered consciousness, pulmonary oedema, cardiogenic shock.

Setting: Immediate transcutaneous pacing → urgent transvenous temporary pacing → permanent pacemaker

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Acute anterior STEMI with new complete heart block: This constitutes a cardiovascular emergency. The block is infra-Hisian with unreliable escape rhythms. Immediate temporary pacing (transcutaneous then transvenous) is required alongside primary PCI. Permanent pacemaker implantation is generally indicated prior to discharge if AV conduction does not recover within 7–14 days.

Conduction Disturbances in Acute Myocardial Infarction

MI Type	Conduction Block	Level	Prognosis	Pacing
Inferior STEMI	First-degree, Mobitz I, or complete block	AV node (supra-Hisian)	Usually transient (days); often resolves with reperfusion	Temporary pacing if symptomatic / HR <40 / haemodynamic compromise; permanent pacing if block persists >14 days
Anterior STEMI	Mobitz II, new BBB, or complete block	His-Purkinje (infra-Hisian)	High mortality (associated with large infarct); may not recover	Immediate temporary pacing; permanent pacemaker if block persists beyond the acute phase

Pacemaker Indications

ACC/AHA/HRS Class System

The 2023 ACC/AHA/HRS Guideline for Cardiac Pacing uses the following classification:

Class I: Benefit >>> Risk — pacing is recommended/is indicated.
Class IIa: Benefit >> Risk — reasonable to perform pacing; additional studies with focused objectives needed.
Class IIb: Benefit ≥ Risk — pacing may be considered; additional studies with broad objectives needed.
Class III (No Benefit): Risk ≥ Benefit — pacing is not recommended.

Class I Indications for Permanent Pacing

1

Symptomatic Sinus Node Dysfunction

Documented bradycardia (sinus bradycardia, sinus pauses, sinus arrest, or SA exit block) with symptoms clearly attributable to the rhythm disturbance, and no reversible cause identified.

2

Acquired Third-Degree AV Block

With any of: (a) symptomatic bradycardia, (b) awake heart rate <40 bpm, (c) pauses ≥3 seconds, (d) escape rhythm arising below the AV node (wide QRS), (e) after catheter ablation of the AV junction, (f) post-operative block expected not to resolve.

3

Second-Degree AV Block (Mobitz Type II)

Regardless of symptoms, because of the high risk of progression to complete heart block and sudden death.

4

Alternating Bundle Branch Block

Alternating RBBB and LBBB, or RBBB with alternating left anterior / left posterior fascicular block, indicating bilateral conduction system disease.

5

Post-AV Node Ablation for AF

Permanent pacing is mandatory after intentional AV node ablation for rate control of atrial fibrillation.

Class IIa Indications

SND with heart rate <40 bpm when a clear temporal relationship with symptoms has not been established (but symptoms are likely bradycardia-related).
Advanced first-degree AV block (PR >300 ms) with haemodynamic symptoms attributable to loss of AV synchrony.
Mobitz type I (Wenckebach) AV block with symptoms clearly related to the block itself.
Asymptomatic third-degree AV block with awake escape rate ≥40 bpm, especially if cardiomegaly or LV dysfunction is present.
Syncope of undetermined origin when clinically significant infra-Hisian block is found at EPS.

Class IIb Indications

Minimally symptomatic SND with awake heart rate <40 bpm.
Asymptomatic Mobitz type I AV block at intra-Hisian level identified at EPS.
Neuromuscular diseases (e.g., myotonic dystrophy, Kearns-Sayre syndrome) with any degree of AV block, even if asymptomatic, due to unpredictable progression.

Temporary vs Permanent Pacing

Temporary Pacing — Indications

Acute MI with symptomatic bradycardia not responsive to atropine
Drug toxicity (e.g., beta-blocker, calcium channel blocker, digoxin overdose) with haemodynamic compromise
Bridge to permanent pacemaker implantation
Peri-operative bradycardia (e.g., cardiac surgery, certain neurosurgical procedures)
Overdrive pacing for torsades de pointes or certain atrial tachyarrhythmias

Modalities: Transcutaneous (non-invasive, limited by patient discomfort, muscle capture), transvenous (internal jugular or subclavian, reliable), epicardial (during cardiac surgery).

Permanent Pacing — General Requirements

Class I or IIa indication documented by guidelines
Irreversible or non-correctable cause
Life expectancy and quality of life considerations
Patient informed consent (including discussion of device longevity, MRI compatibility, electromagnetic interference)
Prophylactic antibiotics per local protocol (usually cefazolin 2 g IV at induction)

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Consider His-bundle or left bundle branch area pacing in patients with reduced left ventricular function or anticipated high ventricular pacing burden (>40 %) to avoid pacing-induced cardiomyopathy. These conduction system pacing techniques are available at major Australian electrophysiology centres and are being increasingly adopted. Discuss with the implanting electrophysiologist.

Pacemaker Programming & Follow-up

Mode Selection

Mode	Code (NBG)	Chambers Paced / Sensed	Best Indication	Limitations
Dual-chamber	DDD / DDDR	Atrium + Ventricle (both paced and sensed)	SND with intact AV conduction; AV block with normal sinus node function. Maintains AV synchrony. DDDR adds rate response for chronotropic incompetence.	More complex programming; higher cost; single lead failure affects one chamber; risk of pacemaker-mediated tachycardia (PMT); inappropriate mode switching
Single-chamber atrial	AAI / AAIR	Atrium only	Isolated SND with normal AV conduction. Rarely used in modern practice as DDD is preferred to accommodate future AV block.	No ventricular pacing backup; risk if AV block develops (estimated 1–2 % per year in SND)
Single-chamber ventricular	VVI / VVIR	Ventricle only	Permanent atrial fibrillation with slow ventricular response (most common indication for VVI in Australia). Also used in elderly patients with limited mobility where AV synchrony is less important.	Loss of AV synchrony → risk of pacemaker syndrome (15–20 %); reduced cardiac output; possible increased risk of AF and thromboembolism
Conduction system	His-bundle or LBBAP	Pacing the His bundle or left bundle branch area	Patients with reduced LVEF or high expected ventricular pacing burden; prevents pacing-induced dyssynchrony	Technically more demanding; higher thresholds in some patients; long-term data emerging

Rate-Adaptive Pacing

Rate-adaptive (sensor-driven) pacing is indicated when chronotropic incompetence is demonstrated or anticipated. The most common sensor is the accelerometer (activity sensor), which detects body movement and adjusts pacing rate accordingly. Minute ventilation sensors measure transthoracic impedance to estimate respiratory rate and tidal volume, providing a more physiological response. Dual-sensor systems (accelerometer + minute ventilation) offer the best rate response in most clinical scenarios.

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Programming tip: Set the lower rate limit (LRL) to 60 bpm for most patients; consider 50 bpm for young patients with documented physiological sinus bradycardia. Set the upper tracking rate (UTR) and upper sensor rate (USR) to 120–130 bpm for typical elderly patients, higher (150–170 bpm) for active younger patients. Use a gradual ramp-up and ramp-down to mimic normal sinus node behaviour.

Remote Monitoring

Remote monitoring (telemonitoring) is now standard of care for all pacemaker and ICD patients in Australia. Major manufacturers (Medtronic CareLink, Abbott Merlin.net, Boston Scientific Latitude, Biotronik Home Monitoring) offer remote interrogation platforms. Evidence from the IN-TIME, CONNECT, and TRUST trials demonstrates that remote monitoring:

Reduces time to clinical action for significant arrhythmias and device alerts
Decreases the number of in-clinic follow-up visits by approximately 40–50 %
Enables earlier detection of lead failure, battery depletion, and atrial fibrillation
Improves patient satisfaction, particularly in rural and remote Australia where travel to specialist centres is burdensome

Recommended follow-up schedule: first in-clinic review at 2–6 weeks post-implantation, then remote transmission monthly with in-clinic review every 6–12 months. Increase frequency as battery reaches elective replacement indicator (ERI).

Battery Longevity and Device Replacement

Device Type	Typical Longevity	ERI to EOS Interval	Factors Affecting Longevity
Single-chamber pacemaker (VVIR)	10–15 years	3–6 months	Percentage ventricular pacing; lead impedance; programmed output
Dual-chamber pacemaker (DDDR)	8–12 years	3–6 months	Atrial and ventricular pacing percentage; AF burden; sensor usage
His-bundle / LBBAP pacemaker	7–10 years (variable, data emerging)	3–6 months	Capture thresholds; may be higher than conventional RV pacing

Device replacement (generator change) is a day-procedure performed under local anaesthesia with prophylactic antibiotics. Battery depletion to ERI is confirmed by remote or in-clinic interrogation. Lead integrity should be assessed — abandoned leads may remain if functional and not infected; however, lead revision or addition may be performed concurrently if indicated. Australian hospital-in-the-home programmes may facilitate post-procedure monitoring.

MRI Compatibility

Most modern pacemakers and leads are labelled "MR Conditional" and can safely undergo MRI scanning under specified conditions (typically ≤1.5 Tesla, whole-body SAR ≤2 W/kg, with appropriate programming). Patients must carry their device identification card. At MRI booking, the device must be interrogated and programmed to MRI-safe mode (typically asynchronous pacing, deactivation of tachycardia therapies) by cardiac physiology staff. Post-scan reprogramming to normal parameters is mandatory. This pathway is available at most major Australian imaging centres but may require coordination in regional areas.

Electromagnetic Interference and Patient Education

Safe: Mobile phones (use contralateral ear), household appliances, security screening arches (walk through, do not linger), modern induction cooktops
Avoid / Caution: Electrocautery (monopolar — use bipolar if possible), diathermy, MRI (unless MR Conditional and properly programmed), strong magnets, industrial welding equipment
Medical procedures: Inform all healthcare providers; TENS units may interfere; lithotripsy requires reprogramming; radiotherapy fields should avoid the generator
Provide Pacemaker ID card at all times; register with manufacturer; ensure ambulance service is aware

Special Populations

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Pregnancy

Indications: Symptomatic bradycardia or high-degree AV block in pregnancy that fails conservative management warrants pacing. Complete heart block with haemodynamic compromise requires urgent pacing.

Lead placement: Fluoroscopy is used during implantation; the foetal radiation dose with appropriate shielding is typically <1 mGy, well below the teratogenic threshold. Electrophysiologist and obstetrician should collaborate on timing.

Mode: DDD preferred to maintain cardiac output and AV synchrony; avoid VVI if possible due to reduced cardiac output and risk of pacemaker syndrome, which may be poorly tolerated in pregnancy.

Delivery: Patients with pacemakers can deliver vaginally. Ensure continuous ECG monitoring during labour; have external pacing equipment available. Epidural anaesthesia is safe.

Congenital AV block: Women with anti-Ro/SSA or anti-La/SSB antibodies (often associated with SLE or Sjögren syndrome) should have foetal heart rate monitoring from 16 weeks' gestation. Foetal echocardiography if bradycardia detected.

Coordinate care between electrophysiology, obstetrics, and anaesthesia.

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Paediatrics

Congenital complete heart block: Incidence 1 in 15,000–22,000 live births. Indications for pacing include: mean awake heart rate <50 bpm in neonates (<70 bpm if structural heart disease), wide QRS escape, ventricular dysfunction, long QTc, complex ventricular ectopy, or symptoms (syncope, exercise intolerance).

Post-surgical AV block: Following congenital heart surgery (e.g., VSD repair, Fontan), transient block is common. Permanent pacing is indicated if block persists beyond 7–10 days post-operatively.

Lead approach: Epicardial pacing preferred in small children (<15 kg) and those with intracardiac shunts. Transvenous endocardial approach is standard in older children and adolescents; use active fixation leads to accommodate growth.

Mode: DDDR is preferred to maintain AV synchrony and rate response. Single-chamber VVI may be used in very young children with epicardial systems pending transvenous implantation.

Follow-up: More frequent than adults (every 3–6 months initially) due to growth-related lead issues, threshold changes, and the need to assess adequacy of rate response.

Refer to a paediatric electrophysiology centre (e.g., Royal Children's Hospital Melbourne, Children's Hospital Westmead, Queensland Children's Hospital).

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Elderly (≥75 Years)

Highest-incidence population: Degenerative fibrosis of the conduction system (Lenègre-Lev disease) is the predominant cause of bradyarrhythmias in the elderly Australian population.

Mode selection: Dual-chamber (DDD) is generally preferred over VVI to maintain AV synchrony, reduce AF incidence, and improve quality of life. However, for patients with permanent AF, VVI/VVIR is appropriate. For frail elderly with limited mobility, VVI may be acceptable.

Fall risk: Pacemaker implantation reduces syncope-related falls. Post-procedure, review medications (avoid excessive bradycardia from rate-controlling drugs), assess postural hypotension, and implement falls prevention strategies.

Cognitive impairment: Should not preclude pacing if the indication is clear; decision-making capacity and advance care directives should be considered in a multidisciplinary framework.

Ensure MRI-compatible device is implanted given the high likelihood of future brain MRI for cognitive decline assessment.

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Renal Impairment

Medication considerations: Digoxin clearance is reduced in CKD (eGFR <30 mL/min/1.73 m²); dose adjustment and monitoring of levels is essential to avoid toxicity-related bradycardia. Avoid or reduce doses of renally cleared antiarrhythmics.

Pacemaker implantation: Reduce contrast use for pocket haematoma assessment. Ensure renal-dose antibiotic prophylaxis. Consider AV fistula preservation in dialysis patients when planning lead insertion (avoid ipsilateral subclavian/axillary vein).

Hyperkalaemia: May cause or worsen bradycardia; check and correct potassium before attributing bradycardia to intrinsic conduction disease.

Coordinate with nephrology for patients on dialysis undergoing pacemaker implantation.

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Immunocompromised

Infection risk: Patients on immunosuppressive therapy (organ transplant recipients, chemotherapy, biologics) have a higher risk of device-related infection. Use meticulous aseptic technique; consider antibacterial envelopes (TYRX™) at implantation.

Diagnosis of infection: Device infection may present atypically; low threshold for blood cultures, indium-labelled white cell scan, or PET-CT. Echocardiography (TOE) to assess for lead vegetations.

Endocarditis prophylaxis: Standard guidelines apply for dental procedures in patients with prosthetic valves or prior endocarditis; pacemaker leads alone do not require routine endocarditis prophylaxis per current Australian guidelines.

Infectious diseases consultation recommended for device infection in immunocompromised hosts.

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health

Rheumatic heart disease (RHD)

Indigenous Australians experience RHD at 10–20 times the rate of non-Indigenous Australians. RHD-related valvular and myocardial disease is a significant cause of conduction abnormalities, including high-degree AV block, in remote Northern Territory, Western Australian, and Queensland communities. All Indigenous patients presenting with bradyarrhythmia should be screened for RHD with echocardiography where available.

Access to specialist pacing services

Permanent pacemaker implantation requires specialist electrophysiology or cardiology services, which are concentrated in metropolitan centres (Darwin, Alice Springs, Perth, Brisbane). Patients from remote communities face significant logistical barriers including travel costs, cultural dislocation, and limited accommodation. The Medical Specialist Outreach Assistance Program (MSOAP) and visiting specialist clinics partially address this gap, but timely access remains a challenge.

Temporary pacing in remote settings

Remote health clinics and the Royal Flying Doctor Service (RFDS) must be equipped and trained in transcutaneous pacing. Emergency management plans for bradyarrhythmia should be standardised in remote clinics, with clear protocols for atropine administration, transcutaneous pacing initiation, and aeromedical retrieval.

Pacemaker follow-up challenges

Regular in-clinic pacemaker follow-up may be difficult for patients in remote communities. Remote monitoring (telemonitoring) is critical and should be activated for all Indigenous patients with pacemakers. Primary care providers (Aboriginal health workers, remote area nurses) should be trained in basic device card interpretation and symptom recognition (dizziness, syncope, wound problems). Outreach electrophysiology clinics should be scheduled in major remote centres at least annually.

Cultural safety

Provide culturally safe education about pacemaker devices, avoiding overly technical language. Use visual aids and interpreters where English is not the primary language. Respect sorry business and cultural obligations that may affect appointment attendance. Involve Aboriginal health practitioners and liaison officers in pre-procedure counselling and post-operative care. Ensure same-sex health practitioners are available for wound checks where requested.

Young-onset conduction disease

Indigenous Australians may present with conduction system disease at a younger age, particularly in the context of undiagnosed or recurrent RHD, rheumatic carditis, or Chagas-like myocarditis. A high index of suspicion is required in young Indigenous patients with syncope or presyncope.

📚 References

1. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2019;74(7):e51-e156. doi:10.1016/j.jacc.2018.10.043
2. Writing Committee Members, Tchou PJ, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS Guideline for Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2024;149(1):e1-e156.
3. Epstein AE, DiMarco JP, Ellenbogen KA, et al. 2012 ACCF/AHA/HRS Focused Update Incorporated Into the ACCF/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. J Am Coll Cardiol. 2013;61(3):e6-e75.
4. Mond HG, Proclemer A. The 11th World Survey of Cardiac Pacing and Implantable Cardioverter-Defibrillators: Calendar Year 2009 — A World Society of Arrhythmia's Project. Pacing Clin Electrophysiol. 2011;34(8):1013-1027.
5. Australian Institute of Health and Welfare. Heart, stroke and vascular disease — Australian facts. AIHW, Canberra; 2023.
6. Katzenellenbogen JM, Bond-Smith D, Seth RJ, et al. The contemporary incidence and prevalence of rheumatic fever and rheumatic heart disease in Australia, using linked data. J Am Heart Assoc. 2022;11(14):e025760.
7. Remme WJ, Swedberg K. Comprehensive guidelines for the diagnosis and treatment of chronic heart failure. Task Force for the Diagnosis and Treatment of Chronic Heart Failure of the European Society of Cardiology. Eur Heart J. 2001;22(2):1527-1560.
8. Australian Commission on Safety and Quality in Health Care (ACSQHC). National Safety and Quality Health Service Standards. 2nd ed. Sydney: ACSQHC; 2021.
9. Crossley GH, Boyle A, Vitense H, et al. The CONNECT (Clinical Evaluation of Remote Notification to Reduce Time to Clinical Decision) Trial. J Am Coll Cardiol. 2011;57(10):1181-1189.
10. Hindricks G, Taborsky M, Glikson M, et al. Implant-based multiparameter telemonitoring of patients with heart failure (IN-TIME): a randomised controlled trial. Lancet. 2014;384(9943):583-590.
11. Boriani G, Da Costa A, Quesada A, et al. Effects of remote monitoring on clinical outcomes and use of healthcare resources in heart failure patients with biventricular defibrillators: results of the MORE-CARE multicentre randomized controlled trial. Eur J Heart Fail. 2017;19(3):416-425.
12. RHDAustralia (RHD Australia) and the Australian Government Department of Health and Ageing. The 2020 Australian guideline for prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease. 3rd ed. Darwin: Menzies School of Health Research; 2020.
13. Mulpuru SK, Madhavan M, McLeod CJ, et al. Cardiac Pacemakers: Function, Troubleshooting, and Management: Part 1 of a 2-Part Series. J Am Coll Cardiol. 2017;69(2):189-210.
14. Vijayaraman P, Chung MK, Dandamudi G, et al. His Bundle Pacing: JACC Scientific Expert Panel. J Am Coll Cardiol. 2020;75(11):1347-1363.