Permanent Pacing Indications

Definition

Permanent cardiac pacing is indicated either to relieve symptoms of cerebral hypoperfusion attributable to bradycardia, or to prevent syncope and death from predictable complete AV block — and only after reversible and physiological causes have been excluded. Symptomatic sinus node dysfunction is the most common indication, AV block close behind it. The distinction that governs everything on this page: SND pacing requires symptom–bradycardia correlation, whereas certain forms of infranodal AV block warrant pacing regardless of symptoms. (sources/bradycardia-acc-aha-hrs-2018, rating: very high)

Key Concepts

At a Glance

Before the Indication Is an Indication

Every table below assumes a reversible or physiological cause has already been excluded — the guideline's first recommendation is to look for one. (sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• Drugs: beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, amiodarone and other antiarrhythmics. Withdrawal is the treatment; pacing is for the patient who cannot stop.
• Ischaemia: AV block in inferior MI is usually transient and nodal, and resolves with reperfusion.
• Metabolic and endocrine: hyperkalaemia, hypothyroidism, hypothermia.
• Infection: Lyme carditis causes advanced AV block in 80–90% of cardiac Lyme and is usually transient; endocarditis with perivalvular abscess does not respond to a device alone.
• Infiltrative disease: cardiac sarcoidosis underlies ~30% of unexplained AV block in patients under 60. It can reverse on corticosteroids, but reversibility is unpredictable, so pacing is still usually advised.
• Sleep apnoea: nocturnal bradycardia is not an indication; treating the OSA removes it.
• Physiological vagal tone: high vagal states are not disease, which is why the definition of pathological block requires the exclusion of physiological causes.

Sinus Node Dysfunction

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• There is no minimum heart rate and no minimum pause duration — symptom–bradycardia correlation is the entire indication, and a pause of any length without symptoms is not one.
• Nocturnal bradycardia alone prompts a sleep study, not a pacemaker.
• The benefit is quality of life, not survival. No trial has shown that pacing in SND reduces mortality.

Acquired AV Block — Paced Regardless of Symptoms

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• These are paced whether or not there are symptoms, because infranodal block progresses abruptly to complete block with a slow or absent escape — syncope and death arriving before the next clinic visit.
• The natural-history evidence is 1970s–80s cohort data: untreated Mobitz II and third-degree block produced recurrent syncope, heart failure and excess mortality, and pacing improved survival. Those studies would not be repeated.

Acquired AV Block — Symptom-Dependent

• The two Class I rows here are the exception that proves the rule of the section above: they are rate problems needing support, not conduction disease predicting sudden block. (sources/bradycardia-acc-aha-hrs-2018, rating: very high)

Conduction Disorders with 1:1 AV Conduction

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• Alternating bundle branch block means bilateral bundle disease — every patient should be paced, because the next block is complete.
• Bundle branch block with syncope is an electrophysiology question: an HV ≥70 ms or frank infranodal block at EPS converts syncope into a Class I pacing indication.

Special Disease-Specific Indications

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• Myotonic dystrophy type 1 is the paradigm: up to 20% have AV block on routine ECG, >50% with a normal ECG have infra-Hisian block at EPS, an HV ≥70 ms predicts a 47% risk of high-grade block, and pacing cuts SCD risk by 75%.
• Kearns-Sayre syndrome progresses inexorably, so pacing is reasonable regardless of symptoms.
• The gene decides the device. Neuromuscular and laminopathy patients frequently need defibrillation rather than pacing alone — in LMNA the default is an ICD with pacing capability.

Atrial Standstill

No guideline grades pacing in atrial standstill, because the evidence is case series only. The practical pattern differs from ordinary bradyarrhythmia pacing: (sources/atrial-standstill-hrs-2026, rating: medium)

• Symptomatic bradycardia mandates permanent pacing — universally endorsed, though a no-pacing comparator is ethically impossible.
• Complete standstill → VVI/VVIR, because there is no capturable atrial tissue (9 of 10 implants in the largest Emery-Dreifuss series were VVI/VVIR).
• Partial standstill → electroanatomic-mapping-guided atrial lead placement at a residual viable site can achieve DDD pacing and cut the right ventricular pacing burden from 100% to 4–19%; proximal coronary sinus pacing has also been reported, with 93.7% atrial pacing stable beyond 2 years.
• Expect atrial lead failure — progressive loss of sensing and capture within 3–8 years is common across aetiologies, so these patients need surveillance rather than a one-off implant.
• LBBAP rests on a single case report and carries a theoretical concern about septal pacing in pre-existing His-Purkinje disease. Leadless pacemakers are VVI-only, may suit 15–20%, and giant right atrial anatomy complicates implantation.
• Device type is gene-specific — in Emery-Dreifuss, pacemaker rather than ICD (ICD 3.3%); in laminopathy, ICD with pacing capability (60%). See concepts/Atrial-Standstill, entities/EMD and entities/LMNA.

Special Population: TAVR

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• New LBBB occurs in 19–55%, new high-degree AV block in ~10%, and much of it resolves before discharge — but 29% of patients with new LBBB have their first high-grade episode after discharge, which is why surveillance is graded separately from implantation.
• Early PPM for new LBBB does not protect against the excess mortality associated with that LBBB — the reason the recommendation is IIb rather than I.

Special Population: Acute MI

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• Inferior MI block is transient (vagal and AV nodal ischaemia) and the waiting period exists to avoid implanting a device that the reperfused artery makes unnecessary. Anterior MI block marks extensive myocardial damage, and prognosis is set by infarct size rather than by the block.

Choosing the Device

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

• Four trials — PASE, MOST, CTOPP and UKPACE — established that atrial-based pacing reduces new AF compared with VVI, without changing mortality, stroke or heart-failure hospitalisation. VVI causes pacemaker syndrome through uncoupled AV contraction, valvular regurgitation and symptomatic hypotension.
• The reason DDD is preferred over AAI even when AV conduction looks intact: 3–35% of patients paced atrially develop AV block within five years.
• Pacing-induced cardiomyopathy begins below the guideline's 40% threshold. In a cohort of 257 patients, 13% pacing only 20–39% of the time developed PICM, and pacing percentage did not predict it — male sex (HR 2.15) and native QRS >115 ms did. The 40% cut-off is a guideline convenience, not a biological boundary. (sources/pacing-induced-cmp-hrs-2014, rating: medium)

Do Not Pace

(sources/bradycardia-acc-aha-hrs-2018, rating: very high)

Shared Decision-Making and End of Life

• Shared decision-making is endorsed throughout, and every decision here is patient-specific.
• A patient with capacity may refuse or withdraw pacing, even when pacemaker-dependent. This is palliative care, and explicitly not physician-assisted suicide.
• The decision belongs to the patient, not to the ECG. A device that prevents a fatal bradyarrhythmia is still a device the patient can decline.

Contradictions / Open Questions

• The 40% ventricular-pacing threshold contradicts the data used to justify it. The guideline treats pacing above 40% as the point at which conduction system pacing is needed, yet 13% of patients pacing only 20–39% developed pacing-induced cardiomyopathy and pacing percentage did not predict it. Two patients with identical guideline status can have very different risk. (sources/pacing-induced-cmp-hrs-2014, rating: medium)
• The optimal physiological pacing modality is unresolved. CRT, His bundle pacing and left bundle branch area pacing are all offered for LVEF 36–50% with high pacing burden, and the 2018 guideline predates the trials that now bear on the question. See concepts/Conduction-System-Pacing.
• No randomised trial addresses tachy-brady syndrome specifically, and rhythm control — AF ablation — may remove the pacing indication altogether. The evidence for that is observational. (sources/bradycardia-acc-aha-hrs-2018, rating: very high)
• TAVR pacing timing is unstandardised, with no randomised trial of implantation timing, and early pacing for new LBBB has not been shown to protect against the mortality associated with that LBBB.
• Rate-responsive pacing is recommended but was not beneficial in the RCT that tested it — a trial confounded by >90% right ventricular pacing, which may have masked any rate-response advantage.
• Much of the SND evidence is C-level, and no trial has shown a mortality benefit — pacing in SND is a quality-of-life intervention presented in the same framework as life-saving AV block pacing.
• Atrial standstill has no graded recommendation at all. Pacing is universal practice in symptomatic standstill on the strength of case series with no possible comparator.
• The theophylline trial (IIb) is a pharmacological prediction rather than an outcome study, in a document otherwise built on bradycardic outcomes.
• Prophylactic pacing in neuromuscular disease rests on observational natural history — an HV ≥70 ms predicting 47% progression is a strong association, not a randomised demonstration that earlier pacing changes the outcome.

Connections

• Related to concepts/Sinus-Node-Dysfunction — the SND phenotype, evaluation and evidence base
• Related to concepts/Atrioventricular-Block — definitions, site classification and acute management
• Related to concepts/Conduction-System-Pacing — the physiological pacing option
• Related to concepts/Cardiac-Resynchronization-Therapy — CRT when ejection fraction is reduced and pacing burden high
• Related to concepts/Atrial-Standstill — the indication with no graded recommendation
• Related to concepts/ECG-Conduction-Disturbances — the ECG findings that trigger these indications
• Related to concepts/Cascade-Family-Screening — family screening in genetic and neuromuscular conduction disease
• Related to entities/Atrial-Fibrillation — tachy-brady syndrome, and pacing for AF with symptomatic bradycardia
• Related to entities/Anderson-Fabry-Disease — the Class IIb indication
• Related to entities/EMD — pacemaker rather than ICD in emerinopathy
• Related to entities/LMNA — ICD with pacing capability

Sources

• sources/bradycardia-acc-aha-hrs-2018
• sources/pacing-induced-cmp-hrs-2014
• sources/atrial-standstill-hrs-2026