Clinical Overview

Accelerated junctional rhythm (AJR) is the middle-rate tier of the AV-junctional rhythm genus: a sustained rhythm whose pacemaker sits in the AV junction (the AV node and/or the bundle of His) rather than the sinoatrial (SA) node, running 60-100 bpm. The same anatomic site produces three recognized rate tiers distinguished by rate alone — junctional escape rhythm (40-60 bpm), accelerated junctional rhythm (60-100 bpm), and junctional tachycardia (over 100 bpm, JTach) (Burns and Buttner, LITFL ECG Library, 2024; ACLS Certification Association, 2024).

Where junctional escape rhythm is a protective failsafe stepping in only once the SA node’s own rate falls below the AV junction’s intrinsic 40-60 bpm, AJR works differently: the AV junction’s automaticity accelerates past its normal intrinsic rate and outpaces a sinus node that has not stopped firing, rather than filling in for one that has (Burns and Buttner, LITFL ECG Library, 2024; ACLS Certification Association, 2024). AJR most often reflects a combination of the two — enhanced automaticity in the AV junction paired with reduced automaticity in the sinus node — so the junctional pacemaker takes over even though the SA node keeps discharging on its own, independent schedule (Burns and Buttner, LITFL ECG Library, 2024). Because the impulse originates at or near the AV node, it still conducts forward through the normal His-Purkinje system to produce a narrow QRS, but it also conducts backward (retrograde) into the atria rather than through the SA node’s normal top-down path, so the atria depolarize in reverse without producing a normal upright P wave ahead of the QRS (Burns and Buttner, LITFL ECG Library, 2024; Reid, ECG Lectures, 2025).

Clinical significance tracks the underlying cause more than the rhythm itself. AJR is a classic, well-documented finding in digoxin toxicity, and it is also seen after cardiac surgery, during myocardial ischemia, and with myocarditis (Burns and Buttner, LITFL ECG Library, 2024; ACLS Certification Association, 2024). It is an uncommon presenting sign of light-chain cardiac amyloidosis, reported in at least one case that progressed to complete AV block requiring a pacemaker — a reminder that a new, otherwise-unexplained AJR in a patient with heart-failure symptoms warrants looking beyond the rhythm itself (Faraj et al., Annals of Medicine and Surgery, 2022).

Many patients, especially at more modest rates, have no symptoms and the rhythm is an incidental monitor finding (Cleveland Clinic, 2022). When symptomatic, reported findings include dizziness or lightheadedness, fatigue, palpitations, hypotension, and syncope or near-syncope (Hafeez, Wollard, and Grossman, StatPearls, 2026; Cleveland Clinic, 2022).

Recognized causes and risk factors include digoxin toxicity — a classic and specifically associated trigger — increased vagal tone, myocardial ischemia, myocarditis, recent cardiac surgery, and electrolyte disturbances; beta-blockers and calcium channel blockers are also implicated, both by slowing the sinus node and by their own effects on AV nodal tissue (ACLS Certification Association, 2024; Burns and Buttner, LITFL ECG Library, 2024; Hafeez, Wollard, and Grossman, StatPearls, 2026).

Interpretation Guide

Key Features:

• Rate: 60-100 bpm. A junctional-origin rhythm at 40-60 bpm is junctional escape rhythm rather than accelerated, and one over 100 bpm is junctional tachycardia (Burns and Buttner, LITFL ECG Library, 2024).
• Rhythm: regular, since the AV junction is firing at its own steady accelerated rate (ACLS Certification Association, 2024).
• P waves: absent, or inverted (retrograde) in the inferior leads, appearing just before, buried within, or just after the QRS complex depending on whether retrograde atrial activation or antegrade ventricular activation completes first (Hafeez, Wollard, and Grossman, StatPearls, 2026; Reid, ECG Lectures, 2025).
• PR interval: short (under 0.12 seconds) when a retrograde P wave precedes the QRS; not measurable when the P wave is buried in or follows the QRS (ACLS Certification Association, 2024; Reid, ECG Lectures, 2025).
• QRS complex: narrow, under roughly 0.12 seconds, because the impulse still conducts through the normal His-Purkinje system — unless a pre-existing bundle branch block or rate-related aberrancy is present (Burns and Buttner, LITFL ECG Library, 2024; Hafeez, Wollard, and Grossman, StatPearls, 2026).
• ST segment and T waves are not primary diagnostic features of AJR itself; interpret them against the underlying cause (ischemia, digoxin effect, electrolyte disturbance) rather than the junctional origin.
• QT interval is not a primary diagnostic feature at this rate; assess once a stable strip is captured.
• Other findings: the AV junction can outpace the atria enough that the sinus node’s own P waves and the junctional QRS complexes each march to their own rate without a fixed relationship (AV dissociation), and the ventricular rate is usually the faster of the two (Burns and Buttner, LITFL ECG Library, 2024).

Key Leads

• Leads II, III, and aVF — the most useful leads for confirming a retrograde P wave. Retrograde atrial activation travels superiorly, away from these inferior leads, so an inverted P wave here is the most reliable marker of retrograde conduction (Reid, ECG Lectures, 2025). This is the same junctional depolarization vector documented across the AV-junctional rate family — the corresponding P wave is typically upright in aVR and V1 (Burns and Buttner, LITFL ECG Library, 2024).
• This condition is not lead-agnostic: the defining P-wave finding is best confirmed in the inferior leads. The narrow QRS and regular 60-100 bpm rate that establish the rhythm itself, however, can be assessed from any lead with a clear baseline.

Differential Diagnosis

• Junctional Escape Rhythm (AVJR) — same AV-junctional origin and P-wave behavior, but AVJR is a backup mechanism triggered by a failing or absent sinus impulse rather than the junction’s own automaticity accelerating past a still-active sinus node, and it runs at the junction’s intrinsic 40-60 bpm.
• Junctional Tachycardia (JTach) — same AV-junctional origin, automatic mechanism, and P-wave behavior, but the rate exceeds 100 bpm rather than sitting in the 60-100 bpm accelerated range.
• Sinus Rhythm (SR) — AJR’s rate range overlaps normal sinus rate entirely, but sinus rhythm keeps a normal upright P wave before every QRS with a normal PR interval, versus AJR’s absent or retrograde P wave.
• Ventricular Escape Rhythm (VEsR) — also a ventricular-origin rhythm, but it runs slower (roughly 20-40 bpm) and produces a wide QRS; a ventricular focus that instead accelerates into AJR’s 60-100 bpm range keeps that same wide-QRS tell, and fusion or capture beats at the transition point to a ventricular rather than junctional origin.
• Junctional Premature Beat (JPT) — the same AV-junctional origin and P-wave behavior, but as a single early ectopic beat interrupting an underlying rhythm rather than a sustained accelerated rhythm.

Treatment Brief

Confirm lead placement and capture a longer strip whenever a narrow-complex rhythm at 60-100 bpm with absent or inverted P waves appears, and correlate the finding with vital signs, symptoms, and current medications — a digoxin level and recent-surgery history are worth flagging for the provider given how strongly this rhythm associates with digoxin toxicity (Burns and Buttner, LITFL ECG Library, 2024).

Asymptomatic, well-tolerated AJR generally needs no direct treatment beyond monitoring and investigating the cause (ACLS Certification Association, 2024; Hafeez, Wollard, and Grossman, StatPearls, 2026). When digoxin toxicity is the underlying cause, electrical cardioversion is specifically avoided because it can precipitate ventricular arrhythmias — defibrillation per standard ACLS protocol remains an option if the patient decompensates, but the rhythm itself is not a cardioversion target — so management centers on digoxin-specific antibody fragments and correcting contributing electrolyte disturbances such as hypokalemia (Regina and Hai, StatPearls, 2025). Otherwise, management addresses the underlying trigger directly: adjusting or holding an offending medication, correcting hypoxia or an electrolyte abnormality, or treating the ischemia or inflammation driving it (ACLS Certification Association, 2024; Hafeez, Wollard, and Grossman, StatPearls, 2026; Cleveland Clinic, 2022).