Autoimmune Encephalitis electrocardiogram
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Julinka Auta Fernandes
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Overview
Autoimmune encephalitis has no diagnostic electrocardiogram (ECG) signature. ECG is useful for detecting associated cardiac rhythm disturbances and assessing medication-related cardiac effects. Autonomic dysfunction, especially in N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis, may cause sinus tachycardia, bradycardia, sinus pauses, or severe episodes of asystole.[1]
A normal ECG does not exclude autoimmune encephalitis or intermittent rhythm abnormalities. ECG findings support assessment of cardiac complications rather than establish the neurological diagnosis.[2]
Key ECG Findings in Autoimmune Encephalitis
Autoimmune encephalitis-associated rhythm disturbances are best documented in NMDAR antibody encephalitis. Published cardiac series are small and selected; these findings should not be assumed to occur in every patient or antibody subtype.[1]
| Finding | ECG or rhythm-monitor appearance | Clinical interpretation |
|---|---|---|
| Sinus tachycardia | Accelerated sinus rhythm. | May accompany autonomic activation. Fever, agitation, pain, dehydration, infection, and medications are alternative or contributing explanations. |
| Sinus bradycardia | Slowing of the sinus rhythm. | Can accompany autonomic dysfunction; marked slowing associated with poor perfusion is clinically important. |
| Alternating tachycardia and bradycardia | Episodes of fast and slow sinus rates, sometimes with abrupt transitions. | Reflects fluctuating autonomic control in reported cases and may be missed on a single resting tracing. |
| Sinus pauses or sinus arrest | Interruption of sinus activity producing a pause; escape beats or an escape rhythm may occur. | Some reported events are associated with vagal stimulation. Prolonged or symptomatic pauses require urgent assessment. |
| Asystole | Absence of ventricular electrical activity during a severe event. | A life-threatening complication described in selected severe cases, including pediatric NMDAR antibody encephalitis.[1][3] |
QT Interval and Medication-Related Changes
Autoimmune encephalitis care may involve medicines that prolong ventricular repolarization, reflected by the QT interval and its heart-rate-corrected value, the corrected QT interval (QTc). QT prolongation is not a specific marker of autoimmune encephalitis.
Antipsychotics with QT-prolonging effects, including ziprasidone and intravenous haloperidol, require particular caution in dysautonomic patients with symptomatic bradycardia or heart block. Review concurrent medications and contributing electrolyte abnormalities, including hypokalemia and hypomagnesemia, when interpreting an abnormal tracing.[4]
Indications and Cardiac Monitoring
Autoimmune encephalitis evaluation may include a baseline ECG, particularly when autonomic symptoms, abnormal pulse findings, unexplained collapse, or medicines with potential cardiac effects are present. Published 2026 recommendations for psychiatric care settings advise considering ECG in most patients undergoing evaluation for autoimmune encephalitis.[2]
- Continuous rhythm monitoring is appropriate when significant autonomic dysregulation or intermittent arrhythmia is suspected.
- Repeat ECG assessment may be needed after a new cardiac symptom, a rhythm event, or a medication change with potential cardiac effects.
- Clinical correlation should include the timing of symptoms, seizures, stimulation, medication administration, and associated circulatory instability.
- Severe bradycardia, significant pauses, or asystole warrant urgent cardiology and critical-care assessment.[2][1][3]
Children and Adolescents
Autoimmune encephalitis-associated heart-rate abnormalities in children require age-appropriate interpretation. A recent multicenter pediatric case series documented life-threatening bradycardia, sinus pauses, and asystolic events in NMDAR antibody encephalitis. This selected series demonstrates a possible complication rather than its frequency in the overall pediatric population.[3]
Interpretation and Limitations
Autoimmune encephalitis does not account automatically for every ECG abnormality. Medication effects, electrolyte disturbances, infection, hypoxia, seizure-related changes, and primary cardiac disease should also be considered.[4]
Autonomic rhythm disturbances may improve with neurological recovery, but prolonged severe episodes have also been reported. Monitoring and any need for pacing require individualized specialist assessment; a diagnosis of autoimmune encephalitis alone is not an indication for a pacemaker.[1][3]
Related Microchapters
Electrocardiogram Examples
The following images illustrate general rhythm patterns that may occur with autonomic dysfunction. Neither tracing is from a documented case of autoimmune encephalitis, and neither pattern is diagnostic of the disease.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Nazif TM, Vázquez J, Honig LS, Dizon JM (2012). "Anti-N-methyl-D-aspartate receptor encephalitis: an emerging cause of centrally mediated sinus node dysfunction". Europace. 14 (8): 1188–1194. doi:10.1093/europace/eus014. PMID 22345374.
- ↑ 2.0 2.1 2.2 Endres D, von Zedtwitz K, Tebartz van Elst L; et al. (2026). "Diagnosing autoimmune encephalitis in psychiatry: clinical recommendations and unresolved challenges from the GENERATE network". Molecular Psychiatry. doi:10.1038/s41380-026-03871-2. PMID 42786262 Check
|pmid=value (help). - ↑ 3.0 3.1 3.2 3.3 Tucker S, Das A, Jimenez A; et al. (2026). "Life-Threatening Bradycardia in Anti-NMDA-Receptor Encephalitis and a Novel Use for Permanent Pacing". Annals of Clinical and Translational Neurology. doi:10.1002/acn3.70280. PMID 41412956 Check
|pmid=value (help). - ↑ 4.0 4.1 Abboud H, Probasco J, Irani SR; et al. (2021). "Autoimmune encephalitis: proposed recommendations for symptomatic and long-term management". Journal of Neurology, Neurosurgery & Psychiatry. 92 (8): 897–907. doi:10.1136/jnnp-2020-325302. PMID 33649021 Check
|pmid=value (help). - ↑ Ewingdo. ECG Sinus Tachycardia 125 bpm.jpg. Wikimedia Commons. November 21, 2020. Licensed under Creative Commons Attribution–ShareAlike 4.0. Accessed November 4, 2026.
- ↑ Ewingdo. ECG Sinus Bradycardia 43 bpm.jpg. Wikimedia Commons. November 14, 2020. Licensed under Creative Commons Attribution–ShareAlike 4.0. Accessed November 4, 2026.