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Atrial Standstill

Atrial Standstill — Comprehensive Disease Characteristics Research Report

2026-05-06
Falcon MONDO:0015281 Model: Edison Scientific Literature 41 citations

Atrial Standstill — Comprehensive Disease Characteristics Research Report

Target disease: Atrial standstill (AS)
Category: Heart disorder (arrhythmia / atrial cardiomyopathy)
Report scope: Evidence is primarily from peer‑reviewed human case reports/families and focused cohorts/reviews. No EHR-derived aggregate datasets were retrieved in this run.

Executive summary

Atrial standstill is a rare atrial arrhythmia/atrial myopathy defined by the absence of atrial electrical activity and loss of atrial mechanical contraction, producing absent P waves, atrial electrical silence on intracardiac recordings, and typically junctional/escape bradycardia. It can be transient vs persistent/permanent and partial vs diffuse, and may progress over time from focal right atrial involvement to biatrial electrical failure. AS may arise from acquired/reversible causes (e.g., hyperkalemia, drug toxicity, myocarditis/MI) or genetic/syndromic atrial cardiomyopathies, notably involving SCN5A and EMD among others. Clinically important complications include thromboembolism/stroke from atrial stasis and need for permanent pacing; contemporary real‑world reports demonstrate physiologic pacing approaches such as left bundle branch area pacing (LBBAP) in patients with AS and giant atria. (zheng2022leftbundlebranch pages 1-2, anand2024atrialstandstillin pages 1-3, agrawal2017persistentatrialstandstill pages 3-4, ishikawa2020cardiacemerinopathy pages 1-4)

1. Disease information

1.1 Overview and definition (current understanding)

Multiple sources converge on a core definition: atrial standstill is characterized by absence of atrial electrical activity and atrial mechanical activity. For example, a recent pacing case report states: “Atrial standstill (AS) is a rare condition defined by the lack of atrial electrical and mechanical activities.” (Frontiers in Cardiovascular Medicine; published 2022-03, https://doi.org/10.3389/fcvm.2022.836964) (zheng2022leftbundlebranch pages 1-2). A noninvasive electrophysiology case report similarly defines it as total absence of atrial electrical activity in one or both atria and describes diagnostic confirmation via absent atrial mechanical contraction (Doppler “A” waves, etc.) (published 2017-03, https://doi.org/10.1111/anec.12399) (agrawal2017persistentatrialstandstill pages 1-3, agrawal2017persistentatrialstandstill pages 3-4).

1.2 Key diagnostic concept

A practical set of diagnostic criteria is summarized in a 2024 case report: atrial standstill is characterized by (1) absence of P waves, (2) narrow QRS, (3) evidence of atrial paralysis (e.g., absent jugular venous “a” waves and absent Doppler A wave / tissue Doppler a′), and (4) inability to stimulate/capture the atria even with pacing (Journal of Arrhythmia; published 2024-09, https://doi.org/10.1002/joa3.13150) (anand2024atrialstandstillin pages 1-3).

1.3 Synonyms / terminology

AS is described as transient vs persistent (“permanent”) and partial vs total/diffuse. A clinical review‑style case report explicitly notes classification “as transient (temporary) or persistent (also referred to as permanent)” and uses “partial atrial standstill” for one‑atrium or localized preservation of atrial activity (agrawal2017persistentatrialstandstill pages 1-3). A HeartRhythm Case Reports article also uses “permanent atrial standstill,” “partial atrial electrical standstill,” and “persistent atrial paralysis.” (suzuki2019acaseof pages 3-5)

1.4 Disease identifiers (ontology/coding)

The retrieved evidence contains an explicit Orphanet number and an OMIM reference, but MONDO and MeSH identifiers were not retrieved.

Table (click to expand)
Identifier system (Orphanet/ICD-10/OMIM/MeSH/MONDO/Other) Code/ID Label Notes on evidence strength Source (paper title, year) URL
Orphanet ORPHA:1344 Atrial standstill Reported in a classification table as an Orphanet identifier for atrial standstill; strongest explicit disease identifier found in retrieved evidence (podolec2019clinicalclassificationof pages 2-3) Clinical classification of rare cardiac arrhythmogenic and conduction disorders, and rare arrhythmias (2019) https://doi.org/10.20452/pamw.4451
ICD-10 I45.5 Other specified heart block Listed for atrial standstill as a sample code in the classification table; article notes some rare cardiac disorders are not referenced in ICD-10, so mapping should be treated cautiously (podolec2019clinicalclassificationof pages 2-3) Clinical classification of rare cardiac arrhythmogenic and conduction disorders, and rare arrhythmias (2019) https://doi.org/10.20452/pamw.4451
OMIM 108770 Atrial standstill OMIM number appears in a review of 1q21.1 CNVs that mentions “atrial standstill (OMIM 108770)”; indirect evidence rather than a primary disease ontology source in this conversation (podolec2019clinicalclassificationof pages 2-3) Prenatal phenotypes and pregnancy outcomes of fetuses with recurrent 1q21.1 microdeletions and microduplications (2023) https://doi.org/10.3389/fmed.2023.1207891
MeSH Not found in retrieved evidence No explicit MeSH heading or ID for atrial standstill was retrieved in the available evidence (podolec2019clinicalclassificationof pages 2-3) Not found in retrieved evidence
MONDO Not found in retrieved evidence No explicit MONDO identifier for atrial standstill was retrieved in the available evidence (podolec2019clinicalclassificationof pages 2-3) Not found in retrieved evidence
Other VI-1C-2 Atrial standstill Internal/clinical rare cardiac disease classification code (RCDD code), not a standard biomedical ontology identifier (podolec2019clinicalclassificationof pages 2-3) Clinical classification of rare cardiac arrhythmogenic and conduction disorders, and rare arrhythmias (2019) https://doi.org/10.20452/pamw.4451
Other (synonym/terminology) Atrial standstill (AS) Standard abbreviation used across case reports/reviews; disease-level terminology rather than ontology identifier (zheng2022leftbundlebranch pages 1-2, kato2024atrialstandstilla pages 1-3) Left Bundle Branch Area Pacing in a Giant Atrium With Atrial Standstill (2022); Atrial Standstill: A Rare Cause of Pediatric Stroke and Management Strategies (2024) https://doi.org/10.3389/fcvm.2022.836964; https://doi.org/10.17264/stmarieng.15.21
Other (synonym/terminology) Persistent atrial standstill Explicitly described as a persistent/permanent form in the literature; synonym reflects temporal subtype rather than distinct ontology code (agrawal2017persistentatrialstandstill pages 1-3, agrawal2017persistentatrialstandstill pages 3-4) Persistent atrial standstill following the Cox-maze III procedure (2017) https://doi.org/10.1111/anec.12399
Other (synonym/terminology) Permanent atrial standstill Used interchangeably with persistent atrial standstill in retrieved evidence; terminology/synonym only (agrawal2017persistentatrialstandstill pages 1-3, suzuki2019acaseof pages 3-5) Persistent atrial standstill following the Cox-maze III procedure (2017); A case of atrial standstill with the atrial lead of a dual-chamber pacemaker implanted in the coronary sinus (2019) https://doi.org/10.1111/anec.12399; https://doi.org/10.1016/j.hrcr.2019.03.008
Other (synonym/terminology) Partial atrial standstill Common term for regional/unilateral atrial involvement; descriptive subtype rather than separate coded disease (agrawal2017persistentatrialstandstill pages 1-3, makita2005congenitalatrialstandstill pages 1-2, suzuki2019acaseof pages 3-5) Persistent atrial standstill following the Cox-maze III procedure (2017); Congenital atrial standstill associated with coinheritance of a novel SCN5A mutation and connexin 40 polymorphisms (2005); A case of atrial standstill with the atrial lead of a dual-chamber pacemaker implanted in the coronary sinus (2019) https://doi.org/10.1111/anec.12399; https://doi.org/10.1016/j.hrthm.2005.06.032; https://doi.org/10.1016/j.hrcr.2019.03.008
Other (synonym/terminology) Persistent atrial paralysis Alternate wording used in retrieved case literature; terminology/synonym only (suzuki2019acaseof pages 3-5) A case of atrial standstill with the atrial lead of a dual-chamber pacemaker implanted in the coronary sinus (2019) https://doi.org/10.1016/j.hrcr.2019.03.008

Table: This table compiles disease identifiers and commonly used terminology for atrial standstill using only the retrieved evidence from the conversation. It distinguishes explicit ontology/code evidence from descriptive synonyms and flags weaker mappings such as sample ICD-10 codes.

Note on coding: The ICD‑10 mapping for atrial standstill is not standardized in the retrieved evidence; one classification paper lists an ICD‑10 entry as a sample code and notes some rare cardiac disorders are not referenced in ICD‑10 (podolec2019clinicalclassificationof pages 2-3).

2. Etiology

2.1 Disease causal factors

2.1.1 Genetic causes (primary atrial cardiomyopathy/channelopathy)

Evidence supports a heterogeneous genetic architecture, with strong data for SCN5A and for EMD (emerin) in a defined X‑linked syndrome.

A structured gene/variant summary from the retrieved evidence is provided here:

Table (click to expand)
Gene (HGNC symbol) Inheritance/zygosity (if described) Variant (HGVS protein/cDNA or descriptor) Evidence type (family/case report/cohort) Key phenotypes/complications (stroke, LVNC, conduction disease) Functional evidence (e.g., loss-of-function patch clamp) Publication (year, journal) URL
SCN5A Familial; heterozygous in proband and father with incomplete penetrance; atrial phenotype modified by GJA5 polymorphisms p.Leu212Pro (L212P); coinherited GJA5/Cx40 polymorphisms as modifiers Familial case report with electrophysiology and channel studies Congenital/progressive atrial dysfunction to atrial standstill; absent P waves; right atrium not capturable by pacing; bradyarrhythmia/conduction disease; variable penetrance in family Marked loss-of-function of Nav1.5 with hyperpolarizing shifts of activation/inactivation and delayed recovery; authors infer Cx40 polymorphisms may reduce atrial conduction reserve and modify phenotype (makita2005congenitalatrialstandstill pages 1-2) Makita et al., 2005, Heart Rhythm https://doi.org/10.1016/j.hrthm.2005.06.032
SCN5A Familial; homozygous affected sisters, heterozygous relatives asymptomatic p.Val1340Leu (V1340L) Familial case report with segregation and patch clamp Complete atrial standstill in proband, partial atrial standstill in sister; absent electrical/mechanical atrial activity; sudden death risk reported in family Loss-of-function Nav1.5; reduced current density and depolarizing shift in steady-state activation (WT −35.3±1.62 mV vs V1340L −22.4±2.59 mV; P=0.001) (tan2018ahomozygousscn5a pages 1-4) Tan et al., 2018, Pacing and Clinical Electrophysiology https://doi.org/10.1111/pace.13386
EMD X-linked recessive; affected male carriers, female carriers often asymptomatic Start-loss, splicing, and missense EMD mutations (specific variants not detailed in retrieved evidence) Targeted sequencing cohort plus family-based clinical characterization Progressive atrial arrhythmias culminating in atrial standstill; LVNC; familial stroke/thromboembolism risk; conduction disease; need for pacemaker/defibrillator implantation Genetic/segregation evidence; no patch-clamp assay reported in retrieved excerpt; mechanistic interpretation supports a nonsyndromic “cardiac emerinopathy” causing progressive atrial myopathy (ishikawa2020cardiacemerinopathy pages 1-4) Ishikawa et al., 2020, Circulation: Arrhythmia and Electrophysiology https://doi.org/10.1161/circep.120.008712
HCN4 Autosomal dominant familial inheritance described; heterozygous in reported patient/family c.2063A>C, p.Asn688Thr Case report with family history and multimodal cardiac evaluation Atrial standstill in a young patient with ischemic stroke; absent atrial contraction; dilated right atrium; biatrial late gadolinium enhancement; familial sick sinus syndrome/conduction phenotype No direct in vitro functional assay reported in retrieved excerpt; evidence includes segregation with familial sick sinus syndrome plus EP/MRI phenotype consistent with atrial paralysis (anand2024atrialstandstillin pages 1-3) Anand et al., 2024, Journal of Arrhythmia https://doi.org/10.1002/joa3.13150
CAV3 Not clearly established in retrieved evidence; pediatric single-case finding p.Leu84Pro (L84P); initially likely pathogenic, later reclassified as VUS Pediatric case report Atrial standstill with right atrial scar/electrical silence; inducible left atrial tachycardia; progressive inability to sense/capture atrium; ventricular pacing dependence; no stroke/LVNC reported in retrieved excerpt No direct functional assay in retrieved excerpt; rarity noted (not observed in 6500 individuals in NHLBI GO Exome Sequencing Project), but causal role remains uncertain because variant was reclassified as VUS (gal2017atrialstandstillin pages 1-2) Gal et al., 2017, HeartRhythm Case Reports https://doi.org/10.1016/j.hrcr.2017.07.014

Table: This table summarizes key gene-level associations reported for atrial standstill in the retrieved evidence, including inheritance, variants, major clinical features, and available functional support. It is useful for distinguishing well-supported causal genes such as SCN5A and EMD from more tentative associations such as CAV3.

2.1.2 Acquired / potentially reversible causes

Case-based literature highlights multiple acquired triggers. Examples include hyperkalemia, drug toxicity (digoxin/digitalis, quinidine, verapamil, etc.), reflex syncope, and acute myocardial infarction, and inflammatory/infiltrative disease such as amyloidosis, muscular dystrophies, systemic lupus, and cardiac sarcoidosis (agrawal2017persistentatrialstandstill pages 3-4, suzuki2019acaseof pages 3-5, kim2016atrialstandstillin pages 1-2).

A notable mechanistic acquired example is suspected isolated cardiac sarcoidosis, where imaging (atrial LGE) and biopsy supported atrial fibrosis with inflammatory involvement associated with atrial electrical silence (Journal of Cardiology Cases; 2016-11, https://doi.org/10.1016/j.jccase.2016.06.010) (kim2016atrialstandstillin pages 1-2).

2.2 Risk factors

Risk factors in retrieved evidence are largely etiologic categories rather than quantified epidemiologic risks: - Underlying genetic cardiomyopathy/channelopathy (SCN5A; EMD; HCN4) (tan2018ahomozygousscn5a pages 1-4, ishikawa2020cardiacemerinopathy pages 1-4, anand2024atrialstandstillin pages 1-3) - Systemic/infiltrative/inflammatory disorders (e.g., sarcoidosis, amyloidosis) (kim2016atrialstandstillin pages 1-2, agrawal2017persistentatrialstandstill pages 3-4) - Metabolic or drug-related triggers (hyperkalemia; digoxin/digitalis; quinidine) (agrawal2017persistentatrialstandstill pages 3-4, suzuki2019acaseof pages 3-5)

2.3 Protective factors and gene–environment interactions

No protective genetic variants or robust gene–environment interaction analyses specific to atrial standstill were retrieved. Evidence is insufficient in this run.

3. Phenotypes

3.1 Core phenotype spectrum

Atrial standstill presents with a combination of electrical silence, mechanical failure, and downstream hemodynamic/thromboembolic consequences: - ECG: absent P waves; junctional or ventricular escape rhythm/bradycardia (zheng2022leftbundlebranch pages 1-2, makita2005congenitalatrialstandstill pages 1-2, anand2024atrialstandstillin pages 1-3). - Echo Doppler: absent transmitral/tricuspid A wave; absence of atrial contraction (agrawal2017persistentatrialstandstill pages 3-4, kato2024atrialstandstilla pages 1-3, zheng2022leftbundlebranch pages 1-2). - EP study: inability to capture atria with pacing; atrial electrogram inactivity or markedly low voltage; residual activity may persist in limited regions (e.g., coronary sinus) (suzuki2019acaseof pages 1-3, suzuki2019acaseof pages 3-5). - Structural atrial disease: atrial dilation/giant atrium, atrial fibrosis/scar (often inferred via low-voltage mapping or LGE on CMR) (zheng2022leftbundlebranch pages 1-2, anand2024atrialstandstillin pages 1-3, kim2016atrialstandstillin pages 1-2). - Complications: thromboembolism/stroke risk due to blood stasis from absent contraction (kato2024atrialstandstilla pages 1-3, anand2024atrialstandstillin pages 1-3, ishikawa2020cardiacemerinopathy pages 1-4).

3.2 Phenotype-to-HPO mapping

Table (click to expand)
Phenotype/feature Suggested HPO term (name and HP ID) Notes
Absent P waves on surface ECG Atrial standstill (HP:0011703) Core electrical diagnostic feature of atrial standstill; reports describe no visible P waves on ECG, often with absent atrial electrograms as supportive EP evidence (agrawal2017persistentatrialstandstill pages 1-3, anand2024atrialstandstillin pages 1-3, zheng2022leftbundlebranch pages 1-2).
Junctional escape bradycardia / narrow-complex escape rhythm Bradycardia (HP:0001662); Junctional rhythm (HP:0011675) Typical rhythm disturbance when atrial activation is absent; often described as junctional or escape rhythm accompanying absent P waves (makita2005congenitalatrialstandstill pages 1-2, anand2024atrialstandstillin pages 1-3, zheng2022leftbundlebranch pages 1-2).
Atrial paralysis / no A wave on Doppler echocardiography Atrial standstill (HP:0011703) Mechanical criterion: absent atrial contraction shown by loss of A waves on mitral/tricuspid inflow Doppler, tissue Doppler a′, or jugular/pressure tracings (agrawal2017persistentatrialstandstill pages 3-4, anand2024atrialstandstillin pages 1-3, kato2024atrialstandstilla pages 1-3).
Inability to capture atrium on pacing / atrial inexcitability Atrial standstill (HP:0011703) EP criterion: failure to electrically stimulate/capture right atrium or coronary sinus even at high output; useful for confirming diagnosis and guiding lead strategy (suzuki2019acaseof pages 1-3, anand2024atrialstandstillin pages 1-3, kato2024atrialstandstilla pages 1-3).
Atrial dilation / giant atrium Left atrial dilatation (HP:0001698); Right atrial dilatation (HP:0001719) Structural atrial disease is common in reported cases, including giant atrium and marked right atrial dilation on echo/MRI (zheng2022leftbundlebranch pages 1-2, anand2024atrialstandstillin pages 1-3).
Thromboembolic ischemic stroke Stroke (HP:0001297); Cerebral infarction (HP:0001296) Important complication due to atrial blood stasis from absent contraction; reported in pediatric and young adult cases and used to justify anticoagulation (kato2024atrialstandstilla pages 1-3, anand2024atrialstandstillin pages 1-3, ishikawa2020cardiacemerinopathy pages 1-4).
Left ventricular noncompaction when present Left ventricular noncompaction (HP:0006677) Seen in syndromic/genetic forms, especially EMD-associated “cardiac emerinopathy,” and may compound thromboembolic risk (ishikawa2020cardiacemerinopathy pages 1-4).

Table: This table maps common atrial standstill clinical and diagnostic findings to suggested Human Phenotype Ontology terms. It is useful for structuring phenotype annotation in a disease knowledge base while preserving the diagnostic context from ECG, echocardiography, and electrophysiology studies.

Quality of life impact: Not systematically quantified in retrieved evidence. However, symptomatic bradycardia, presyncope/syncope, heart failure manifestations, and stroke are repeatedly noted as major clinical impacts, often driving permanent pacing and anticoagulation decisions (zheng2022leftbundlebranch pages 1-2, anand2024atrialstandstillin pages 1-3, kato2024atrialstandstilla pages 1-3).

4. Genetic / molecular information

4.1 Causal genes and molecular classes

The retrieved literature supports several mechanistic classes: - Voltage-gated sodium channel dysfunction (SCN5A loss-of-function) with impaired atrial excitability/conduction and progressive atrial electrical failure (tan2018ahomozygousscn5a pages 1-4, makita2005congenitalatrialstandstill pages 1-2). - Gap junction / conduction reserve modification (GJA5 connexin‑40 polymorphisms proposed as modifiers in SCN5A families) (makita2005congenitalatrialstandstill pages 1-2). - Nuclear envelope / myocyte structural integrity disorders (EMD, and broader laminopathy/EDMD context) causing progressive atrial myopathy leading to standstill and thromboembolism risk (ishikawa2020cardiacemerinopathy pages 1-4, valenti2022clinicalprofilearrhythmias pages 1-2). - Pacemaker channel association (HCN4) in familial bradyarrhythmia syndromes with atrial standstill in a reported family (anand2024atrialstandstillin pages 1-3).

4.2 Variant interpretation and population frequency

Only limited population frequency information was retrieved directly: the CAV3 p.Leu84Pro variant was reported as not observed in 6500 individuals in the NHLBI GO Exome Sequencing Project but was later reclassified as a VUS, underscoring the need for cautious interpretation (gal2017atrialstandstillin pages 1-2). Broader allele-frequency statistics (e.g., gnomAD) were not retrieved in this run.

5. Environmental information

Evidence in this run is primarily clinical; nevertheless, non-genetic contributors include metabolic derangement (hyperkalemia), drug toxicity (digitalis/quinidine), hypoxia, and ischemic/inflammatory myocardial conditions (myocarditis, MI, sarcoidosis) reported as associated causes/precipitants (agrawal2017persistentatrialstandstill pages 3-4, suzuki2019acaseof pages 3-5, kim2016atrialstandstillin pages 1-2).

6. Mechanism / pathophysiology

6.1 Causal chain (integrated model)

A consistent disease model across genetic and acquired contexts is:

Trigger/primary substrate (channelopathy; nuclear envelope myopathy; infiltrative/inflammatory disease; metabolic/drug injury) → atrial myocyte dysfunction and/or structural remodeling → atrial fibrosis/scar with low-voltage substrate → loss of atrial excitability and conduction (electrical silence; inability to pace-capture) → loss of atrial mechanical contraction (absent Doppler A waves) → blood stasis → thromboembolism/stroke; in parallel, junctional/escape rhythms and bradycardia drive symptoms and pacing need. Evidence for atrial fibrosis/structural disease (e.g., LGE in both atria) and electrical silence is reported in sarcoidosis-associated AS and in genetic cases with biatrial LGE (kim2016atrialstandstillin pages 1-2, anand2024atrialstandstillin pages 1-3).

6.2 Upstream vs downstream mechanisms

6.3 Spatial progression and anatomical localization

Several reports describe progression beginning in the high/midlateral right atrium and spreading to the entire right atrium and then left atrium, with some patients retaining small islands of viable atrial tissue. A striking example is residual atrial electrical activity confined to the coronary sinus, enabling coronary-sinus atrial lead placement (suzuki2019acaseof pages 1-3, suzuki2019acaseof pages 3-5).

6.4 Suggested ontology terms for mechanisms (GO/CL/UBERON)

UBERON (anatomy): - UBERON:0000948 (heart) — general - UBERON:0002079 (right atrium) and UBERON:0002078 (left atrium) — atrial myocardium involvement - UBERON:0002347 (coronary sinus) — residual atrial activity/pacing site in partial AS cases (suzuki2019acaseof pages 1-3)

Cell Ontology (CL) (major involved cell types): - CL:0000746 (cardiac muscle cell / cardiomyocyte) - CL:0002548 (cardiac fibroblast) — fibrosis substrate (mechanistic inference consistent with atrial fibrotic substrate discussed across sources)

GO biological process (examples): - “cardiac muscle cell action potential” (GO:0086001) - “regulation of heart rate” (GO:0002027) - “cardiac conduction” (GO:0061337) - “extracellular matrix organization” (GO:0030198) - “fibroblast proliferation” (GO:0048144)

(These ontology suggestions are consistent with the electrophysiologic and fibrotic remodeling substrate described in the retrieved literature, although GO IDs are not explicitly cited in the sources.) (agrawal2017persistentatrialstandstill pages 3-4, kim2016atrialstandstillin pages 1-2, anand2024atrialstandstillin pages 1-3)

7. Anatomical structures affected

8. Temporal development

AS may be intermittent or permanent and progressive. Several sources describe progression from partial/focal atrial involvement to diffuse standstill, often with evolving atrial scarring and eventual atrial pacing failure risk (suzuki2019acaseof pages 3-5, agrawal2017persistentatrialstandstill pages 3-4). Recovery of atrial activity is possible in select contexts, including reports of reversal with sustained atrial/AV sequential pacing after surgery and recovery after months in a pediatric case (agrawal2017persistentatrialstandstill pages 1-3, kato2024atrialstandstilla pages 1-3).

9. Inheritance and population

9.1 Epidemiology

AS is consistently described as rare, but population prevalence/incidence estimates for atrial standstill overall were not retrieved.

A partial quantitative window comes from EDMD/laminopathy-focused systematic review data (not population-wide): in EDMD/cardiolaminopathies, the incidence rate (IR) for atrial standstill ranged from 0 to 2 events per 100 patient-years in the reviewed cohorts (Biology; published 2022-03, https://doi.org/10.3390/biology11040530) (valenti2022clinicalprofilearrhythmias pages 1-2).

9.2 Inheritance patterns (genetic forms)

10. Diagnostics

10.1 Clinical tests and diagnostic workflow (practical)

The contemporary case literature supports a multimodal workflow: 1) ECG (absent P waves; escape rhythm) (zheng2022leftbundlebranch pages 1-2)
2) Echocardiography with Doppler/TDI (absent A wave; atrial dilation) (agrawal2017persistentatrialstandstill pages 3-4, anand2024atrialstandstillin pages 1-3)
3) Electrophysiology study / mapping to confirm atrial inexcitability and identify residual viable tissue for lead placement (suzuki2019acaseof pages 1-3, suzuki2019acaseof pages 3-5)
4) Cardiac MRI with LGE to assess atrial fibrosis and associated cardiomyopathy (biatrial LGE reported in genetic and inflammatory cases) (kim2016atrialstandstillin pages 1-2, anand2024atrialstandstillin pages 1-3)

A structured summary with MAXO-aligned intervention labels is provided here:

Table (click to expand)
Intervention/test Suggested MAXO term (name and MAXO ID if known; otherwise leave blank) Indication in atrial standstill Evidence source
12-lead electrocardiogram (ECG) Electrocardiographic monitoring First-line diagnostic test; typically shows absent P waves with junctional or ventricular escape rhythm/bradycardia, helping establish electrical atrial silence (agrawal2017persistentatrialstandstill pages 1-3, anand2024atrialstandstillin pages 1-3, zheng2022leftbundlebranch pages 1-2) Agrawal et al., 2017, Annals of Noninvasive Electrocardiology; Anand et al., 2024, Journal of Arrhythmia; Zheng et al., 2022, Frontiers in Cardiovascular Medicine
Ambulatory ECG / Holter monitoring Ambulatory electrocardiographic monitoring Detects persistent bradyarrhythmia, pauses, junctional rhythm burden, and progression of atrial electrical inactivity; useful in symptomatic or pediatric cases (gal2017atrialstandstillin pages 1-2) Gal et al., 2017, HeartRhythm Case Reports
Echocardiography with Doppler (mitral/tricuspid inflow, tissue Doppler) Echocardiography Demonstrates absent mechanical atrial contraction, especially loss of A waves on transmitral/tricuspid inflow or tissue Doppler; also assesses atrial dilation/giant atrium (agrawal2017persistentatrialstandstill pages 3-4, anand2024atrialstandstillin pages 1-3, kato2024atrialstandstilla pages 1-3, zheng2022leftbundlebranch pages 1-2) Agrawal et al., 2017, Annals of Noninvasive Electrocardiology; Anand et al., 2024, Journal of Arrhythmia; Kato et al., 2024, Journal of St. Marianna University; Zheng et al., 2022, Frontiers in Cardiovascular Medicine
Electrophysiology (EP) study and electroanatomic mapping Electrophysiologic study Confirms atrial inexcitability when atria cannot be captured at high output; maps residual viable atrial tissue (often only coronary sinus or limited regions) and guides lead placement if atrial pacing is attempted (suzuki2019acaseof pages 1-3, anand2024atrialstandstillin pages 1-3, gal2017atrialstandstillin pages 1-2) Suzuki et al., 2019, HeartRhythm Case Reports; Anand et al., 2024, Journal of Arrhythmia; Gal et al., 2017, HeartRhythm Case Reports
Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) Cardiac magnetic resonance imaging Characterizes atrial cardiomyopathy/fibrosis and associated structural disease; in reported cases showed biatrial LGE, right atrial dilation, or LV noncompaction (anand2024atrialstandstillin pages 1-3, ishikawa2020cardiacemerinopathy pages 1-4) Anand et al., 2024, Journal of Arrhythmia; Ishikawa et al., 2020, Circulation: Arrhythmia and Electrophysiology
Permanent pacemaker implantation: single-chamber ventricular pacemaker Cardiac pacemaker implantation Main symptomatic treatment for bradycardia/escape rhythm when atrial capture is absent or atrial lead placement fails; used in diffuse/persistent atrial standstill (zheng2022leftbundlebranch pages 1-2, gal2017atrialstandstillin pages 1-2) Zheng et al., 2022, Frontiers in Cardiovascular Medicine; Gal et al., 2017, HeartRhythm Case Reports
Atrial lead implantation at residual excitable tissue (e.g., coronary sinus) when feasible Cardiac pacemaker implantation Considered in partial atrial standstill if viable atrial myocardium remains; EP mapping can identify coronary sinus or localized atrial sites suitable for sensing/capture (suzuki2019acaseof pages 1-3, agrawal2017persistentatrialstandstill pages 3-4) Suzuki et al., 2019, HeartRhythm Case Reports; Agrawal et al., 2017, Annals of Noninvasive Electrocardiology
Physiologic pacing: left bundle branch area pacing (LBBAP) Physiologic cardiac pacing Alternative ventricular pacing strategy for patients needing permanent pacing, aiming to avoid dyssynchrony associated with right ventricular apical pacing; successfully implemented in atrial standstill with giant atrium (zheng2022leftbundlebranch pages 1-2, zheng2022leftbundlebranch media 3add666d) Zheng et al., 2022, Frontiers in Cardiovascular Medicine
Anticoagulation for thromboembolism prevention Anticoagulant therapy Used because absent atrial contraction causes blood stasis and raises risk of thromboembolism/stroke; particularly relevant after ischemic stroke or with atrial standstill plus LVNC/atrial enlargement (kato2024atrialstandstilla pages 1-3, anand2024atrialstandstillin pages 1-3, ishikawa2020cardiacemerinopathy pages 1-4) Kato et al., 2024, Journal of St. Marianna University; Anand et al., 2024, Journal of Arrhythmia; Ishikawa et al., 2020, Circulation: Arrhythmia and Electrophysiology

Table: This table summarizes the main diagnostic tests and management approaches reported for atrial standstill, including suggested MAXO-aligned intervention labels. It is useful for knowledge-base curation because it links each intervention to its clinical role and supporting source evidence.

10.2 Differential diagnosis (high-level)

Within retrieved evidence, AS is contrasted clinically with atrial fibrillation in that AF has fibrillatory activity rather than true atrial electrical silence; EP recordings and inability to pace-capture support AS rather than AF (suzuki2019acaseof pages 1-3, anand2024atrialstandstillin pages 1-3).

11. Outcomes / prognosis

Outcome data are sparse and are primarily case-based, but several consistent risk themes emerge: - Thromboembolism/stroke risk: 2024 pediatric/young adult cases emphasize that loss of atrial contraction “will likely cause blood flow stagnation in the atria” with highly prevalent thromboembolic complications in such settings, prompting anticoagulation strategies (kato2024atrialstandstilla pages 1-3, anand2024atrialstandstillin pages 1-3). - Need for chronic pacing: symptomatic bradycardia is common, frequently requiring permanent pacing (zheng2022leftbundlebranch pages 1-2). - Progression / pacing failure risk: progressive atrial disease can cause eventual atrial pacing failure, motivating careful follow-up and EP-guided lead strategies (suzuki2019acaseof pages 3-5, gal2017atrialstandstillin pages 1-2).

Quantitative cohort-level complication rates specific to atrial standstill (outside EDMD/laminopathy contexts) were not retrieved.

12. Treatment

12.1 Pharmacotherapy

No disease-specific pharmacologic reversal therapy is established in the retrieved evidence. However, anticoagulation is a recurring, real-world intervention for thromboembolism prevention: - A 2024 HCN4-associated case states: “The patient was started on anticoagulation therapy to prevent further thromboembolic events.” (anand2024atrialstandstillin pages 1-3) - A 2022 LBBAP case used apixaban 2.5 mg bid for embolism prevention (zheng2022leftbundlebranch pages 1-2). - A pediatric stroke case used edoxaban for secondary prevention (kato2024atrialstandstilla pages 1-3). - A post-surgical case used warfarin as postoperative medication (agrawal2017persistentatrialstandstill pages 1-3).

12.2 Device therapy (mainstay): pacemakers and lead strategies

Permanent pacing is repeatedly described as required for symptomatic bradycardia.

Standard approaches in the case literature include: - Single-chamber ventricular pacing when atrial capture is absent or atrial lead placement fails (gal2017atrialstandstillin pages 1-2, zheng2022leftbundlebranch pages 1-2). - Dual-chamber pacing with atrial lead in coronary sinus when residual atrial myocardium is present there, enabling AV sequential pacing (suzuki2019acaseof pages 3-5). - AV sequential pacing potentially reversing standstill in select postoperative contexts (agrawal2017persistentatrialstandstill pages 1-3).

Physiologic pacing development / real-world implementation: A notable technical development is the application of left bundle branch area pacing (LBBAP) in AS with a giant atrium. The 2022 case emphasizes avoidance of dyssynchrony associated with traditional RV apical pacing and reports successful LBBAP implantation with stable parameters; their figures show absent atrial activity and LBBAP capture characteristics (zheng2022leftbundlebranch media 3add666d).

12.3 Suggested MAXO terms (selected)

  • Cardiac pacemaker implantation (MAXO ID not retrieved)
  • Physiologic cardiac pacing (MAXO ID not retrieved)
  • Anticoagulant therapy (MAXO ID not retrieved)

(IDs were not available in retrieved evidence; terms are provided for knowledge-base alignment.)

12.4 Experimental treatments / clinical trials

A ClinicalTrials.gov search did not retrieve atrial-standstill-specific trials. Related bradyarrhythmia physiologic pacing trials include His bundle pacing studies (e.g., NCT03590353, NCT03685617) in slow arrhythmias, which may be relevant to pacing strategy selection but are not AS-specific in the retrieved records.

13. Prevention

No atrial-standstill-specific primary prevention strategies were identified. Secondary/tertiary prevention in retrieved evidence centers on: - Stroke prevention via anticoagulation in AS with atrial paralysis/large atria and/or prior stroke (anand2024atrialstandstillin pages 1-3, zheng2022leftbundlebranch pages 1-2, kato2024atrialstandstilla pages 1-3). - Monitoring atrial activity for progression or recovery (kato2024atrialstandstilla pages 1-3).

14. Other species / natural disease

No veterinary or non-human natural disease evidence was retrieved for atrial standstill in this run.

15. Model organisms

No atrial-standstill-specific model organism studies were retrieved.

Expert opinion and authoritative synthesis (interpretation grounded in retrieved sources)

Atrial standstill can be viewed as an end-stage atrial cardiomyopathy phenotype with a final common pathway of atrial fibrosis/low-voltage substrate and atrial paralysis, regardless of whether the upstream driver is genetic (e.g., SCN5A/EMD) or acquired (e.g., sarcoidosis, drug/metabolic injury). This framework is supported by mechanistic descriptions of progressive atrial electrogram loss, scarring, and atrial inexcitability in electrophysiology-focused case literature and by the EDMD/cardiolaminopathy systematic review emphasizing structured surveillance for atrial arrhythmias and thromboembolic prevention in high-risk genetic substrates (agrawal2017persistentatrialstandstill pages 3-4, suzuki2019acaseof pages 3-5, valenti2022clinicalprofilearrhythmias pages 1-2).

Key evidence gaps (important for knowledge-base curation)

  • MONDO and MeSH IDs for atrial standstill were not retrieved in this run; additional ontology-directed searches would be required for canonical identifiers.
  • Population-level prevalence/incidence of atrial standstill in the general population was not retrieved; available quantitative rates are primarily within EDMD/laminopathy cohorts.
  • Limited systematic data on quality of life and long-term outcomes outside case reports.

Appendix: Visual evidence (example)

In the LBBAP case report, a figure panel demonstrates absence of atrial activity (no P waves) consistent with atrial standstill alongside pacing documentation, supporting the ECG-based definition and contemporary pacing implementation (zheng2022leftbundlebranch media 3add666d).

References

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  15. (zheng2022leftbundlebranch media 3add666d): Jingang Zheng, Qing-zhen Yang, Jia-sheng Zheng, Qiang Chen, and Qi Jin. Left bundle branch area pacing in a giant atrium with atrial standstill: a case report and literature review. Frontiers in Cardiovascular Medicine, Mar 2022. URL: https://doi.org/10.3389/fcvm.2022.836964, doi:10.3389/fcvm.2022.836964. This article has 3 citations and is from a peer-reviewed journal.