Short QT syndrome (SQTS) is a rare inherited cardiac channelopathy defined by marked abbreviation of the QT interval, shortened atrial and ventricular refractory periods, and high susceptibility to atrial and ventricular tachyarrhythmias in structurally normal hearts. The shared disease mechanism is accelerated myocardial repolarization, most definitively linked to gain-of-function potassium-channel defects and, in some families, loss-of-function calcium-channel defects. This abbreviated repolarization creates a re-entry-prone substrate that manifests clinically as palpitations, syncope, atrial fibrillation, ventricular fibrillation, and sudden cardiac death.
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name: Short QT Syndrome
creation_date: '2026-04-12T22:34:01Z'
updated_date: '2026-04-13T01:09:03Z'
description: >-
Short QT syndrome (SQTS) is a rare inherited cardiac channelopathy defined by
marked abbreviation of the QT interval, shortened atrial and ventricular
refractory periods, and high susceptibility to atrial and ventricular
tachyarrhythmias in structurally normal hearts. The shared disease mechanism
is accelerated myocardial repolarization, most definitively linked to
gain-of-function potassium-channel defects and, in some families,
loss-of-function calcium-channel defects. This abbreviated repolarization
creates a re-entry-prone substrate that manifests clinically as palpitations,
syncope, atrial fibrillation, ventricular fibrillation, and sudden cardiac
death.
synonyms:
- SQTS
- short-QT syndrome
- familial short QT syndrome
category: Genetic
disease_term:
preferred_term: short QT syndrome
term:
id: MONDO:0000453
label: short QT syndrome
parents:
- Cardiac Arrhythmia
- Channelopathy
prevalence:
- population: Global
percentage: Rare
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Short QT syndrome ( SQTS ) is a rare inheritable disease associated with
sudden cardiac death.
explanation: >-
Supports classifying SQTS as a rare inherited arrhythmia syndrome without
asserting a numeric prevalence estimate not stated in the abstract.
genetic:
- name: KCNH2 gain-of-function variants
association: Causative
features: >-
Gain-of-function KCNH2 variants cause SQTS1 by increasing IKr and
abbreviating ventricular action potential duration and refractoriness.
gene_term:
preferred_term: KCNH2
term:
id: hgnc:6251
label: KCNH2
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:14676148
reference_title: >-
Sudden death associated with short-QT syndrome linked to mutations in
HERG.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In 2 of them, we identified 2 different missense mutations resulting in
the same amino acid change (N588K) in the S5-P loop region of the cardiac
IKr channel HERG (KCNH2).
explanation: >-
Establishes KCNH2 as a causative SQTS gene in the best-characterized
potassium-channel subtype.
- reference: CGGV:assertion_6b033c3f-04de-4806-a9f3-0b318082b32e-2020-08-03T160000.000Z
reference_title: "KCNH2 / short QT syndrome (Definitive)"
supports: SUPPORT
evidence_source: OTHER
snippet: "KCNH2 | HGNC:6251 | short QT syndrome | MONDO:0000453 | AD | Definitive"
explanation: ClinGen classifies the KCNH2-short QT syndrome gene-disease relationship as definitive with autosomal dominant inheritance.
- name: KCNQ1 gain-of-function variants
association: Causative
features: >-
Gain-of-function KCNQ1 variants cause SQTS2 within the potassium-channel
subgroup of autosomal dominant SQTS.
gene_term:
preferred_term: KCNQ1
term:
id: hgnc:6294
label: KCNQ1
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:15159330
reference_title: >-
Mutation in the KCNQ1 gene leading to the short QT-interval syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Functional and computational studies of the KCNQ1 V307L mutation
identified in a patient with this disorder favor the association of short
QT with mutation in KCNQ1.
explanation: >-
Abstract-based human genetic evidence supporting KCNQ1 as a causative
SQTS gene.
- reference: CGGV:assertion_5000dde0-156c-45b0-87db-35a935c69cb7-2020-10-27T160000.000Z
reference_title: "KCNQ1 / short QT syndrome (Strong)"
supports: SUPPORT
evidence_source: OTHER
snippet: "KCNQ1 | HGNC:6294 | short QT syndrome | MONDO:0000453 | AD | Strong"
explanation: ClinGen classifies the KCNQ1-short QT syndrome gene-disease relationship as strong with autosomal dominant inheritance.
- name: KCNJ2 gain-of-function variants
association: Causative
features: >-
Gain-of-function KCNJ2 variants cause SQTS3 within the potassium-channel
subgroup of autosomal dominant SQTS.
gene_term:
preferred_term: KCNJ2
term:
id: hgnc:6263
label: KCNJ2
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:15761194
reference_title: >-
A novel form of short QT syndrome (SQT3) is caused by a mutation in the
KCNJ2 gene.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The affected members of a single family had a G514A substitution in the
KCNJ2 gene that resulted in a change from aspartic acid to asparagine at
position 172 (D172N).
explanation: >-
Abstract-based family evidence supporting KCNJ2 as the causative gene in
SQTS3.
- reference: CGGV:assertion_9111653a-7d9c-4d0e-94d9-daaa208a0b05-2020-10-27T160000.000Z
reference_title: "KCNJ2 / short QT syndrome (Moderate)"
supports: SUPPORT
evidence_source: OTHER
snippet: "KCNJ2 | HGNC:6263 | short QT syndrome | MONDO:0000453 | AD | Moderate"
explanation: ClinGen classifies the KCNJ2-short QT syndrome gene-disease relationship as moderate with autosomal dominant inheritance.
- name: CACNA1C loss-of-function variants
association: Causative
features: >-
Loss-of-function CACNA1C variants cause SQTS4 within the calcium-channel
subgroup of autosomal dominant SQTS.
gene_term:
preferred_term: CACNA1C
term:
id: hgnc:1390
label: CACNA1C
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
An SQTS -related gene was found in 76% of the patients as follows: KCNH 2
( SQTS 1) in 4, CACNA 1C ( SQTS 4) in 3, and CACN b2 ( SQTS 5) in 6.
explanation: >-
Abstract-based cohort evidence identifying CACNA1C as the calcium-channel
gene underlying SQTS4 in this series.
- name: CACNB2 loss-of-function variants
association: Causative
features: >-
Loss-of-function CACNB2 variants cause SQTS5 within the calcium-channel
subgroup of autosomal dominant SQTS.
gene_term:
preferred_term: CACNB2
term:
id: hgnc:1402
label: CACNB2
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
An SQTS -related gene was found in 76% of the patients as follows: KCNH 2
( SQTS 1) in 4, CACNA 1C ( SQTS 4) in 3, and CACN b2 ( SQTS 5) in 6.
explanation: >-
Abstract-based cohort evidence identifying CACNB2 as the calcium-channel
gene underlying SQTS5 in this series.
- name: CACNA2D1 loss-of-function variants
association: Causative
features: >-
Loss-of-function CACNA2D1 variants cause SQTS6 within the calcium-channel
subgroup of autosomal dominant SQTS.
gene_term:
preferred_term: CACNA2D1
term:
id: hgnc:1399
label: CACNA2D1
inheritance:
- name: Autosomal dominant
evidence:
- reference: PMID:21383000
reference_title: >-
Identification of a novel loss-of-function calcium channel gene mutation
in short QT syndrome (SQTS6).
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In the present study, we report the first pathogenic mutation in the
CACNA2D1 gene in humans, which causes a new variant of SQTS.
explanation: >-
Abstract-based evidence that pathogenic CACNA2D1 variation causes SQTS6.
- name: SLC4A3
gene_term:
preferred_term: SLC4A3
term:
id: hgnc:11029
label: SLC4A3
association: Pathogenic Variants
evidence:
- reference: CGGV:assertion_b5f6fcca-f8a9-47c2-bae9-a72df92f3bd1-2020-08-03T160000.000Z
reference_title: "SLC4A3 / short QT syndrome (Moderate)"
supports: SUPPORT
evidence_source: OTHER
snippet: "SLC4A3 | HGNC:11029 | short QT syndrome | MONDO:0000453 | AD | Moderate"
explanation: ClinGen classifies the SLC4A3-short QT syndrome gene-disease relationship as moderate with autosomal dominant inheritance.
pathophysiology:
- name: Ion-channel gain- and loss-of-function variants
conforms_to: "cardiac_ion_channel_repolarization#Cardiac Ion-Channel or Calcium-Handling Variant"
role: trigger
description: >-
The upstream trigger of SQTS is a pathogenic germline variant that alters a
cardiac ion channel. Gain-of-function variants in the potassium channels
KCNH2 (IKr), KCNQ1 (IKs), and KCNJ2 (IK1) increase repolarizing current,
while loss-of-function variants in the L-type calcium channel subunits
CACNA1C and CACNB2 reduce inward calcium current. Either route shifts the
net balance of currents toward accelerated repolarization in structurally
normal myocardium.
genes:
- preferred_term: KCNH2
term:
id: hgnc:6251
label: KCNH2
- preferred_term: KCNQ1
term:
id: hgnc:6294
label: KCNQ1
- preferred_term: KCNJ2
term:
id: hgnc:6263
label: KCNJ2
- preferred_term: CACNA1C
term:
id: hgnc:1390
label: CACNA1C
- preferred_term: CACNB2
term:
id: hgnc:1402
label: CACNB2
cell_types:
- preferred_term: cardiomyocyte
term:
id: CL:0000746
label: cardiac muscle cell
molecular_functions:
- preferred_term: monoatomic ion channel activity
term:
id: GO:0005216
label: monoatomic ion channel activity
modifier: ABNORMAL
locations:
- preferred_term: heart
term:
id: UBERON:0000948
label: heart
evidence:
- reference: PMID:14676148
reference_title: >-
Sudden death associated with short-QT syndrome linked to mutations in
HERG.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In 2 of them, we identified 2 different missense mutations resulting in
the same amino acid change (N588K) in the S5-P loop region of the cardiac
IKr channel HERG (KCNH2).
explanation: >-
Identifies the gain-of-function KCNH2 (HERG) variant that is the upstream
ion-channel trigger of SQTS.
- reference: PMID:16039272
reference_title: >-
Modulation of I(Kr) inactivation by mutation N588K in KCNH2: a link to
arrhythmogenesis in short QT syndrome.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Physiologically the N588K mutation abolishes rectification of HERG
currents and specifically increases I(Kr) in the ventricle with minimal
effects on the Purkinje fiber action potential duration.
explanation: >-
Mechanistic electrophysiology showing how the channel variant alters
channel function to increase ventricular repolarizing current, the
variant-to-current step of the trigger node.
downstream:
- target: Accelerated myocardial repolarization
description: >-
The gain-of-function potassium or loss-of-function calcium variant shifts
the net current balance toward repolarization, abbreviating the action
potential and refractory period in working myocardium.
- name: Accelerated myocardial repolarization
role: central_effector
conforms_to: "cardiac_ion_channel_repolarization#Altered Action Potential and Calcium Handling"
description: >-
The core electrophysiologic lesion in SQTS is accelerated repolarization,
typically due to increased repolarizing potassium current in ventricular
myocardium. This abbreviates action potential duration and refractory
periods, producing the characteristic shortened QT interval and reducing the
margin against re-entry.
cell_types:
- preferred_term: cardiomyocyte
term:
id: CL:0000746
label: cardiac muscle cell
biological_processes:
- preferred_term: membrane repolarization during cardiac muscle cell action potential
term:
id: GO:0086013
label: membrane repolarization during cardiac muscle cell action potential
modifier: DYSREGULATED
- preferred_term: ventricular cardiac muscle cell action potential
term:
id: GO:0086005
label: ventricular cardiac muscle cell action potential
modifier: DYSREGULATED
- preferred_term: cardiac muscle cell action potential
term:
id: GO:0086001
label: cardiac muscle cell action potential
modifier: DYSREGULATED
locations:
- preferred_term: heart
term:
id: UBERON:0000948
label: heart
evidence:
- reference: PMID:14676148
reference_title: >-
Sudden death associated with short-QT syndrome linked to mutations in
HERG.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The mutations dramatically increase IKr, leading to heterogeneous
abbreviation of action potential duration and refractoriness, and reduce
the affinity of the channels to IKr blockers.
explanation: >-
Establishes the canonical SQTS mechanism of increased repolarizing
current with abbreviated action potentials and refractory periods.
- reference: PMID:29574456
reference_title: >-
Modeling Short QT Syndrome Using Human-Induced Pluripotent Stem
Cell-Derived Cardiomyocytes.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
The hiPSC-CMs from the patient showed increased rapidly activating
delayed rectifier potassium channel current (IKr) density and shortened
action potential duration compared with healthy control hiPSC-CMs.
explanation: >-
Patient-specific hiPSC-cardiomyocytes recapitulate the increased IKr and
shortened action potential phenotype at the cellular level.
- reference: PMID:16039272
reference_title: >-
Modulation of I(Kr) inactivation by mutation N588K in KCNH2: a link to
arrhythmogenesis in short QT syndrome.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Physiologically the N588K mutation abolishes rectification of HERG
currents and specifically increases I(Kr) in the ventricle with minimal
effects on the Purkinje fiber action potential duration.
explanation: >-
Provides mechanistic electrophysiology showing how a canonical KCNH2 SQTS
mutation selectively increases ventricular repolarizing current.
downstream:
- target: Re-entry-prone arrhythmia substrate
description: >-
Shortened refractory periods and impaired adaptation of repolarization
favor rotor stabilization and re-entry in atrial and ventricular tissue.
- name: Re-entry-prone arrhythmia substrate
role: amplifier
conforms_to: "cardiac_ion_channel_repolarization#Arrhythmogenic Substrate and Triggered Activity"
description: >-
Abbreviated refractory periods and impaired rate adaptation create a
myocardial substrate that is vulnerable to atrial and ventricular
fibrillation. At the tissue level this is expressed as shortened
excitation wavelength, enhanced inducibility of sustained spiral waves, and
increased ventricular vulnerability to fibrillation.
cell_types:
- preferred_term: cardiomyocyte
term:
id: CL:0000746
label: cardiac muscle cell
biological_processes:
- preferred_term: cardiac muscle cell action potential
term:
id: GO:0086001
label: cardiac muscle cell action potential
modifier: DYSREGULATED
- preferred_term: cardiac conduction
term:
id: GO:0061337
label: cardiac conduction
modifier: DYSREGULATED
evidence:
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
During electrophysiological study, short atrial and ventricular
refractory periods were documented in all and increased ventricular
vulnerability to fibrillation in 3 of 4 patients.
explanation: >-
Human electrophysiology directly demonstrates the shortened refractory
periods and ventricular fibrillation vulnerability that define the SQTS
substrate.
- reference: PMID:31072576
reference_title: >-
Modeling Reentry in the Short QT Syndrome With Human-Induced Pluripotent
Stem Cell-Derived Cardiac Cell Sheets.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Optical mapping of the SQTS-hiPSC-CCSs revealed shortened APD, impaired
APD-rate adaptation, abbreviated wavelength of excitation, and increased
inducibility of sustained spiral waves.
explanation: >-
Tissue-scale hiPSC cardiac sheet modeling links abbreviated repolarization
to re-entry and sustained arrhythmia induction.
downstream:
- target: Atrial and ventricular fibrillation susceptibility
description: >-
The re-entry-prone substrate manifests clinically as atrial fibrillation,
ventricular fibrillation, syncope, and sudden cardiac death.
- name: Atrial and ventricular fibrillation susceptibility
role: effector
conforms_to: "cardiac_ion_channel_repolarization#Ventricular Tachyarrhythmia"
description: >-
SQTS clinically presents with malignant atrial and ventricular arrhythmias.
Atrial fibrillation is common and may be the presenting feature, whereas
ventricular fibrillation underlies aborted cardiac arrest and sudden cardiac
death.
cell_types:
- preferred_term: cardiomyocyte
term:
id: CL:0000746
label: cardiac muscle cell
biological_processes:
- preferred_term: cardiac muscle cell action potential
term:
id: GO:0086001
label: cardiac muscle cell action potential
modifier: DYSREGULATED
- preferred_term: cardiac conduction
term:
id: GO:0061337
label: cardiac conduction
modifier: ABNORMAL
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Five patients had syncope (29%) and 9 (53%) had atrial fibrillation or
atrial flutter.
explanation: >-
Long-term family follow-up shows that atrial arrhythmia and syncope are
common manifestations of clinically diagnosed SQTS.
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The short QT syndrome is characterized by familial sudden death, short
refractory periods, and inducible ventricular fibrillation.
explanation: >-
Directly connects the SQTS clinical syndrome to ventricular fibrillation
and sudden death risk.
downstream:
- target: Syncope and Sudden Cardiac Death
description: >-
Sustained ventricular fibrillation abolishes effective cardiac output,
producing syncope and, if not terminated, sudden cardiac death.
- name: Syncope and Sudden Cardiac Death
role: outcome
conforms_to: "cardiac_ion_channel_repolarization#Syncope and Sudden Cardiac Death"
description: >-
Loss of effective cardiac output from sustained ventricular fibrillation (or
self-terminating tachyarrhythmia) causes transient cerebral hypoperfusion
and syncope and, when the rhythm does not terminate, sudden cardiac death.
These are the shared clinical endpoints of SQTS and are frequently the
sentinel manifestation, occurring in infants, children, and young adults
with structurally normal hearts.
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Short QT syndrome ( SQTS ) is a rare inheritable disease associated with
sudden cardiac death.
explanation: >-
Human clinical evidence tying SQTS to sudden cardiac death as the terminal
outcome of the cascade.
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The short QT syndrome is characterized by familial sudden death, short
refractory periods, and inducible ventricular fibrillation.
explanation: >-
Connects the SQTS substrate to familial sudden death as the clinical
endpoint.
phenotypes:
- category: Cardiovascular
name: Shortened QT Interval
diagnostic: true
description: >-
Marked QT abbreviation on surface ECG is the defining diagnostic
electrophysiologic feature of SQTS.
phenotype_term:
preferred_term: Shortened QT interval
term:
id: HP:0012232
label: Shortened QT interval
evidence:
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
At baseline ECG, all patients exhibited a QT interval <or=280 ms (QTc
<or=300 ms).
explanation: >-
Documents the hallmark ECG phenotype that defines SQTS in the original
familial cohort.
- category: Cardiovascular
name: Atrial Fibrillation
description: >-
Atrial fibrillation is a common presenting arrhythmia and may precede more
severe ventricular events.
phenotype_term:
preferred_term: atrial fibrillation
term:
id: HP:0005110
label: Atrial fibrillation
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Five patients had syncope (29%) and 9 (53%) had atrial fibrillation or
atrial flutter.
explanation: >-
Supports atrial fibrillation as a common clinical manifestation in SQTS
families.
- category: Cardiovascular
name: Ventricular Fibrillation
description: >-
Ventricular fibrillation reflects the malignant ventricular re-entry
phenotype responsible for aborted cardiac arrest and sudden death in SQTS.
phenotype_term:
preferred_term: ventricular fibrillation
term:
id: HP:0001663
label: Ventricular fibrillation
evidence:
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The short QT syndrome is characterized by familial sudden death, short
refractory periods, and inducible ventricular fibrillation.
explanation: >-
Establishes ventricular fibrillation as a central malignant arrhythmia in
SQTS.
- category: Cardiovascular
name: Syncope
description: >-
Transient loss of consciousness can result from brief self-terminating or
sustained tachyarrhythmia in SQTS.
phenotype_term:
preferred_term: syncope
term:
id: HP:0001279
label: Syncope
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Five patients had syncope (29%) and 9 (53%) had atrial fibrillation or
atrial flutter.
explanation: >-
Direct long-term cohort evidence that syncope is part of the SQTS
phenotype spectrum.
- category: Cardiovascular
name: Palpitations
description: >-
Palpitations are a common symptom of atrial or ventricular tachyarrhythmia
in affected individuals.
phenotype_term:
preferred_term: palpitations
term:
id: HP:0001962
label: Palpitations
evidence:
- reference: PMID:12925462
reference_title: 'Short QT Syndrome: a familial cause of sudden death.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Several members of 2 different families were referred for syncope,
palpitations, and resuscitated cardiac arrest in the presence of a
positive family history for sudden cardiac death.
explanation: >-
Shows palpitations among the presenting manifestations in the original
SQTS family series.
- category: Cardiovascular
name: Sudden Cardiac Death
description: >-
Sudden cardiac death is the most severe outcome of SQTS and may occur in
infants, children, or young adults with structurally normal hearts.
phenotype_term:
preferred_term: sudden cardiac death
term:
id: HP:0001645
label: Sudden cardiac death
evidence:
- reference: PMID:14676148
reference_title: >-
Sudden death associated with short-QT syndrome linked to mutations in
HERG.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We demonstrate a novel genetic and biophysical mechanism responsible for
sudden death in infants, children, and young adults caused by mutations
in KCNH2.
explanation: >-
Confirms sudden cardiac death as a defining high-severity clinical outcome
of SQTS.
treatments:
- name: Quinidine/Hydroquinidine Therapy
description: >-
Hydroquinidine is the best-supported pharmacologic therapy for SQTS. It
prolongs the QT interval and ventricular refractory period and can suppress
inducible or recurrent ventricular arrhythmias.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: quinidine
term:
id: CHEBI:28593
label: quinidine
evidence:
- reference: PMID:15093889
reference_title: 'Short QT syndrome: pharmacological treatment.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Only hydroquinidine administration caused a QT prolongation, which
increased from 263 +/- 12 ms to 362 +/- 25 ms (calculated QT from 290 +/-
13 ms to 405 +/- 26 ms).
explanation: >-
Demonstrates that hydroquinidine, unlike the other tested agents,
meaningfully prolongs the abbreviated QT interval in SQTS.
- reference: PMID:31427960
reference_title: Impact of Antiarrhythmic Drugs on the Outcome of Short QT Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
HQ increases the corrected QT interval and prevents VAs in the majority
of the patients in this cohort.
explanation: >-
Supports hydroquinidine as the most consistently effective long-term
antiarrhythmic drug reported for SQTS.
- name: Implantable Cardioverter-Defibrillator
description: >-
ICD implantation is used for secondary prevention or in high-risk patients,
especially after aborted cardiac arrest or when malignant ventricular
arrhythmia risk remains high.
treatment_term:
preferred_term: implantable cardioverter-defibrillator placement
term:
id: MAXO:0000004
label: surgical procedure
evidence:
- reference: PMID:30571592
reference_title: >-
Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile
and Outcome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Five patients (29%) received an implantable cardioverter-defibrillator
and 5 patients received long-term prophylaxis with hydroquinidine.
explanation: >-
Long-term cohort follow-up shows ICD use as a standard individualized
management strategy in SQTS.
notes: >-
This entry is intentionally framed at the shared Short QT syndrome disease
level rather than being split into individual subtype entries. The curation
emphasizes the common repolarization-abbreviation mechanism and the clinical
arrhythmia substrate across genetically heterogeneous SQTS families.