Long Qt Syndrome 3 C1859062
Long QT Syndrome type 3 is a genetic disorder of the heart's electrical activity. This condition may cause fainting or dangerous heart rhythms, often during rest or sleep. Treatment typically involves medication and sometimes a device to regulate heartbeat.
Key facts at a glance
- ICD-10
- I45.81
- ICD-11
- BA00.0
- Body system
- cardiovascular
- Severity
- severe
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Syncope
Torsades de pointes
Palpitations
Chest discomfort or palpitations
(cardiovascular)Significant symptoms that substantially affect daily functioning.
Frequency: Common at all stages
Dizziness
(cardiovascular)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Beta-blocker therapy
First-line pharmacologic treatment using beta-blockers to reduce sympathetic stimulation and prevent cardiac arrhythmias. In LQT3, sodium channel blockers may be added as adjunctive therapy.
Disease management and monitoring
Active treatment with regular monitoring by a healthcare provider is recommended.
ICD implantation
Implantable cardioverter-defibrillator placement for high-risk patients, particularly important in LQT3 where arrhythmias may occur during sleep or rest periods.
Additional treatment options
Sleep safety modifications
Environmental modifications to reduce sudden auditory trigger risks during sleep, including avoiding sudden alarm sounds and implementing softer wake-up methods.
lifestyleSodium channel blocker adjunctive therapy
Addition of sodium channel blockers such as mexiletine to standard beta-blocker therapy, particularly in LQT3 patients to reduce arrhythmic events during rest and sleep.
medicationNocturnal cardiac monitoring
Enhanced overnight monitoring protocols including extended Holter monitoring or bedside event recorders to detect silent arrhythmias occurring during rest periods common in LQT3.
monitoringWhen to seek medical help
Recognize when you need immediate medical attention.
See a doctor within 24 hours
Moderate to severe symptoms that may indicate worsening of this condition. Prompt medical evaluation is recommended.
Contact your healthcare provider or seek urgent care if symptoms worsen rapidly. Go to the emergency department for life-threatening symptoms.
Frequently asked questions
Common questions about this topic.
What is Long Qt Syndrome 3 C1859062?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalMedication Comparisons
Compare medications used to treat Long Qt Syndrome 3 C1859062. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy