Long Qt Syndrome 2: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Long Qt Syndrome 2?
A primary care doctor often starts by ordering an electrocardiogram and reviewing symptoms and family history. People with confirmed Long Qt Syndrome 2 are usually referred to a cardiologist, and often to a heart rhythm specialist called an electrophysiologist. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Long Qt Syndrome 2?
Long Qt Syndrome 2 is an inherited heart rhythm problem that affects the electrical system of the heart. People who have it can develop a fast, dangerous heartbeat.
The QT interval, seen on an electrocardiogram, is the time the heart takes to reset between beats. In Long Qt Syndrome 2, the heart takes longer than normal to reset, which can allow a dangerous rhythm to start, especially after stress, exercise, or a sudden scare.
Symptoms
Many people have no symptoms. When symptoms happen, fainting is the most common, often during exercise, stress, or a sudden noise like an alarm. Some people have seizures, which can be mistaken for epilepsy. In serious cases, the dangerous rhythm can cause cardiac arrest.
Causes and who gets it
Long Qt Syndrome 2 is caused by a change in a gene called KCNH2, also known as HERG. This gene helps control the electrical signals that reset the heart between beats. It is passed down from a parent, so it often runs in families.
How doctors diagnose it
Doctors start with an electrocardiogram to measure the QT interval. They also ask about fainting spells and family members with fainting, seizures, or sudden death at a young age. Genetic testing on a blood sample can confirm the gene change.
Treatment
Most patients take a beta blocker, which lowers the risk of dangerous rhythms. Doctors also recommend avoiding certain medicines that lengthen the QT interval and limiting some strenuous activities or loud alarms. People at higher risk may need an implantable defibrillator.
When to see a doctor
See a doctor if you have fainting spells, unexplained seizures, or a family history of sudden death at a young age. If someone collapses and is not breathing, call 911.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can be a helpful partner. They can order an electrocardiogram, watch for symptoms, and coordinate care.
Common questions
Can people with Long Qt Syndrome 2 exercise?
Many people can stay active with guidance from their care team. Limits depend on each person's risk, and some competitive sports may be discouraged.
Will my children inherit it?
A parent with the gene change has a 50 percent chance of passing it to each child. Genetic testing can show whether a child has it. Not everyone with the change has symptoms.
Are there medicines I should avoid?
Yes. Many common medicines, including some antibiotics and some allergy drugs, can lengthen the QT interval. Patients should check new medicines with their doctor or pharmacist.
Is there a cure?
There is no cure, because the condition comes from a gene change. Treatment can lower the risk of dangerous rhythms, and many people live full lives with proper care.
Sources
- NIH Genetic and Rare Diseases Information Center - Long QT syndrome
- National Organization for Rare Disorders (NORD) - Isolated congenital Long QT Syndrome
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
