Table of ContentsView AllTable of ContentsWhat It Feels LIkeTypesSymptomsCausesRisk FactorsScreeningDiagnosisTreatmentReducing RisksLife ExpectancyWhen to Call a Provider
Table of ContentsView All
View All
Table of Contents
What It Feels LIke
Types
Symptoms
Causes
Risk Factors
Screening
Diagnosis
Treatment
Reducing Risks
Life Expectancy
When to Call a Provider
Long QT syndrome is a medical condition that causes abnormalelectrical conduction in the heart. When graphed on anelectrocardiogram (EKG or ECG)each heartbeat has five distinct waves: P, Q, R, S, and T. Long QT refers to a longer space between the Q and T waves. This space is also known as the QT interval.
This long QT interval can cause no symptoms at all or serious symptoms, including fainting, seizure, and death.This article will discuss long QT syndrome symptoms, causes, and treatments. It will also cover risk factors and screening options.
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What Does Long QT Syndrome Feel Like?
Long QT syndrome may have no symptoms. However, it can feel like:
When long QT syndrome causes a fatalarrhythmia(abnormal rhythm of heartbeats), the person has symptoms that lead to them collapsing and cause sudden cardiac death.
Long QT Syndrome Types
Long QT syndrome is either acquired at some point during life or is an inherited condition that you are born with.
Inherited Long QT Syndrome
Inheritedlong QT syndrome is diagnosed in people who were born with the condition. People who have inherited long QT syndrome typically have one of the following three subtypes:
Acquired Long QT Syndrome
If a medication or condition is identified as the cause, stopping or correcting it may resolve the symptoms.
TermsIn this article, the terms for sex or gender from the sources cited are used. These generally relate to anatomical or chromosomal characteristics at birth. Verywell recognizes that people may have a gender identity that differs from the source’s use of the terms.
Terms
In this article, the terms for sex or gender from the sources cited are used. These generally relate to anatomical or chromosomal characteristics at birth. Verywell recognizes that people may have a gender identity that differs from the source’s use of the terms.
What Are the Symptoms of Long QT Syndrome?
The symptoms of long QT syndrome are:
Some people who have long QT syndrome do not have any symptoms at all. These people may learn they have the condition only after being evaluated for other conditions.
One in 10 people with long QT syndrome discover they have the syndrome after they have a sudden cardiac arrest.Sudden cardiac arrest is a medical condition in which the heart stops beating due to an arrhythmia. It is fatal unless treatment is received immediately.
What Causes Long QT Syndrome?
Ion channels in the heart open and close to letsodium,calcium, and potassium move in and out of the heart cells. This is part of how the heart creates electrical activity. When the ion channels do not work correctly or if there are not enough of them then the heart’s electrical activity can become irregular and cause a heart arrhythmia.
Up to 75% of people diagnosed with long QT syndrome have inherited the condition.Other people will have acquired the condition from a medication or another medical condition.
Risk Factors for Long QT Syndrome
The risk factors for long QT syndrome include:
Can You Get Screened for Long QT Syndrome?
When someone in the family has been diagnosed with long QT, other family members may want to be screened to see if they are at risk.
Genetic testinglooks atgenetic markersthat can show long QT syndrome. The tests can catch long QT syndrome in 3 of 4 people with the condition.If genetic testing indicates that someone could have long QT syndrome, a healthcare provider may order additional testing, like an EKG.
How Is Long QT Syndrome Diagnosed?
Long QT syndrome is diagnosed using several diagnostic tools. They include:
How Is Long QT Syndrome Treated?
Long QT syndrome is treated using a combination of several therapies.
Beta-blockersare a class of medications that prevent the heart from beating too fast. They are a mainstay treatment in people with long QT syndrome.
Electrolyte replacements can help maintain normal levels of potassium, calcium, and sodium, which are necessary for normal electrical activity within the heart.
An implantedpacemakeris a device that generates an electrical pulse when it senses that the heart is beating irregularly or too slowly. In some cases, a pacemaker can also have aninternal defibrillatorthat sends an electrical shock when it senses that the heart rhythm is abnormal.
How to Reduce Your Risk of Cardiac Arrest
People with long QT syndrome should talk to their healthcare provider about ways they can reduce the risk of acardiac arrest.
The healthcare provider may suggest avoiding activities that can trigger long QT episodes, likeexercise, stress, swimming, and loud noises. They may also suggest eating foods high in potassium.
Always make sure to take prescribed medications and contact a healthcare provider if you have symptoms that could indicate that you are having a long QT episode.
How Does Long QT Syndrome Affect Life Expectancy?
Long QT syndrome is typically a condition that someone has to live with for the rest of their life. When left untreated, the risk of sudden cardiac death is high. However, after someone has been diagnosed with long QT syndrome and receives adequate treatment, they can lead a full life.
A 2017 study looked at 166 people diagnosed with long QT syndrome. Seven years after diagnosis, 92% had not had a breakthrough cardiac event (such as fainting, seizure, cardiac arrest, or implanted defibrillator shocks to end defibrillation).While this was a small study, it helps illustrate that, with treatment, most people with long QT syndrome can live without experiencing cardiac events.
When to Contact a Healthcare Provider
Contact a healthcare provider if you experience symptoms of long QT syndrome. If the symptoms includedifficulty breathing,seizures, or chest pain, call 911 immediately.
Someone diagnosed with long QT syndrome should have instructions from their healthcare provider on when to call the provider or 911. The instructions will clarify what to do if they feel new symptoms or prolonged symptoms.
Summary
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Heart, Lung, and Blood Institute.Long QT syndrome.Johns Hopkins Medicine.Long QT syndrome (LQTS).Stanford Medicine.Types of long QT syndrome.Wilde AAM, Amin AS, Postema PG.Diagnosis, management and therapeutic strategies for congenital long QT syndrome.Heart. 2022;108(5):332-338. doi:10.1136/heartjnl-2020-318259Children’s Hospital of Philadelphia.Long QT syndrome.Rohatgi RK, Sugrue A, Bos JM, et al.Contemporary outcomes in patients with long qt syndrome.Journal of the American College of Cardiology. 2017;70(4):453-462. doi:10.1016/j.jacc.2017.05.046
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Heart, Lung, and Blood Institute.Long QT syndrome.Johns Hopkins Medicine.Long QT syndrome (LQTS).Stanford Medicine.Types of long QT syndrome.Wilde AAM, Amin AS, Postema PG.Diagnosis, management and therapeutic strategies for congenital long QT syndrome.Heart. 2022;108(5):332-338. doi:10.1136/heartjnl-2020-318259Children’s Hospital of Philadelphia.Long QT syndrome.Rohatgi RK, Sugrue A, Bos JM, et al.Contemporary outcomes in patients with long qt syndrome.Journal of the American College of Cardiology. 2017;70(4):453-462. doi:10.1016/j.jacc.2017.05.046
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Heart, Lung, and Blood Institute.Long QT syndrome.Johns Hopkins Medicine.Long QT syndrome (LQTS).Stanford Medicine.Types of long QT syndrome.Wilde AAM, Amin AS, Postema PG.Diagnosis, management and therapeutic strategies for congenital long QT syndrome.Heart. 2022;108(5):332-338. doi:10.1136/heartjnl-2020-318259Children’s Hospital of Philadelphia.Long QT syndrome.Rohatgi RK, Sugrue A, Bos JM, et al.Contemporary outcomes in patients with long qt syndrome.Journal of the American College of Cardiology. 2017;70(4):453-462. doi:10.1016/j.jacc.2017.05.046
National Heart, Lung, and Blood Institute.Long QT syndrome.
Johns Hopkins Medicine.Long QT syndrome (LQTS).
Stanford Medicine.Types of long QT syndrome.
Wilde AAM, Amin AS, Postema PG.Diagnosis, management and therapeutic strategies for congenital long QT syndrome.Heart. 2022;108(5):332-338. doi:10.1136/heartjnl-2020-318259
Children’s Hospital of Philadelphia.Long QT syndrome.
Rohatgi RK, Sugrue A, Bos JM, et al.Contemporary outcomes in patients with long qt syndrome.Journal of the American College of Cardiology. 2017;70(4):453-462. doi:10.1016/j.jacc.2017.05.046
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