Understanding and treating long QT syndrome

January 4, 2018 by From Mayo Clinic News Network, Mayo Clinic News Network

DEAR MAYO CLINIC: I recently read that long QT syndrome is quite common. What is it, and how is it diagnosed? I have read that fainting may be one sign of the disorder. Can long QT syndrome be treated?

ANSWER: Long QT is a that is diagnosed due to symptoms, an abnormal 12-lead electrocardiogram (ECG), or as a result of a family history of the disease. Once it's diagnosed, long QT syndrome often can be treated effectively.

Your heart circulates blood throughout your body each time it beats. The chambers of your heart contract and relax to pump the blood. These actions are controlled by electrical impulses that travel through your heart. After each heartbeat, your heart's electrical system recharges itself in preparation for the next heartbeat.

In long QT syndrome, the heart muscle takes longer than normal to electrically recharge after it contracts. A test called an electrocardiogram (also called an ECG or EKG) can detect this problem. Most people don't have routine ECGs, though, so catching it with this test if you haven't had any symptoms, or if you don't have a of the disorder, is less common.

Congenital or inherited long QT syndrome affects about 1 in 2,000 people. That statistic, however, is likely an underestimate, because people can have the disorder for years and not know it. In addition, some unexplained deaths, such as those by drowning or unexplained vehicle accidents, may be the result of triggered by long QT syndrome.

As you note, one of the most frequent symptoms of long QT syndrome is fainting. The disorder triggers fainting when the heartbeat becomes irregular—usually during exercise or other physical exertion, or when you become scared, excited or angry. If the heartbeat continues to be dangerously fast and erratic for a prolonged period of time, long QT syndrome also can lead to seizures due to lack of oxygen to the brain. If the heartbeat doesn't return to normal, can occur.

At this time, universal screening does not include long QT syndrome. In most cases, it's diagnosed with an ECG after someone experiences a warning symptom—usually fainting without warning. Because long QT syndrome often has a genetic component, some people may be diagnosed if a family member has the disorder. Or, in some cases, first-degree family members (parents, siblings and children) may be tested for long QT syndrome when there is an unexplained, sudden death in a family. Genetic testing should be recommended as part of evaluation for long QT syndrome.

Once long QT syndrome is diagnosed, treatment usually starts with a medication called a beta-blocker. Other medications to counteract irregular heart rhythm may be used in conjunction with beta-blockers.

If medication isn't enough to control long QT, a surgery called left cardiac sympathetic denervation may be recommended. During this minimally invasive procedure, nerves that release a chemical called noradrenalin onto the heart's muscle are removed from along the left side of the spine. The surgery significantly reduces the risk of a long QT-triggered faint, seizure or sudden death.

Sometimes, despite medications and/or the denervation surgery, a person with long QT syndrome may be at unacceptably high risk for sudden death. In those situations, a defibrillator may be implanted under the skin of the chest. The device can stop a potentially fatal by delivering an electric shock to reset the rhythm back to normal.

Treatment for long QT syndrome is tailored to the individual after a comprehensive risk assessment. In most cases, once it's identified, long QT syndrome can be treated successfully so the patient should be able to live and thrive despite the diagnosis.

"Given the complexity of this disease and the importance of getting the diagnosis and treatment plan right, people suspected of having long QT syndrome should be referred to a center of excellence dedicated to families with this potentially lethal, yet highly treatable, genetic disease". - Dr. Michael J. Ackerman, Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.

Explore further: How a bite of a hot dog threatened and saved a boy's life

2 shares

Related Stories

How a bite of a hot dog threatened and saved a boy's life

September 6, 2017
(HealthDay)—A 9-year-old boy in Turkey opened wide for a big bite of a tasty hot dog, but had no idea the simple act might almost kill him.

Sudden cardiac death of teen reminds physicians of precision medicine

October 31, 2016
The sudden death of a 13-year-old boy resulted in more than 20 relatives to be incorrectly diagnosed as having a potentially lethal heart rhythm condition. This erroneous diagnosis occurred as a result of inappropriate use ...

Device may help doctors diagnose lethal heart rhythm in womb

November 11, 2013
A promising technology may enable doctors to diagnose and possibly treat in utero a common cause of stillbirth and sudden death in infants, according to research published in the American Heart Association journal Circulation.

Study re-examines sports restrictions for children with heart rhythm disorder

April 20, 2015
Sports participation may be safer than previously thought for children with the heart rhythm disorder long QT syndrome, and authors of a new study in JACC: Clinical Electrophysiology say restrictions should be eased to allow ...

Team discovers patient-specific cure for dangerous heart rhythm disorder

September 17, 2013
The National Heart Centre Singapore (NHCS) research team has successfully and completely reversed the effects of the hERG (human ether-a-go-go-related gene) mutation in long QT syndrome 2 (LQTS 2) in patient-specific heart ...

Recommended for you

Biomechanical mapping method aids development of therapies for damaged heart tissue

January 23, 2018
Researchers have developed a new way to capture the detailed biomechanical properties of heart tissue. The high-resolution optical technique fills an important technology gap necessary to develop and test therapies that might ...

Researchers borrow from AIDS playbook to tackle rheumatic heart disease

January 22, 2018
Billions of US taxpayer dollars have been invested in Africa over the past 15 years to improve care for millions suffering from the HIV/AIDS epidemic; yet health systems on the continent continue to struggle. What if the ...

A nanoparticle inhalant for treating heart disease

January 18, 2018
A team of researchers from Italy and Germany has developed a nanoparticle inhalant for treating people suffering from heart disease. In their paper published in the journal Science Translational Medicine, the group describes ...

Starting periods before age of 12 linked to heightened risk of heart disease and stroke

January 15, 2018
Starting periods early—before the age of 12—is linked to a heightened risk of heart disease and stroke in later life, suggests an analysis of data from the UK Biobank study, published online in the journal Heart.

'Decorated' stem cells could offer targeted heart repair

January 10, 2018
Although cardiac stem cell therapy is a promising treatment for heart attack patients, directing the cells to the site of an injury - and getting them to stay there - remains challenging. In a new pilot study using an animal ...

Exercise is good for the heart, high blood pressure is bad—researchers find out why

January 10, 2018
When the heart is put under stress during exercise, it is considered healthy. Yet stress due to high blood pressure is bad for the heart. Why? And is this always the case? Researchers of the German Centre for Cardiovascular ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.