Learn more about the causes and treatment of this heart rhythm condition that can potentially cause fast, chaotic heartbeats.
Long QT syndrome (LQTS) is a heart rhythm condition that can potentially cause fast, chaotic heartbeats. These rapid heartbeats might trigger you to suddenly faint. Some people with the condition have seizures. In some severe cases, LQTS can cause sudden death.
Some people are born with a genetic mutation that causes long QT syndrome (congenital long QT syndrome). Long QT syndrome may be caused by certain medications, mineral imbalances or medical conditions (acquired long QT syndrome).
Long QT syndrome is treatable. You might need to avoid or take certain medications to prevent dangerous heartbeat episodes. Sometimes, treatment for long QT syndrome involves surgery or an implantable device.
Many people who have long QT syndrome don't have any signs or symptoms. You might be aware of your condition only because of:
Fainting is the most common sign of long QT syndrome.
Fainting (syncope) occurs when the heart temporarily beats in an unorganized way. You might faint when you're excited, angry or scared or during exercise. Things that startle you — for example, a telephone or an alarm clock — can cause you to lose consciousness. A fainting spell from long QT syndrome can occur with little to no warning. Some people have a warning sign first, such as lightheadedness, heart palpitations, weakness or blurred vision.
Seizures also may occur in some people with LQTS.
Generally, the heart returns to its normal rhythm. If this doesn't happen by itself, or if an external defibrillator isn't used in time to set your heartbeat back to normal, sudden death will occur.
Most people with symptoms of long QT syndrome have their first episode by age 40. However, congenital long QT syndrome signs and symptoms can occur in babies during the first weeks to months after birth, or in childhood or later. Some people with congenital long QT syndrome never have signs or symptoms.
Signs and symptoms of long QT syndrome might occur during sleep.
Call your doctor if you suddenly faint during physical activity or emotional excitement or after taking any new medication. If you have a first-degree relative (parent, sibling or child) with long QT syndrome, it's important to let your doctor know. Long QT syndrome can run in families.
Long QT syndrome is a heart rhythm disorder caused by abnormalities in the heart's electrical recharging system. The heart's structure is normal.
Normally, the heart sends blood out to the body during each heartbeat. The heart's chambers contract and relax to pump the blood. This coordinated action is controlled by your heart's electrical system. Electrical signals (impulses) travel from the top to the bottom of your heart and trigger it to contract and beat. After each heartbeat, the system recharges itself to prepare for the next heartbeat.
In long QT syndrome, your heart's electrical system takes longer than normal to recharge between beats. This delay, which often can be seen on an electrocardiogram (ECG), is called a prolonged QT interval.
Long QT syndrome is often grouped into two main categories, depending on the cause.
More than 17 genes have been linked to long QT syndrome so far, and researchers have identified hundreds of mutations within these genes.
Doctors have described two forms of congenital long QT syndrome:
More than 100 medications — many of them common — can lengthen the QT interval in otherwise healthy people and cause acquired long QT syndrome.
Medications that can cause acquired long QT syndrome include:
If your condition is caused by a medication, it may be called drug-induced long QT syndrome. Always tell your doctor about all the medications you take, including those you buy without a prescription.
Other causes of acquired long QT syndrome include:
The following things may increase your risk of developing congenital or acquired long QT syndrome or its symptoms:
Sexual intercourse doesn't appear to be high risk for patients with long QT syndrome. Pregnancy and delivery aren't associated with an increased risk of symptoms in women diagnosed with long QT syndrome. However, if you have the condition and are pregnant, your doctor will want to carefully monitor you during and after pregnancy.
Proper medical treatment and lifestyle changes can help prevent complications related to long QT syndrome.
Complications of long QT syndrome include:
Torsades de pointes ('twisting of the points'). This is a life-threatening form of ventricular arrhythmia. Your heart's two lower chambers (ventricles) beat fast and chaotically, making the waves on an ECG monitor look twisted. The heart pumps out less blood. The lack of blood to the brain causes you to faint suddenly and, often, without warning.
If the episode lasts for a long time, fainting can be followed by a full-body seizure. If the dangerous rhythm does not correct itself, then a life-threatening arrhythmia called ventricular fibrillation follows.
Congenital long QT syndrome is caused by a genetic mutation. There is no known prevention. However, with proper treatment, you can prevent the dangerous heartbeats that can lead to long QT syndrome complications.
You may be able to prevent the health conditions that lead to some types of acquired long QT syndrome with regular health checkups and good communication with your doctor. It is especially important to avoid medications that can affect your heart rhythm and cause prolongation of the QT interval.
To diagnose long QT syndrome, your doctor will perform a physical exam and ask questions about your or your child's symptoms and medical and family history. Your doctor will use a stethoscope to listen to your heart.
An electrocardiogram is the most common test used to diagnose long QT syndrome.
An electrocardiogram is a quick and painless test that records the electrical signals in your heart. You might have an ECG while at rest or while exercising on a treadmill or stationary bicycle. If you cannot safely exercise, you may be given a medication such as epinephrine (Adrenalin) that stimulates your heart in a way similar to exercise.
During an ECG, sticky patches (electrodes) are placed on your chest to record your heart's electrical signals, which cause your heart to beat. The signals are shown as waves on an attached computer monitor or printer.
An ECG can tell if you are having a prolonged QT interval. The test labels the heart's electrical signals as five waves using the letters P, Q, R, S and T. The waves labeled Q through T show the electrical activity in your heart's lower chambers (ventricles).
The space between the start of the Q wave and the end of the T wave is the QT interval. That's the time it takes for your heart to contract and refill with blood before it beats again.
What's normal for you depends on your age, your sex and your individual heart rate. Your doctor will consider this information. If the interval takes longer than normal to occur, it's called a prolonged QT interval.
If your long QT symptoms tend to come and go, they may not be captured during a standard ECG recording. In this case your doctor may recommend remote or continuous ECG monitoring. There are several different types.
A genetic test for long QT syndrome is available and recommended by many doctors to confirm the diagnosis. Check with your insurer to see if it is covered.
It's important to understand that genetic tests for long QT syndrome can't detect all inherited cases of long QT syndrome. It's recommended that families speak to a genetic counselor before and after testing.
If you have a positive genetic test for long QT syndrome, your doctor may recommend that other family members also be tested to determine whether they inherited the same gene.
Treatment for long QT syndrome involves lifestyle changes, medications, and possibly surgery or other procedures.
The goal of treatment is to prevent erratic heartbeats and sudden death. Your doctor will discuss with you the most appropriate treatment options based on your symptoms and your type of long QT syndrome. Your doctor might suggest treatment even if you don't often have signs or symptoms.
If you have drug-induced long QT syndrome, stopping the medication causing your symptoms may be all that is needed to treat the condition. Your doctor can tell you how to safely do so.
For other cases of acquired long QT syndrome, treating the underlying condition is necessary. Treatment varies but may include magnesium or other fluids given by IV to correct electrolyte imbalances.
Medications won't cure long QT syndrome, but they can help protect against possible life-threatening heart rhythm changes.
Medications used to treat long QT syndrome may include:
Always take the medications your doctor prescribes as directed.
Depending on your symptoms, your doctor might consider other long QT syndrome treatments for you, including:
Left cardiac sympathetic denervation (LCSD) surgery. In this procedure, surgeons remove specific nerves along the left side of your spine in your chest. These nerves are part of the body's sympathetic nervous system, which helps control your heart rhythm.
LCSD is generally reserved for people with long QT and persistent heart rhythm problems who are at high risk of symptoms and cannot take or tolerate beta blockers. It doesn't cure long QT syndrome, but it does help reduce the risk of sudden death.
Implantable cardioverter-defibrillator (ICD). An ICD is implanted under the skin of your chest and continuously monitors your heartbeat. It can stop a potentially life-threatening arrhythmia. When an ICD detects an abnormal heart rhythm, it delivers electrical shocks to reset the heart back to normal.
Most people with long QT syndrome do not need an ICD. However, the procedure may be done in certain athletes to allow return to competitive sports. The decision to implant an ICD, especially in children, needs to be carefully considered. Implanting an ICD is a major procedure and can result in inappropriate shocks and other complications.
In addition to recommending medications or surgery, your doctor might suggest lifestyle changes to reduce your chances of a long QT syndrome-related fainting spell or sudden cardiac death.
Worrying about possible dangerous heart rhythms associated with long QT syndrome can cause stress for you and your loved ones. Take steps to help your loved ones better understand how to support you and care for you in an emergency.
If you develop signs and symptoms of long QT syndrome, contact your doctor. After an initial exam, your doctor likely will refer you to a doctor trained in diagnosing and treating heart conditions (cardiologist), a doctor trained in heart rhythm conditions (electrophysiologist) or a cardiologist who specializes in genetic heart conditions (genetic cardiologist).
Here's some information to help you prepare for your appointment and know what to expect from your doctor.
Questions to ask the doctor at your initial appointment include:
Questions to ask if you're referred to a cardiologist or electrophysiologist include:
Questions to ask if your doctor recommends surgery include:
Additional questions include:
In addition to the questions that you've prepared ahead of time, don't hesitate to ask other questions during your appointment if you don't understand something.
A doctor who sees you for possible long QT syndrome might ask a number of questions, including:
While you wait for your appointment, check with your family members to find out if you have a family history of long QT syndrome or unexplained death.
Having a first-degree relative who died from an unexpected cause — such as sudden infant death syndrome (SIDS), drowning or other accident — is an important clue for your doctor. In general, knowing as much as possible about your family's health history will help your doctor determine the next steps for your diagnosis and treatment.
November 10th, 2021
