Long QT Syndrome (LQTS)

Diagnosis

A doctor will examine you physically and inquire about your symptoms, medical history, and family history in order to identify long QT syndrome. The doctor listens to your heart with a stethoscope. Tests to examine the heart’s rhythm can be performed if your physician believes you have an irregular heartbeat.

Tests

Testing is done to confirm the diagnosis of long QT syndrome or to look for other disorders that could cause irregular heartbeats or interfere with the heart’s rhythm.

Electrocardiogram (ECG or EKG)

The most used test for long QT syndrome diagnosis is this one. The electrical signals in the heart are recorded by a simple and painless examination called an ECG. Electrodes, or sensors, are attached to the chest and sometimes affixed to the arms or legs during an ECG. The length and timing of each electrical phase of a heartbeat are measured by an ECG. The signals appear on a connected printer or computer monitor as waves.

• An ECG uses the letters P, Q, R, S, and T to identify the five waves that make up the heart’s electrical signals.
• The electrical activity in the ventricles, the bottom chambers of the heart, is displayed by waves Q through T.
• The interval between the beginning of the Q wave and the conclusion of the T wave is known as the QT interval. The time it takes for the heart to contract and fill up with blood before it begins to beat again is known as the interval. A prolonged QT interval occurs when the interval takes longer than usual.

Your age, gender, and unique heart rate all affect the optimal QT interval.

Long QT symptoms can not show up on a typical ECG if they are not frequent. Remote ECG monitoring might be advised if this occurs. There are numerous varieties.

• Holter monitor. This portable ECG gadget can be suggested by your doctor so you can keep an eye on your heart rate at home. To track the heart’s activity during daily activities, it is worn for at least one day.
• Event monitor. You can use this portable ECG gadget for up to 30 days, or until you have symptoms or an arrhythmia. Usually, you click a button when the symptoms appear. Certain devices initiate automatic recording upon detection of an arrhythmia, or abnormal heartbeat.

Some personal electronics, such smartwatches, can monitor an ECG. Find out from your healthcare provider if you have this as a choice.

Exercise stress test

This kind of test usually entails riding a stationary bike or walking on a treadmill while having an ECG taken. Exercise tests are useful in determining the heart’s response to physical exertion. You might be prescribed a medicine that stimulates the heart similarly to exercise if you are unable to exercise.

Genetic testing

To confirm the diagnosis, a genetic test for long QT syndrome is available. 

Your doctor can advise testing additional family members to see if they shared the same gene if the results of your genetic test reveal that you have long QT syndrome.

It’s critical to realize that not all inherited cases of long QT syndrome may be identified by genetic testing. Families should consult a genetic counselor both prior to and following testing.

Treatment

Long QT syndrome (LQTS) can be managed through various approaches, including medication, surgical procedures, and lifestyle adjustments.

The primary goal of LQTS treatment is to prevent irregular heartbeats and sudden death. Your doctor will tailor the best treatment plan for you, taking into account your specific LQTS type and symptoms. Even if your symptoms are infrequent, therapy may still be necessary.

For drug–induced long QT syndrome, discontinuing the medication or substance responsible for the symptoms may be the only necessary treatment. Your doctor will guide you on how to do this safely.

In cases of other types of acquired long QT syndrome, addressing the underlying illness is crucial. Treatment options vary, but magnesium or intravenous fluids to correct electrolyte imbalances may be used.

Medications

Long QT syndrome cannot be cured, however medications can help prevent potentially fatal heart rhythm abnormalities.

The following drugs may be used to treat long QT syndrome:

• Beta blockers. Most patients with long QT syndrome receive standard therapy with these medications. They reduce the heart rate and lower the risk of prolonged QT events. Propranolol and nadolol are two examples of beta blockers used to treat long QT syndrome.
• Mexiletine. Combining this heart rhythm medication with a beta blocker may help decrease the QT interval and lower the chance of passing out, having a seizure, or fainting.

Take prescriptions exactly as directed.

Surgery or other procedures

Some patients with long QT syndrome may require surgery or other medical interventions to help regulate their heartbeat. The following procedures and treatments for LQTS may be performed:

• Left Cardiac Sympathetic Denervation (LCSD) surgery. Surgery to correct long QT syndrome and persistent arrhythmias is often only advised for patients who are intolerant to beta blockers or cannot take them. While it doesn’t treat long QT syndrome, it does lessen the chance of unexpected death. Surgeons extract particular nerves along the left side of the spine in the chest during this treatment. The sympathetic nervous system of the body, which includes these nerves, aids in regulating the heart’s rhythm.
• Implantable Cardioverter–Defibrillator (ICD). Similar to a pacemaker, an ICD is a battery–operated device that is implanted beneath the skin close to the collarbone. The heart rhythm is continuously monitored by the ICD. The gadget shocks the heart to restore its usual rhythm if it notices an irregular heartbeat. It can halt an arrhythmia that might be fatal.

Those who have long QT syndrome typically do not require an ICD. For some athletes, nevertheless, an ICD might be advised in order to resume competitive sports. It is important to give serious thought to the decision to implant an ICD, particularly in children. ICD implantation is a significant operation that carries a risk of improper shocks and other issues.