Long QT Syndrome - Causes, Risks, Symptoms, Diagnosis, Treatment, and Prevention

What Is Long QT Syndrome?

The heart is divided into four chambers. The two upper divisions are the right and left atrium, and the two lower chambers are right and left ventricles. Long QT syndrome or LQTS refers to a heart rhythm disorder that has the potential to be fatal. Long QT syndrome results in fast and chaotic heartbeats in either the ventricle or the atrium, which may trigger sudden episodes of unconsciousness as well as seizures. Rarely does long QT syndrome cause death. Individuals born with genetic abnormalities and mutations may lead to long QT syndrome.

Certain drugs or nutrient imbalances may additionally cause long QT syndrome. Fortunately, long QT syndrome is treatable. You might need to avoid or take certain medications to prevent dangerous heartbeat episodes. At times, the treatment for long QT syndrome may require surgery. Management also encompasses limiting strenuous exercise with a sufficient intake of potassium. For patients who suffer from Long QT syndrome and who have survived an episode of cardiac arrest, the odds of death within a span of 15 years is approximately 50 %. This percentage dropped to 1 % in 20 years with prompt treatment.

What Are the Signs and Symptoms of Long QT Syndrome?

There is an amplitude of people who suffer from long QT syndrome but show no signs or symptoms. They are generally those who have a congenital disability. Additionally, many of the below-mentioned symptoms occur during sleep. Nevertheless, there are some clinical manifestations that point out the presence of long QT syndrome.

• Fainting.

• Syncope.

• Loss of consciousness.

• Lightheadedness.

• Frequent heart palpitations.

• Generalized weakness.

• Blurred vision.

• Seizures.

• Abnormal rhythm of the heart.

• Sudden death.

• Sudden emotional excitement.

• Cardiac arrest.

• A fluttering feeling in the chest.

• Shortness of breath.

• Mental stress.

What Are the Causes of Long QT Syndrome?

Long QT syndrome is caused by malfunctioning of the heart's electrical conduction system. When the heart's structure is standard, it transfers blood out to the body during each heartbeat while the four chambers of the heart contract and relax to pump the blood. All of this coordinated action is maintained by the heart's electrical conduction. After every heartbeat, the heart's electrical system recharges and prepares itself for the next heartbeat. In long QT syndrome, the heart's electrical conduction network takes longer than usual to renew itself. This delay causes the heart to stop working for a moment and can often be visualized on an electrocardiogram.

Mentioned below are some of the causes of long QT syndrome:

• Congenital long QT syndrome.

• Genetic testing.

• An underlying medical or other cardiovascular condition.

• The autosomal dominant form of Romano-Ward syndrome (autosomal dominant state).

• The autosomal recessive form of Jervell and Lange-Nielsen syndrome.

• Antibiotics therapy such as Erythromycin and Azithromycin.

• Yeast infections.

• Antifungal medications.

• Diuretics.

• Antiarrhythmic medications.

• Low potassium levels.

• Antidepressants.

• Antipsychotics.

• Metabolic imbalance.

• Antiemetics.

• Low calcium level or hypocalcemia.

• Low magnesium level or hypomagnesemia.

• COVID-19 infection.

What Increases the Risk of Long QT Syndrome?

The following factors are known to increase the chances of developing long QT syndrome:

• Female gender.

• A family history of long QT syndrome.

• Personal history of cardiac arrest.

• Profuse vomiting and diarrhea.

• Electrolyte imbalance caused by eating disorders like anorexia nervosa.

How to Diagnose Long QT Syndrome?

In order to diagnose long QT syndrome, the healthcare provider and team shall perform a vigorous physical examination as well as investigate the medical and family history. In addition, a routine checkup of the heartbeat through a stethoscope may also help in the early-stage detection of long QT syndrome.

A few of the tests that may be done to diagnose long QT syndrome are mentioned below.

• Electrocardiography.

• Ultrasound of the heart.

• Event monitor for the cardiovascular system.

• Holter monitoring.

• Genetic testing.

How to Treat Long QT Syndrome?

Early detection of long QT syndrome can avoid invasive treatment modalities. Medications are generally used to manage a case of long QT syndrome. Treatment depends on the severity of the condition; there are options for both noninvasive drug therapy as well as invasive surgical corrections. The aim of treating a case of long QT syndrome is to avoid erratic and abnormal heartbeats that are currently the leading cause of unexpected death in patients suffering from long QT syndrome.

Mentioned below are some of the ways long QT syndrome is treated:

• Beta-blockers and related medications.

• Anti-arrhythmic drugs.

• Surgical intervention such as left cardiac sympathetic denervation or LCSD

• Implantable cardioverter-defibrillator or ICD.

What Are the Complications of Long QT Syndrome?

The following are the complications associated with long QT syndrome:

• Unexplainable fainting.

• Seizures.

• Ventricular fibrillation (rapid beating of heart that causes cessation of the pumping function).

• Torsades de pointes (a fatal condition characterized by twisting of points in the ECG due to rapid beating of heart).

• Sudden death.

How Can We Prevent Long QT Syndrome?

In order to avoid long QT syndrome, lifestyle changes such as eating a heart-smart diet, being physically active, doing regular exercise, and timely intake of medications are a must.

Conclusion:

Long QT syndrome or LQTS is a congenital heart disorder characterized by an elongation of the QT interval of the heart on an electrocardiogram. It results in a part of the heart beating extremely fast called ventricular tachyarrhythmias, or a part of the heart beating extremely slow. It also causes a temporary pause in heartbeats. Over a period, all of these clinical manifestations tend to lead to syncope and cardiac arrest. If the case of long QT is left untreated, sudden death may occur. In rare situations, long QT syndrome is only diagnosed after a family member has a fatal episode of cardiac arrest. An electrocardiograph picks up the prolongation of the QT interval and thus is one of the best tools for diagnosing long QT syndrome. Post the completion of treatment and correction of heartbeats; the patient needs to make an effort to modify their habits and lifestyle.