Long QT syndrome (LQTS) is a potentially serious heart rhythm disorder that affects the heart’s electrical system, causing rapid and irregular heartbeats. These abnormal rhythms, known as arrhythmias, can sometimes be life-threatening. The condition interferes with the electrical signals that control each heartbeat, leading to dangerous disturbances in heart rhythm, especially during stress, exercise, or sleep.
On an electrocardiogram (ECG), doctors measure the heart’s electrical activity using labeled waves. The QT interval—the time between the start of the Q wave and the end of the T wave—represents the period during which the heart’s lower chambers recharge after each beat. When this interval is longer than normal, it means the heart takes too long to reset between beats, increasing the risk of sudden, abnormal rhythms.
There are two main types of LQTS. Congenital LQTS is inherited and caused by mutations in genes that regulate heart ion channels, which control the flow of charged particles in and out of heart cells. Acquired LQTS, on the other hand, develops later in life and is often linked to certain medications, low blood levels of potassium or calcium, or underlying medical conditions such as heart failure. Drugs that may trigger acquired LQTS include some antiarrhythmics, antibiotics, and antipsychotics.
Symptoms can vary but often include fainting, lightheadedness, blurred vision, weakness, and palpitations—a feeling of the heart pounding or fluttering. In severe cases, LQTS can cause seizures or sudden cardiac arrest, where the heart stops beating effectively. Without immediate treatment, this can lead to sudden death. Babies with congenital LQTS may show symptoms within weeks of birth, though others may not experience problems until adolescence or adulthood.
Treatment focuses on preventing dangerous heart rhythms. Doctors may recommend lifestyle changes, such as avoiding intense exercise or stress triggers, and medications like beta-blockers to steady the heart’s rhythm. In some cases, an implantable cardioverter-defibrillator (ICD) or surgery may be necessary.
With proper diagnosis and management, most people with long QT syndrome can lead safe, active lives. Early detection and awareness remain crucial in preventing its potentially fatal consequences.What You Need to Know About Long QT Syndrome
