What is LQTS?

Long QT Syndrome (LQTS) is a condition affecting the electrical system of the heart. In a healthy heart, the "QT interval" — the time it takes the heart to recharge electrically after each beat — falls within a normal range. In LQTS, this interval is prolonged, which can disrupt the normal rhythm of the heart and potentially trigger fast, dangerous arrhythmias.

LQTS can be congenital (present from birth, due to genetic mutations affecting heart ion channels) or acquired (caused by medications, electrolyte imbalances, or other conditions). Congenital LQTS is estimated to affect approximately 1 in 2,000 people in the United States.

LQTS is one of the leading causes of sudden cardiac death in people under 20 years of age. However, with appropriate diagnosis and management, most children with LQTS can live healthy lives.

Common Symptoms

• Syncope (fainting), particularly during exercise, strong emotion, or being startled
• Palpitations — a fluttering or pounding sensation in the chest
• Seizures (which may be misidentified as a neurological condition)
• Sudden cardiac arrest in severe cases
• No symptoms at all in some individuals — LQTS can be "silent" until triggered

Who Can Be Affected?

• LQTS can affect individuals of all ages, including infants, children, and adolescents
• Congenital LQTS is inherited — a parent with LQTS has approximately a 50% chance of passing the gene variant to each child
• Children who are deaf at birth may have a specific form of LQTS (Jervell and Lange-Nielsen syndrome)
• Acquired LQTS can develop in anyone due to certain medications, low electrolyte levels, or underlying health conditions

What Daily Life Can Look Like

• Regular follow-up appointments with a pediatric cardiologist
• Careful review of any new medications — many common drugs can prolong the QT interval and require avoidance
• Activity modifications — some children may need to limit competitive sports, though this is determined individually by their cardiologist
• An emergency action plan, including whether a family member should learn CPR
• Possible medical alert bracelet or identification to inform emergency responders
• For some children, carrying an AED (automated external defibrillator) or having one accessible at school may be recommended

Common Misconceptions

Diagnosis & Treatment Overview

LQTS is typically identified through an electrocardiogram (ECG/EKG), which measures the heart's electrical activity and can detect a prolonged QT interval. Genetic testing may identify the specific gene variant involved, which helps guide treatment decisions.

Family screening is important — because LQTS is often inherited, first-degree relatives of a diagnosed individual are typically recommended for evaluation.

Treatment may include:

• Beta-blocker medications, which are the most common first-line treatment for congenital LQTS
• Avoidance of QT-prolonging medications — a comprehensive list is maintained by medical organizations
• Implantable cardioverter-defibrillator (ICD) for higher-risk individuals
• Left cardiac sympathetic denervation (LCSD), a surgical option for some patients
• Lifestyle modifications as recommended by the treating cardiologist

Care is typically led by a pediatric electrophysiologist or pediatric cardiologist with experience in inherited arrhythmia syndromes.

How to Support Someone

• Learn basic CPR — for children with LQTS, having CPR-trained people nearby can be life-saving
• Understand which medications the child must avoid and communicate this to school nurses and coaches
• Support the child's adherence to their medication schedule
• Work with the school to create an appropriate emergency action plan
• Be aware of the child's individual activity guidelines — don't assume restrictions; ask their cardiologist
• Recognize that living with a heart condition can be emotionally challenging for a child and their family

Trusted Resources

The following organizations provide additional information. Heart & Hope Project is not affiliated with these organizations.