What is the morbidity and mortality associated with long QT syndrome (LQTS)?

Updated: Nov 29, 2017
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Mikhael F El-Chami, MD  more...
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Mortality, morbidity, and responses to pharmacologic treatment differ in the various types of LQTS. This issue is under investigation.

LQTS may result in syncope and lead to sudden cardiac death, which usually occurs in otherwise healthy young individuals. LQTS is thought to cause about 4,000 deaths in the United States each year. The cumulative mortality rate reaches approximately 6% by the age of 40 years.

Although sudden death usually occurs in symptomatic patients, it can also materialize with the first episode of syncope in about 30% of the patients. This finding emphasizes the importance of diagnosing LQTS in the presymptomatic period. Depending on the type of mutation present, sudden cardiac death may take place during exercise, emotional stress, at rest, or at sleep. LQT4 is associated with paroxysmal atrial fibrillation.

Studies have shown an improved response to pharmacologic treatment with a lowered rate of sudden cardiac death in LQT1 and LQT2, compared with LQT3.

Neurologic deficits after aborted cardiac arrest may complicate the clinical course of patients with LQTS after successful resuscitation.

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