Value of history-taking in syncope patients: in whom to suspect long QT syndrome?

Long QT syndrome (LQTS), a potentially fatal disorder, has to be distinguished from non-fatal conditions. Our aim was to investigate whether history-taking can be used in identifying patients likely to have LQTS.

We compared the characteristics of a group of LQTS patients with syncope patients presenting at the emergency department (ED) and vasovagal patients younger than 40 years of age. Thirty-two LQTS patients were included. We included 113 patients at the ED and 69 vasovagal patients. Family history of syncope, sudden cardiac death, or cardiovascular disease was found more often in LQTS patients. Palpitations were the only symptom reported more often in this group. Syncope while supine, during emotional stress and associated with exercise was also more common among LQTS. Standing as a trigger was found more often in ED and vasovagal patients.

We conclude that a family history for syncope and sudden cardiac death, palpitations as a symptom, supine syncope, syncope associated with exercise, and emotional stress place patients at higher risk for LQTS. These findings should alert physicians to the potentially life-threatening illness of LQTS, and act accordingly by obtaining an electrocardiogram and paying specific attention to the QT interval.