Authors: Paul Shiu, Teri M. Kozik.
Background: Long QT syndrome (LQTS) is the prolongation of the QT interval, a surrogate measure of the ventricular action potential on the electrocardiogram (ECG). LQTS may lead to tachydysrhythmias resulting in death. Studies have shown mortality may be as high as 20% within the first year among untreated symptomatic patients. Symptoms include syncope, seizures or palpitations; however, LQTS may be asymptomatic. It is most often associated with the administration of QT-prolonging medications, especially in intensive care unit patients. Few studies have examined the prevalence among those discharged from the emergency department (ED).
Aim: The aim of this study was to observe the prevalence of LQTS among ED patients discharged from a community hospital.
Methods: A retrospective review of sequential ECGs from an electronic health record during the study period was completed. Variables examined were sex, age, heart rate, average QRS interval, and QTc interval according to the Bazett’s formula. Patients were excluded if they had a wide QRS complex such as a bundle branch block or paced rhythm, atrial flutter or fibrillation, or supraventricular tachycardia.
Results: Of the 1693 patients examined, 939 patients qualified and 151 (16%) had a prolonged QTc interval.
Conclusion: With nearly two in ten patients discharged with LQTS, judicious use of QT-prolonged medications is advised. More long-term follow-up studies of these patients may also yield interesting insights into the prevalence of cardiac morbidities associated with LQTS.
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