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World Journal of Emergency Medicine ›› 2023, Vol. 14 ›› Issue (6): 454-461.doi: 10.5847/wjem.j.1920-8642.2023.104

• Original Article • Previous Articles     Next Articles

Prevalence and risk factors for acquired long QT syndrome in the emergency department: a retrospective observational study

Diogo de Almeida Fernandes1,3, Guilherme de Freitas Camões2,3(), Diana Ferreira2,3, Carolina Queijo3, Carlos Fontes-Ribeiro3,4, Lino Gonçalves1,3,4, Rui Pina2, Natália António1,3,4   

  1. 1Department of Cardiology, Coimbra Hospital and University Centre (CHUC), Coimbra 3000-075, Portugal
    2Department of Internal Medicine, Coimbra Hospital and University Centre (CHUC), Coimbra 3000-075, Portugal
    3Faculty of Medicine, University of Coimbra, Coimbra 3000-370, Portugal
    4Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra 3000-548, Portugal
  • Received:2023-06-27 Accepted:2023-08-21 Online:2023-11-10 Published:2023-11-01
  • Contact: Guilherme de Freitas Camões, Email: guilherme_camoes@hotmail.com

Abstract:

BACKGROUND: Long QT syndrome (LQTS) is a heterogeneous syndrome that may be congenital or, more frequently, acquired. The real-world prevalence of acquired LQTS (aLQTS) in the emergency department (ED) remains to be determined. The aim of this study was to determine prevalence of aLQTS and its impact on symptoms on ED admissions.

METHODS: Electrocardiograms (ECG) of 5,056 consecutively patients admitted in the ED of a tertiary hospital between January 28th and March 17th of 2020 were reviewed. All patients with aLQTS were included. Clinical data with a focus on QT prolonging drugs and clinical factors were recorded. Statistical comparison was made between the groups with and without corrected QT (QTc) interval greater than 500 ms (value that is considered severely increased).

RESULTS: A total of 383 ECGs with prolonged QTc were recognized, corresponding to a prevalence of aLQTS at admission of 7.82%. Patients with aLQTS were more commonly men (53.3%) with an age of (73.49±14.79) years old and QTc interval of (505.3±32.4) ms. Only 20.4% of these patients with aLQTS were symptomatic. No ventricular arrhythmias were recorded. Patients with QT interval greater than 500 ms were more frequently female (59.5%; P<0.001) and were more frequently on QT prolonging drugs (77.3%; P=0.025). Main contributing factor was intake of antibiotics (odds ratio [OR] 4.680) followed by female gender (OR 2.473) and intake of antipsychotics (OR 1.925).

CONCLUSION: aLQTS is particularly prevalent in the ED. Female patients on antibiotics and antipsychotics are at particularly high risk. Efforts must be made to avoid, detect and treat aLQTS as early as possible.

Key words: Long QT syndrome, Epidemiology, Drug interactions, Emergency department