QT prolongation predicts short-term mortality

Charlotte Gibbs has looked at predictors of short- and long-term mortality in a cohort of patients presenting at a local hospital with prolonged QT intervals.


  1. A prolonged corrected QT interval of at least 500 ms is associated with high short-term mortality in hospitalized patients.
  2. Long-term prognosis is related to comorbidities such as heart failure and stroke rather than QT interval length.
  3. Pathological genes for long QT syndrome are found in a substantial amount of patients with QT prolongation.


Thesis: Prevalence of congenital long QT syndrome and acquired QT prolongation in a hospital cohort
Candidate: Charlotte Gibbs
Time: May 27, 2020 at 13:15
Place: Online-based solution, due to the covid-19 situation
Link to university website


Gibbs’ studies include restrospective electrocardiogram data from up to 1531 patients with a corrected QT interval length of minimum 500 ms. All patients were treated at Telemark Hospital Trust between 2004 and 2014.

(1) QT prolongation was only registered in 12% of the medical records. 50% of the patients died during a mean follow-up period of 952 days. Patients hospitalized due to aborted cardiac arrest, stroke or head trauma had more than doubled risk. Heart failure and male gender were also independent predictors of long-term mortality, in addition to electrolyte disturbances, age and medication with known and possible risk for torsades des points.

Gibbs and her coworkers also constructed a corrected QT mortality score based on these findings. Increasing score was associated with increased mortality.

(3) Corrected QT intervals of at least 500 ms were independently associated with 30-day mortality. The risk was almost doubled compared to age-, sex-, comorbidity-, and diagnosis-matched patients without QT prolongation. During the following three years, there was no difference in mortality between the groups.

(2) 6.5% of the patients had a genetic diagnosis of long QT syndrome. The estimated population prevalence is only 1:2000. Thus, the prevalence were 130-fold higher in the patients.


(1) Gibbs, C., Thalamus, J., Heldal, K., Holla, Ø. L., Haugaa, K. H., & Hysing, J. (2018). Predictors of mortality in high-risk patients with QT prolongation in a community hospitalEP Europace20(FI1), f99-f107

(2) Gibbs, C., Thalamus, J., Tveten, K., Busk, Ø. L., Hysing, J., Haugaa, K. H., & Holla, Ø. L. (2018). Genetic and phenotypic characterization of community hospital patients with QT prolongationJournal of the American Heart Association7(16), e009706.

(3) Gibbs, C., Thalamus, J., Kristoffersen, D. T., Svendsen, M. V., Holla, Ø. L., Heldal, K., Haugaa, K. H., & Hysing, J. (2019). QT prolongation predicts short-term mortality independent of comorbidityEP Europace21(8), 1254-1260.

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