To recognize and validate the predictor of risk factors for ICU patients with QTc intervals ≥500 ms.
We retrospectively reviewed 160 ICU patients with their medical electronic records including all demographic data, diagnosis measurements, ECGs and medication from March 1, 2018 to December 1, 2018. All information of patients’ baseline, comorbidities, electrolytes and Long QT syndrome (LQTS)-inducing medications of patients with QT interval corrected (QTc) ≥ 500 ms (n = 80) and <500 ms (n = 80) were collected and analyzed using univariate and multivariate analyses to find predictors.
Comparing to patients with QTc < 500 ms, patients with QTc ≥ 500 ms had increased SOFA (P = 0.010) and APACHE II scores (P = 0.002), longer lengths of ICU stays (P < 0.001), greater incidence of congestive heart failure (P = 0.005) and more preset risk factors (P < 0.001). The frequency of administration of mosapride (P = 0.015), amiodarone (P = 0.027) and number of combined LQTS-inducing medications (P = 0.012) were greater in patients with QTc ≥ 500 ms than in those with QTc < 500 ms. But after multivariate analysis, we found that risk factors related to a QTc ≥ 500 ms were only congestive heart failure (OR: 5.28), number of combined LQTS-inducing medications (OR: 1.60) and APACHE II score (OR: 1.08).
For critically ill patients, congestive heart failure, number of combined LQTS-inducing medications and APACHE II score are proved as risk factors associated with QTc > 500 ms.

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