Abstract 13441: The QTc Interval Does Not Predict Mortality at the Emergency Department
Introduction: The Bazett corrected QT interval (QTcB) has been shown a predictor of outcome at the Emergency Department (ED). Since the known limitations of QTcB at higher heart rates, we investigated the use of a recently proposed QRS width dependent QTc algorithm (QTcA) at the ED.
Methods: We performed a retrospective age- and sex-matched cohort study, powered to detect mortality differences between normal and prolonged (> 450/470 ms in men and women respectively) QTcB at the ED. QTcA, Fridericia formula is used when QRS<120ms and Rautaharju when ≥120ms, was compared with QTcB. Cox regression modeling for in-hospital mortality was performed.
Results: In total 1930 patients, age 72 ± 16 y, 63% male and mean triage code 2.5 ± 0.6, were included. The mean heart rate was 81 ± 22 bpm. 18% patients had a QRS duration ≥120ms and 81% had sinus rhythm. In-hospital mortality was 4.4% and 1 y mortality was 19.5%.
Using QTcB, 50% of patients had prolonged QTc, whereas only 17.4% using QTcA. In-hospital mortality in the prolonged QTcB group was significantly higher (6.0%) compared to the control group (2.8%, p<0.001), whereas with QTcA mortality rates were similar (5.4% vs 4.2% respectively, p=0.349). Also, 1 y mortality was significantly higher in patients with prolonged QTcB (22.6% vs 16.4%, p=0.001), while prolonged QTcA showed only a trend to worse survival (22.9% vs 18.8%, p=0.080).
In univariate Cox regression for in-hospital mortality, QTcB was a predictor of mortality (HR 1.004, 95%CI 1.000 - 1.009), while QTcA was not (HR 1.001, 95%CI 0.995 - 1.008).
After multivariate analysis QTcB did not remain as independent predictor of mortality. Independent predictors were heart rate (HR 1.02, 95%CI 1.01-1.03), history of cardiovascular disease (HR 1.66, 95%CI 1.00-2.76), witnessed arrhythmia requiring CPR (HR 3.79, 95%CI 1.66-8.67), neurological events (CVA, epileptic insult, IC bleeding or hematoma) (HR 3.51, 95%CI 1.91-6.43), age-adjusted Charlson Comorbodity Index (HR 1.18, 95%CI 1.10-1.27), lower eGFR (HR 0.99, 95%CI 0.98-1.00) and higher leukocyte count (HR 1.02, 95%CI 1.01-1.03).
Conclusion: Several easily obtainable parameters and risk factors can be useful for risk stratification at the ED, however adequate corrected QT was not an independent predictor of mortality.
Author Disclosures: B. Vandenberk: None. C. Siau: None. E. Vandael: Research Grant; Modest; funding of the Belgian government agency for Innovation by Science and Technology (IWT). V. Foulon: None. S. Verelst: None. R. Willems: Other; Modest; The university of Leuven receives unconditional grant support from Biotronik, Boston Scientific and Medtronic Belgium. RW is funded as a clincal researcher by the FWO..
- © 2016 by American Heart Association, Inc.