A prolonged QTc‐interval at the emergency department: Should we always be prepared for the worst?

摘要

Abstract Introduction QTc‐interval prolongation is associated with ventricular arrhythmias and mortality in a general population. Bazett's correction formula (QTcB) is routinely used despite its overcorrection at high heart rates. Recently, we proposed a patient‐specific QT correcting algorithm (QTcA) resulting in improved rate correction and predictive value in a general population. We hypothesize risk stratification at the Emergency Department (ED) could be improved using QTcA. Methods and Results A retrospective case‐control study including a randomized age‐ and sex‐matched control population was performed at a tertiary care ED. A total of 1930 patients were included in the analysis (63.0% males, age 71.5?±?15.6?years). Patient characteristics, history, and test results at the time of the electrocardiogram were collected. QTc was dichotomized as prolonged (450?millisecond for men, 470?millisecond for women) or severely prolonged (500?millisecond). Implementation of QTcA would reduce the number of patients considered to have a prolonged QTc by 65.2%, for severely prolonged QTc 79.6%. Multivariate regression was performed for in‐hospital mortality, cardiovascular endpoints, and hospital admission. Neither a prolonged QTcB (HR 1.04; 95% CI, 0.64‐1.69) nor QTcA (HR 0.76; 95% CI, 0.42‐1.38) was an independent predictor of in‐hospital mortality. A severely prolonged QTcA (OR, 2.54; 95% CI, 1.04‐6.23) was an independent predictor of cardiovascular events. Both a prolonged QTcA (OR, 1.52; 95% CI, 1.06‐2.18) and a prolonged QTcB (OR, 1.37; 95% CI, 1.05‐1.79) were associated with higher hospitalization rates. Conclusions QTcA reduced the number of patients considered at risk. Neither QTcB nor QTcA were predictors of in‐hospital mortality. A severely prolonged QTcA was associated with cardiovascular events.