Abstract 14277: Institution Wide QT Alert System Identifies Patients with High Risk of Mortality

Abstract

Objectives QT prolongation is an independent risk factor for cardiovascular mortality. Because QT prolonging medications and conditions cross all disciplines of medicine, an institution wide computer-based clinical decision support system was designed and implemented at the Mayo Clinic, Rochester, MN. This QT alert system automatically screens all ECGs and alerts the providers if the QTc is > 500ms. Here, we analyzed the frequency of QTc alerts and outcome of patients with an alerted QTc.

Methods During 7 months, 86,107 ECGs were performed in 53,286 patients. Alerts were sent for 1145 patients (2%). All alerted ECGs were reviewed manually. QT-influencing clinical diagnoses, laboratory abnormalities, and medications were collected from the electronic medical records and summarized in a Pro-QTc score with each QT prolonging factor receiving one point. Survival was compared to 52,141 Mayo Clinic patients with QTc < 500 ms during the same time period.

Results Of the 1145 patients with a QTc alert, 470 (41%) patients exhibited a QTc ≥ 500 ms and QRS ≤ 120 ms (55±24 years, 56% female). Mean Pro-QTc score was 2.5 (range 0-8). All-cause mortality during 224±173 days of follow-up was ~20% (87/470) which was increased compared to 5% for patients with QTc < 500 ms (2793/52141, log rank p<0.001). Mortality was increased markedly in patients with a Pro-QTc score ≥ 4 (Figure). The Pro-QTc score was an age and sex independent predictor of mortality (HR 1.20, 95%CI 1.07-1.35, p<0.01).

Conclusions This novel institution-wide QT-alert system is able to identify patients with high risk of mortality. Patients with QTc ≥ 500 ms had higher mortality than those with QTc < 500 ms. The Pro-QTc score was an independent predictor of mortality. Considering that many components of the Pro-QTc score are modifiable, a QTc alert system which increases physicians’ awareness of QT-predicted mortality could help to not only identify an at-risk patient but to also intervene by lowering their Pro-QTc score.