Relation of QRS Voltage and Prolonged QTc Interval to One-Year Mortality

The association between QRS voltage and QTc interval prolongation with mortality for up to 1 year after recording an ECG on patients attending emergency departments (EDs) was examined in a retrospective register-based observational study on 37,473 patients attending 2 Danish EDs. Of 37,473 patients who had an ECG performed on their first ED presentation 2,164 (5.8%) died within 30 days of presentation and 6,395 (17.1%) died within a year. Compared with survivors, patients who died had significantly longer QRS intervals and lower QRS voltages. A combined lead I and II QRS voltage <=1.4 mV was consistently associated with approximately twice the risk of mortality for up to at least 1 year after the ECG recording and this risk was not influenced by the length of the QTc interval. The increased mortality risk of a low QRS voltage remained even after adjustment for age, gender, Charlson co-morbidity index, and abnormal sodium and urea levels. In conclusion, low QRS voltage is a simple measurement that could potentially be used as an objective prognostic marker.