Correlation between QT dispersion and burn severity

QT dispersion, defined as the maximal-minus-minimal QT interval on a 12-lead electrocardiogram, has emerged as a non-invasive measurement for quantifying the spatial inhomogeneity of ventricular repolarization under various conditions, including acute stress. Because burn injuries elicit acute stress reactions, it was hypothesized that QT dispersion increases with the severity of the burn injury. To test the hypothesis, 13 burned patients (age range of 22–76 years, nine males, ranging from 4.0 to 75.0% of total body surface area burned) in whom a measurable 12-lead electrocardiogram had been obtained within 4 h after arrival at the emergency department were identified retrospectively, and their QTc intervals, i.e. QT intervals corrected for heart rate by the standard Bazett formula, were measured. QTc dispersion (QTcd) was then calculated, and correlations were assessed with burn severity (burn index, BI; prognostic burn index, PBI). Of the 13 patients, nine patients had a prolonged QTcd (>40 ms), and linear correlation analyses showed significant positive correlations between QTcd and both BI and PBI (r=0.61 and 0.62, respectively). In conclusion, QT dispersion was greater in the burned patients, and although the pathophysiology was unclear from the present study, the findings suggested that acute stress contributed to the spatial inhomogeneity of ventricular repolarization.