Prevalence and Prognostic Significance of Short QT Interval in a Middle-Aged Finnish Population

Abstract

Background— Short-QT syndrome is an inherited disorder characterized by a short QT interval and an increased risk of sudden cardiac death. The clinical significance of a short QT interval observed in a randomly recorded ECG is not known. Therefore, we assessed the prevalence and prognostic significance of a short QT interval in a general population. Methods and Results— QT intervals were measured from the 12-lead ECGs of 10 822 randomly selected middle-aged subjects (5658 males, mean age 44±8.4 years) enrolled in a population study and followed up for 29±10 years. The end points were all-cause and cardiovascular mortality. In addition to Bazett’s method (corrected QT interval, or QTc), the Fridericia (QTfc) and nomogram (QTnc) methods were used to correct the QT interval for heart rate. The cutoff values for short QT intervals were defined as 320 ms (very short) and 340 ms (short). The prevalence of QT interval Conclusion— A short QT interval does not appear to indicate an increased risk for all-cause or cardiovascular mortality in middle-aged nonreferral, community-based individuals.