Effects of aging and gender on QT dispersion in an overtly healthy population

The objective of this study was to measure the normal variation of QT dispe rsion (QT(d)) with respect to age and gen der. The QT interval is a measure of the duration of ventricular depolarization and repolarization, while th e QT(d) is a measure of the variability of the ventricular recovery time. T he QT(d) has been suggested as a means of identifying those patients at ris k for sustained ventricular tachyarrythmias and sudden cardiac death (SCD). A total of 250 patients (120 women, 130 men; age range 20-86 years) were r ecruited for this study. The QT intervals were measured in each of the 12 s tandard leads of the electrocardiogram. Data are presented as mean (mu) +/- SD. The QT(d) did not vary significantly within the same gender. A signifi cant difference (P < 0.001) was noted in QT(d) between men (age [mu] = 53.3 +/- 15.6 years, QT(d) = 0.044 +/- 0.019 s) and women (age [mu] = 52.1 +/- 15.1 years, QT(d) = 0.034 +/- 0.015 s). Overall, men had a greater QT(d), w hile women had a longer QT. In conclusion, we found that men had a longer Q T(d), which may explain the increased risk of SCD. However, women have a lo nger QT interval with a smaller QT(d). A longer QT(min), as opposed to a lo nger QT(max), is responsible for the shorter QT(d) in women. This longer QT (min) in women may predispose to an increased risk of drug induced torsades de pointes.