Gender Differences in Ventricular Repolarization:

The incidence of sudden death is lower in women than in men, although women have a longer QT interval and are more prone to develop torsades de points than men. It has been recently proposed that the time interval between the apex and end of the T wave (Ta-e) represents the transmural dispersion of ventricular repolarization. Gender and age differences in Ta-e interval have not been fully assessed previously. Standard surface 12-lead ECGs recorded in 760 healthy subjects (382 women, 0-88 years of age) were studied. The intervals from j-point to the apex of the T wave (JaT) and to the end of the T wave (JeT) were measured in lead V5 in each ECG and corrected by preceding RR intervals using the formula of Bazett (JaTc and JeTc). The Ta-e and Ta-e/JeT ratio were also evaluated. Both JaTc and JeTc intervals were significantly longer in women aged > 20 years than in men of the same age (P < 0.0001). The difference was due to shortening of these intervals after puberty in men. However, the Ta-e interval was significantly shorter in women than in men (P < 0.05) and subsequently the Ta-e/JeT ratio was significantly smaller in women than in men (P < 0.0001). The results showed gender differences in the Ta-e interval and JaTc and JeTc intervals in healthy adults, and suggest that the small transmural dispersion of repolarization in women, in spite of the long JaTc and JeTc intervals, might be a beneficial antiarrhythmic property.