title: Maximal ascending and descending slopes of the T wave in men and women.
abstract: To investigate possible sex differences in the dynamics of T wave generation, the maximum instantaneous slope of the ascending and descending limbs of the T wave (max dV/dt and min dV/dt, respectively), were calculated. These rate of repolarization parameters, as well as more traditional repolarization duration parameters (QT, JT, Q to T wave peak [QTm] and J to T wave peak [JTm]), were measured by computer using digitized electrocardiograms (ECGs) from the V5 lead in 562 normal subjects (443 men and 119 women; mean age 37 years), whose heart rates (HRs) were confined to one of three narrow ranges, namely 60 +/- 1, 70 +/- 1, or 80 +/- 1 beats/min. In both men and women, for each HR range absolute values of min dV/dt exceeded those of max dV/dt (P < .0001). However, absolute values of both max dV/dt and min dV/dt were consistently greater in men than in women for each HR range (P < .0001 at HR 60 +/- 1; P < .02 at HR 70 +/- 1, or 80 +/- 1). By using correlation analysis, max dV/dt and min dV/dt were shown to be independent of the repolarization duration variables (r < .30). Thus, whereas in both men and women the descending limb of the T wave is steeper than the ascending limb, the maximum slope of each limb of the T wave is steeper in men than in women. These findings add to a growing body of data indicating fundamental sex differences in the physiology of cardiac repolarization and propensity to torsade de pointes.
authors.affiliation: Arrhythmia Center, Sinai Hospital Detroit, Michigan 48235, USA.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Elko
authors.forename: B S
authors.initials: BS
authors.lastname: Fromm
authors.forename: J J
authors.initials: JJ
authors.lastname: Baga
authors.forename: L A
authors.initials: LA
authors.lastname: Pires
authors.forename: C D
authors.initials: CD
authors.lastname: Schuger
authors.forename: R T
authors.initials: RT
authors.lastname: Steinman
authors.forename: M H
authors.initials: MH
authors.lastname: Lehmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012727:Sex Characteristics; D012815:Signal Processing, Computer-Assisted