Sex Differences in the Morphology of RR-Matched T-waves

Evidence of sex-related differences in cardiac risk is emerging, but whether these reflect sex-related differences in ventricular electrophysiology remains unclear. Our aim was to quantify T-wave morphological differences between men and women across different leads and RR interval values. We analysed 12-lead ECG recordings from 23,962 participants in the UK Biobank without known cardiovascular disease, and subsequently clustered them into bins of RR interval. In each cluster, we derived a lead and sex-specific mean warped T-wave (MWT). Then, we quantified differences between MWT in men and women in time and amplitude using linear,
$d_{w}$
and
$d_{a}$
, and non-linear markers,
$d_{w}^{NL}$
and
$d_{a}^{NL}$
. Leads V3 and aVR showed the lowest differences between men and women (median
$d_{w}, d_{w}^{NL}, d_{a}$
and
$d_{a}^{NL}$
of 1.12 ms, 0.69 ms, 3.29 and 1.20, respectively), while V1 showed the largest (5.69 ms, 4.50 ms, 208.94 and 199.45, respectively). Sex-related differences in MWT increased with the RR interval
$(d_{w}, d_{w}^{NL}, d_{a}$
and
$d_{a}^{NL}$
ranging 1.44 - 5.89 ms, 1.23 - 3.97 ms, 8.58 - 28.38 and 1.53 - 4.41, respectively). These values compare to those found for morphological T-wave variations due to large changes in heart rate (5.66 ms, 2.35 ms, 57.61 and 9.51, respectively). These results indicate sex and lead should be considered when using T-wave morphologies for cardiovascular risk prediction.