Electrocardiogram pattern in hypercholesterolemic women: the influence of hormone replacement therapy

The aim of this study was to delineate electrocardiogram (ECG) patterns in postmenopausal women with hypercholesterolemia and to assess the possible influence of female sex hormones.

A total of 72 postmenopausal women with moderately elevated total cholesterol levels constituted the case group, of which 48 came from a clinical trial and 24 from a cohort study. Some 236 women aged 50-59 years with normal levels of cholesterol were participants in the same cohort study in the local area. These 236 women had been subdivided into three groups: premenopausal, postmenopausal and postmenopausal with hormone replacement therapy (HRT). Of the 48 women in the clinical study group, 12 patients showed pathological ECG changes. Six of these patients were treated with HRT for 2 years (transdermal estradiol 50 micrograms/day and a daily dose of 5 mg medroxyprogesterone acetate, MPA) and the rest were non-users of HRT.

In the women with hypercholesterolemia, 16 of 72 patients (22%) showed ischemic ECG changes, compared to nine of 88 (10%) with normal cholesterol levels (p = 0.04). We found no significant difference in the prevalence of ECG changes between postmenopausal women with and without HRT in the groups with normal levels of cholesterol. In the hormone treatment group, four of six patients showed an improvement in ECG pattern, in contrast to two of six non-users of HRT.

This preliminary study revealed a higher prevalence of pathological ECG changes in postmenopausal women who had hypercholesterolemia than in normocholesterolemic women. These findings support the idea that hyperlipidemia contributes to the overall increase in cardiovascular disease, as this is also associated with ECG changes. Transdermal estradiol combined with MPA has a beneficial effect in reversing the process of atherosclerosis, as well as improving the ECG pattern. The prevalence of pathological ECG patterns was similar for HRT users and non-users. This outcome may be affected by several factors. Hence, further research is warranted.