Estrogen variation and resting left ventricular structure and function in young healthy females.

Abstract

A potential confounding factor in the interpretation of left ventricular (LV) structural and functional data in female subjects could be menstrual phase or contraceptive use upon assessment. To date no study has addressed this issue. Seventeen eumenorrheic (EU; mean +/- SD age = 21 +/- 3 yr) and 14 combined-oral contraceptive pill-using (COC: mean +/- SD age = 21 +/- 3 yr) females volunteered to participate. The EU had stable menstrual cycles and the COC had all been using the same pill preparation for a minimum of 6 months. Echocardiographic examinations occurred during the mid-follicular phase and mid-luteal phases in the EU and during mid-consumption and mid-end of withdrawal in the COC. LV structure and function were assessed using M-mode and pulsed-wave Doppler echocardiography. Data were compared via Student t-tests and limits of agreement (LoA) were calculated. Structure and function did not significantly differ between phases of the menstrual cycle or between consumption and withdrawal of oral contraception (P > 0.05). However, there was considerable variance in the LoA between variables. Smaller LoA were reported for those variables directly measured from echocardiograms compared with those from derived data. For example, in a measured variable such as LV internal dimension in diastole, the LoA data represented a variation of +/- 0.4 mm (+/- 1%) between phases. Conversely, data for LV mass, a derived variable, reported LoA values of +/- 15 g (10%) between phases. The LoA were consistent between EU and COC. Variation in both measured and derived variables were within, or close to, accepted limits of measurement or biological error. It would seem that in studies assessing LV structure and function in women the influence of menstrual phase or oral contraceptive use is of minor significance.