Cardiovascular responses of perimenopausal women to hormonal replacement therapy

Objective: This study was undertake to test the hypothesis that hormone replacement therapy alters cardiovascular function during the first several months of therapy. Study Design: Serial estimates of blood pressure, heart rate, stroke volume, and venous capacitance were obtained before and at 1, 5, 9, and 21 weeks after the beginning of hormone replacement therapy with daily estradiol and intermittent norethindrone. Measurements were performed by means of electrocardiography, automated blood pressure measurement (Dynamap; Critikon Company LLC, Tampa, Fla), echocardiography, and plethysmography. Results: Hormone replacement therapy did not alter heart rate, blood pressure, or venous capacitance. End-diastolic volume and stroke volume were unchanged after 1 week of hormone replacement therapy but rose thereafter. After 5 weeks of hormone replacement end-diastolic volume and stroke volume were increased by 13 ± 5 mL and 9 ± 2 mL, respectively, and after 9 weeks the increases totaled 23 ± 5 mL and 17 ± 3 mL, respectively. As a result cardiac output rose progressively to a level 1.1 ± 0.3 L/min (18%) greater than pretreatment values and systemic vascular resistance fell 15%. These changes were associated with a 3-fold increase in serum estradiol levels. Conclusion: The studied regimen of hormone replacement therapy produces progressive cardiac remodeling and peripheral vasodilatation during the first 2 months of therapy. (Am J Obstet Gynecol 2000;182:17-22.)