Cardiovascular responses of perimenopausal women to hormonal replacement therapy

OBJECTIVE: This study was undertake to test the hypothesis that hormone rep lacement therapy alters cardiovascular function during the first several mo nths 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 electr ocardiography, automated blood pressure measurement (Dynamap; Critikon Comp any LLC, Tampa, Fla), echocardiography, and plethysmography. RESULTS: Hormone replacement therapy did not alter heart rate, blood pressu re, or venous capacitance. End-diastolic volume and stroke volume were unch anged after 1 week of hormone replacement therapy but rose thereafter. Afte r 5 weeks of hormone replacement end-diastolic volume and stroke volume wer e 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 resul t cardiac output rose progressively to a level 1.1 +/- 0.3 L/min (18%) grea ter than pretreatment values and systemic vascular resistance fell 15%. The se changes were associated with a 3-fold increase in serum estradiol levels . CONCLUSION: The studied regimen of hormone replacement therapy produces pro gressive cardiac remodeling and peripheral vasodilatation during the first 2 months of therapy.