The effects of acute β‐Adrenergic blockade on aortic wave reflection in post‐menopausal women

Abstract

Acute ß‐adrenergic blockade (BB) increases aortic wave reflection in young women, however, it is unknown if this effect extends to post‐menopausal women. Thus, we examined systemic BB on aortic wave reflection in 14 post‐menopausal women (58 ± 2 yr). Non‐invasive aortic pressure waveforms were synthesized from high‐fidelity radial pressure waveforms obtained from applanation tonometry before and during systemic BB (0.25mg/kg bolus, with 0.004 mg/kg/min continuous infusion of propranolol). Aortic blood pressure, augmentation index (AIx), AIx adjusted for heart rate (AIx@75), aortic augmented pressure (AP), and wasted left ventricular energy (Ew) were calculated from the aortic pressure waveform. Heart rate (60 ± 2 vs. 51 ± 2 bpm) and mean arterial pressure (95 ± 3 vs. 91 ± 3 mmHg) were reduced with BB (P < 0.05 for both). AIx increased during BB (32 ± 2 vs. 35 ± 2%, P < 0.01), however, AIx@75 was unchanged (25 ± 2 vs. 24 ± 2%, ns). Additionally, AP (20 ± 2 vs. 20 ± 2 mmHg, ns) and Ew (4313 ± 538 vs. 4277 ± 537 dyne*cm2/sec, ns) remained unchanged during BB. When compared to our previously published study in young women, indices of aortic wave reflection were significantly less affected in post‐menopausal women in response to acute systemic BB. Taken together, our data suggest that the negative effects (i.e. increased aortic wave reflection) of non‐selective BB are less pronounced in post‐menopausal women.