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Association of cardiac baroreflex sensitivity with blood pressure transients: influence of sex and menopausal status.

Barnes JN, Matzek LJ, Charkoudian N, Joyner MJ, Curry TB, Hart EC - Front Physiol (2012)

Bottom Line: The magnitude of decrease in blood pressure (BP) during a vasoactive drug bolus may be associated with the calculated baroreflex sensitivity (BRS).However, there was no relationship between the decrease in BP and sympathetic BRS.The fact that these relationships do not exist in young women suggest that the female sex hormones influence baroreflex responses.

View Article: PubMed Central - PubMed

Affiliation: Human Integrative Physiology Laboratory, Department of Anesthesiology, Mayo Clinic, Rochester MN, USA.

ABSTRACT
The magnitude of decrease in blood pressure (BP) during a vasoactive drug bolus may be associated with the calculated baroreflex sensitivity (BRS). The purpose of the present study was to evaluate whether sympathetic and/or cardiac BRS relates to the extent of change in BP and whether this was altered by sex hormones. Fifty-one young women (27 ± 1 years), 14 older women (58 ± 1 years), and 36 young men (27 ± 1 years) were studied. Heart rate, BP, and muscle sympathetic nerve activity (MSNA) were monitored. Sympathetic BRS was analyzed using the slope of the MSNA-diastolic blood pressure (DBP) relationship and cardiac BRS was analyzed using the R-R interval-systolic blood pressure (SBP) relationship. Young women and men had similar mean arterial pressures (MAP, 91 ± 1 vs. 90 ± 1 mmHg), cardiac BRS (19 ± 1 vs. 21 ± 2 ms/mmHg), and sympathetic BRS (-6 ± 1 vs. -7 ± 1 AU/beat/mmHg), respectively. Older women had higher MAP (104 ± 4 mmHg, p < 0.05) and lower cardiac BRS (7 ± 1 ms/mmHg, p < 0.05), but similar sympathetic BRS (-8 ± 1 AU/beat/mmHg). There was no association between BP transients with either cardiac or sympathetic BRS in young women. In the older women, the drop in SBP, DBP, and MAP were associated with cardiac BRS (r = 0.60, r = 0.59, and r = 0.70, respectively; p < 0.05), but not sympathetic BRS. The decrease in SBP was positively related to cardiac BRS in young men (r = 0.41; p < 0.05). However, there was no relationship between the decrease in BP and sympathetic BRS. This indicates that older women and young men with low cardiac BRS have larger transients in BP during nitroprusside. This suggests a more prominent role for cardiac (as opposed to sympathetic) BRS in responding to acute BP changes in young men and older women. The fact that these relationships do not exist in young women suggest that the female sex hormones influence baroreflex responses.

No MeSH data available.


Baseline and nadir SBP and DBP of young women, young men, and older women. *p < 0.05 vs. young women and young men.
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Figure 2: Baseline and nadir SBP and DBP of young women, young men, and older women. *p < 0.05 vs. young women and young men.

Mentions: During the vasoactive drug bolus of nitroprusside, young women and young men had similar changes in SBP and PP while older women had significantly greater decreases in SBP and PP (Table 2). The decrease in DBP was similar between young women, young men, and older women (Table 2). This change in BP is further illustrated in Figure 2 as well. The decrease in MAP was similar between young women and older women, while young men had significantly smaller decreases in MAP. In addition, the older women had a significantly smaller increase in HR during infusion of nitroprusside compared to young women and men (Table 2).


Association of cardiac baroreflex sensitivity with blood pressure transients: influence of sex and menopausal status.

Barnes JN, Matzek LJ, Charkoudian N, Joyner MJ, Curry TB, Hart EC - Front Physiol (2012)

Baseline and nadir SBP and DBP of young women, young men, and older women. *p < 0.05 vs. young women and young men.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369369&req=5

Figure 2: Baseline and nadir SBP and DBP of young women, young men, and older women. *p < 0.05 vs. young women and young men.
Mentions: During the vasoactive drug bolus of nitroprusside, young women and young men had similar changes in SBP and PP while older women had significantly greater decreases in SBP and PP (Table 2). The decrease in DBP was similar between young women, young men, and older women (Table 2). This change in BP is further illustrated in Figure 2 as well. The decrease in MAP was similar between young women and older women, while young men had significantly smaller decreases in MAP. In addition, the older women had a significantly smaller increase in HR during infusion of nitroprusside compared to young women and men (Table 2).

Bottom Line: The magnitude of decrease in blood pressure (BP) during a vasoactive drug bolus may be associated with the calculated baroreflex sensitivity (BRS).However, there was no relationship between the decrease in BP and sympathetic BRS.The fact that these relationships do not exist in young women suggest that the female sex hormones influence baroreflex responses.

View Article: PubMed Central - PubMed

Affiliation: Human Integrative Physiology Laboratory, Department of Anesthesiology, Mayo Clinic, Rochester MN, USA.

ABSTRACT
The magnitude of decrease in blood pressure (BP) during a vasoactive drug bolus may be associated with the calculated baroreflex sensitivity (BRS). The purpose of the present study was to evaluate whether sympathetic and/or cardiac BRS relates to the extent of change in BP and whether this was altered by sex hormones. Fifty-one young women (27 ± 1 years), 14 older women (58 ± 1 years), and 36 young men (27 ± 1 years) were studied. Heart rate, BP, and muscle sympathetic nerve activity (MSNA) were monitored. Sympathetic BRS was analyzed using the slope of the MSNA-diastolic blood pressure (DBP) relationship and cardiac BRS was analyzed using the R-R interval-systolic blood pressure (SBP) relationship. Young women and men had similar mean arterial pressures (MAP, 91 ± 1 vs. 90 ± 1 mmHg), cardiac BRS (19 ± 1 vs. 21 ± 2 ms/mmHg), and sympathetic BRS (-6 ± 1 vs. -7 ± 1 AU/beat/mmHg), respectively. Older women had higher MAP (104 ± 4 mmHg, p < 0.05) and lower cardiac BRS (7 ± 1 ms/mmHg, p < 0.05), but similar sympathetic BRS (-8 ± 1 AU/beat/mmHg). There was no association between BP transients with either cardiac or sympathetic BRS in young women. In the older women, the drop in SBP, DBP, and MAP were associated with cardiac BRS (r = 0.60, r = 0.59, and r = 0.70, respectively; p < 0.05), but not sympathetic BRS. The decrease in SBP was positively related to cardiac BRS in young men (r = 0.41; p < 0.05). However, there was no relationship between the decrease in BP and sympathetic BRS. This indicates that older women and young men with low cardiac BRS have larger transients in BP during nitroprusside. This suggests a more prominent role for cardiac (as opposed to sympathetic) BRS in responding to acute BP changes in young men and older women. The fact that these relationships do not exist in young women suggest that the female sex hormones influence baroreflex responses.

No MeSH data available.