Determination of vagal baroreflex sensitivity in normal subjects.
BACKGROUND
The Valsalva maneuver (VM) is used widely to quantify the sensitivity of the vagal baroreflex loop (vagal baroreflex sensitivity, BRS_v), but most studies have focused on the heart rate (HR) response to blood pressure (BP) decrement (BRS_v↓), even though the subsequent response to an increment in BP after the VM (BRS_v↑) is important and different.


METHODS
We evaluated recordings of HR and BP in 187 normal subjects during the VM and determined both BRS_v↑, as determined by relating HR to the BP increase after phase III and BRS_v↓.


RESULTS
BRS_v↑ was related inversely to age. In addition, BRS_v↓, age, and magnitude of phase IV were independent predictors of BRS_v↑ in a multivariate model, accounting for 47% of the variance of BRS_v↑.


CONCLUSIONS
The results indicate that both BRS_v↑ and BRS_v↓ become blunted with increasing age and that these indices relate to each other.
Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905, USA; Hidaka kai, Hidaka Hospital, Takasaki, Gunma, Japan.
Naoki
N
Wada
Wolfgang
W
Singer
Tonette L
TL
Gehrking
David M
DM
Sletten
James D
JD
Schmelzer
Mikihiro
M
Kihara
Phillip A
PA
Low
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013223:Statistics as Topic; D014630:Vagus Nerve / Q000502:physiology*; D014636:Valsalva Maneuver / Q000502:physiology*; D055815:Young Adult
Valsalva maneuver; age; baroreflex sensitivity; blood pressure; normal subject