Beta-adrenergic blocking treatment and 24-hour baroreflex sensitivity in essential hypertensive patients.
We dynamically evaluated the effects of beta-blockade on the sensitivity of arterial baroreflex control of heart rate in 10 mild or moderate essential hypertensive patients in whom blood pressure was recorded intra-arterially for 24 hours in ambulatory conditions. Twenty-four-hour baroreflex sensitivity was assessed by both (1) a time-domain approach based on the calculation of the slope of the regression line between linearly related progressive increases in systolic blood pressure and pulse interval (+PI/+SBP sequences) and decreases in systolic blood pressure and pulse interval (-PI/-SBP sequences) and (2) a frequency-domain approach, ie, the ratio between the spectral powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha coefficient). Data were obtained before and after 1 month of administration of either acebutolol (n = 5) or labetalol (n = 5). Before treatment, the 24-hour average slopes of the +PI/+SBP and -PI/-SBP sequences were 4.36 +/- 0.32 and 4.05 +/- 0.27 ms/mm Hg, respectively, while the alpha coefficient was 7.78 +/- 0.7 ms/mm Hg. After beta-blockade, these values were increased by 25.3 +/- 6.8%, 25.0 +/- 8.0%, and 32.1 +/- 9.3%, respectively (P < .01 for all values). Thus, beta-blockers potentiate baroreflex sensitivity in daily life. Time-domain and frequency-domain methods yielded superimposable results in dynamically evaluating 24-hour baroreflex sensitivity and its changes after beta-blockade.
Parati
G
G
Clinica Medica and Medicina Interna I, Università di Milano, Italy.
Mutti
E
E
Frattola
A
A
Castiglioni
P
P
di Rienzo
M
M
Mancia
G
G
D000070:Acebutolol / Q000627:therapeutic use; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007741:Labetalol / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011674:Pulse
D000319:Adrenergic beta-Antagonists; D000070:Acebutolol; D007741:Labetalol