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Age, hypertension, and cardiac responses to β‐agonist in humans
Author(s) -
White Michel,
Fourney Anne,
Leenen Frans H. H.
Publication year - 1998
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1016/s0009-9236(98)90090-x
Subject(s) - medicine , chronotropic , heart rate , isoprenaline , agonist , blockade , blood pressure , cardiology , essential hypertension , baroreflex , receptor , stimulation
Objectives To evaluate the effects of hypertension on heart rate and left ventricular responses to β‐agonist in young and older subjects, as well as the modulating effect of the arterial baroreflex on these responses. Methods Isoproterenol (INN, isoprenaline) alone was infused in 14 young normotensive subjects (mean age, 30 ± 2 years), 18 older normotensive subjects (mean age, 60 ± 2 years), 11 young hypertensive subjects (mean age, 36 ± 1 years), and 17 older hypertensive subjects (mean age, 59 ± 1 years); isoproterenol combined with ganglionic blockade (trimethaphan [INN, trimetaphan]) was administered to eight young normotensive subjects and eight young hypertensive subjects. Isoproterenol was infused at three to four incremental rates, each rate for 8 minutes. Left ventricular responses were assessed by echocardiography. Results Isoproterenol caused similar increases in heart rate in all four groups. With ganglionic blockade, heart rate responses were enhanced but were similar in the young normotensive and hypertensive subjects. In young subjects, hypertension did not affect left ventricular responses to isoproterenol alone, whereas older hypertensive subjects showed some blunting of left ventricular responses compared with older normotensive subjects. With ganglionic blockade, young hypertensive subjects also showed mild blunting of left ventricular responses. Conclusion These results show that, in humans, hypertension does not lead to a decrease in chronotropic responses to infusion of the β‐agonist isoproterenol and causes only a modest decrease in left ventricular responses. Clinical Pharmacology & Therapeutics (1998) 63 , 663–671; doi: