XXXX . Central haemodynamics at rest and during exercise in essential @entity101 : acute and chronic studies.

@entity1 @entity64 @entity101 @entity3194 @entity10129 @entity591 @entity460
@entity460 blockers may reduce contractility of vascular smooth muscle as well as that of myocardial cells. Therefore, falls in both total peripheral vascular resistance (TPR) and cardiac output (CO) might be responsible for a fall in blood pressure (BP) caused by @entity460 blockers in essential @entity101 . We have studied the acute and chronic haemodynamic effects of @entity10129 (a new @entity460 blocker) in 19 @entity1 with essential @entity101 at rest in the supine and sitting positions and during 100-W dynamic exercise to investigate whether CO might be compromised by acute and chronic @entity460 blockade. Intra-arterial pressure, CO (by @entity3194 ), @entity64 volume, heart rate and TPR were measured hourly after the first dose of 10 mg @entity10129 (acute study) and then after 1 year of @entity10129 treatment (mean dose 25 mg; chronic study). The maximal first dose response was seen after 1 h, i.e. a fall in intra-arterial pressure (9%) and TPR (19%) and a reflex rise in heart rate (9%) and CO (12%). The effects levelled off during the next 2 h. After 1 year of treatment there was a more marked reduction in BP: at rest intra-arterial pressure fell (14% supine, 16% sitting) due to fall in TPR (19%) but without significant changes in heart rate or CO; during 100-W exercise, intra-arterial pressure fell (14%) due to reduction in both TPR (7%) and CO (6%). In conclusion, @entity10129 lowers BP by reducing TPR, both acutely and chronically. The initial reflex @entity591 and rise in CO disappear during long-term treatment, probably due to resetting of the baroreceptors.(ABSTRACT TRUNCATED AT 250 WORDS)
