The relationship of blood pressure to cardiac hypertrophy: experimental studies in rats.
Cardiac hypertrophy is an independent predictor of morbidity and mortality. The exact relationship between blood pressure, hormones and cardiac hypertrophy is unclear. This study was undertaken to determine if intermittent elevation of blood pressure could cause left ventricular hypertrophy. Blood pressure was elevated intermittently by intraperitoneal injections of angiotensin II, noradrenalin and methoxamine. Blood pressure was acutely elevated by 60 mmHg or more for periods lasting up to 1 hour on up to 4 occasions each day. Cardiac index was measured 2 and 4 weeks after the experiment started. The cardiac index was increased by all procedures. The results were complicated by a retardation of growth in some experimental groups, meaning that the cardiac weight did not increase though the index did. In a study looking at the interaction of sodium and angiotensin II high sodium intake caused left ventricular hypertrophy and injections of angiotensin II caused further left ventricular hypertrophy. This study indicated that acute intermittent elevation of blood pressure could cause left ventricular hypertrophy and suggests that wall stress rather than 24 hour workload is the important triggering mechanism.
Morgan
T
T
Department of Physiology, University of Melbourne, Victoria, Australia.
Brunner
H
H
Aubert
J F
JF
Connell
P
P
D000804:Angiotensin II / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D006332:Cardiomegaly / Q000209:etiology* / Q000503:physiopathology*; D006973:Hypertension / Q000139:chemically induced / Q000150:complications / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000503:physiopathology; D008729:Methoxamine / Q000008:administration & dosage; D009638:Norepinephrine / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012982:Sodium, Dietary / Q000008:administration & dosage
D012982:Sodium, Dietary; D000804:Angiotensin II; D008729:Methoxamine; D009638:Norepinephrine