THE RELATIONSHIP OF BLOOD-PRESSURE TO CARDIAC-HYPERTROPHY - EXPERIMENTAL STUDIES IN RATS

Cardiac hypertrophy is an independent predictor of morbidity and morta lity. The exact relationship between blood pressure, hormones and card iac 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 intraperito neal injections of angiotension II, noradrenalin and methoxamine. Bloo d 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 measure d 2 and 4 weeks after the experiment started. The cardiac index was in creased by all procedures. The results were complicated by a retardati on of growth in some experimental groups, meaning that the cardiac wei ght did not increase though the index did. Ina study looking at the in teraction of sodium and angiotensin II high sodium intake caused left ventricular hypertrophy and injections of angiotensin II caused furthe r left ventricular hypertrophy, This study indicated that acute interm ittent elevation of blood pressure could cause left ventricular hypert rophy and suggests that wall stress rather than 24 hour workload is th e important triggering mechanism.