Cardiovascular response to sympathetic stimulation in normal subjects with or without familial hypertension

The aim of our study was to seek out a possible different reactiveness to cardiovascular stimulation tests among normotensives with and without positive family history of essential hypertension. We have studied about 200 inhabitants of Ustica and 49 medicine students, all normotensives according to the World Health Organization and the Joint National Committee criteria. In an isolated room and in a supine position, blood pressure (BP) and heart rate were measured every 30 s for 15 min with an automatic sphygmomanometer. Averages of last 4 measurements were considered baseline values. Then we have carried out mental stress (MS), handgrip and active orthostatism test (AO) in the inhabitants of Ustica; cold pressor test and AO in students. Patients were divided in 2 groups, genetics and controls, on the basis of a positive family history of essential hypertension. The 2 groups, in every sample, were similar for sex, age, body mass index and alimentary and life habits. RESULTS: a preliminary estimation of Ustica sample showed a different prevalence of positive history between hypertensives and normotensives (63.9% vs 46.61%; p less than 0.05) and no difference between hypertensive and borderline patients (63.9% vs 64.2%); BP and heart rate were slightly higher in controls; there was no statistical difference between genetics and controls. CONCLUSIONS: our results can be explained in various ways: pressor dysregulation in candidates for hypertension may be masked in a large group of normotensives; exaggerated pressor response do not exist in genetics or this pressor dysregulation is impossible to find out with the cardiovascular stimulation tests we have used; other mechanisms are responsible for genetic hypertension.