Design
Prospective, hospital-based study.

Setting
Department of Neurology of a university medical center.

Subjects
Forty-two patients with essential hypertension and 45 patients who were normotensive.

Main Outcome Measures
Extent of autonomic activation following stroke as indicated by circadian blood pressure patterns, serum norepinephrine levels, and cardiovascular variables.

Results
Normotensive patients with insular infarction showed a significantly reduced circadian blood pressure variation and a higher frequency of nocturnal blood pressure increase compared with patients suffering from essential hypertension and insular stroke. These findings were also associated with higher serum norepinephrine concentrations and more frequent electrocardiographic abnormalities. No significant changes in these variables were seen between normotensive and hypertensive patients without insular involvement.

Conclusions
Our findings suggest a difference in cortical control of autonomic function between hypertensive and normotensive patients after stroke and point to a possible role of the insular cortex in the pathogenesis of essential hypertension.