Autonomic imbalance, hypertension, and cardiovascular risk.

Essential hypertension conveys an increased risk of cardiovascular morbidity and mortality. The common finding of an autonomic imbalance in these patients contributes not only to the etiology of hypertension itself, but also to the cardiac risk and resulting adverse sequelae. A high sympathetic tone in particular is responsible for many of the metabolic, hemodynamic, trophic, and rheologic abnormalities that cluster in patients with high blood pressure. Methods to clarify the respective importance of prereceptor versus receptor abnormalities for the etiology of insulin resistance are warranted. Results of large hypertension clinical trials examining the degree of cardioprotection offered by newer medications that are neutral or beneficial to the vast array of underlying abnormalities are a few years away. In the meantime, utilization of antihypertensive drugs that reduce sympathetic overactivity and are metabolically beneficial is a reasonable clinical alternative in hypertensive patients with the metabolic syndrome or with signs of autonomic imbalance.