Sympatho-Vagal Imbalance in Hypertension

This chapter focuses on sympatho-vagal imbalance in hypertension and effects of therapeutic interventions on hypertension-related autonomic dysfunction. Autonomic control of the cardiovascular system undergoes profound changes in hypertension with resultant sympathetic activation and parasympathetic inhibition. The sympathetic nervous system also participates in this heart rate increase, due to the tachycardic effects adrenergic neurotransmitters have on sinus node activity. Data collected in hypertensive patients with an end-stage renal disease indicate that in this condition also sympathetic activation seen in the high blood pressure state undergoes a further potentiation. Given the relevance of autonomic dysfunction to the development or progression of the hypertensive state as well as to the hypertension-related end-organ damage, sympathetic deactivation represents an important goal of the nonpharmacological as well as pharmacological interventions aimed at lowering elevated blood pressure values. There is evidence that some pharmacologic classes of antihypertensive drugs may elicit profound sympathoinhibitory effects, while other classes may leave unchanged, or even further increase the adrenergic cardiovascular drive