| Popis: |
One third of patients with prehypertension have hyperkinetic circulation characterized by tachycardia and increased cardiac output. The hyperkinetic circulation is a predictor of future established hypertension. However, patients with established hypertension characteristically have increased vascular resistance and a normal cardiac output. This chapter describes the mechanisms by which in the course of hypertension the hemodynamic picture alters from high cardiac output to a high-resistance state. The “normalized” cardiac output in established hypertension reflects a decrease of the stroke volume due to increased cardiac stiffness. In parallel the increased vascular resistance in established hypertension mirrors the ensuing restructuring of resistance arterioles. This restructuring enhances vascular contraction to all constricting agonists and, if untreated, predicts future increases of the blood pressure. |
