Use of Impedance Cardiography and Applanation Tonometry for Prediction of the Antihypertensive Effect of Two Drugs

The principal aim of the study is to determine whether the hemodynamic parameters measured with the two methods -impedance cardiography and applanation tonometry- can be predictive of the antihypertensive effect of two different classes of drugs, ATII antagonists and diuretics. The drugs that will be used in the study are olmesartan and chlorthalidone and the duration of the study is 12 months. The other basic aim of the study is to determine whether there is a difference (\>6mmHg) between the two drugs regarding the reduction of the mean 24hour blood pressure and the effect of them on the hemodynamic parameters. The hemodynamic parameters that will be measured by applanation tonometry are augmentation index, central blood pressure and pulse wave velocity. The hemodynamic parameters that will be measured by impedance cardiography are cardiac index, thoracic fluid content index, systemic vascular resistance index and others.