Bioimpedance Evaluation of Therapeutic Titration in Essential, Refractory Hypertension

* Patients with higher vascular resistance index and/or lower arterial compliance index will lower BP faster and to a greater degree overall when receiving vasodilating agents - such as ACEI's, ARB's, dihydropyridine CCB's, direct vasodilators, and central alpha agonists. * Patients with an elevated cardiac index will lower BP faster and to a greater degree overall when receiving agents that reduce contractility, heart rate, or blood volume - such as beta blockers, non-dihydropyridine CCB's, and other agents that are known to reduce cardiac index. * Patients with an elevated thoracic fluid content or lower orthostatic change in thoracic fluid content will lower BP faster and to a greater degree overall when receiving diuretics (thiazide, loop, potassium sparing), however - one of these agents will emerge as a superior alternative to reduce BP in patients with high thoracic fluid content / low orthostatic change in thoracic fluid content.