 - Diagnosis of resistant hypertension RH within the last 6 months. In the absence of a specific RH diagnosis, individuals being treated for two or more weeks with at least 3 antihypertensive medications of different classes, including a diuretic, with clinic SBP 140 mm Hg or DBP 90 mm Hg, will be eligible. Individuals being treated with 4 or more anti-hypertensive medications including a diuretic with SBP 130 or DBP 85 mm Hg will also be eligible. 