Hypertension, or high blood pressure, is one of the major risk factors for cardiovascular disease-left untreated, it can lead to heart attack, heart failure, stroke, and kidney disease or failure. The Centers for Disease Control and Prevention estimates that 28-30 percent of American adults have hypertension (see chart). If you have hypertension that is difficult to control, it may be due to a rare condition called primary aldosteronism (PA) or hyperaldosteronism. It was once thought that less than one percent of people with hypertension have PA. However, "As screening for PA becomes more common, evidence is emerging that it may be responsible for a higher incidence of hypertension, heart disease, stroke, and cardiac arrhythmias (irregular heart rhythm) than was previously believed," says Fetnat Fouad, MD, head of the Syncope Clinic at Cleveland Clinic.