Ambulatory blood pressure monitor. Male smoker wearing an ambulatory blood pressure monitor on his hip and upper arm. This device allows measurement of a patient's blood pressure at home or at work, over an extended period. Such measurement avoids the white coat effect" in which a patient's blood pressure rises significantly when it is measured in a clinical setting. High blood pressure (hypertension) can be caused by kidney disease, hormonal disorders and congenital problems and if left untreated can lead to heart and kidney failure. Low blood pressure (hypotension) can result from a heart attack, a severe infection or acute abdominal conditions."