Ambulatory blood pressure monitoring: an historical perspective.

Since blood pressure was first measured more than 250 years ago, it has been assumed to be a fluctuating phenomenon, but always it has been determined by static measurements in the physician's office. In the 1940s, self-measurement at home was attempted, and two decades later the first ambulatory blood pressure recording devices were developed. These have since been improved, made more convenient, rendered automatic, and are now available for 24-h measurement during a patient's normal day. It is now increasingly recognized that such measurement is more physiologically valid and more accurate in diagnosing hypertension than clinic measurement. In addition, such monitoring may have special utility in assessing response to treatment.