The clinical significance of diurnal blood pressure variations. Dippers and nondippers.

In this issue of Circulation, Verdecchia et al' suggest that the diurnal pattern of blood pressure, evaluated by noninvasive ambulatory monitoring, may be an important factor in determining the extent of left ventricular hypertrophy (LVH) in hypertensive patients. It illustrates the point that the introduction of a new diagnostic technique often raises as many questions as answers. The rationale for the introduction of ambulatory monitoring as a clinically useful diagnostic tool was provided by both the increasing awareness of the intrinsic variability of blood pressure and the disturbing fact that the conventional clinic measurements of pressure, which have formed the mainstay of our knowledge of the risks associated with hypertension, may in some patients be quite unrepresentative of their overall level of pressure.2,3