Explanation of ABPM plots

24 h ambulatory blood pressure profile showing a nocturnal dip in a hypertensive subject. In most individuals blood pressure falls by 10 - 20% during the night.

This 24 h ABPM shows sustained hypertension with the absence of a nocturnal dip. Absence of a normal diurnal profile may be associated with increased risk of target organ damage.

Plot of ambulatory blood pressure profile obtained from a diabetic patient, with reversal of the normal diurnal profile (higher pressures at night).

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Explanation of ABPM plots

Each of the ABPM profiles in this package is laid out as follows:

• X axis: time (24 h)
• Y axis: blood pressure (mm Hg)
• The yellow line adjacent to the Y axis represents the clinic blood pressure obtained for that patient.
• The horizontal grey bars represent the accepted normal limits for systolic and diastolic blood pressure obtained by ABPM, including the nocturnal dip.
• The vertical bars on the left of the profile represent the "white coat" window, when the effect of medical staff on blood pressure may still be evident.
• The darker vertical band of shading represents night time.

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