Review Article

Patterns of Circadian Variation in 24-Hour Ambulatory Blood Pressure, Heart Rate, and Sympathetic Tone Correlate with Cardiovascular Disease Risk: A Cluster Analysis

Figure 1

Time series clustering patterns of SBP, DBP, HR, and sympathetic tone. Each time series measurement is represented in matrix form ( hourly measurements [column]) and visualized using a color map (blue denotes a low value, and yellow denotes a high value for each variable). The measurement time is arranged from left to right in the sequence of morning, afternoon, evening, night, and dawn. Time series patterns are observed to differ by cluster.