Transient circadian hyper-amplitude-tension (CHAT) may be intermittent: case reports illustrating gliding spectral windows.

Taking the heart rate (HR) for one cycle, whether to examine behavior in the region of periods of 1 s, 1 day, 1 week, 1.3 or 10.5 years, etc., is hazardous. Replications, when possible are mandatory for examining altered variability, whatever the period(s) involved may be. This replication in the individual, and across individuals when the periods are long, measured in decades, may serve for diagnosis and treatment. This rule applies in particular to a seemingly transient circadian hyper-amplitude-tension (CHAT), an over peer-threshold variability in blood pressure (BP), based on the fit of a 24-h cosine curve to time series of appropriate length, rather than to a mere snapshot covering just a single day or week. Transient CHAT may turn into intermittent CHAT, as determined in two cases presented herein. One case of transient CHAT could be so named after a successful treatment (Rx) change eliminated CHAT as an effect validated by monitoring at 30-min intervals for a 7-day span on a new treatment. CHAT disappeared for over 300 consecutive half-hourly measurements, but thereafter it reappeared. During the ensuing nearly continuously monitored 5 years, CHAT continued to appear and disappear sometimes without a treatment change. In another case, which was responsive to a change in the timing of medication, CHAT also disappeared and thereafter reappeared. In a short-term perspective of weeks or months of monitoring, CHAT seemed to be transient, but further monitoring again revealed it to be intermittent. Cases of intermittent CHAT require follow-up for outcomes by comparison with the population at large. Miniaturized instrumentation for their detection should be a high priority, but it must be realized that the automatic ambulatorily functioning monitors, available at 10% of the regular price through a BIOCOS project (corne001@umn.edu), already signify great progress, as compared to previously used manual measurements made around the clock by hypertensive opinion leaders in medicine from diagnosis to death. On automatically collected time series of BP and HR, gliding pergressive spectral windows as such, or such pergressive windows aligned further with global spectral windows, visualize the changing dynamics involved in health and disease, in the steps of Werner Menzel and Paolo Scarpelli.