The Phoenix Project

Usage – Germaine Cornélissen

© 2007 Germaine G Cornelissen-Guillaume. Copying and distribution of this document is permitted in any medium, provided this notice is preserved.

www.phoenix.tc-ieee.org

• Problem: Blood pressure is highly variable (from moment to moment, from one day to

another, …). Are fixed limits such as 140/90 mmHg (systolic/diastolic BP) warranted?

• BP variability is not trivial: Abnormal variability in blood pressure and/or heart rate is associated with an increased vascular disease risk, even in the absence of “hypertension”. Abnormalities include:

1. a decreased standard deviation of HR2. an elevated pulse pressure (SBP-DBP)3. an excessive circadian BP variation (CHAT)4. an odd timing of the circadian BP rhythm

• Sphygmochron Analysis: Data are analyzed parametrically (to assess the circadian charcateristics) and non-parametrically (to check for BP/HR excess or deficit), using reference limits that are time-specified and further qualified by gender and age.

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0 90 180 270 360 450 540 630 720 810

MESOR(Midline EstimatingStatistic Of Rhythm)

Period

Phase

Reference time

Acrophase

Amplitude

• Treatment: Certain BP/HR abnormalities can be treated by selecting the appropriate medication and a suitable time of administration. For instance, reducing CHAT is associated with better outcomes.

• Merit of chronobiologic approach

Higher predictive value of the circadian amplitude and phase interpreted in the light of gender-and age-specified norms as compared to day-night ratio.Diagnosis of Circadian Ecphasia and/or CHAT in DBP

For Vascular Disease Risk Assessment Is Not Matched By Focus On Dipping*

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Ecphasia Acceptable CHAT RD ND DP EDDiagnosis:

LV

MI

(g/m2 )

* CHAT: Circadian Hyper-Amplitude-Tension; Ecphasia: Odd timing of circadian pattern of diastolic blood pressure (DBP). RD: Reverse Dipper; ND: Non-Dipper; DP: Dipper; ED: Extreme Dipper. Circadian Decreased Heart Rate Variability, and Excessive Pulse Pressure not assessed in this analysis.

All: P<0.001F: P<0.001M: P=0.011 All: P=0.186 F: P=0.043 M: P=0.664

Mean ± SE

Diastolic ecphasia or CHAT is more discriminatory (P<0.001) than reverse ( d 1> d 2) or extreme ( D 1> D 2) dipping (P>0.10).

No difference between dippers and non-dippers

D2

D1

d1

d1

N: 73 1039 67 131 343 482 223

Summary• Blood pressure is highly variable.• Abnormal BP/HR variability is not trivial as it is

associated with increased vascular disease risk.• Parametric and non-parametric endpoints are

interpreted in the light of norms that are specified as a function of circadian stage, gender, and age.

• Certain BP/HR variability disorders can be treated and their treatment is associated with improved outcomes.

• A chronobiologic approach relying on the circadian amplitude and phase interpreted in the light of time-, gender-, and age-specified norms, has better predictive value than day-night ratios.