A Brief History of Tau with Links You Might Need!

A Brief History of Tau

1976, Weiss found Tau.
1992, the first non-invasive calculation.
1992, a formula involving Tau.
1993, an important improvement with decent data.
1995, a similar strategy applied to AI patients.
1995, I published a formula with one assumption.
1997, Cleveland validated the aforementioned formula with 5 hypotheses.
2005, Langer presented a non-zero asymptote model.
2008, I improved my formulas, without assumption now.
2008, I did a similar method in AI patients.
2008, Chen developed program for my formulas, free download.
2008, my poster in ASE 19th Annual Scientific Sessions.
2009, my poster in CSE forum.
2009, DF guideline (ASE) recommended Cleveland's formula.
2009, I gave my opinion about the guideline method.
2009, "Response to Bai" from guideline writing group. It motivated me to create this Blog.
2010, Dr Wang and me pushed Tau to all cardiac functions.
2011-11-29, I gave a talk in National Capital Echo Round (Ottawa)
2016-03-29, I gave a talk at the Heart Institute, the North Hospital (Shenyang, China)
2016-04-01, I gave a talk at the Cardiac Function Dept., the 1st Clinical College, Chinese University of Medicine. (Shenyang, China)
2016, Symmetry inspired by Tau
2017, Calculation of LAP got Chinese Natural Science Founding.
2017, Mindray made the first Tau measurable ultrasound machine.

Sunday, October 31, 2010

-dp/dt max is equivalent to Tau

Recently, an editorial (1) from Circulation Heart Failure claimed “Tau derived from the monoexponential model is less dependent on loading conditions than peak -dp/dt and has been used as a reliable index for LV relaxation in many clinical and experimental studies.”

I think –dp/dt max and Tau are the SAME in terms of clinical significance.


This is the proof:
Weiss’ formula:
                   P = e(exp)(t /T+B) +C
The derivative of both sides:
                  dp = e(exp)(t /T+B) (1/T )dt    or:
              dp/dt = e(exp)(t /T+B) (1/T )
Since t starts from peak -dp/dt,  when t=0, we have:
      dp/dt max = e(exp)B (1/T ) = e(exp)B /Tau

Because e(exp)B is a constant, it means -dp/dt max and Tau share a relationship of one to one correspondence. We can draw the conclusion that -dp/dt max and Tau are equivalent indices in clinical significance.



References:

(1)   Kazuhiro Yamamoto. The Time Constant of Left Ventricular Relaxation: Extrication from Load Dependence and overestimation of Functional Abnormality. Circ Heart Fail. 2010;3:178-180.

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