Is Tau dispensable?

Left ventricular diastolic time constant, Tau is the most established index to describe diastolic function. A Harvard method of Tau was invented by Dr JD Thomas has been dominant non-invasive Tau measurement for more than two decades. Now, Tau is dead clinically. Only when the logically flawed celebrity method is objectively reassessed and discarded, can Tau be given a chance. A new method is dawning and promising…

A Brief History of Tau with Links You Might Need!

A Brief History of Tau

1976, Tau was born in John Hopkins.
1992, the first non-invasive try, Harvard.
1992, the first formula, with four assumptions, Harvard.
1993, another non-invasive try with decent data, Mayo Clinic.
1995, a similar strategy applied to AI patients, Japan.
1995, I published a MR based formula with one assumption.
1997, the Harvard formula was validated in Cleveland.
2005, Langer presented a non-zero asymptote model.
2008, I improved my MR based formulas, without assumption.
2008, I did a similar deduction for AI based Tau.
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 Harvard formula.
2009, I gave my opinion about the guideline recommendation.
2009, "Response to Bai" from guideline writing group. It motivated me to create this Blog.
2010, Dr Wang and me presented general Tau.
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 the approach of Tau.
2017, Calculation of LAP (based on my formulas) got a Chinese Natural Science Founding.

Sunday, April 3, 2022

A Public Letter to ASE

Raymond Stainback, MD, FASE
Texas Heart Institute, Baylor St. Luke’s Medical Center
Houston, TX


Dear Mr. president,


On behalf of a bunch of Tau enthusiasts, please investigate a research misconduct with many connections to ASE.


Tau, left ventricular diastolic time constant is well accepted as the most established index to describe diastolic function. Unfortunately, nobody is measuring it in daily clinic as a direct consequence of this research misconduct. 


A distinguished ASE member, Dr James Thomas invented a Tau formula that is logically flawed. 

Both its experimental and clinical “verification” has to be motivated reasoning. Nobody can get good data with unintentional mistakes. Anyone can tell it is not working by simply checking it on a random patient. The result will go to nowhere. Nevertheless, this incorrect theory has been recommended in both ASE’s textbooks and diastolic function guidelines till today. 


Fair to say motivated reasoning is not strange in researchers. If an influential researcher used it to justify a wrong method or a tool, it is like put the lighthouse on a wrong place. Traumatic events could follow in consequence of the reckless behaviour. 


Not only the incorrect theory is misleading, but also it has negative effect on genuine Tau research and development. All the papers mentioned here had been rejected several times by mainstream journals, yet measurement of Tau thrived on the other side of the planet. Mindray launched the first Tau-measurable Echo machine 5 years ago. 


Tau is the only one index directly related to how powerful the cardiac muscle is. Once it is excluded, all the approaches from the ASE diastolic function guidelines have to be indirect descriptions. Comparison with Tau, the routine assessment of diastolic function could be inaccurate up to around 30% of the studies. We can elaborate it on request.


Tens of thousands of diastolic dysfunction diagnoses are made everyday in the world. 

Imagine up to 30% could be inaccurate! 

Imagine some of the patients got treatment based on those diagnoses!

Imagine sometimes the treatment is invasive, like IASD…


Please investigate and give Tau a chance, which is consistent with the mission of “to advance cardiovascular ultrasound and improve lives through excellence in education, research, innovation, advocacy, and service to the profession and the public.”


Please don’t hesitate to let me know if further explanation is needed.


Xufang Bai, MD, PhD 


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