#### References

Regression equations for calculation of z scores of cardiac structures in a large cohort of healthy infants, children, and adolescents: an echocardiographic study. Pettersen MD, Du W, Skeens ME, Humes RA. J Am Soc Echocardiogr. 2008 Aug;21(8):922-34.#### Comments

On Saturday Apr 19 2008, Dan said: version 0.1, April 19 2008

On Tuesday Apr 22 2008, Dan said: version 0.2 constrained the calculations to subjects with BSA < 2.0. See this post.

On Thursday May 01 2008, Rick Jensen said: Very easy and helpful; feels trustworthy. I thought there were ascending aortic values?

On Thursday May 01 2008, Dan said: Curiously, the AAO did not make it into this publication, but they

*did*include aortic measurements like the "distal aortic arch" and "aorta at diaphragm" ... Go figure.On Sunday May 25 2008, Yael said: Excellent job!! One thing though, It is easier to have the results as you enter the numbers kike un the coronary artery section and not to hit the calculate button. Yael

On Sunday May 25 2008, Lloyd Marks said: Although I can access your site on my Treo, I can't run the application. Any way to create an application that would allow you to do this on a Treo nor other PDA. One idea - Perhaps you could get Epocrates to add this to their medmath functions. Maybe they would even pay you for it.

On Sunday May 25 2008, Dan said: @ Yael: Good point- it is quite cumbersome at this point. I only recently figured out JavaScript and it's "onChange" event... Updating this calculator is now on my "to do" list. @Dr. Marks: You are way ahead of the curve there on your Treo. This site was developed primarily as a tool for our echo lab- as an extension to our report writing software. Considerations for mobile devices never entered the picture.

On Monday May 26 2008, John Plowden said: Great job Dan. Would be nice to have the option of entering the weight in pounds and oz and the length in inches and have the program convert it automatically. Just a thought, probably would not be too hard to do. Thanks again for all of your efforts

On Tuesday May 27 2008, Giacomo Pongiglione said: Well done. Thanks.

On Tuesday May 27 2008, Dan said: Thanks for the kind words. @ Dr. Plowden: We can't afford to lose another Mars Explorer. *grin* I thought the International System was

*the standard*for reporting height and weight units of measure, no?On Wednesday May 28 2008, Jorge Gomez said: Seams accurate. Very Helpful!!!

On Thursday May 29 2008, Richard W Gratian, M.D. said: We started using your calculator today. It is very convenient but unfortunately, the upper limit appears to be 2.0 m2 which we found out with our third patient. Is there a calculator for patients above 2.0 m2? Thanks. Rick Gratian

On Thursday May 29 2008, Dan said: Dr. Gratian: You raise an interesting point. Shortly after I built this calculator and starting using it myself, I noticed some unbelievable results on patients with BSA > 2.0 m2. I went back to the article and sought the descriptive characteristics of their patient population.

*These descriptive characteristics were missing from the article.*(as of right now, this article is still an "In Press Corrected Proof" so I suppose the information could yet be added). The supplied*figures*for the article top out at 2.0 m2, so I chose to constrain the calculations at this limit. Thanks for your comments!On Friday May 30 2008, Dan said: modified the calculator to update the z-scores as the data is entered

On Wednesday Jun 04 2008, bleb said: entering Z-values for ascending aora (after ST junction) would be helpful. e.g. Bic Ao valve, Turner S.

On Thursday Jun 05 2008, giacomo said: Did you ceck the equations and the coefficients provided in your paper? The result of your equation 2 is -0.384 (how can a negative value be the mean?) while it should be 0.68. On the other end, if you enter 0.68 as Mean y into equation 4 the resulting z value is not - 2.48

On Thursday Jun 05 2008, Dan said: Bleb: the authors did not include data for the AAO- I can't answer as to why... Dr. Pongiglione: the results of "equation 2" in the article refers to the natural log-transformed predicted value. To get the value (y) back in the original units, it needs to be

*back-transformed*, i.e. e raised to the power y; the JavaScript equivalent is Math.exp(y) I hope this helps.On Tuesday Jun 17 2008, kalyani trivedi said: fantastic; now I can be very precise with ease. Thank you very much for putting this together.

On Thursday Jun 19 2008, Volker Petersen said: This ist what I was looking for a long time, thank you

On Friday Jun 20 2008, satish adwani said: Excellent! Keep it up. Very helpful. I always keep it on when I do Echo's in my clinic!

On Wednesday Jul 23 2008, Marcos said:

On Friday Jul 25 2008, Peter said: Thank you very much. Not only I have waited such a long time for an easy way to get these data calculated for each of our patients.

On Thursday Jul 31 2008, MARIO CAZZANIGA said: do you have Z score calculations of magnetic resonance: RVEDV, RVESV, LVEDV, LVESV, RVEF, LVEF ?

On Thursday Jul 31 2008, Dan said: Mario: Sorry, my primary focus has been on reference values for pediatric

*echocardiography*.On Monday Aug 04 2008, Jan du Plessis said: This is an extremely useful site

On Thursday Aug 07 2008, ayse sarioglu said: This an extremely useful site.Thank you very much for your excelent work.

On Thursday Aug 14 2008, Dr Rezoana said: Would u please help us to find the Z score of above mentioned psarameters

On Sunday Aug 31 2008, Keyhan Sayadpour, MD said: At Children's Medical Center, Tehran, Iran, we routinely use this website. It is great and very helpful.

On Wednesday Sep 03 2008, shanthi sivanadam said: Would appreciate if you could add Z-score/percentile .