Friday, March 14, 2008

Understanding and interpreting your Transthoracic Echocardiogram.

I think that most of the aortic root measurements can be obtained using different "views". I understand the "Left para-sternal long axis view" best.

http://www.med.yale.edu/intmed/cardio/echo_atlas/contents/index.html
http://www.echopedia.org/wiki/Parasternal_long_axis
http://www.chfpatients.com/tests/echo.htm

Monday, March 10, 2008

Z-Scale Chart



The horizontal axis (x-axis) is Body Surface Area axis. Calculate your Body Surface Area by going to this site: http://www.halls.md/body-surface-area/bsa.htm, and typing in the required values.

Now if your BSA is 1.79 (height 192cm, weight 60kg), look in the chart, on the horizontal axis, and mark a point approximately where 1.79 lies. Now check if your aortic root at Sinuses of Valsalva fall within the safe zone (the greyed out area). For "Young adults" with a BSA of 1.79, the safe aortic diameters are from 2.5 to 3.4 cm diastole.





The Aorta is a long pipe that is NOT uniform in diameter. Measuring the aortic diameter at a random location, via a echo-cardiogram or CT, is of no use if your purpose is to compare your aortic diameter against a statistically significant percentage of the population, which is what the Z scale is all about. The reading is taken at the Sinuses of Valsalva at diastole! Also note that: what is considered a "safe" aortic value may vary, as indicated by the second and third image. The second image is taken from: "Essential Echocardiography - Scott Solomon" and the third one from: "Feignebaum's Echocardiography, 6e". The most accurate way is to compare your body mass using the Z-scale ans see if you lie within a statistics based safe zone.



Note the 4 positions where you need to take the aortic measurements for Marfan's patients. The radiographic view is the PLAX - Parasternal Long Axis View and the mode is 2 Dimensional (2D mode).

Useful doc's that are available on Rapidshare.

1. Usefulness of Enalapril Versus Propranolol or Atenolol
for Prevention of Aortic Dilation in Patients With the
Marfan Syndrome
http://rapidshare.com/files/97442658/ACE_vs_BB_in_Prevention_of_Aortic_Dilation.pdf.html

2. Angiotensin II Type 2 Receptor Mediates Vascular Smooth
Muscle Cell Apoptosis in Cystic Medial Degeneration
Associated With Marfan’s Syndrome
http://rapidshare.com/files/97443056/ACEi_and_Marfan_Article.pdf.html

3. The third word document contains the Ahimastos/perindopril article. You need to scroll down a bit within the doc.
http://rapidshare.com/files/97444069/Marfan_Articles--ACEi_only.doc.html

[Please tell me if any links go inactive due to disuse. If people don't download from Rapidshare within x number of days, they purge the download.]