Talk:Aortic valve stenosis

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[edit] HOCM

hypertrophic obstructive subaortic stenosis

Is this the same as HOCM? JFW | T@lk 22:08, 19 Apr 2004 (UTC)

Current terminology is hypertrophic obstructive cardiomyopathy (HOCM). I'll make the change. Ksheka 17:45, Apr 27, 2004 (UTC)

[edit] Area calculation

This section should be moved to it's own page, or a subpage here. Dlodge 23:54, 11 January 2007 (UTC)

  • Agree. The section should be moved. The Aortic valve area calculation would be an appropriate name. Beyond that, the notation should be cleaned-up and wikification should take place. Continuity isn't something that was made-up for measuring aortic valves... so, linking would be good. That said... an article that explains the idea without calculus needs to be written so that is accessible to more people. The Navier-Stokes equations article is nice but it looks like complete gibberish if you don't have a grounding in math. Nephron  T|C 02:52, 12 January 2007 (UTC)
    • Agree. I went ahead and changed this. I can't think of any good reason not too. I have an extensive math background (engineering degree), but my eyes tend to glaze over when I see math these days. On a technical point, there actually isn't any calculus on this page, just a lot of symbols. It might be good to have a little table of what you need to know, and what the result is. I.e. the variables. Dlodge 04:05, 12 January 2007 (UTC)

Probably worthwhile to point out these values are calculated (not measured, as in open-heart surgery or autopsy) using other physical values (pressure / flow velocity). Dlodge 04:05, 12 January 2007 (UTC)

[edit] Murmur louder in expiration

Surely

[edit] vs. sclerosis

It would be useful to put a comparison of aortic sclerosis and stenosis in this article, since they're heard in the same place but have different features and sequelae. 71.234.109.192 00:39, 15 October 2007 (UTC)rhetoric

[edit] Equation relating pressure drop and velocity

Folk, the equation Gradient = 4(velocity)2 mmHg is claimed to be a form of the Bernoulli equation, v2/2+gh+p/ρ=constant . This is my derivation.

The height term gh can be moved to the right hand side. If height is assumed constant in the region of interest, a second constant appears.
v2/2+p/ρ=constant-gh=constant'

Multiplying by ρ yields,
(ρ/2)v2+p=ρ*constant' .
If ρ is also a constant, the right hand side is a third constant.
(ρ/2)v2+p=constant

Now we consider two points on a streamline denoted by subscripts 1 and 2.
(ρ/2)v12+p1 = constant=(ρ/2)v22+p2

Rearranging terms yields,
p1-p2 = (ρ/2)(v22-v12) .

In some special cases, v12 will be negligible compared to v22. For these cases this equation applies.
p1-p2 = (ρ/2)(v22)

The density of blood is approximately 1 gm/cm3.
pressure of 1 mm Hg = γ(pressure of 1 mm of water)

= γ(0.1 gm/cm3)980 cm/s2
= γ 98 gm/cm s2.
Ie. 1 = (pressure of 1 mm Hg)/(γ 98 gm/cm s2)
Substituting the density of blood, multiplying by 1 and simplifying yields this equation.
p1-p2 = (v2 s/cm)2 (1 mm Hg pressure/2646)
If velocity is measured in cm/s, units inside the first pair of parentheses cancel and the result is pressure drop in mm Hg.
If s/cm is replaced with s/0.01 m the this equation results.
p1-p2 = (v2 s/m)2 (1 mm Hg pressure/0.2646)
Equivalently,
p1-p2 = 3.8(v2 s/m)2 (1 mm Hg pressure)
This suggests that the equation in the article is intended for flow velocity measured in m/s.

I prefer to see this derivation rather than have the physiological equation simply quoted. At the very least the latter should be stated correctly without the units fudged. The terms "pressure gradient" and "pressure drop" should be used appropriately.

   PeterEasthope (talk) 00:12, 29 December 2007 (UTC)