From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med.cardiology,sci.med
Subject: Re: angina and ECG
Date: 19 Aug 1998 04:47:59 GMT

In <6rck79$soe$1@nnrp1.dejanews.com> tiftrn03@cunyvm.cuny.edu writes:

>What other non-invasive diagnostic tools [for possible cardiac angina]
>can the physician employ?


   The best are the various thallium radioisotope redistribution scans.
 Thallium acts like potassium, and is taken up by muscle cells which
have good blood supply.  Inject Tl-210 into a heart which has areas of
bad blood flow (during exercise, say), and a scan will show patches
where it's not going.  If those patches fill in when the heart is at
rest, it shows that these areas have muscle which isn't being
adequately supplied during exercise.  Ergo, you have stress induced
ischemia and coronary insufficiency.  Dead, or scarred parts of the
heart never do take up the isotope, and can be differentiated that way.
And there are scans which use two isotopes, so you don't have to rely
one redistribution of one of them.

Second best non-invasive technique is stress echo, where wall motion
abnormalities are looked for.  Ischemic muscle doesn't contract well,
and if you have a segment of heart that contracts at rest, but not
during exercise, you can also infer exercise related ischemia.  But
these things take much more talent to do, and to read.  Whether they
approach the sensitivity and specificity of ischemia isotope scan(s)
depends on the skill of the echo-tech and radiographer.  Advantage of
echo, however, is that it tells you all kinds of other things about a
heart that you want to know.  So most cardiologists end up doing both
isotope scans and echos on their tough cases.

                                       Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Subject: Re: ultra-fast CT, any good?
Date: 20 Jun 1997
Newsgroups: sci.med

In <33a98a9c.14047178@news.li.net> jminasi@northeast.net (Jerry Minasi)
writes:

>On Wed, 11 Jun 1997 23:21:29 GMT, sidheld@ix.netcom.com (Sidney Held)
>wrote:
>
>>In the Los Angeles area they advertise ultra fast CT as being a great
>>diagnostic tool. Any information is welcome.
>>
>>sidheld@ix.netcom.com
>>
>>Sidney Held
>
>look at http://www.heartinfo.com/Ima_hp.html this is the Imatron,s
>Ultrafast CT Electron Beam tomography home page.
>check it out. the pictures show the calcium deposits in the arteries
>around the heart.  This is a quick and non- invasive way to indicate
>whether more invasive diagnostic action is indicated.


   Wrong.  Invasive diagnostic action is not indicated unless you have
a hemodynamically significant lesion.  To find out if you do, you need
some variety of stress test.  You need a stress test if CT shows
calcium, because not all calcified plaques are large.  You need a
stress test if CT is negative, because not all large plaques are
calcified.  If you need a stress test either way, why not have the
stress test first, and save your CT money?  Unless you want the neat
pictures.

                                      Steve Harris, M.D.