Re: cardiac arrest [HAPP-L]

[Marc Walters <mwalters@xxxxxxx>]

I would consult a textbook of pathophysiology and read on two subjects:  1. 
Cardiac arrest and 2. Congestive heart failure.  I think you might be 
confusing the two concepts a bit.

Heart failure, (most often associated with backup of fluid in the lungs, 
etc. so it's called congestive heart failure (CHF)), is often a chronic 
condition due to factors such as hypertension, valvular heart disease, 
previous or current myocardial infarction, cardiomyopathies, arrhythmias 
such as atrial-(not ventricular)-fibrillation, etc.  It is basically a 
condition where the heart can't pump enough blood to supply adequate flow 
to the tissues (often cardiac output is low); the heart often has to 
maintain elevated diastolic volumes to be functional.

Ventricular fibrillation (vfib.) causes cardiac arrest, not CHF.  When I 
was a med. student, we actually opened dog's chests and induced vfib. with 
potassium injections...the heart quits pumping and instead looks like a 
"bag of worms".  So vfib doesn't cause congestive heart failure...it's 
worse than that!

Renal failure can do lots of things to the heart.  Some examples are:
1. Vfib. due to hyperkalemia, so potassium must be monitored.
2. Uremic pericarditis, pericardial effusions, and pericardial tamponade
3. Fluid overload and heart failure
4. Cardiomyopathy secondary to chronic hypertension from the renal failure


For references, I suggest getting a copy of the pathophysiology text by 
Porth or the text by Copstead.  For more advanced reading I would buy 
"Pathologic Basis of Disease" by Robbins et. al. or a textbook of internal 
medicine, such as the one by Harrison or Cecil.


At 04:15 PM 1/23/2003 -0600, you wrote:
> I am trying to find, or if I have to, make, a flow chart showing the 
> relationship between myocardial infarction, ventricular fibrillation, and 
> heart failure.  I don't want something comprehensive, rather something 
> appropriate for sophomore A&P, that covers terms that students are likely 
> to run across.  Physiological events that ultimately lead to heart failure 
> is what I am after.  If I am oversimplifying to the point where such a 
> flow chart would be misleading, I'd like to know that too.
>
> My questions:
> 1)  does anyone know of such a flow chart?
>
> 2)  immediate causes of heart failure - usually ventricular 
> fibrillation?  hemorrhage could cause low CO directly, is there anything 
> else that would bypass fibrillation?
>
> 3)  can MI cause heart failure without V fib?
>
> 4)  renal failure - would that be likely to lead to V fib?
>
> I realize my questions may not be concise enough, but anyone who knows a 
> lot about heart failure, maybe you can see where I am trying to go.
>
> thanks.
>
> alice
>
> Dr. Alice Mills
> Dept. of Biological Sciences
> University of Tennessee at Martin
> Martin, TN  38238
> (731) 587-7175
> (731) 587-7187 (fax)

Yours truly,

Marc


Marc H. Walters, M.D.           Internet: mwalters@xxxxxxx
Biology                         Telephone: (503)977-4404
PCC Sylvania                            FAX:  503-977-8164
PO Box 19000
Portland, OR  97280-0990


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