Thursday, July 7, 2011

Diastolic Dysfunction: Beware the Revolving Door

As a lumper, not a splitter, I tend to think of heart failure as a rather monolithic disease process when, in fact, one can divide heart failure into two distinct physiologic camps, traditional systolic failure and non-traditional diastolic dysfunction.  Why the distinction?  Because treatment and outcomes are different.

Traditional systolic heart failure is the more common entity and can be thought of as a rusty revolving door.  This door fills with people, just like the heart fills w/blood, but neither can get its contents thru to the "other side".  In the case of the door, it doesn't move/spin in a smooth fashion to allow visitors thru.  Likewise, in systolic failure, the heart is very inefficient at pumping out blood, dropping to below 55% left ventricular ejection fraction. 

Non-traditional diastolic failure can then be thought of as the revolving door that spins too quickly for people to judge exactly when to enter and thus get across to the other side.  Likewise, diastolic heart failure is characterized by a normal ejection fraction in the presence of a stiff ventricle that makes it difficult to fill w/blood.

It turns out, from a study published last week, that moderate & severe diastolic dysfunction are both associated with increased mortality.  In other words, regardless of how/why your heart isn't pumping properly, your risk of dying is greater compared to someone w/normal cardiac function.  

Sounds intuitive, right?  What good is separating heart failure into two camps?  Well, we've learned our lesson from the Women's Health Initiative about not making assumptions and taking things for granted.  We want proof.  And now we have it after reviewing the echocardiograms of over 36,000 individuals who were then followed for over 6 years.

The next step is figuring how to treat these folks with diastolic dysfunction.  Is it any different from treating their systolic dysfunction siblings?  Stay tuned . . .

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