Monday, July 14, 2008

Diastolic dysfunction

The diagnosis of diastolic heart failure, unfortunately, is often missed by unwary physicians.

Before I say more than a few words about diastolic dysfunction, I want to note that I am mostly not unwary. Who'd want to go to an unwary physician anyway? I will admit, however, that I was a little unwary regarding the consequences of diastolic dysfunction, but I am no longer so. Here's the scoop.

If diastolic dysfunction is a new one to you, I'm here to tell you it was not part of my original medical education. When I learned about heart function gone awry, it was all about a delivery deficiency. In other words, a failing heart is unable to squeeze out sufficient blood with each beat. As a result, tissues receive less oxygenated blood, the lungs receive less blood to oxygenate, blood backs up as it waits for its turn to pass through the stressed-out heart, and the lungs, liver, and legs fill with fluid. All this is now known as systolic heart failure or a failure of the heart to adequately eject blood during contraction aka systole. What a messy fluid build-up and lack of blood flow results from systolic heart failure after heart attacks, viral infections, rhythm disturbances, or alcohol toxicity among other things.

So several years ago, I started seeing 'diastolic dysfunction' showing up on echocardiogram results. "What on earth," I asked my friends the cardiologists, what were they seeing on ultrasound examinations of the heart that qualified as an abnormality of the relaxation phase of the heartbeat.

Whereas systolic dysfunction is a delivery problem as noted above, I learned that diastolic dysfunction is an acceptance problem. Once blood is squeezed out during systole, the heart relaxes to accept a new load of blood in preparation for its next beat. The heart muscle slackens, the mitral valve opens, and blood rushes in to the big chamber known as the ventricle. Just to get that extra kick, the top chamber known as the atria squeezes a bit more in just before the ventricle begins to contract once again. If the ventricle is stiff, however, from years of working out against high blood pressure, diastole does not go so well. The ventricle is unable to accept as much blood.

Early on in diastolic troubles, that last atrial squeeze gets the heart volume up to normal. The patient motors on oblivious to the chaos brewing in his/her overworked heart (Naw, Doc, I don't check my blood pressure. I feel fine.) Then stiff becomes stiffer in a ventricular sense, and the heart no longer fills with enough blood to meet the demands of exercise. Fluid begins to back up in the lungs when the patient tries to mow the lawn or go for a walk. The volume overload in the lungs creates pulmonary hypertension which further accelerates the diastolically failing heart thing.

What brought this all to my mind? One of my patients, younger than me, came in with swollen legs. She's a skinny lady, so her edematous ankles were particularly alarming. She has an unfortunate history of hypertension, high cholesterol, smoking, and an inability to exercise for years due to a back injury. Her echocardiogram showed that her heart was pumping okay but she had serious diastolic dysfunction and severe pulmonary hypertension. As if this was not sufficient trouble, her chest x-ray shows one side of her diaphragm is paralyzed, so we are currently looking for a possible lung cancer high in her lungs squashing her phrenic nerve.

So that is why I: 1) ask my patients not to smoke, and 2) press them to keep after their pressure.


kenju said...

That's worrisome to me. I have edematous ankles, moderately high cholesterol, I smoked for 23 years and I have only recently begun to exercise again. I take Torsemide every other day, but I do get short of breath on exertion.

Wendy said...

That was very interesting. And well explained. Good advice - to check BP. It's not invasive and easy to do. The not smoking goes without saying.
Great post!

Mauigirl said...

My aunt has this type of heart failure, although she does not smoke. It's so ironic - she's the one who walked to the bus stop for years when she worked (a good long hike to and from every day) and continued to walk for exercise well into old age. She has high blood pressure now and heart failure. My mom, her sister, as I've mentioned before, smokes and has never exercised and is 2 years older and is 100% healthy.

Anonymous said...

I am only 12 and when I breath in, my heart beats normally. However when I relax and breath out my heart beats unusually slow. Does anyone have any suggestions? Is this deadly? I also get dizzy easily and have hypotension, which is low blood pressure.