8- systolic and diastolic failure

KYJ8 - Systolic failure vs Diastolic failure
Knowing your Jargon episode 8

In this episode of KYJ we take a look at the two categories of Left Heart Failure.  First recap blood flow-

Venous blood returns to the right heart from the body.
Right heart pumps blood to lungs
Diffusion of oxygen and CO2 takes place.
Oxygenated blood returns to left heart.
Lefty pumps blood out around the body.

Now "systolic" means the pumping stroke of the heart. It refers to the ejection or squirting of blood out of the ventricle during contraction.

"Diastolic" is an adverb that describes the relaxation phase after contraction. After systole (contraction) the squished heart now relaxes back to its resting state, and as it does it fills partially with blood.  This relaxation is what is called "diastole".

Both systole and diastole require energy.

In left heart failure, the forward momentum of blood is impaired for a variety of reasons.

Systolic failure is when the heart muscle can not contract with the "oomph" that it needs. We see systolic failure in people after cardiac injuries or heart attacks (myocardial infractions). These muscles demonstrate poor contraction (systole) and as a result the force of ejection of blood into arterial circulation is limited. Normally your heart pumps out 60-70% of it's filled volume (ie ejection fraction= 60-70%) but in a systolic failure, the volume ejected is alot lower than normal. Over the course of a minute, the cardiac output is diminished.
Systolic failure is a failure to pump.

Diastolic failure
In diastolic failure, we see a reduced cardiac output for other reasons. To first pump blood, the heart has to fill with blood. Stiff old hearts with loss of stretch don't fill well. Given that a healthy heart might fill with 100-120 ml of blood, a stiff heart might only fill with 60-80 ml or worse. If this happens then the ejection of blood over a given minute is much less than normal.

These patients are exhibiting diastolic failure. Rather than failure to contract, diastolic failure is failure to fill.

There it is.  A sentence with the word "failure" in it three times.

I hope you are enjoying these "KYJ" snippets.