September 01, 2015

A stiff heart

A type of heart failure

Heart

You received a diagnosis of heart failure a few months back. Since then, you've been exercising more, eating less salt and taking your medications. Recently, you heard news of a new medication for heart failure. Interested, you inquire about it at your next checkup, but your doctor says it's not effective for the kind of heart failure that you have. It turns out not all heart failure is the same.

In the past, heart failure was largely thought to be the result of a heart too weak to pump out the right amount of blood. But in a large and growing group of people, heart failure develops even when the pumping ability of the heart muscle remains relatively intact.

Both types of heart failure result in a reduced amount of blood being distributed to the rest of the body and consequently lead to similar symptoms, such as feeling weak, tired and short of breath. However, scientists are discovering that these two types of heart failure are actually quite different in their mechanisms and in how they respond to treatment.

Pumping problems

One way doctors measure how well your heart is pumping is by checking your ejection fraction — the percentage of blood pumped out of your left ventricle with each heartbeat. Since the heart doesn't empty completely, the ejection fraction is never 100 percent. Instead, it's normally somewhere between 50 and 70 percent. The remaining 50 to 30 percent stays in the ventricle. This contraction phase where blood is pumped out of the heart is called systole.

If your heart muscle weakens, it can't pump...