Ejection Fraction. To help determine severity, doctors use a calculation called an ejection fraction. This is the percentage of the blood pumped out during each heartbeat. An ejection fraction of 50 - 75% is considered normal, and, in general, a low percentage is considered an indication of failure. The ejection fraction in left-side heart failure typically falls below 40%. In severe failure it may drop as low as 5%.
Of note, between 20 - 50% of patients with heart failure have a normal ejection fraction, an indication of diastolic heart failure.
Previous Section
