What percentage is good heart function?

Normal is 65%: A way of defining heart function is the ejection fraction (ef). This is the percentage of blood pumped out of the heart with a heart beat. So if full heart had 100ml of blood then it it pumped out 65ml that would be ef 65%. Good can be hard to define. Many people can function fine with an ef down to 35-40% and medical management. If it gets below 25% then we would define that as heart failure.