EF stands for ejection fraction. It is how they measure how much blood your heart pumps out with every contraction. Normal is around 50 percent. Mine has been measured at a high of 51 and a low of 30. It will vary somewhat from day to day and even possibly during the day, depending on your activity.
Sorry for the jargon.

I when to the hospital thinking it was my blood pressure was to high, being diabetic. Was hospitalized and told that my heart was pumping at 20 percent? Was implanted with a pacemaker

What is EF? New at this!!!

Once upon a time, a long, long time ago, I was told if my EF dropped below 30 percent, I would get an L-VAD. And, yes, I realize an L-VAD is not a pacemaker but I wonder if the criteria might be similar.

A cardiologist will check you out and tell you. You may need to wear a monitor to follow bpm more than just at doctor.