EF is ejection fraction, a subjective measurement of how much of the blood in your heart is pumped out with each beat. “Normal” is around 60. You can live with much lower and feel ok. My EF is between 10 and 15, I am told.
ICD is an Implantable Cardiac Defibrillator. It sends a shock to the heart when needed to get it back into a normal rhythm. Mine is paired with a pacemaker in the same device which controls the rhythm of your heart.
HCM is Hypertrophic Cardiomyopathy, a heart condition where the walls of the heart thicken. It can decrease the amount of blood in the chamber, and causes stiffness of the heart muscle making pumping more difficult. It may be genetic but not necessarily so.
I hope I have these correct. All of these terms can be Googled for a better explanation. I hope this helps.

I had a Medtronic CRT-D implanted one year ago. I have a 17% EF, and unfortunately it will not improve as there is too much damage to the left ventricle.

However, with this unit and I have to add, a strict healthy lifestyle, plenty of proper exercise, diet and rest I am doing extremely well considering my condition.

Some days I forget I have this in me and have this condition. I love life, friends and family too much to allow this to rattle my cage.

So, in summary it has made me physically and mentally feel better.

Great job explaining it,
your correct on all things. Life is wonderful.

I have cardiomyopathy. It was diagnosed as idiopathic as it did not fit any category. I also had a bundle branch blockage preventing the electrical signals from reaching the ventricles and my pulse rate dropped to 20 bpm and I was fainting all the time. My ejection fraction was as low as 30%. I was given a pacemaker and after 1 year the EF went to 20% and was told I had "pacemaker syndrome". They implanted a biventricular pacemaker and a defibrillator combined (ICD).
My EF then went to 36% and I feel better however because of the size and location of the ICD I developed "Thoracic outlet syndrome".
This is pressure on a nerve bundle caused by weakness in the thoracic muscles and compression caused by the placement of the ICD.
Still working on it and it is getting better with exercise and strengthening the muscles.

My EF was 15 when I suffered Cardiac Arrest on March 30th. I saw my Cardiologist last week and after an Echo, she informed me my EF has risen to 35. She is very happy with what I'm doing and to keep it up.