Can you tell me the difference between heart failure from myocardial infarction?

Yes: Heart failure is a condition where the heart does not function normally causing shortness of breath, ankle swelling, and a variety of other symptoms. There may be 100 or more heart conditions that can result in congestive heart failure. Myocardial infarction occurs when a heart artery closes resulting in damage to the muscle of the heart. This may or may not result in congestive heart failure.

Yes: Myocardial infarction ("heart attack") is permanent injury to heart muscle from lack of blood supply. Heart failure is a syndrome that can occur from many causes when the heart doesn't pump effectively. One of those causes can be myocardial infarction but CHF can also occur from high blood pressure, valve abnormalities, rhythm disturbances, infection, tumor, senescence and many, many other causes.

Blockage vs Weakness: Myocardial infarction is the end-product of ischemia, or reduced blood flow due to a coronary artery blockage. An infarct, or heart attack, results in death of that part of the heart muscle that was starved of blood. Heart failure can result after an mi but otherwise is due to other medical factors which results in a weakened portion of the heart. This causes decreased pump efficiency.

HF and MI: Hf is due to ineffective pumping action of the heart resulting in fluid overload. Mi is due to blockage of one or several arteries that supply and nourish the heart. It might result in various complications.