Are you taking any meds? I have coronary spasms also, and I have Nitro and take a ccb to keep these under control. You can improve your heart function with diet exercise and meds. And making some lifestyle changes.
"Does a minor heart attack always lead to cardiomyopathy or to a progressive deterioration over time?"
No. Have they given you a Nitro spray to use should another attack occur? The problem you face is a situation with no warning. The spasms must contrict the artery a considerable amount for a heart attack to result and so I assume they have warned you of this? In some people there is a trigger for the spasm, but it is very rare to find that trigger. Medication is important to try and keep them at bay and the first line of defence is usually a NItro patch. However, these don't help everyone and the second line of defence is usually Calcium channel blockers. Tiny tubes (channels) in artery linings allow calcium to be absorbed into the artery muscle which is used in a chemical reaction to create energy, allowing the muscle to tighen the artery, making the area for blood flow less. However, calcium channel blockers prevent the absorption of calcium from the blood. The more the dosage the higher the restriction. The lack of calcium availability to the artery muscle makes it harder work for it to function, but at the same time stops it having the energy to have a spasm.
The other side of this is that calcium channel blockers work on smooth muscle function, and the heart itself is smooth muscle. The calcium channel blockers will work in a similar way to beta blockers, keeping the heart more relaxed. This again depends on the dosage as to how much effect it has. There are a few theories as to why spasm occurs, one being that the build up of fats inside the lining can cause it.
would suggest a ref to cardiologist to asess you!!