I read up on Da Costa's syndrome because I have never heard of that before. But the article that I read did go on to say that a lot of the symptoms since that time that were grouped and called that, have been identified as different things.
Anxiety and depression can manifest itself in physical problems and can also exacerbate any medical conditions that already exist.
When I meant the syndrome, it is also known a soldiers heart, a form of anxiety state, when gets converted to bodily symptoms(somatization) may very well resemble a heart attack.
I am having these also, they do seem to be almost like a heart attack, I do tend to get scared sometime, but am adjusting better, I do feel like stress is one major factor, and not resting properly..maybe this can help you some on how you are feeling also
It's no surprise you have a panic attack when you get those types of symptoms.
It could be a muscular thing related to muscles and tendons and could also be spine related. Do you have any spinal problems?
Your vision problem and the fact that you have difficulty on concentrating on anything when you experience this spasm, suggests that there is insufficient oxygen getting to the brain. This can happen if you have any neck problems.
Sometimes muscle spasms can just come on by the slightest of movement.
If you keep getting these problems, perhaps you should ask your doctor to send you to get an xray of your spine. Getting a appointment with an ophthalmologist may also be a good idea to rule out any vision problems.
Let me know how you get on.