I read your question and I understand your concern. Yes the two things can be connected. First if he s had a heart attack with some residual damage he might be prone to heart arrhythmias which are a main risk factor for stroke and stroke can manifest with seizures. Another possibility is the eventuality of a stroke related to damage directly to brain supplying blood vessels. We already know he has had impairment and blockage of heart vessels and since blood vessels are damaged by the same factors, chances are other vessels in his body including his cerebral blood vessels are involved as well. So stroke whether generated from heart or cerebral vessels could cause his seizure. Of course that is if it was indeed a seizure, at times loss of consciousness could be a case of syncope related to his heart problems. If the episode is indicative of a seizure then he should be evaluated with brain imaging for stroke or other possible brain lesions as well as EEG for brain epileptiform activity. I hope to have been of help.