Can an infected tooth cause heart attack?

Yes of course it can! It may lead to a cardiovascular disease. Also a rotten tooth may cause a Heart disease.

An infected tooth may cause myocarditis which is the weakening of the heart muscle, but it can't cause, at least directly, a heart attack. If not treated it may lead to many serious health troubles. However, except for uncultured people, living in undeveloped countries, it is very simple to cure.