Doctors ruled out a heart attack, but the patient had a sense that something was very wrong. The 52-year-old man pushed back from his dinner plate. A terrible pressure radiated across his chest. His first bite of supper felt like an enormous rock scraping its way ever so slowly down to his stomach. It was hard to take a good breath. His face felt flushed and hot. Then, gradually, the grip around his chest seemed to loosen, and he could breathe again.
