Someone suffering an attack usually has up to two hours to get emergency treatment, but the key is in recognizing the symptoms of an attack, such as sudden breathlessness, discomfort, tiredness and pains, usually in the chest and arms.
But when these symptoms are occurring over a few hours, sufferers may not realize they're experiencing a heart attack, and gradual attacks don't usually follow physical exertion—often the case with a sudden, acute, case—which can be another reason why people don't realize what's happening.
Researchers from the University of Illinois realized that gradual attacks are not being recognized when they examined 474 heart attack (myocardial infarction) cases that were treated in emergency wards.
Of the 261 cases of acute, or sudden, heart attack, 54 per cent had happened after physical exertion, and 207 patients had experienced gradual symptoms that hadn't had an obvious cause. It was these sufferers in particular who needed to know they were suffering a heart attack, and to get to hospital immediately. The optimum time to treat is up to two hours after an attack, and heart tissue is permanently damaged after six hours without treatment, the researchers say.