Gradual symptoms begin with mild discomfort that slowly worsens, while abrupt symptoms are sudden and severe pain, according to authors of a study published Sept. 12 in the European Journal of Cardiovascular Nursing.
"Both are a medical emergency and require urgent help," said study author Sahereh Mirzaei, from the University of Illinois at Chicago. "But our study shows that gradual symptoms are not taken seriously."
She and her team analyzed data from 474 heart attack patients seen at U.S. emergency departments. Symptoms were gradual in 44% and abrupt in 56% of these patients.
Overall, the average time between the start of symptoms and arrival at the hospital was four hours. Those with gradual symptoms waited eight hours to seek medical help, compared to 2.6 hours for those with abrupt symptoms.
A delay of no more than two hours is recommended for the best outcomes. Waiting longer increases patients' risk of serious complications and death, according to the researchers.
Both women and men sought medical help sooner when they had abrupt symptoms.
"Nearly half of patients had a slow onset, so this is not uncommon," Mirzaei said in a journal news release.
"Chest pain, chest discomfort, and chest pressure are warning signs that an artery may be blocked, and patients should call the emergency medical services immediately," she said.
Arrival by ambulance was associated with quicker medical care, but only 45% of patients called for one; 52% used their own transportation, and 3% were transferred from another hospital.
Uninsured patients were more likely to delay calling for help, the study found.
It also found that symptoms were triggered by exertion, such as running, climbing stairs or shoveling snow, in 54% of men with abrupt onset and a diagnosis of ST-elevation myocardial infarction. Also known as STEMI, this is a particularly serious type of heart attack requiring quick restoration of blood flow to blocked arteries.
Mirzaei said men with ischemic heart disease or multiple risk factors such as high blood pressure, diabetes, high cholesterol or a family history of heart disease should be aware that chest pain or discomfort after physical activity or exercise could be a heart attack.
"Symptoms can also include pain in the throat, neck, back, stomach or shoulders, and may be accompanied by nausea, cold sweat, weakness, shortness of breath, or fear," she said. "Call an ambulance straight away; the sooner you get help, the better your prognosis."