Two thirds of people who suffer a heart attack experience the slow onset of symptoms, not the sudden and dramatic onset depicted in TV dramas and movies, new research has found.

The findings are the result of a major new Irish study carried out by researchers at the School of Nursing and Midwifery at Trinity College Dublin.

The research, published in the international Journal of Emergency Medicine and funded by the Health Research Board, involved 900 patients across five Irish hospitals.

It studied the type of symptoms experienced by patients who suffered heart attacks and the length of time it took for them to get to hospital.

It found just 35% of them had what is traditionally considered by the public to be the typical presentation of a heart attack - sudden intense and severe onset of symptoms, like chest pain, tightness and discomfort.

The remaining majority experienced what is known as slow-onset Acute Coronary Syndrome (ACS), where the symptoms come on much slower and are milder.

The researchers found that perceptions about heart attack symptoms often contribute to patients delaying seeking pre-hospital assistance.

Slow-onset ACS patients wait on average 1.5 hours longer to arrive at an Emergency Department than those with fast-onset symptoms.

According to the researchers, delays in treatment can have a significant impact on whether a heart attack patient survives and whether they suffer potential damage to the heart muscle.

According to best practice, anyone experiencing a heart attack should get medical treatment within two hours and ideally within one hour of symptom onset.