Seeking treatment immediately after heart attack symptoms begin could reduce heart damage, according to new research published online in JACC: Cardiovascular Interventions.

A heart attack occurs every 43 seconds in the United States and affects about 735,000 Americans annually, according to the Centers for Disease Control and Prevention. Symptoms of this cardiac event, which occurs when a part of the heart muscle suddenly becomes blocked and the heart can't get oxygen, includes shortness of breath, tightness or pain in the chest, lightheadedness and nausea. The more time that passes without treatment to restore blood flow, the greater the damage to the heart muscle.

The study revealed that in about 90 percent of cases involving percutaneous coronary intervention, a procedure used to open blocked coronary arteries, blood flow is restored in the surface of the heart, but in about one-third of patients, blood flow is not restored to the heart. This is possibly due to delays in recognizing symptoms and seeking treatment.

Researchers compared the impact of the time from the onset of heart attack symptoms to heart attack to treatment and door-to-balloon time — the time from when a heart attack patient arrives in the emergency room until they receive treatment to restore blood flow — on heart muscle function.

"This study highlights the need to reconsider the role of door-to-balloon as a performance metric and examine the utility of a broader metric of systems delay such as first medical contact to balloon time as well as total ischemic time," study author Roxana Mehran said in a statement.

American College of Cardiology(ACC)/American Heart Association guidelines state that hospitals treating patients who have had a full-blown heart attack with emergency percutaneous coronary intervention should do so within 90 minutes or less of reaching the hospital. The ACC launched the Door-to-Balloon (D2B) Alliance in 2006 in an effort to reduce the time it takes to treat heart attack patients once they arrive at the hospital.

Researchers examined the records of more than 2,000 people who enrolled in a trial that compared patients with symptom onset-to-balloon time in three categories: 1) two hours and less, 2) more than two hours to four hours, and 3) more than four hours.

They found that people who took a total of two to four hours or longer from the onset of symptoms to get treated with a balloon angioplasty to restore blood flow to the heart were less likely to have blood flow fully restored to the heart and were more likely to die within three years than patients treated more quickly.

"The decrease in median door-to-balloon time in recent years has not resulted in a reduction in mortality in [heart attack] patients," study author Roxana Mehran said in a statement.

The findings illustrate that in addition to the door-to-balloon metric, physicians should also pay attention to symptoms and signs of the onset of ischemia, which is loss of blood flow, as the relationship between the delay in treatment was more robust for ischemia duration from the onset of symptoms to treatment than the door-to-balloon time.

Source: Prasad A, Gersh B, Mehran R, et al. Effect of Ischemia Duration and Door-to-Balloon Time on Myocardial Perfusion in ST-Segment Elevation Myocardial Infarction. JACC: Cardiovascular Interventions. 2015.