New way to abate heart attacks before patients get to the hospital

The study showed that patients who received GIK immediately after being diagnosed with acute coronary syndrome -- which indicates a heart attack is either in progress or on the way -- were 50 percent less likely to have cardiac arrest (a condition in which the heart suddenly stops beating) or die than those who received a placebo, although the treatment did not prevent the heart attack from occurring. Over the first month following the event, patients who received GIK were 40 percent less likely to have cardiac arrest, die or be hospitalized for heart failure.

The effect was even more striking for patients with ST-elevation heart attacks, which require immediate treatment. For those patients, immediate GIK was associated with a 60 percent reduction in cardiac arrest or death.

"When started immediately in the home or on the way to the hospital -- even before the diagnosis is completely established -- GIK appears to reduce the size of heart attacks and to reduce by half the risk of having a cardiac arrest or dying," said Harry P. Selker, MD, MSPH, executive director of the Institute for Clinical Research and Health Policy Studies at Tufts Medical Center, who led the study with Joni Beshansky, RN, MPH, co-principal investigator and project director. "Acute coronary syndromes represent the largest cause of death in this country. GIK is a very inexpensive treatment that appears to have promise in reducing those deaths and morbidity."

The cost of the treatment is about $50.

"Because the trial is the first to show GIK is effective when used by paramedics in real-world community settings, it could have important implications for the treatment of heart attacks," Dr. Selker said. Previous clinical trials have shown no consistent effect, likely because the GIK was given too late to help. This study, the "IMMEDIATE Trial," was the first to test the effectiveness of administering GIK at the very first signs of a threatening heart attack, in the community, rather than waiting hours until the diagnosis was well-established at a hospital, as done in previous clinical trials.

"We wanted to do something that is effective and can be used anywhere," said Dr. Selker. "We've done a lot of studies of acute cardiac care in emergency departments and hospitals, but more people die of heart attacks outside the hospital than inside the hospital. Hundreds of thousands of people per year are dying out in the community; we wanted to direct our attention to those patients."

The researchers trained paramedics in 36 Emergency Medical Services systems in 13 cities across the country to administer GIK after determining that a patient was likely having a threatened or already established heart attack using electrocardiograph-based ACI-TIPI (acute cardiac ischemia time-insensitive predictive instrument) and thrombolytic predictive instrument decision support that prints patient-specific predictions on the top of an electrocardiogram. The paramedics used these predictions to decide if a patient would likely benefit from treatment. There were 911 patients randomized to receive either the GIK treatment or a placebo.

Administering GIK immediately also reduced the severity of the damage to the heart tissue from the heart attack. On average, 2 percent of the heart tissue was destroyed by the heart attack in people receiving GIK, compared with 10 percent in those who received the placebo. Although a significant proportion of suspected heart attacks are later determined to be false alarms (23 percent in this study), administering GIK does not appear to cause any harmful effects in such patients.

The research team will follow up with study participants at six and 12 months to evaluate the longer-term benefit of the GIK treatment.

This study was funded by the NIH's National Heart, Lung and Blood Institute.