In patients with acute myocardial infarction but no signs of heart failure, intravenous infusion of glucose, insulin, and potassium reduces mortality by almost three quarters, according to an article in the September 3rd issue of the Journal of the American College of Cardiology. Researchers believe that glucose provides most of the benefit, with potassium and insulin acting as facilitators of glucose entry into myocardial cells.

"In the subgroup of patients without signs of heart failure at admission, the addition of glucose-insulin-potassium infusion to primary coronary angioplasty significantly reduced mortality. Over 9 out of 10 patients belong to this subgroup," said Iwan C. C. van der Horst, MD, lead author of the Dutch study.

From April 1998 to September 2001, 940 Dutch patients admitted for myocardial infarction who were evaluated for same-day angioplasty treatment were randomly assigned to either a continuous glucose-insulin-potassium infusion for 8 to 12 hours or to no infusion. All patients received angiography testing and angioplasty, if indicated.

Overall, there was no statistically significant difference in 30-day mortality rates for the control group (5.8 percent) compared with the glucose-insulin-potassium infusion group (4.8 percent). However, when 84 patients showing signs of heart failure were removed from the analysis, a clear benefit appeared among the 856 remaining patients. In this subgroup, which included roughly 90 percent of patients, the 30-day mortality was almost 72 percent lower among the patients receiving the infusion (1.2 percent vs. 4.2 percent).

Although the researchers said this study does not explain why a glucose-insulin-potassium infusion would not help patients with heart failure, they noted that the large fluid volume of the infusion is a concern.

Lead author van der Horst said, "Also the effect of glucose-insulin-potassium on secondary endpoints is interesting. In this article the effect of glucose-insulin-potassium on recurrent myocardial infarction and repeat angioplasty are mentioned. The combined endpoint of 30-day mortality, recurrent myocardial infarction, and repeat angioplasty was significantly lower in patients without signs of heart failure treated with glucose-insulin-potassium. And even in the overall population, after correction for baseline differences, a strong trend was observed."

Despite the dramatic apparent benefit among the majority of patients in this study, the researchers said their results need to be confirmed. "To change current recommendations on the treatment of patients with acute myocardial infarction, it is likely that a new study has to confirm the beneficial results of the glucose-insulin-potassium infusion," van der Horst said.

Carl S. Apstein, MD, who wrote an editorial in the journal, called the results reported by van der Horst et al. remarkable: "I consider this to be a landmark study for the treatment of myocardial infarction. It has the potential to reduce the absolute mortality rate by 3 percent, saving approximately 30,000 lives per year, if one could extrapolate this Dutch study to the U.S., and there's no reason why one couldn't."

Apstein said follow-up studies should be undertaken in the United States, including some that could investigate whether earlier initiation of the glucose-insulin-potassium infusion might offer additional benefit. He said that the generic solution is inexpensive and could be easily included in standard therapy if follow-up studies confirm the life-saving benefit seen in the current trial.