Computer analyzes cause of chest pain.

Diagnosing a heart attack - and deciding how to treat it - is not an exact science. Even with an electrocardiogram (ECG) and a complete medical history, about three percent of emergency room patients who are having heart attacks are misdiagnosed and sent home.

A new piece of software that works with an electrocardiograph may help lower that percentage, as well as cut back dramatically on the unnecessary hospital admissions of ER patients who have chest pain unrelated to their hearts. Studies indicate that two-thirds of people who go to emergency rooms with chest pain are not having heart attacks, but about half of them are hospitalized anyway.

The software computes and prints at the top of the ECG the probability that a particular patient is having a heart attack, giving physicians one more evaluative tool to use in diagnosis. The calculation - based on a mathematical formula developed by a team at the New England Medical Center and Tufts University School of Medicine - factors in the ECG, whether chest pain is a primary complaint, and the patient's age and sex.

The computations of the Acute Cardiac Ischemia Time-Insensitive Predictive Instrument (ACI-TIPI)...