SAN FRANCISCO — An ECG mapping device improved the diagnosis of acute coronary syndrome, compared with standard ECG, and provided information that could help with treatment, said Gregory J. Fermann, M.D., at the annual meeting of the American College of Emergency Physicians.
In a study of 90 adult patients, those evaluated in the emergency department for acute coronary syndrome by ECG and cardiac markers underwent both the standard 12-lead ECG and cardiac mapping using the Prime ECG System. Approved in 2001, the Prime ECG uses 72 unipolar leads placed in a vest-like distribution over the front, back, and sides of the patient's torso to obtain a three-dimensional view of cardiac electrical activity. Standard ECG uses six unipolar leads. Both ECG systems use six additional limb leads.
Meridian Medical Technologies, which makes the Prime ECG System, funded the study.
Physicians managing the patients were first given results of the standard ECG and asked to estimate the probability that the patient had acute coronary syndrome. They then received the cardiac mapping results and were asked the same question. The physicians were also asked whether the cardiac mapping gave them additional information, compared with standard ECG, and whether the mapping might help guide treatment. Patients were followed for objective evidence of acute coronary syndrome in the hospital and assessed 30 days after discharge for adverse outcomes.
The investigators compared physicians' responses with the diagnosis of acute coronary syndrome. Estimates based on cardiac mapping were more sensitive than estimates based on standard ECG at identifying acute coronary syndrome (40% vs. 20%). Standard ECG and cardiac mapping showed similar specificity (93% vs. 92%, respectively) in diagnosing acute coronary syndrome, said Dr. Fermann, director of clinical operations at the University of Cincinnati.
Physicians in the study said cardiac mapping provided additional information in 51 of the 90 cases and said the results would assist in treatment in 53 cases, Dr. Fermann reported. The cardiac mapping results increased the likelihood of a diagnosis of acute coronary syndrome in 11 cases and decreased the likelihood in 32 cases. Cardiac mapping was more sensitive than standard ECG in diagnosing a subset of patients who had acute coronary syndrome, those with non-ST segment elevation MI.