正常ECG無法排除ACS

Normal ECG During Chest Pain Does Not Rule Out ACS
Among chest pain patients with normal initial ECGs, a similar percentage had acute coronary syndrome whether the ECG was performed when chest pain was present or absent.

A normal electrocardiogram does not exclude acute coronary syndrome (ACS) in patients who present with chest pain, but many clinicians believe that ACS is unlikely to be the cause of the chest pain if the normal ECG was obtained during a pain episode. To clarify this issue, these authors conducted a prospective, observational study of 387 patients who presented to an emergency department with chest pain, had normal initial ECGs, and were admitted for evaluation for ACS.

Patients were divided into two groups, based on whether they had active chest pain during acquisition of the normal initial ECG: 126 had chest pain and 261 did not. ACS was defined as non–ST-segment-elevation myocardial infarction, >70% stenosis on coronary angiography, or positive noninvasive cardiac stress test. The prevalence of ACS did not differ significantly between the groups that did and did not have chest pain when the normal initial ECG was obtained (16% and 20%).

Comment:
Lack of changes on an ECG performed during chest pain often is thought to reduce the likelihood of ACS. Findings from this and a previous study (JW Emerg Med Dec 22 2006) show that this assumption is erroneous and that, in fact, the likelihood of serious cardiac disease in patients who present with chest pain and an initial normal ECG is the same whether or not chest pain was present when the ECG was obtained.

— Diane M. Birnbaumer, MD, FACEP
Published in Journal Watch Emergency Medicine June 12, 2009

Citation(s): Turnipseed SD et al. Frequency of acute coronary syndrome in patients with normal electrocardiogram performed during presence or absence of chest pain. Acad Emerg Med 2009 Jun; 16:495.