Atypical chest pain renders AMI more likely

A prospective study of 796 ED patients with suspected cardiac chest pain assessed the value of individual historical and examination findings for diagnosing acute myocardial infarction (AMI) and the occurrence of adverse events (death, AMI or urgent revascularization) within 6 months. AMI was diagnosed in 148 (18.6%) of the 796 patients recruited.

The results may surprise some physicians:

Sweating observed by the ED physician was the strongest predictor of AMI (adjusted OR 5.18, 95% CI 3.02–8.86).

Reported vomiting was also a fairly strong predictor of AMI (adjusted OR 3.50, 1.81–6.77).

Pain located in the left anterior chest was found to be the strongest negative predictor of AMI (adjusted OR 0.25, 0.14–0.46).

Patients who described the pain as being the same as previous myocardial ischaemia were significantly less likely to be having AMI!

Following adjustment for age, sex and ECG changes, the following characteristics made AMI more likely (adjusted odds ratio, 95% confidence intervals):

  • pain radiating to the right arm (2.23, 1.24-4.00)
  • pain radiating to both arms (2.69, 1.36-5.36)
  • vomiting reported (3.50, 1.81-6.77), central chest pain (3.29, 1.94-5.61)
  • sweating observed by physician (5.18, 3.02-8.86)

Pain in the left anterior chest made AMI significantly less likely (0.25, 0.14-0.46)
The presence of rest pain (0.67, 0.41-1.10) or pain radiating to the left arm (1.36, 0.89-2.09) did not significantly alter the probability of AMI.

Compare these results with the American Heart Association guidelines which state that “chest or left arm pain or discomfort as the chief symptom reproducing prior documented angina” is associated with a high likelihood of ACS, or the European Society of Cardiology guidelines which state that “the typical clinical presentation of NSTE-ACS is retrosternal pressure or heaviness radiating to the left arm, neck or jaw”, which the authors of this study point out are statements made based on expert opinion for which references are not given.

The authors summarise with a powerful message: ‘Several ‘atypical’ symptoms actually render AMI more likely, whereas many ‘typical’ symptoms that are often considered to identify high-risk populations have no diagnostic value.’

The value of symptoms and signs in the emergent diagnosis of acute coronary syndromes
Resuscitation. 2010 Mar;81(3):281-6