Detecting Transient Myocardial Ischemia in the Context of Acute Coronary Syndrome in the Emergency Department

Diagnostic value of the left atrial electrical potentials detected by body surface potential mapping in the prediction of coronary artery disease

BACKGROUND

The electrocardiographic diagnosis of significant coronary artery stenosis (CAD) is often based on the investigation of the left ventricular repolarization changes during exercise ECG stress test (EST). Our aim was to prove that the electric activity of the left atrium can indicate the ischemic damage of the left ventricle, and furthermore, it is able to indicate CAD without exercise.

METHODS AND RESULTS

Patients with chest complaints but without evidence of acute coronary syndrome were investigated by EST and body surface potential mapping (BSPM, 63 leads). CAD was proven in 45 cases (32 men, years 40-76) and excluded in 50 cases (35 men, years 38-72) with coronary angiography. Left atrial electric potentials (EP-LA) before and after 0.08 mg sublingual nitroglycerine administration differed significantly (p<0.001) in the two groups. According to Fischer linear discriminant analysis, this difference in % (EP-LA(d%)) was the best separating parameter: below limit of -14.17% (CAD prevalence was considered) this parameter predicted CAD with 93% sensitivity, 100% specificity, >10 positive and 0.05 negative likelihood ratio (weighted for prevalence). The EST predicted CAD with 71% sensitivity, 78% specificity, 2.43 positive and 0.28 negative likelihood ratios.

CONCLUSION

The electrical activity changes of the left atrium seemed to be suitable to predict CAD as an EST-alternative resting method.