The value of cardiac magnetic resonance in patients with acute coronary syndrome and normal coronary arteries

INTRODUCTION AND OBJECTIVES

A number of different conditions can present with symptoms similar to acute coronary syndrome (ACS): chest pain, electrocardiographic changes and elevated levels of markers of myocardial damage. Even after coronary angiography has been performed, differential diagnosis can be challenging. The aim of this study was to evaluate the usefulness of cardiac magnetic resonance (CMR) for diagnosing conditions that present like ACS but in which the coronary arteries are normal.

METHODS

The study involved 80 patients with suspected ACS and normal coronary arteries. Their mean age was 48+/-15 years and their mean troponin-T (TnT) level was 1.8+/-0.9 ng/ml. A CMR study, which involved T2-weighted imaging to detect edema and delayed contrast-enhancement (DCE) imaging 10 minutes after gadolinium administration, was performed.

RESULTS

In 51 patients (63%), the final diagnosis was acute myocarditis. In all these cases, DCE was observed in subepicardial and middle segments of the myocardium. The final diagnosis was acute myocardial infarction in 12 patients (15%), all of whom exhibited subendocardial or transmural DCE. In the 9 (11%) who exhibited abnormal contractility on baseline echocardiography with subsequent normalization, CMR did not show DCE, a finding that is characteristic of Takotsubo cardiomyopathy. In addition, 4 patients had a final diagnosis of pericarditis, while no diagnosis could be established in another 4.

CONCLUSIONS

The clinical presentation of acute myocarditis and Takotsubo syndrome can be similar to that of ACS. The presence and distribution of DCE on CMR are of great help in establishing a diagnosis.