Diagnostik af iskaemisk hjertesygdom. Arbejds-ekg versus myokardiescintigrafi og koronararteriografi
Sammanfattning
Introduction: Exercise EKG (EE) is frequently used for the detection of ischaemic heart disease (IHD). Comparisons with coronary angiography (CAG) have called the diagnostic capability of EE into question. We have compared EE with the results of myocardial perfusion imaging (MPI), a physiological imaging modality that demonstrates regional myocardial perfusion directly, and with the results of CAG. Materials and methods: A retrospective survey was performed of 122 patients with known or suspected angina pectoris, all of whom were examined by EE, MPI and CAG. Results: The prevalence of myocardial ischaemia, i.e., regional hypoperfusion as assessed by MPI, was 70%, and the positive and negative predictive values (PVpos and PVneg) were 87% and 41%, respectively (sensitivity 47%, specificity 84%). The values, when compared with those of CAG, were about the same. Among patients with previous myocardial infarction (MI), the prevalence of ischaemia was 91%, PVpos was 95% and PVneg was 11% (sensitivity 44%, specificity 75%). In patients without previous MI, the corresponding figures were 56%, 81% and 57%, respectively (sensitivity 50%, specificity 85%). Discussion: Both the nosographic probabilities and the predictive diagnostic values were in general so low that - despite the limitations of this study - one must question the reliability of EE in diagnosing IHD. In particular, EE was poor in ruling out IHD in that > 50% of patients with a normal EE had ischaemia as judged by MPI.