Quantitative clinical assessment of chronic anterior myocardial infarction with delayed enhancement magnetic resonance imaging and QRS scoring.

ABSTRACT

BACKGROUND: Both the regional and global myocardial extent of chronic myocardial infarction (MI) are important prognostic factors for length and quality of life and also crucial for the choice of therapy in patients with ischemic heart disease. Our aim was to develop and validate techniques for comparison between regional and global size of remote anterior MI in the left ventricle quantified with both magnetic resonance imaging (MRI) and electrocardiogram (ECG). METHODS: Delayed-enhancement (DE) MRI was used as a clinical "gold standard" for MI size to evaluate the extent of MI estimated with the commonly available standard 12-lead ECG. A method for comparing global and regional quantifications of MI with DE-MRI and ECG was developed. The Selvester QRS-scoring system was used for estimating MI size electrocardiographically. RESULTS: Twenty-five patients with chronic single anterior MI, documented with DE-MRI, were studied. The best agreement for mean % MI per regional segment of the left ventricle was found in the middle third (26% vs 27%), whereas the most significant discrepancy was found in the apex (56% vs 30%). The global MI size of the left ventricle averaged 21 +/- 9% with DE-MRI and 22% +/- 12% with ECG, with a correlation of r = 0.40 (P <.05). CONCLUSIONS: The current Selvester QRS scoring system performs well for quantifying anterior MI in the mid-regions of the left ventricle. The diagnostic performance of the Selvester QRS-scoring system for quantifying MI in the other regions, particularly the left ventricular apex, can potentially be improved, with DE-MRI as the gold standard.