ABSTRACT
Introduction: The presence of a Q-wave on a 12-lead electrocardiogram (ECG) has been considered a marker of a large myocardial infarction (MI). However, the correlation between the presence of Q-waves and nonviable myocardium is still controversial. The aims of this study were to 1) test QWA, a novel ECG approach, to predict transmural extent and scar volume using a 3.0 Tesla scanner, and 2) assess the accuracy of QWA and transmural extent. Methods: Consecutive patients with a history of coronary artery disease who came for myocardial viability assessment by CMR were retrospectively enrolled. Q-wave measurements parameters including duration and maximal amplitude were performed from each surface lead. A 3.0 Tesla CMR was performed to assess LGE and viability. Results: Total of 248 patients were enrolled in the study (with presence (n ¼ 76) and absence of pathologic Q-wave (n ¼ 172)). Overall prevalence of pathologic Q-waves was 27.2% (for LAD infarction patients), 20.0 % (for LCX infarction patients), and 16.8% (for RCA infarction patients). Q-wave area demonstrated high performance for predicting the presence of a nonviable segment in LAD territory (AUC 0.85, 0.77e0.92) and a lower, but still significant performance in LCX (0.63, 0.51e0.74) and RCA territory (0.66, 0.55e0.77). Q-wave area greater than 6 ms mV demonstrated high performance in predicting the presence of myocardium scar larger than 10% (AUC 0.82, 0.76e0.89). Conclusion: Q-wave area, a novel Q-wave parameter, can predict non-viable myocardial territories and the presence of a significant myocardial scar extension.
ABSTRACT
In patients with non-ischemic cardiomyopathy (NICM), risk stratification for sudden cardiac death (SCD) and selection of patients who would benefit from prophylactic implantable cardioverter-defibrillators remains challenging. We aim to discuss the evidence of cardiac magnetic resonance (CMR)-derived myocardial scar for the prediction of adverse cardiovascular outcomes in NICM. From the 15 studies analyzed, with a total of 2747 patients, the average prevalence of myocardial scar was 41%. In patients with myocardial scar, the risk for adverse cardiac events was more than 3-fold higher, and risk for arrhythmic events 5-fold higher, as compared to patients without scar. Based on the available observational, single center studies, CMR scar assessment may be a promising new tool for SCD risk stratification, which merits further investigation.