Myocardial Scar Imaging: Viability Beyond REVIVED

Abstract Purpose of Review It was previously believed that the presence of myocardial viability in patients with significant coronary artery disease improved outcomes following revascularisation, but the landmark STITCH trial found no significant correlation between viability and overall survival. However, the study used single photon emission contrast tomography or dobutamine stress echocardiography for viability assessment, but late gadolinium enhanced cardiac magnetic resonance imaging (LGE-CMR) has since become the gold standard for viability assessment. Additionally, there has been significant progress in heart failure pharmacotherapy. Leveraging these advances, the REVIVED study authors revisited the role of revascularisation on heart failure patient clinical outcomes. Similar to the STITCH study, REVIVED also identified a lack of correlation between viability and outcomes, confirming its limited role in revascularisation decision making. The purpose of this review is to discuss the advances in myocardial viability imaging and the role of LGE-CMR scar assessment beyond the REVIVED study. Recent Findings Myocardial scar predisposes to ventricular arrythmias and sudden cardiac death (SCD). It is the authors’ opinion that beyond REVIVED, focus should be placed on optimising the management of ventricular arrhythmias through visualisation and characterisation of cardiac scar to improve clinical outcomes. A significant proportion of SCDs occur in patients who remain unprotected if guided by current recommendations. Several studies have confirmed the presence and burden of scar as a better predictor of clinical outcomes in comparison to the current gold standard of left ventricular ejection fraction (LVEF). Summary The potential of machine learning and radiomics to visualise cardiac anatomy and characterise scar, leveraged with the ability to integrate segmented CMR and clinical electroanatomic maps intraoperatively shows promise in improving outcomes in VT ablations and delivering precision treatment based on individual risk.