Role of Cardiac Magnetic Resonance Imaging in Detecting Myocardial Viability in Patients with Chronic Ischaemic Heart Disease: A Prospective Observational Study

Introduction: Myocardial viability refers to a phenomenon in which dysfunctional myocardium, due to acute or chronic ischaemia, retains the potential to recover its systolic function after revascularisation. The assessment of myocardial viability using Contrast-enhanced Magnetic Resonance Imaging (CEMRI) has become a quintessential imaging method for the guidance of treatment in patients with Myocardial Infarction (MI). Aim: To assess cardiac morphology, function, perfusion and myocardial viability in patients with chronic ischaemic heart disease, and to stratify patients into conservative and operative management based on the myocardial viability. Materials and Methods: The present hospital-based prospective observational study was conducted in the Department of Radiodiagnosis, Gauhati Medical College and Hospital, Guwahati, Assam, India, from April 2021 to October 2022. A total of 50 patients with a prior history of MI and abnormal findings on electrocardiography and echocardiography were subjected to cardiac MRI (3 Tesla). Functional parameters like wall motion and Left Ventricular Ejection Fraction (LVEF) were evaluated along with perfusion scan. On Late Gadolinium Enhancement (LGE) scan, patients were classified into two categories: ≤50% LGE (viable) and >50% LGE (non viable). The quantitative values like age and LVEF were summarised as mean and Standard Deviation (SD) based on the distribution of data. A Pearson’s correlation test was done to check the correlation between various parameters. A p-value (using Chi-square test) of less than 0.05 was considered statistically significant. Results: The mean age was 52±14 years. A total of 27 (54%) patients were males and 23 (46%) patients were females. Out of 50 patients, 17 showed an LGE score ≤50%, while 33 showed an LGE score >50%. The segments showing >50% LGE showed more severe wall motion abnormalities than those with ≤50% LGE (p-value <0.005). There was positive correlation between perfusion defect and LGE (Pearson’s correlation 0.951). Out of 17 patients in LGE ≤50% group, 15 (88.2%) patients had clinical improvement, whereas out of 33 patients in the LGE >50% group, only 2 (6.10%) patients had clinical improvement following coronary revascularisation. Conclusion: Delayed Enhanced-Cardiac Magnetic Resonance (DE-CMR) imaging assesses severity of the infarcted myocardium and helps in predicting recovery following intervention.