Background and objectives: The diagnosis of ischemic (ICM) and non-ischemic cardiomyopathy (NICM) is conventionally determined by the presence or absence of coronary artery disease (CAD) in the setting of a reduced left systolic function. However the presence of CAD may not always indicate that the actual left ventricular (LV) dysfunction mechanism is ischemia, as other non-ischemic etiologies can be responsible. We investigated patterns of myocardial fibrosis using delayed hyperenhancement (DHE) on cardiac magnetic resonance (CMR) in ICM and NICM.
Subjects and methods: Patients with systolic heart failure who underwent a CMR were prospectively analyzed. The heart failure diagnosis was based on the modified Framingham criteria and LVEF <35%. LV dysfunction was classified as ICM or NICM based on coronary anatomy.
Results: A total of 101 subjects were analyzed; 34 were classified as ICM and 67 as NICM. The DHE pattern was concordant with the conventional diagnosis in 27 (79.4%) of the patients with ICM and 62 (92.5%) of the patients with NCIM. A discordant NICM DHE pattern was present in 8.8% of patients with ICM, and an ICM pattern was detected 6.0% of the patients with NICM. Furthermore, 11.8% of the patients with ICM and 1.5% of those with NICM demonstrated a mixed pattern.
Conclusion: A subset of patients conventionally diagnosed with ICM or NICM based on coronary anatomy demonstrated a discordant or mixed DHE pattern. CMR-DHE imaging can be helpful to determine the etiology of heart failure in patients with persistent LV systolic dysfunction.
Keywords: Cardiac imaging technique; Cardiomyopathies; Magnetic resonance imaging.