Background: Patients with non-ischemic cardiomyopathy exhibit a range of myocardial fibrosis (MF) patterns on cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) imaging. Data suggests that ring-like MF is associated with worse prognosis. In the present study it was sought to analyze the prevalence of parametric mapping abnormalities in ring-like MF and their prognostic value for arrhythmic events.
Methods: Patients undergoing clinical CMR at 1.5T/3T were evaluated for ring-like MF defined as midwall/subepicardial fibrosis involving ≥ 3 contiguous left ventricular segments. CMR protocol included cine imaging, T1 and T2 mapping, and LGE. Mean native T1, ECV, and T2 values and a number of mid short axis segments with elevated values were calculated. LGE extent was assessed segmentally. Arrhythmic outcomes were defined as appropriate device shock, premature ventricular contractions ≥ 10%, non-sustained/sustained ventricular tachycardia, or ventricular fibrillation.
Results: In total 49 patients (53 ± 17 years, 26.5% female) were analyzed. Many patients had elevated global/segmental mapping values: 45%/76% in native T1, 57%/57% in T2, and 57%/78% in ECV. During median follow-up of 12 months, arrhythmic events occurred in 65% of patients. There was no association between native T1/T2 elevation or number of LGE segments and arrhythmic outcomes. There was a significant association between ECV and arrhythmic outcomes, both septal ECV (p = 0.036) and any segmental ECV elevation (p = 0.03).
Conclusion: T1 and T2 myocardial tissue abnormalities are common in patients with ring-like MF. ECV elevation was associated with arrhythmic events in this cohort. Further studies are needed to establish the diagnostic and prognostic value of parametric mapping in patients with ring-like MF.
Keywords: cardiovascular magnetic resonance imaging; parametric mapping; ring like fibrosis; ventricular arrhythmia.