Extracellular volume is an independent predictor of arrhythmic burden in dilated cardiomyopathy

Abstract

The current stratification of arrhythmic risk in dilated cardiomyopathy (DCM) is sub-optimal. Cardiac fibrosis is involved in the pathology of arrhythmias; however, the relationship between cardiovascular magnetic resonance (CMR) derived extracellular volume (ECV) and arrhythmic burden (AB) in DCM is unknown. This study sought to evaluate the presence and extent of replacement and interstitial fibrosis in DCM and to compare the degree of fibrosis between DCM patients with and without AB. This is a prospective, single-center, observational study. Between May 2019 and September 2020, 102 DCM patients underwent CMR T1 mapping. 99 DCM patients (88 male, mean age 45.2 ± 11.8 years, mean EF 29.7 ± 10%) composed study population. AB was defined as the presence of VT or a high burden of PVCs. There were 41 (41.4%) patients with AB and 58 (58.6%) without AB. Replacement fibrosis was assessed with late gadolinium enhancement (LGE), whereas interstitial fibrosis with ECV. Overall, LGE was identified in 41% of patients. There was a similar distribution of LGE (without AB 50% vs. with AB 53.7%; p = 0.8) and LGE extent (without AB 4.36 ± 5.77% vs. with AB 4.68 ± 3.98%; p = 0.27) in both groups. ECV at nearly all myocardial segments and a global ECV were higher in patients with AB (global ECV: 27.9 ± 4.9 vs. 30.3 ± 4.2; p < 0.02). Only indexed left ventricular end-diastolic diameter (HR 1.1, 95%CI 1.0–1.2; p < 0.02) and global ECV (HR 1.12, 95%CI 1.0–1.25; p < 0.02) were independently associated with AB. The global ECV cut-off value of 31.05% differentiated both groups (AUC 0.713; 95%CI 0.598–0.827; p < 0.001). Neither qualitative nor quantitative LGE-based assessment of replacement fibrosis allowed for the stratification of DCM patients into low or high AB. Interstitial fibrosis, expressed as ECV, was an independent predictor of AB in DCM. Incorporation of CMR parametric indices into decision-making processes may improve arrhythmic risk stratification in DCM.

Prognostic value of cardiovascular magnetic resonance T1 mapping and extracellular volume fraction in nonischemic dilated cardiomyopathy

“…Nevertheless, this difference of LGE prognostic value in NIDCM patients may be due to the causes of DMC, to differences in the population baseline characteristics but also in LGE evaluation. In our study, almost half of patients without any MACE had an LGE, which is comparable to Rubis et al population [ 12 ] but much higher than Di Marco et al population. The high prevalence in our cohort of LGE in both MACE and without MACE group may explain the lack of prognostic value of LGE, but also suggests a limitation and lack of reproducibility of LGE assessment compared to quantitative tissue characterization based on T1 and ECV.…”

“…Also, T1 was evaluated only in the mid-ventricular short axis slice. The prevalence of arrhythmia-related events also differed from the one found in Rubis et al [ 12 ] who had different outcomes for arrhythmia burden endpoint (presence of VT or high burden of premature ventricular contraction). The consistency in ECV findings may suggest ECV consideration as an additional risk factor along those already included in the brand new 2022 European Society of Cardiology guidelines [ 22 ], while the place of native T1 remains to be further investigated.…”

“…Our results on ECV are consistent with the recent literature. Two recent cohorts analyzed T1 and ECV prognostic value in arrhythmia-related events in NIDCM patients [ 12 , 25 ]. Both studies found that ECV was the strongest independent predictor of arrhythmia-related events with an ECV optimal cut-off value very similar to ours, strengthening the potential role of ECV as a predictive marker of arrhythmia-related events.…”

“…Indeed, T1 mapping performed prior to and after gadolinium injection can provide an estimate for extracellular volume fraction (ECV), which is a quantitative marker of interstitial contrast agent accumulation [ 11 ]. Most studies evaluating T1 mapping parameters were monocentric, based on a single CMR scan, or more focused on HF-related events [ 8 , 12 – 14 ]. Puntmann et al [ 8 ] assessed the prognostic value of T1 mapping parameters in a large multicentric, without special regard of arrhythmic endpoints despite their importance in NIDCM.…”

Comparison of Clinical Course and Outcomes between Dilated and Hypokinetic Non-Dilated Cardiomyopathy

“…Between 2010 and 2021, we managed 890 DCM patients at our centre. All of whom underwent detailed diagnostic work-up [1, 2, 4, 6, 7]. From the initial number, 785 patients were included in the analysis, consisting of those who still fulfilled the criteria of “classic” DCM or HNDC at least a year after diagnosis (e.g., having excluded patients with “supranormal” LV reverse remodelling, resulting in the normalization of LV diameters and/or LVEF – online suppl.…”