Interstitial Myocardial Fibrosis Assessed as Extracellular Volume Fraction with Low-Radiation-Dose Cardiac CT

Abstract Background The Catheter Ablation versus Standard Conventional Therapy in Patients with Left Ventricular Dysfunction and Atrial Fibrillation (CASTLE-AF) trial has shown that the catheter ablation (CA) for atrial fibrillation (AF) significantly reduced the risk of death and hospitalization for heart failure in patients with non-ischemic dilated cardiomyopathy (NIDCM) and AF (N Engl J Med 2018; 378:417–27). In addition, the Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction (CAMERA-MRI) study demonstrated that the absence of myocardial fibrosis on late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) is associated with improvement of left ventricular systolic function after CA in NIDCM patients with AF (J Am Coll Cardiol 2017; 70:1949–61). Extracellular volume fraction (ECV) by T1 mapping has emerges as a non-invasive mean to quantify diffuse myocardial fibrosis. Purpose The aim of this study was to compare the predictive value of LGE-MRI and ECV by T1 mapping for the prediction of improvement of LVEF after CA in NIDCM patients. Methods A total of twenty-eight patients with NIDCM and AF (age: 67±10 years; 25 (89%) male; LVEF: 34.1±8.8%) were studied. Using a 1.5T MR scanner and 32 channel cardiac coils, cine MRI, LGE-MRI, pre- and post- T1 mapping images of LV wall at mid-ventricular level (modified Look-Locker inversion recovery sequence) were acquired. Myocardial fibrosis on LGE was defined as area with >5SD signal intensity of normal myocardium. ECV from six segments of mid ventricular level were averaged for each patient. All patients underwent CA for AF, and the improvement of LVEF before and after CA were evaluated by echocardiography. Results All patients restored sinus rhythm after CA at the time of echocardiography. The mean LVEF was 34.1±8.8% before CA and 49.1±12.0% after CA (p<0.001), resulting an improvement of 15.0±11.8%. Significant correlation was found between improvements in LVEF and amount of fibrosis on LGE-MRI (r=−0.40, p=0.034), improvement of LVEF and ECV (r=−0.55, p=0.008). In the ROC analysis, ECV had a higher discriminative ability for the improvement of LVEF after CA compared with amount of fibrosis on LGE-MRI (AUC 0.885 vs 0.650) (Figure). Conclusions In NIDCM patients with AF, ECV by T1 mapping had better predictive ability for improvement of LVEF after CA in comparison to LGE-MRI. ROC curves of ECV and LGE-MRI Funding Acknowledgement Type of funding source: None

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Effect of sarcomere and mitochondria-related mutations on myocardial fibrosis in patients with hypertrophic cardiomyopathy

Journal of Cardiovascular Magnetic Resonance ◽

10.1186/s12968-021-00718-3 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Hyemoon Chung ◽

Yoonjung Kim ◽

Chul-Hwan Park ◽

Jong-Youn Kim ◽

Pil-Ki Min ◽

...

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Myocardial Fibrosis ◽

Nuclear Dna ◽

Volume Fraction ◽

Wide Spectrum ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Gadolinium Enhancement ◽

Uncertain Significance ◽

Mutation Group

Abstract Background Myocardial fibrosis is an important prognostic factor in hypertrophic cardiomyopathy (HCM). However, the contribution from a wide spectrum of genetic mutations has not been well defined. We sought to investigate effect of sarcomere and mitochondria-related mutations on myocardial fibrosis in HCM. Methods In 133 HCM patients, comprehensive genetic analysis was performed in 82 nuclear DNA (33 sarcomere-associated genes, 5 phenocopy genes, and 44 nuclear genes linked to mitochondrial cardiomyopathy) and 37 mitochondrial DNA. In all patients, cardiovascular magnetic resonance (CMR) was performed, including 16-segmental thickness, late gadolinium enhancement (LGE), native and post-T1, extracellular volume fraction (ECV), and T2, along with echo-Doppler evaluations. Results Patients with sarcomere mutation (SM, n = 41) had higher LGE involved segment, % LGE mass, ECV and lower post-T1 compared to patients without SM (n = 92, all p < 0.05). When classified into, non-mutation (n = 67), only mitochondria-related mutation (MM, n = 24), only-SM (n = 36) and both SM and MM (n = 5) groups, only-SM group had higher ECV and LGE than the non-mutation group (all p < 0.05). In non-LGE-involved segments, ECV was significantly higher in patients with SM. Within non-SM group, patients with any sarcomere variants of uncertain significance had higher echocardiographic Doppler E/e’ (p < 0.05) and tendency of higher LGE amount and ECV (p > 0.05). However, MM group did not have significantly higher ECV or LGE amount than non-mutation group. Conclusions SMs are significantly related to increase in myocardial fibrosis. Although, some HCM patients had pathogenic MMs, it was not associated with an increase in myocardial fibrosis.

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Myocardial extracellular volume fraction quantification in an animal model of the doxorubicin-induced myocardial fibrosis: a synthetic hematocrit method using 3T cardiac magnetic resonance

Quantitative Imaging in Medicine and Surgery ◽

10.21037/qims-20-501 ◽

2021 ◽

Vol 11 (2) ◽

pp. 510-520

Author(s):

Zhen Zhou ◽

Rui Wang ◽

Hui Wang ◽

Yi Liu ◽

Dongxu Lu ◽

...

Keyword(s):

Animal Model ◽

Cardiac Magnetic Resonance ◽

Magnetic Resonance ◽

Myocardial Fibrosis ◽

Volume Fraction ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Synthetic Hematocrit

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Abstract 16663: Importance of Assessment for Diffuse Ventricular Fibrosis in Atrial Fibrillation Using Cardiac Ct-Derived Myocardial Extracellular Volume Fraction

Circulation ◽

10.1161/circ.142.suppl_3.16663 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Hisanori Kanazawa ◽

Miwa Ito ◽

Yusei Kawahara ◽

Tadashi Hoshiyama ◽

Kenichi Tsujita

Keyword(s):

Atrial Fibrillation ◽

Cardiac Ct ◽

Volume Fraction ◽

Extracellular Volume ◽

Extracellular Volume Fraction ◽

Left Ventricular ◽

Volume Index ◽

Characteristic Analysis ◽

Recurrence Group ◽

Af Recurrence

Introduction: Previous cardiac MRI studies reported that the baseline diffuse LV fibrosis status should be evaluated before performing catheter ablation (CA) to identify the responders early and triage them with appropriate treatment. However, no study has been conducted to evaluate diffuse LV fibrosis in conjunction with pre-ablation planning cardiac CT. Objectives: The purpose of this study was to quantify diffuse left ventricular (LV) fibrosis by the CT-derived extracellular volume fraction (CT-ECV%) in conjunction with cardiac CT performed for CA planning and evaluate its determinants in patients with atrial fibrillation (AF). Methods: Prior to AF ablation, 98 patients (50 patients with paroxysmal AF and 48 patients with persistent AF) underwent pre-ablation planning cardiac CT. Additionally, delayed cardiac CT was performed to measure CT-ECV% as an index of diffuse myocardial fibrosis. Results: Persistent AF patients more frequently had a history of heart failure. Left atrial (LA) volume index was greater in persistent AF patients compared with paroxysmal AF patients. CT-ECV% of persistent AF patients was significantly higher than that of paroxysmal AF patients (30 ± 5 % vs. 26 ± 5 %, p < 0.001). Univariate and multivariate analysis revealed that only persistent AF was independent associated with CT-ECV%. Furthermore, CT-ECV% in recurrence group after CA for AF was higher than that in non-recurrence group (29 ± 4 % vs. 26 ± 5 %, p = 0.013). Multivariate logistic regression analysis revealed that CT-ECV% was significantly correlated with AF recurrence after CA for AF. Receiver operating characteristic analysis showed that more than 28 % in the CT-ECV% was a significant predictor of AF recurrence (area under the curve 0.692, log-rank test: p < 0.001). Conclusions: The quantification of diffuse LV fibrosis by CT-ECV% in conjunction with pre-ablation planning cardiac CT is feasible in AF patients, and persistent AF is independently associated with increasing diffuse LV fibrosis. Furthermore, CT-ECV% was significantly associated with AF recurrence after CA for AF. These findings suggested that it was more important to evaluate cardiac remodeling using CT and intervene early in AF.

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