使用CMR評估肥厚性心肌病變之瀰漫性纖維化對心臟功能的影響

肥厚型心肌病（hypertrophic cardiomyopathy, HCM）是一種少數從嬰兒到老年時期任何階段都有可能發病的遺傳性心血管疾病之一，HCM的特徵為心肌呈現不對稱性左心室肥大，與一般對稱性的心肌肥大不同。而HCM患者也會伴隨著缺血性組織纖維化和瀰漫性心肌纖維化。瀰漫性心肌纖維化可能造成心肌組織缺乏彈性，使得心臟的舒張功能受到影響，心血管磁振造影（cardiovascular magnetic resonance, CMR）是能在一次檢查當中同時評估心肌表徵和心臟功能的儀器。本研究目的是使用CMR評估HCM患者的瀰漫性纖維化對心臟功能的影響。本研究回顧性收集了125位臨床確診HCM的患者及58位臨床上無心肌結構異常的Brugada綜合徵受試者做為控制組。使用造影劑前後的T1 Mapping和Cine圖像來評估心肌的瀰漫性纖維化程度和測量心臟功能指數。使用Mann-Whitney U檢驗分析HCM和控制組之間的組比較，並使用spearman相關係數來評估其關聯性。統計檢驗是兩尾的，統計學意義定義為p＜0.05。結果對於組比較，HCM患者的細胞外體積分率高於控制組（27.5±4.9%對25.0±2.3%，p＜0.001），左心室射血分率（LVEF）明顯較高於控制組（82.3±9.8%對75.9±7.7%，p＜0.001），左心室最大射血分率（LVPER）也與控制組有明顯差異（4.7±1.3 S^(-1)對3.8±0.7 S^(-1)，p＜0.001），左心室最大充盈分率（LVPFR）相較控制組低（3.9±1.4 S^(-1)對4.6±1.0 S^(-1)，p＜0.001）。在關聯性分析方面，細胞外體積分率與左心室最大充盈分率（LVPFR）呈現具統計意義的負相關性（r＝0.21，p＜0.01），在控制組無發現此現象。本研究結果顯示，HCM病患的心肌瀰漫性纖維化也與心臟舒張功能有關，可能代表心肌瀰漫性纖維化導致心肌變厚變硬，使得心臟舒張能力變差，因此，利用心臟磁振造影技術可用來評估肥厚型心肌病患者其瀰漫性纖維化和心臟功能的進展，提供臨床醫師進行診療的參考，避免疾病進一步惡化。

關鍵字

細胞外體積分數；肥厚型心肌病；心血管磁振造影

並列摘要

Hypertrophic cardiomyopathy (HCM) is one of the few inherited cardiovascular diseases that can develop at any stage from infancy to old age. HCM is also associated with ischemic tissue fibrosis and diffuse myocardial fibrosis. Diffuse myocardial fibrosis may cause a lack of elasticity in the myocardial tissue, compromising the diastolic function of the heart. Cardiovascular magnetic resonance (CMR) is a device that can assess both myocardial symptoms and cardiac function in a single visit. Our aim was to evaluate the effect of diffuse fibrosis on cardiac function in patients with HCM using CMR. In this study, 125 patients with clinically confirmed HCM and 58 subjects with Brugada syndrome without clinical myocardial structural abnormalities were retrospectively collected as a control group. Pre- and post-contrast T1 Mapping and Cine images were used to assess the degree of diffuse myocardial fibrosis and to measure cardiac functional indices. Group comparisons between the HCM and control groups were analyzed using the Mann-Whitney U test. The association was assessed using the Spearman correlation coefficient. Statistical tests were two-tailed, with statistical significance defined as p ＜ 0.05. Results for group comparisons were higher in patients with HCM than in controls (27.5±4.9% vs. 25.0±2.3%, p ＜ 0.001), and left ventricular ejection fraction (LVEF) was significantly higher than in controls (82.3±9.8% vs. 75.9±7.7%, p ＜ 0.001). Maximum left ventricular ejection fraction (LVPER) was also significantly different from the control group (4.7±1.3 S^(-1) versus 3.8±0.7 S^(-1), p ＜ 0.001), and maximum left ventricular filling fraction (LVPFR) was lower compared to the control group (3.9±1.4 S^(-1) versus 4.6±1.0 S^(-1), p ＜ 0.001). In the correlation analysis, the extracellular volume fraction showed a statistically significant negative correlation with the left ventricular maximum filling fraction (LVPFR) (r = 0.21, p ＜ 0.01), which was not found in the control group. Our findings suggest that myocardial fibrosis in HCM patients is associated with the diastolic dysfunction, which indicate that myocardial fibrosis causes myocardial thickening and stiffening, resulting in poor diastolic function.

並列關鍵字

ECV ； HCM ； CMR

參考文獻

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