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Abstract：
BACKGROUND: The left ventricular (LV) changes which occur in Friedreich ataxia (FRDA) are incompletely understood.
METHODS: Cardiac magnetic resonance (CMR) imaging was performed using a 1.5T scanner in subjects with FRDA who are homozygous for an expansion of an intron 1 GAA repeat in the FXN gene. Standard measurements were performed of LV mass (LVM), LV end-diastolic volume (LVEDV) and LV ejection fraction (LVEF). Native T1 relaxation time and the extracellular volume fraction (ECV) were utilised as markers of left ventricular (LV) diffuse myocardial fibrosis and late gadolinium enhancement (LGE) was utilised as a marker of LV replacement fibrosis. FRDA genetic severity was assessed using the shorter FXN GAA repeat length (GAA1).
RESULTS: There were 93 subjects with FRDA (63 adults, 30 children, 54% males), 9 of whom had a reduced LVEF (<55%). A LVEDV below the normal range was present in 39%, a LVM above the normal range in 22%, and an increased LVM/LVEDV ratio in 89% subjects. In adults with a normal LVEF, there was an independent positive correlation of LVM with GAA1, and a negative correlation with age, but no similar relationships were seen in children. GAA1 was positively correlated with native T1 time in both adults and children, and with ECV in adults, all these associations independent of LVM and LVEDV. LGE was present in 21% of subjects, including both adults and children, and subjects with and without a reduced LVEF. None of GAA1, LVM or LVEDV were predictors of LGE.
CONCLUSIONS: An association between diffuse interstitial LV myocardial fibrosis and genetic severity in FRDA was present independently of FRDA-related LV structural changes. Localised replacement fibrosis was found in a minority of subjects with FRDA and was not associated with LV structural change or FRDA genetic severity in subjects with a normal LVEF.
METHODS: Cardiac magnetic resonance (CMR) imaging was performed using a 1.5T scanner in subjects with FRDA who are homozygous for an expansion of an intron 1 GAA repeat in the FXN gene. Standard measurements were performed of LV mass (LVM), LV end-diastolic volume (LVEDV) and LV ejection fraction (LVEF). Native T1 relaxation time and the extracellular volume fraction (ECV) were utilised as markers of left ventricular (LV) diffuse myocardial fibrosis and late gadolinium enhancement (LGE) was utilised as a marker of LV replacement fibrosis. FRDA genetic severity was assessed using the shorter FXN GAA repeat length (GAA1).
RESULTS: There were 93 subjects with FRDA (63 adults, 30 children, 54% males), 9 of whom had a reduced LVEF (<55%). A LVEDV below the normal range was present in 39%, a LVM above the normal range in 22%, and an increased LVM/LVEDV ratio in 89% subjects. In adults with a normal LVEF, there was an independent positive correlation of LVM with GAA1, and a negative correlation with age, but no similar relationships were seen in children. GAA1 was positively correlated with native T1 time in both adults and children, and with ECV in adults, all these associations independent of LVM and LVEDV. LGE was present in 21% of subjects, including both adults and children, and subjects with and without a reduced LVEF. None of GAA1, LVM or LVEDV were predictors of LGE.
CONCLUSIONS: An association between diffuse interstitial LV myocardial fibrosis and genetic severity in FRDA was present independently of FRDA-related LV structural changes. Localised replacement fibrosis was found in a minority of subjects with FRDA and was not associated with LV structural change or FRDA genetic severity in subjects with a normal LVEF.
摘要：
背景：Friedreich共济失调（FRDA）中发生的左心室（LV）变化尚未完全了解。
方法：使用1.5T扫描仪对FXN基因内含子1GAA重复扩增纯合的FRDA受试者进行心脏磁共振（CMR）成像。对左心室质量(LVM)进行标准测量，左室舒张末期容积(LVEDV)和左室射血分数(LVEF)。利用固有T1弛豫时间和细胞外体积分数（ECV）作为左心室（LV）弥漫性心肌纤维化的标志物，并利用晚期钆增强（LGE）作为LV替代纤维化的标志物。使用较短的FXNGAA重复长度(GAA1)评估FRDA遗传严重程度。
结果：有93名受试者患有FRDA（63名成人，30个孩子,54%的男性），其中9人的LVEF降低（<55％）。低于正常范围的LVEDV为39%，LVM高于正常范围22%，89％受试者的LVM/LVEDV比率增加。在LVEF正常的成年人中，LVM与GAA1呈独立正相关,与年龄呈负相关,但是在儿童中没有看到类似的关系。在成人和儿童中，GAA1与原生T1时间呈正相关。成人的ECV，所有这些关联独立于LVM和LVEDV。LGE出现在21%的受试者中，包括成人和儿童，以及具有和不具有降低的LVEF的受试者。GAA1、LVM或LVEDV均不是LGE的预测因子。
结论：弥漫性间质性LV心肌纤维化与FRDA基因严重程度之间的关联独立于FRDA相关的LV结构变化。在少数FRDA受试者中发现了局部替代纤维化，并且在LVEF正常的受试者中与LV结构变化或FRDA遗传严重程度无关。
方法：使用1.5T扫描仪对FXN基因内含子1GAA重复扩增纯合的FRDA受试者进行心脏磁共振（CMR）成像。对左心室质量(LVM)进行标准测量，左室舒张末期容积(LVEDV)和左室射血分数(LVEF)。利用固有T1弛豫时间和细胞外体积分数（ECV）作为左心室（LV）弥漫性心肌纤维化的标志物，并利用晚期钆增强（LGE）作为LV替代纤维化的标志物。使用较短的FXNGAA重复长度(GAA1)评估FRDA遗传严重程度。
结果：有93名受试者患有FRDA（63名成人，30个孩子,54%的男性），其中9人的LVEF降低（<55％）。低于正常范围的LVEDV为39%，LVM高于正常范围22%，89％受试者的LVM/LVEDV比率增加。在LVEF正常的成年人中，LVM与GAA1呈独立正相关,与年龄呈负相关,但是在儿童中没有看到类似的关系。在成人和儿童中，GAA1与原生T1时间呈正相关。成人的ECV，所有这些关联独立于LVM和LVEDV。LGE出现在21%的受试者中，包括成人和儿童，以及具有和不具有降低的LVEF的受试者。GAA1、LVM或LVEDV均不是LGE的预测因子。
结论：弥漫性间质性LV心肌纤维化与FRDA基因严重程度之间的关联独立于FRDA相关的LV结构变化。在少数FRDA受试者中发现了局部替代纤维化，并且在LVEF正常的受试者中与LV结构变化或FRDA遗传严重程度无关。
