Monash Cardiovascular Research Centre, MonashHeart and Department of Medicine (School of Clinical Sciences at Monash Health), Monash University and Monash Health, Clayton, Victoria, Australia.
Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America.
PLoS One. 2024 May 30;19(5):e0303969. doi: 10.1371/journal.pone.0303969. eCollection 2024.
The left ventricular (LV) changes which occur in Friedreich ataxia (FRDA) are incompletely understood.
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).
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.
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.
弗里德赖希共济失调（FRDA）患者左心室（LV）的变化尚不完全清楚。
使用 1.5T 扫描仪对 FXN 基因内含子 1 GAA 重复扩增纯合子的 FRDA 患者进行心脏磁共振（CMR）成像。对 LV 质量（LVM）、LV 舒张末期容积（LVEDV）和 LV 射血分数（LVEF）进行标准测量。利用 LV 弥漫性心肌纤维化的标记物——LV 固有 T1 弛豫时间和细胞外容积分数（ECV），以及 LV 替代纤维化的标记物——延迟钆增强（LGE），对 FRDA 遗传严重程度进行评估。
共纳入 93 例 FRDA 患者（63 例成人，30 例儿童，54%为男性），其中 9 例 LVEF 降低（<55%）。39%的患者 LVEDV 低于正常范围，22%的患者 LVM 高于正常范围，89%的患者存在增加的 LVM/LVEDV 比值。在 LVEF 正常的成人中，LVM 与 GAA1 呈正相关，与年龄呈负相关，但在儿童中未观察到类似的关系。GAA1 与成人和儿童的 LV 固有 T1 时间呈正相关，与成人的 ECV 呈正相关，这些相关性均独立于 LVM 和 LVEDV。21%的患者（包括成人和儿童）存在 LGE，且无论 LVEF 是否降低，均存在 LGE。GAA1、LVM 或 LVEDV 均不能预测 LGE。
FRDA 弥漫性间质 LV 心肌纤维化与遗传严重程度之间存在关联，这种关联独立于 FRDA 相关的 LV 结构变化。少数 FRDA 患者存在局灶性替代纤维化，且在 LVEF 正常的患者中，这种纤维化与 LV 结构变化或 FRDA 遗传严重程度无关。
