This study aimed to evaluate the early morphology and function of the left heart in hypertrophic obstructive cardiomyopathy (HOCM) after transapical beating-heart septal myectomy (TA-BSM) using cardiovascular magnetic resonance (CMR). Between April 2022 and January 2023, HOCM patients who underwent CMR before and 3 months after TA-BSM were prospectively and consecutively enrolled in the study. Preoperative and postoperative cardiac morphological and functional parameters, including those for the left atrium (LA) and left ventricle (LV), were compared. The left ventricular remodeling index (LVRI) was defined as the ratio between left ventricular mass (LVM) and left ventricular end-diastolic volume (LVEDV). Healthy participants with a similar age and sex distribution were enrolled for comparison. Pearson or Spearman correlation analysis was used to investigate the relationships between the parameters and LVRI. Last, univariate and multivariate linear regression identified variables associated with the LVM index (LVMI) and LVRI. Forty-one patients (mean age ± standard deviation, 46 ± 2 years; 27 males) and 41 healthy control participants were evaluated. Eighteen (44%) HOCM patients were classified as having a sigmoid septum, and 23 patients had a reverse septal curvature. LA volume, diameter and function were significantly improved postoperatively, but still worse than healthy controls (all p < 0.001). Compared to before the operation, left ventricular wall thickness, left ventricular ejection fraction (LVEF), LVMI, and LVRI decreased after TA-BSM (all p < 0.001). The left ventricular end-diastolic volume index (LVEDVI) and left ventricular end-diastolic diameter (LVEDD) decreased in patients with a sigmoid septum. However, LVEDVI and LVEDD increased in those with a reverse septal curvature (both p < 0.001). In addition, both preoperative and postoperative LVRI was positively correlated with LVMI (r = 0.734 and 0.853, both p < 0.001) and maximum wall thickness (r = 0.679 and 0.676, both p < 0.001), respectively. In the multivariable analysis, the weight of the resected myocardium (adjusted β = 0.476, p = 0.005) and △mitral regurgitation degree (adjusted β = − 0.245, p = 0.040) were associated with △LVRI. Last, the △LVOTG (adjusted β = 0.436, p = 0.018) and baseline LVMI (adjusted β = 0.323, p = 0.040) were independently associated with greater left ventricular mass regression after TA-BSM. CMR confirmed early reverse remodeling of left heart morphology and function in HOCM patients following TA-BSM.

中文翻译：

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心脏磁共振评估肥厚型梗阻性心肌病经心尖搏动室间隔心肌切除术后左心形态和功能的早期逆重塑

本研究旨在利用心血管磁共振（CMR）评估肥厚型梗阻性心肌病（HOCM）经心尖搏动心室间隔肌切除术（TA-BSM）后左心的早期形态和功能。2022年4月至2023年1月期间，在TA-BSM之前和之后3个月接受CMR的HOCM患者前瞻性地连续纳入该研究。比较术前和术后心脏形态和功能参数，包括左心房（LA）和左心室（LV）的参数。左心室重塑指数（LVRI）定义为左心室质量（LVM）与左心室舒张末期容积（LVEDV）之间的比率。招募具有相似年龄和性别分布的健康参与者进行比较。采用 Pearson 或 Spearman 相关分析来研究参数与 LVRI 之间的关系。最后，单变量和多元线性回归确定了与 LVM 指数 (LVMI) 和 LVRI 相关的变量。对 41 名患者（平均年龄±标准差，46±2 岁；27 名男性）和 41 名健康对照参与者进行了评估。18 名 (44%) HOCM 患者被归类为具有乙状间隔，23 名患者具有反向间隔弯曲。术后 LA 体积、直径和功能均显着改善，但仍差于健康对照（均 p < 0.001）。与术前相比，TA-BSM 后左心室壁厚度、左心室射血分数 (LVEF)、LVMI 和 LVRI 均下降（均 p < 0.001）。乙状结肠间隔患者的左心室舒张末期容积指数 (LVEDVI) 和左心室舒张末期直径 (LVEDD) 降低。然而，室间隔反向弯曲的患者的 LVEDVI 和 LVEDD 增加（均 p < 0.001）。此外，术前和术后 LVRI 分别与 LVMI（r = 0.734 和 0.853，均 p < 0.001）和最大壁厚（r = 0.679 和 0.676，均 p < 0.001）呈正相关。在多变量分析中，切除心肌的重量（调整后的β=0.476，p=0.005）和△二尖瓣反流程度（调整后的β=−0.245，p=0.040）与△LVRI相关。最后，△LVOTG（调整后的β = 0.436，p = 0.018）和基线LVMI（调整后的β = 0.323，p = 0.040）与TA-BSM后更大的左心室质量消退独立相关。CMR 证实 HOCM 患者在 TA-BSM 后出现了左心形态和功能的早期逆转重塑。