BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in hypertrophic cardiomyopathy (HCM) and is associated with adverse outcomes in HCM patients. Although the left atrial (LA) diameter has consistently been identified as a strong predictor of AF in HCM patients, the relationship between LA dysfunction and AF still remains unclear. The aim of this study is to evaluate the LA function in patients with non-obstructive HCM (NOHCM) utilizing cardiovascular magnetic resonance feature tracking (CMR-FT). METHODS Thirty-three patients with NOHCM and 28 healthy controls were studied. The global and regional LA function and left ventricular (LV) function were compared between the two groups. The following LA global functional parameters were quantitively analyzed: reservoir function (total ejection fraction [LA total EF], total strain [εs], peak positive strain rate [SRs]), conduit function (passive ejection fraction [LA passive EF], passive strain [εe], peak early-negative SR [SRe]), and booster pump function (active ejection fraction [LA active EF], active strain [εa], peak late-negative SR [SRa]). The LA wall was automatically divided into 6 segments: anterior, antero-roof, inferior, septal, septal-roof and lateral. Three LA strain parameters (εs, εe, εa) and their corresponding strain rate parameters (SRs, SRe, SRa) during the reservoir, conduit and booster pump LA phases were segmentally measured and analyzed. RESULTS The LA reservoir (LA total EF: 57.6 ± 8.2% vs. 63.9 ± 6.4%, p < 0.01; εs: 35.0 ± 12.0% vs. 41.5 ± 11.2%, p = 0.03; SRs: 1.3 ± 0.4 s- 1 vs. 1.5 ± 0.4 s- 1, p = 0.02) and conduit function (LA passive EF: 28.7 ± 9.1% vs. 37.1 ± 10.0%, p < 0.01; εe: 18.7 ± 7.9% vs. 25.9 ± 10.0%, p < 0.01; SRe: - 0.8 ± 0.3 s- 1 vs. -1.1 ± 0.4 s- 1, p < 0.01) were all impaired in patients with NOHCM when compared with healthy controls, while LA booster pump function was preserved. The LA segmental strain and strain rate analysis demonstrated that the εs, εe, SRe of inferior, SRs, SRe of septal-roof, and SRa of antero-roof walls (all p < 0.05) were all decreased in the NOHCM cohort. Correlations between LA functional parameters and LV conventional function and LA functional parameters and baseline parameters (age, body surface area and NYHA classification) were weak. The two strongest relations were between εs and LA total EF(r = 0.84, p < 0.01), εa and LA active EF (r = 0.83, p < 0.01). CONCLUSIONS Compared with healthy controls, patients with NOHCM have LA reservoir and conduit dysfunction, and regional LA deformation before LA enlargement. CMR-FT identifies LA dysfunction and deformation at an early stage.

中文翻译：

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非阻塞性肥厚型心肌病患者左心房功能通过心血管磁共振特征跟踪成像的量化：可行性和可重复性研究。

背景技术心房纤颤（AF）是肥厚型心肌病（HCM）中最常见的心律不齐，与HCM患者的不良结局有关。尽管一直认为左心房（LA）直径是HCM患者房颤的重要预测指标，但LA功能障碍与房颤之间的关系仍然不清楚。这项研究的目的是通过心血管磁共振特征跟踪（CMR-FT）评估非阻塞性HCM（NOHCM）患者的LA功能。方法对33例NOHCM患者和28例健康对照者进行研究。比较两组的整体和局部LA功能以及左心室（LV）功能。对以下LA全局功能参数进行了定量分析：储层功能（总射流分数[LA total EF]，总应变[εs]，峰值正应变率[SRs]），导管功能（被动射血分数[LA被动EF]，被动应变[εe]，峰值早期负SR [SRe]）和增压泵功能（主动射血分数[LA主动EF] ，活性菌株[εa]，峰值晚期阴性SR [SRa]）。LA壁自动分为6个部分：前，前房顶，下，隔，房顶和外侧。分别测量和分析了油藏，导管和增压泵LA相期间的三个LA应变参数（εs，εe，εa）及其对应的应变速率参数（SRs，SRe，SRa）。结果LA储层（LA总EF：57.6±8.2％vs. 63.9±6.4％，p <0.01;εs：35.0±12.0％vs. 41.5±11.2％，p = 0.03; SR：1.3±0.4 s-1 vs 1.5±0.4 s-1，p = 0.02）和导管功能（LA被动EF：28.7±9.1％vs. 37.1±10.0％，p <0.01;εe：18.7±7。9％和25.9±10.0％，p <0.01；与健康对照组相比，NOHCM患者的SRe：-0.8±0.3 s-1与-1.1±0.4 s-1，p <0.01）均受损，而LA增压泵功能得以保留。LA节段应变和应变率分析表明，在NOHCM队列中，下位的εs，εe，SRe，隔室屋顶的SRs，隔室屋顶的SRe和前屋顶壁的SRa均降低（所有p <0.05）。LA功能参数与LV常规功能以及LA功能参数与基线参数（年龄，体表面积和NYHA分类）之间的相关性较弱。两个最强的关系是εs和LA总EF（r = 0.84，p <0.01），εa和LA活性EF（r = 0.83，p <0.01）之间。结论与健康对照组相比，NOHCM患者的LA储液和导管功能异常，LA扩大之前的局部LA变形。CMR-FT可以在早期识别出LA功能障碍和变形。