BACKGROUND Left atrial (LA) enlargement is associated with atrial fibrillation (AF), but new-onset AF often occurs in the absence of LA enlargement. AF may be related to myocardial fibrosis, and even though left ventricular fibrosis is associated with mechanical dispersion, this phenomenon is not well studied in AF. We hypothesized that detection of LA dysfunction and mechanical dispersion using strain echocardiography is useful for predicting new-onset AF. METHODS Baseline echocardiography was performed at entry in 576 community-based participants at risk of heart failure or AF. In this case-control study, we compared 35 individuals with new-onset AF (age 70 ± 4 years; 57% men) over 2 years of follow-up with 35 age- and sex-matched individuals who did not develop AF from the same cohort. Using speckle-tracking echocardiography, we measured the LA strain in each of 12 segments in the two- and four-chamber views. LA mechanical dispersion was defined as the SD of time to peak positive strain corrected by the R-R interval (SD-TPS, %). RESULTS There was no significant difference in LA volume index (32.5 ± 9.2 mL/m2 vs 29.5 ± 8.3 mL/m2; P = .16); patients with new-onset AF had significantly worse LA pump strain (16.6% ± 4.3% vs 20.6% ± 4.3%; P < .01) and reservoir strain (31.4% ± 7.7% vs 38.0% ± 7.3%; P < .01) than those without AF. SD-TPS was significantly higher in patients with AF than in those without it (6.3% ± 2.3% vs 3.9% ± 1.6%; P < .01). SD-TPS was independently associated with new-onset AF after adjustment for patient characteristics, LA volume, and strain (hazard ratio = 1.26; 95% CI, 1.10-1.45; P < .01). In the nested Cox models, the model based on the LA volume and strain for predicting new onset AF was significantly improved by adding SD-TPS (P < .01). CONCLUSIONS LA dispersion obtained from strain echocardiography seems to provide incremental information about LA volume and function in the prediction of new-onset AF and warrants testing in a larger study.

中文翻译：

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应变超声心动图评估左心房机械分散性，作为新发房颤的独立预测因子：一项病例对照研究。

背景技术左心房（LA）增大与房颤（AF）相关，但是新发房颤通常在没有LA增大的情况下发生。AF可能与心肌纤维化有关，即使左心室纤维化与机械性弥散相关，但在AF中对此现象的研究尚不完善。我们假设使用应变超声心动图检测LA功能障碍和机械弥散有助于预测新发房颤。方法576名以心衰或AF为风险的社区参与者在入院时进行了基线超声心动图检查。在这项病例对照研究中，我们比较了35名在2年的随访中患有新发房颤的患者（年龄70±4岁； 57％的男性）与35名年龄和性别相匹配的未因房颤而发展为房颤的患者。同一个队列。使用斑点跟踪超声心动图，我们在二室和四室视图中分别测量了12个节段中的LA应变。洛杉矶机械色散定义为通过RR间隔校正的达到正应变峰值的时间的SD（SD-TPS，％）。结果LA体积指数无显着差异（32.5±9.2 mL / m2与29.5±8.3 mL / m2； P = .16）。新发房颤患者的LA泵应变（16.6％±4.3％vs 20.6％±4.3％; P <.01）和储层应变（31.4％±7.7％vs 38.0％±7.3％）明显更差）比没有AF的人。房颤患者的SD-TPS明显高于无房颤的患者（6.3％±2.3％对3.9％±1.6％； P <0.01）。调整患者特征，LA体积和应变后，SD-TPS与新发房颤独立相关（危险比= 1.26； 95％CI，1.10-1.45； P <.01）。在嵌套的Cox模型中，通过添加SD-TPS，基于LA体积和应变的用于预测新发房颤的模型得到了显着改善（P <.01）。结论从应变超声心动图获得的LA弥散似乎可以提供有关LA体积和功能的增量信息，以预测新发房颤，并有必要进行更大规模的研究。