BACKGROUND Although left ventricular noncompaction (LVNC) has been associated with an increased risk of adverse cardiovascular events, the accurate incidence of cardiovascular morbidity and mortality is unknown. We, therefore, aimed to assess the incidence rate of LVNC-related cardiovascular events. METHODS We systematically searched observational studies reporting the adverse outcomes related to LVNC. The primary end point was cardiovascular mortality. RESULTS We identified 28 eligible studies enrolling 2501 LVNC patients (mean age, 46 years; male/female ratio, 1.7). After a median follow-up of 2.9 years, the pooled event rate for cardiovascular mortality was 1.92 (95% CI, 1.54-2.30) per 100 person-years. LVNC patients had a similar risk of cardiovascular mortality compared with a dilated cardiomyopathy control group (odds ratio, 1.10 [95% CI, 0.18-6.67]). The incidence rates of all-cause mortality, stroke and systemic emboli, heart failure admission, cardiac transplantation, ventricular arrhythmias, and cardiac device implantation were 2.16, 1.54, 3.53, 1.24, 2.17, and 2.66, respectively, per 100 person-years. Meta-regression and subgroup analyses revealed that left ventricular ejection fraction, not the extent of left ventricular trabeculation, had an important influence on the variability of incidence rates. The risks of thromboembolism and ventricular arrhythmias in LVNC patients were similar to dilated cardiomyopathy patients. However, LVNC patients had a higher incidence of heart failure hospitalization than dilated cardiomyopathy patients. CONCLUSIONS Patients with LVNC carry a similar cardiovascular risk when compared with dilated cardiomyopathy patients. Left ventricular ejection fraction-a conventional indicator of heart failure severity, not the extent of trabeculation-appears to be an important determinant of adverse outcomes in LVNC patients. Registration: https://www.crd.york.ac.uk/PROSPERO/ Unique identifier: CRD42018096313.

中文翻译：

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左心室致密化不全的预后意义：观察性研究的系统回顾和荟萃分析。

背景虽然左心室致密化不全（LVNC）与不良心血管事件风险增加相关，但心血管发病率和死亡率的准确发生率尚不清楚。因此，我们的目的是评估 LVNC 相关心血管事件的发生率。方法 我们系统地检索了报告 LVNC 相关不良后果的观察性研究。主要终点是心血管死亡率。结果 我们确定了 28 项合格研究，纳入了 2501 名 LVNC 患者（平均年龄 46 岁；男女比例为 1.7）。中位随访 2.9 年后，心血管死亡率的汇总事件率为每 100 人年 1.92 例（95% CI，1.54-2.30）。与扩张型心肌病对照组相比，LVNC 患者的心血管死亡风险相似（比值比，1.10 [95% CI，0.18-6.67]）。全因死亡率、卒中和全身性栓塞、心力衰竭入院、心脏移植、室性心律失常和心脏装置植入的发生率分别为每100人年2.16、1.54、3.53、1.24、2.17和2.66。荟萃回归和亚组分析显示，左心室射血分数，而不是左心室小梁的程度，对发病率的变异性有重要影响。LVNC 患者发生血栓栓塞和室性心律失常的风险与扩张型心肌病患者相似。然而，LVNC 患者心力衰竭住院的发生率高于扩张型心肌病患者。结论 与扩张型心肌病患者相比，左心室NC 患者具有相似的心血管风险。左心室射血分数——心力衰竭严重程度的传统指标，而不是小梁形成的程度——似乎是 LVNC 患者不良结局的重要决定因素。注册：https://www.crd.york.ac.uk/PROSPERO/ 唯一标识符：CRD42018096313。