Multi-system inflammatory syndrome in children and Kawasaki disease have overlapping clinical features but comparative echocardiographic studies are lacking.

We reviewed echocardiography findings of all multi-system inflammatory syndrome cases between 1st April and 31st July, 2020 and typical Kawasaki disease patients with coronary arteries abnormalities consecutively followed between 1st October, 2016 and June 30th, 2019.

We included 40 multi-system inflammatory syndrome children (25 males, 62.5%) and 45 Kawasaki disease patients (31 males, 68.9%) at a mean age of 6.4 years old and 8 years old, respectively. Four out of 40 multi-system inflammatory syndrome children had coronary arteries abnormalities. Left ventricle ejection fraction was normal in both groups. Global longitudinal strain was normal although Kawasaki disease group had significantly lower values (–20.0 versus –21.7%; p = 0.02). Basal segments were the most affected in Kawasaki disease patients with significant differences in the basal anterior, anterolateral, and anteroseptal strain: –18.2 versus –23.0% (p = 0.002), –16.7 versus –22.0% (p < 0.001), –16.7 versus –19.5% (p = 0.034), respectively. The basal anterolateral and anteroseptal segments in Kawasaki disease patients were the only ones with an absolute reduction of longitudinal strain (–16.7% both) consistent with the greater left main coronary involvement in this cohort.

Our findings are consistent with the transient cardiac involvement in multi-system inflammatory syndrome, as opposed to the subtle and chronic myocardial involvement in Kawasaki disease children with coronary arteries abnormalities. We speculate that the mechanism of cardiac impairment in the few multi-system inflammatory syndrome children with reduced global longitudinal strain is not related to coronary arteries abnormalities.

儿童多系统炎症综合征与川崎病具有重叠的临床特征，但缺乏对比超声心动图研究。

我们回顾了2020年4月1日至7月31日期间所有多系统炎症综合征病例以及2016年10月1日至2019年6月30日连续随访的冠状动脉异常典型川崎病患者的超声心动图检查结果。

我们纳入了 40 名多系统炎症综合征儿童（25 名男性，62.5%）和 45 名川崎病患者（31 名男性，68.9%），平均年龄分别为 6.4 岁和 8 岁。40 名多系统炎症综合征儿童中有 4 名患有冠状动脉异常。两组的左心室射血分数均正常。尽管川崎病组的值显着较低（–20.0 与 –21.7%；p = 0.02），但总体纵向应变正常。川崎病患者的基底节段受影响最严重，基底前部、前外侧和前间间隔应变存在显着差异：–18.2 对比 –23.0% (p = 0.002)、–16.7 对比 –22.0% (p < 0.001)、–16.7分别为 –19.5% (p = 0.034)。川崎病患者的基底前外侧和前间隔节段是唯一纵向应变绝对减少的节段（均为 –16.7%），与该队列中左主干冠状动脉受累程度一致。

我们的研究结果与多系统炎症综合征中短暂的心脏受累一致，而不是冠状动脉异常的川崎病儿童中微妙且慢性的心肌受累。我们推测，少数全身纵向应变减少的多系统炎症综合征儿童的心脏损害机制与冠状动脉异常无关。