Noonan syndrome is a genetic disorder characteried by short stature, typical facial features, developmental delay, and CHD. In this single-centre retrospective study, we analysed typical Noonan syndrome-related electrocardiographic features in 95 patients with clinically and molecularly confirmed Noonan syndrome. Typical Noonan syndrome-related electrocardiographic features are left axis deviation, small left precordial R-waves, large right precordial S-waves, abnormal Q-wave, and abnormal wide QRS complex. In this representative cohort, CHD was found in 59 patients (62.1%) and typical Noonan syndrome-related electrographic features in 60 patients (63.2%). The typical Noonan syndrome-related electrographic features were also increased over baseline in patients without CHD (41.7%). Of all 95 patients, left axis deviation was seen in 46.3%, small left precordial R-waves in 30.5%, large right precordial S-waves in 5.3%, and abnormal Q-wave and wide QRS complex in 2.1%. There was no significant difference in the frequency of the individual-specific electrographic features between the group with CHD and the group without CHD. However, there were significantly more patients with a small left precordial R-wave in the subgroup with pulmonary stenosis compared to patients without pulmonary stenosis. Conclusion: Specific Noonan syndrome-related electrographic features are frequently present in patients with Noonan syndrome, also in the absence of CHD. These results suggest that there may be a continuum of cardiac anomalies from overt CHD to milder abnormalities that are only seen on electrocardiogram.

Noonan综合征是一种以身材矮小、五官典型、发育迟缓和冠心病为特征的遗传性疾病。在这项单中心回顾性研究中，我们分析了 95 名临床和分子证实的 Noonan 综合征患者的典型 Noonan 综合征相关心电图特征。典型的 Noonan 综合征相关心电图特征是电轴左偏、左胸前区 R 波小、右胸前区 S 波大、Q 波异常和 QRS 波群异常宽。在这个具有代表性的队列中，59 名患者 (62.1%) 发现了 CHD，60 名患者 (63.2%) 发现了典型的 Noonan 综合征相关的电图特征。在没有 CHD 的患者中，典型的 Noonan 综合征相关的电图特征也比基线增加（41.7%）。在所有 95 名患者中，46.3% 的患者出现电轴左偏，30.5% 的左侧胸前 R 波小，5.3% 的右侧胸前 S 波大，2.1% 的 Q 波异常和宽 QRS 波群。CHD组与非CHD组个体特异性电图特征频率无显着差异。然而，与没有肺动脉狭窄的患者相比，有肺动脉狭窄的亚组中左心前区 R 波较小的患者明显更多。结论：特定的 Noonan 综合征相关的电图特征经常出现在 Noonan 综合征患者中，在没有 CHD 的情况下也是如此。这些结果表明，从明显的 CHD 到仅在心电图上可见的轻度异常，可能存在一系列心脏异常。