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Of all patients with Noonan syndrome, 50-90% have one or more congenital heart defects. The most frequent occurring are pulmonary stenosis (PS) and hypertrophic cardiomyopathy. The electrocardiogram (ECG) of a patient with Noonan syndrome often shows a characteristic pattern, with a left axis deviation, abnormal R/S ratio over the left precordium, and an abnormal Q wave. The objective of this study was to determine if these ECG characteristics are an independent feature of the Noonan syndrome or if they are related to the congenital heart defect. A cohort study was performed with 118 patients from two university hospitals in the United States and in The Netherlands. All patients were diagnosed with definite Noonan syndrome and had had an ECG and echocardiography. Sixty-nine patients (58%) had characteristic abnormalities of the ECG. In the patient group without a cardiac defect (n = 21), ten patients had a characteristic ECG abnormality. There was no statistical relationship between the presence of a characteristic ECG abnormality and the presence of a cardiac defect (p = 0.33). Patients with hypertrophic cardiomyopathy had more ECG abnormalities in total (p = 0.05), without correlation with a specific ECG abnormality. We conclude that the ECG features in patients with Noonan syndrome are characteristic for the syndrome and are not related to a specific cardiac defect. An ECG is very useful in the diagnosis of Noonan syndrome; every child with a Noonan phenotype should have an ECG and echocardiogram for evaluation. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to determine whether pulmonary artery intervention in patients with unilateral proximal pulmonary artery stenosis (PAS) improves exercise capacity, abnormal ventilatory response to exercise, and symptoms., Background: Stenosis of the branch pulmonary arteries results in pulmonary blood flow maldistribution (PBFM). The resulting ventilation-perfusion mismatch is associated with an increased ventilatory response to exercise and decreased exercise capacity. It is unclear if technical success in relieving branch PAS translates to clinical improvement in exercise capacity and ventilatory response., Methods: Twenty patients with biventricular circulation and a minimum 10% PBFM who underwent transcatheter relief of PAS were enrolled in a multi-institutional prospective cohort study. Pre- and post-procedure assessment of the degree of PBFM, exercise capacity, ventilatory response to exercise, and subjective assessment of breathlessness were collected and analyzed., Results: Technical success was achieved in all patients with significant angiographic improvement in minimal lumen diameter (p = 0.001) and peak gradient (p = 0.001). Median PBFM improved (19.5% [range 12.0% to 31.0%] before vs. 7.0% [range 0% to 33.0%] after; p = 0.003). Exercise capacity was low at baseline and improved significantly post-intervention; percent predicted peak oxygen consumption improved from 70% (range 45% to 96%) to 83% (range 47% to 121%) (p = 0.02). Percent predicted oxygen pulse improved (p = 0.02). Ventilatory response to exercise improved; ventilatory equivalent of carbon dioxide slope post-intervention decreased to 29.3 versus 32.5 pre-intervention (p = 0.01). Subjective assessment of dyspnea improved. Five patients with minimal improvement in PBFM also showed minimal improvement in exercise parameters., Conclusions: Successful relief of unilateral branch PAS results in significant improvements in exercise capacity, ventilatory efficiency, and symptoms., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)