Management of Cardiac Abnormalities in Noonan Syndrome

Common Cardiac Abnormalities and Initial Evaluation

Right ventricular hypertrophy and increased right ventricular free wall thickness are characteristic findings in patients with Noonan syndrome, according to the European Heart Journal 1
Biventricular involvement with global left ventricular hypokinesia can occur in patients with Noonan syndrome, as reported in the European Heart Journal 1
The American College of Cardiology recommends transthoracic echocardiography (TTE) as the first-line imaging modality for all patients with suspected or confirmed Noonan syndrome 2
Comprehensive evaluation should include measurement of maximum diastolic wall thickness in all LV segments, as suggested by the European Heart Journal 4
Evaluation of LV diastolic function, including pulsed Doppler of mitral valve inflow, tissue Doppler velocities, pulmonary vein flow velocities, and pulmonary artery systolic pressure, is recommended by the European Heart Journal 4
Assessment of left atrial size and volume is also recommended by the European Heart Journal 4
Evaluation for right ventricular free wall thickness, which is characteristically increased in Noonan syndrome, is suggested by the European Heart Journal 1

Regular follow-up echocardiography is essential to monitor for recurrent stenosis in patients with pulmonary valve stenosis, as recommended by the American College of Cardiology 3
Comprehensive evaluation of LV diastolic function is recommended for patients with hypertrophic cardiomyopathy (HCM), as restrictive LV filling patterns may indicate higher risk for adverse outcomes, according to the European Heart Journal 5
Cardiac MRI should be considered when echocardiographic images are suboptimal or to better characterize the extent of hypertrophy in patients with HCM, as suggested by Circulation 6
Cardiac MRI is beneficial for accurate and reproducible aortic measurements, as aortic dilatation can occur in Noonan syndrome, according to Circulation 7
Cardiac MRI is also beneficial for evaluation of the entire aorta, as genetic aortopathies can affect multiple segments, as reported by Circulation 7

Transoesophageal echocardiography should be considered when transthoracic windows are inadequate, as recommended by the European Heart Journal 4
Cardiac MRI is beneficial for assessment of interventricular dependence, although this recommendation is from Praxis Medical Insights, an alternative source suggests similar benefits 8