Significance of Proximal Septal Thickening on Echo with Normal EF

Differential Diagnosis

Proximal septal thickening is a hallmark finding in Hypertrophic Cardiomyopathy (HCM), even with preserved ejection fraction, requiring careful evaluation as it may represent early disease, according to the European Society of Cardiology 1, 2.

Left atrial enlargement is an associated finding that increases concern for HCM, as recommended by the European Society of Cardiology 1, 2.
Diastolic dysfunction on Doppler assessment is an associated finding that increases concern for HCM, as recommended by the European Society of Cardiology 1.
Left ventricular outflow tract obstruction is an associated finding that increases concern for HCM, as recommended by the European Society of Cardiology 1, 2.
Family history of HCM or sudden cardiac death is an associated finding that increases concern for HCM, as recommended by the European Society of Cardiology 1.

A comprehensive echocardiographic assessment, including measurement of septal thickness at multiple levels, is recommended by the European Society of Cardiology to evaluate proximal septal thickening 1.
Assessment for systolic anterior motion of the mitral valve is recommended by the European Society of Cardiology to evaluate proximal septal thickening 1.
Evaluation of diastolic function with Doppler imaging is recommended by the European Society of Cardiology to evaluate proximal septal thickening 1, 3.
Measurement of left atrial size is recommended by the European Society of Cardiology to evaluate proximal septal thickening 1.
Consideration of cardiac MRI is recommended by the European Society of Cardiology if there is diagnostic uncertainty, as it provides better tissue characterization and can detect fibrosis 1.
Family screening is recommended by the European Society of Cardiology if HCM is suspected, as first-degree relatives should be screened 1.
Genetic testing is recommended by the European Society of Cardiology if there are other features suggestive of HCM 1.

Normal EF with septal thickening may represent early disease with preserved systolic function, according to the European Society of Cardiology 1, 2.
Longitudinal strain measurements may detect early systolic dysfunction even when EF is normal, as reported in the European Heart Journal 4.
Serial echocardiography is recommended by the European Society of Cardiology to assess for progression of septal hypertrophy 1.
Global longitudinal strain (GLS) may provide prognostic information even when EF is normal, as reported in the European Heart Journal 4.

Dismissing proximal septal thickening as a normal variant without thorough evaluation, especially if septal thickness exceeds 13mm, is a pitfall to avoid, as recommended by the American Heart Association 5.
Relying solely on ejection fraction is a pitfall to avoid, as it may be normal or even increased in early HCM despite underlying myocardial dysfunction, according to the European Society of Cardiology 1, 2.
Overlooking diastolic dysfunction is a pitfall to avoid, as it often precedes systolic dysfunction in HCM and can cause symptoms despite normal EF, according to the European Society of Cardiology 1, 3.
Failing to assess for dynamic obstruction during Valsalva maneuver is a pitfall to avoid, as it may unmask latent obstruction, according to the European Society of Cardiology 1.
Ignoring family history is a pitfall to avoid, as HCM is often inherited in an autosomal dominant pattern, according to the European Society of Cardiology 1.