Midsystolic Doppler Signal Void Identifies Midapical Obstruction in Hypertrophic Cardiomyopathy

Area of Science:

• Cardiology
• Medical Imaging
• Echocardiography

Background:

• Mid-apical obstruction is a distinct phenotype in hypertrophic cardiomyopathy (HCM).
• Standardized echocardiographic criteria for mid-apical obstruction are limited.
• Pathophysiological and prognostic implications of mid-apical obstruction are not fully understood.

Purpose of the Study:

• To investigate the characteristics and implications of midsystolic Doppler signal void in HCM.
• To determine associations between Doppler signal void and specific HCM phenotypes.
• To evaluate the prognostic value of Doppler signal void in HCM.

Main Methods:

• Studied 606 HCM patients, stratifying by midsystolic Doppler signal void presence.
• Assessed left ventricular morphology, intracavitary flow, apical aneurysm, cardiac troponin I (cTnI), and global longitudinal strain (LV-GLS).
• Utilized continuous-wave Doppler to identify systolic cavity obliteration.

Main Results:

• Midsystolic Doppler signal void was found in 23.4% of patients.
• Patients with signal void showed more pronounced mid-apical and papillary muscle hypertrophy, smaller LV volumes, and higher gradients.
• Apical aneurysm and lower LV-GLS were independently associated with Doppler signal void.

Conclusions:

• Midsystolic Doppler signal void identifies a distinct mid-apical obstructive phenotype in HCM.
• This finding complements gradient-based assessment.
• It helps identify HCM patients with adverse structural remodeling and high-risk features.