Quantitative Analysis of Left Ventricular Flow Dynamics in Latent Obstructive Hypertrophic Cardiomyopathy Using...

Area of Science:

• Cardiology
• Medical Imaging
• Fluid Dynamics

Background:

• Hypertrophic cardiomyopathy (HCM) is a genetic heart muscle disease.
• HCM can present with or without left ventricular outflow tract obstruction.
• Distinguishing between obstructive and nonobstructive forms is clinically important.

Purpose of the Study:

• To assess left ventricular (LV) energy loss (EL), circulation, and vortex area using vector flow mapping (VFM).
• To compare hemodynamic parameters between patients with latent obstructive HCM (LOHCM), nonobstructive HCM (NOHCM), and healthy controls.
• To evaluate the diagnostic capability of VFM parameters in differentiating LOHCM from NOHCM.

Main Methods:

• Transthoracic echocardiography was performed on 14 LOHCM patients, 10 NOHCM patients, and 11 controls.
• Offline VFM workstation analyzed LV blood flow patterns and fluid dynamics.
• Hemodynamic parameters, including EL, circulation, and vortex area, were calculated across 7 cardiac phases.

Main Results:

• LOHCM patients showed significantly higher LV EL during rapid ejection, slow ejection (SE), and isovolumetric relaxation phases compared to controls and NOHCM patients (p < 0.05).
• Increased circulation during SE was observed in LOHCM patients compared to the other groups (p < 0.05).
• LV EL during SE demonstrated high diagnostic accuracy (AUC=0.964) for differentiating LOHCM from NOHCM, with a cutoff of 6.34 J/m3/s (100% sensitivity, 80% specificity).

Conclusions:

• Vector flow mapping (VFM) can detect abnormal LV energy loss and vortex dynamics in HCM patients.
• LOHCM patients exhibit impaired systolic and diastolic function compared to controls and NOHCM patients.
• VFM parameters, particularly LV EL during SE, are valuable for distinguishing between LOHCM and NOHCM.