Evaluation of Cardiac Mechanical Dyssynchrony in Heart Failure Patients Using Current Echo-Doppler Modalities

Area of Science:

• Cardiology
• Medical Imaging
• Heart Failure Management

Background:

• Cardiac resynchronization therapy (CRT) guidelines primarily use electrical dyssynchrony for patient selection.
• A significant portion (25-35%) of patients show suboptimal responses to CRT.
• Evaluating mechanical dyssynchrony offers potential for improved CRT patient selection.

Purpose of the Study:

• To assess various cardiac mechanical dyssynchrony parameters in heart failure patients.
• To analyze the association between mechanical and electrical dyssynchrony.
• To explore the utility of mechanical dyssynchrony indices for predicting CRT response.

Main Methods:

• 120 patients with heart failure with reduced ejection fraction (HFrEF) were included.
• Left ventricular mechanical dyssynchrony (LVMD) and interventricular mechanical dyssynchrony (IVMD) were assessed using echo-Doppler modalities.
• Patients were categorized by QRS duration (<120 ms, 120-149 ms, ≥150 ms) and QRS morphology (LBBB vs. non-LBBB).

Main Results:

• Patients with wider QRS duration (≥150 ms) exhibited significantly higher IVMD, LVMD indices, and LVMD scores.
• Speckle-tracking echocardiography (STE) parameters like TS-SD (time to peak longitudinal strain standard deviation) were elevated in patients with wider QRS.
• LVMD score, TS-SD 12 TDI, and TS-SD 12 STE showed strong correlations with QRS duration.

Conclusions:

• Wider QRS duration in HFrEF patients correlates with more pronounced LVMD.
• Substantial LVMD is present in patients with intermediate QRS duration (120-150 ms), irrespective of QRS morphology.
• LVMD indices may serve as additive criteria for predicting CRT response, particularly in patients with intermediate QRS durations.