Four-dimensional flow magnetic resonance imaging visualizes reverse vortex pattern and energy loss increase in left...

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Hemodynamics

Background:

• Left bundle branch block (LBBB) is a cardiac condition affecting ventricular activation.
• Understanding the impact of LBBB on intraventricular blood flow is crucial for patient management.
• Four-dimensional flow magnetic resonance imaging (4D-flow MRI) offers advanced visualization of blood flow dynamics.

Purpose of the Study:

• To investigate and characterize the intraventricular blood flow patterns in patients with LBBB.
• To compare hemodynamic parameters between LBBB patients and a control group using 4D-flow MRI.
• To assess the potential of vortex patterns and energy loss as biomarkers for LBBB.

Main Methods:

• 16 LBBB patients and 16 propensity score-matched non-LBBB controls underwent 4D-flow MRI.
• Analysis of left ventricular (LV) blood flow patterns, including vortex formation and direction.
• Quantification of energy loss (EL) within the LV.

Main Results:

• A significantly higher prevalence of counterclockwise rotating vortices (reverse pattern) was observed in LBBB patients (94%) compared to non-LBBB controls (19%).
• Maximum energy loss (EL) in the LV was significantly elevated in the LBBB group.
• Interobserver agreement for streamline analysis was good (kappa = 0.68).

Conclusions:

• LBBB patients exhibit inefficient LV hemodynamics characterized by non-physiological vortices and increased energy loss.
• Vortex shape and EL may serve as indicators of LV mechanical dyssynchrony in LBBB.
• These hemodynamic markers could be explored as predictors for cardiac resynchronization therapy response.