Effects of left bundle-branch block on cardiac structure, function, perfusion, and perfusion reserve: implications...

Area of Science:

• Cardiology
• Medical Imaging
• Echocardiography

Background:

• Left bundle-branch block (LBBB) can affect cardiac function and diagnostic accuracy of imaging tests.
• Assessing coronary artery disease (CAD) in LBBB patients presents unique challenges.

Purpose of the Study:

• To investigate cardiac effects of LBBB using myocardial contrast echocardiography (MCE).
• To determine MCE's value in detecting CAD in LBBB patients.
• To uncover mechanisms affecting single-photon emission computed tomography (SPECT) accuracy in LBBB.

Main Methods:

• Sixty-three LBBB patients and control groups underwent resting echocardiography.
• Rest and vasodilator MCE and SPECT were performed in LBBB patients.
• Measurements included wall thickness, thickening, myocardial blood flow (MBF), and MBF reserve.

Main Results:

• Septal and posterior wall thickness/thickening were reduced in LBBB patients.
• MBF reserve was reduced in LBBB patients, but resting MBF was preserved.
• MCE sensitivity (92%) was similar to SPECT (92%), but MCE specificity (95%) was superior to SPECT (47%) for CAD detection.

Conclusions:

• LBBB patients show asymmetrical wall thickening despite preserved MBF and reduced MBF reserve.
• Partial volume effects compromise SPECT accuracy for CAD detection in LBBB.
• MCE demonstrates superior specificity compared to SPECT in this patient cohort.