Ventricular dyssynchrony patterns in left bundle branch block, with and without heart failure.

Area of Science:

• Cardiology
• Echocardiography
• Heart Failure Management

Background:

• Ventricular dyssynchrony assessment is crucial for cardiac resynchronization therapy (CRT) candidate selection.
• Regional dyssynchrony patterns in heart failure (HF) with left bundle branch block (LBBB) are not well-defined.

Purpose of the Study:

• To delineate regional dyssynchrony patterns in patients with LBBB, with and without heart failure.

Main Methods:

• Tissue Doppler Imaging (TDI) analyzed velocity curves from septal and lateral walls.
• Interventricular dyssynchrony (IVD) and left ventricular dyssynchrony (LVD) assessed by timing differences.
• A delay of ≥40 msec defined significant dyssynchrony.

Main Results:

• 72% of HF patients with LBBB exhibited dyssynchrony versus 16% in controls (P<0.01).
• Lateral wall dyssynchrony was prevalent in HF (37%) but absent in controls (P<0.01).
• Septal dyssynchrony was similar between groups (16%, P=NS).

Conclusions:

• Significant dyssynchrony is common in HF patients with LBBB, with heterogeneous regional distribution.
• Dyssynchrony can occur in LBBB without HF, but typically spares the lateral wall.
• Lateral wall delay may be a more specific indicator of dyssynchrony in HF patients.