[Septal displacements during intraventricular conduction disorders. Echocardiographical study].

Area of Science:

• Cardiology
• Cardiac Electrophysiology
• Diagnostic Imaging

Context:

• Intra-ventricular conduction disorders, particularly left bundle branch block (LBBB), can alter cardiac mechanics.
• Echocardiography is a key tool for assessing cardiac structure and function.
• Understanding septal motion abnormalities is crucial for diagnosing conduction system diseases.

Purpose:

• To investigate the pattern of septal displacement during the cardiac cycle in patients with left bundle branch block (LBBB).
• To correlate echocardiographic findings with electrical conduction abnormalities.
• To explore the relationship between abnormal septal motion and the spread of ventricular excitation.

Summary:

• Echocardiographic analysis of healthy subjects, patients with conduction disorders, and those with temporary pacemakers revealed a characteristic pre-ejection septal displacement towards the posterior wall in LBBB.
• This was often followed by a 'paradoxical' anterior displacement during systole, creating a 'beaked' echocardiographic image.
• This 'beaked' image was specifically associated with complete LBBB, whether spontaneous or functionally induced by a pacemaker, supporting the hypothesis that abnormal excitation spread influences septal motion.

Impact:

• The findings support the hypothesis linking abnormal septal displacement in LBBB to the sequence of ventricular electrical activation.
• Demonstrates how altered septal forces, relative to left ventricular free wall forces during pre-ejection, contribute to observed motion.
• Highlights the diagnostic utility of the 'beaked' septal image in identifying complete LBBB, especially when correlated with QRS duration and electrical axis deviation.