Histopathologic correlates of left posterior fascicular block

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Pathology

Background:

• Left posterior fascicular block (LPFB) is a conduction abnormality within the heart's electrical system.
• Its underlying causes and pathological correlates require further elucidation, particularly in relation to coronary artery disease.

Purpose of the Study:

• To investigate the pathological substrate of left posterior fascicular block.
• To correlate the severity and location of conduction system damage with clinical presentation.

Main Methods:

• Post-mortem examination of 13 hearts from patients with diagnosed left posterior fascicular block.
• Histopathological analysis of the left bundle branch system and coronary arteries.

Main Results:

• LPFB was frequently associated with right bundle branch block or alternated with left anterior fascicular block.
• Severe coronary artery disease was prevalent, with lesions often concentrated proximally in the left bundle branch system.
• In chronic cases, pathology included cardiac skeleton calcification or myocarditis.

Conclusions:

• The pathological basis of LPFB involves significant, proximal damage to the posterior left bundle branch fibers.
• Compared to left anterior fascicular block, LPFB alterations are less widespread but more severe and proximally located.
• LPFB can be associated with serious arrhythmias, including complete heart block.