Transient bifascicular block during Prinzmetal's variant angina

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Electrophysiology

Background:

• Prinzmetal's angina, a form of vasospastic angina, can present with various cardiac complications.
• Conduction abnormalities in the His-Purkinje system can lead to significant bradyarrhythmias and heart block.

Observation:

• A 49-year-old male experienced bradycardia-hypotension syndrome and transient conduction abnormalities, including right bundle branch block with left anterior fascicular block.
• These events occurred during an episode of Prinzmetal's angina.

Findings:

• Coronary arteriography revealed 50% proximal left anterior descending artery obstruction, which progressed to subtotal occlusion upon ergonovine administration.
• The observed conduction abnormalities, specifically transient right bundle branch block with left anterior fascicular block, correlated temporally with the vasospastic event.

Implications:

• The findings suggest that diminished blood supply to the proximal His-Purkinje system is a probable mechanism for these conduction abnormalities during Prinzmetal's angina.
• This case highlights the potential for coronary vasospasm to directly impact cardiac electrical conduction pathways.
• Understanding this mechanism is crucial for managing patients with Prinzmetal's angina and associated conduction disturbances.