Transient post-reperfusion left bundle branch block and accelerated idioventricular rhythm with paradoxical QRS...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Diagnostics

Background:

• Accelerated idioventricular rhythm (AIVR) is a recognized reperfusion arrhythmia following coronary interventions.
• Transient left bundle branch block (LBBB) after reperfusion is rare and often attributed to procedural complications.

Observation:

• This case report details electrocardiograms (ECGs) from a patient experiencing acute lateral myocardial infarction.
• The ECGs captured simultaneous AIVR and a transient LBBB post-intervention.

Findings:

• The coexistence of AIVR and LBBB resulted in the formation of fusion complexes.
• These fusion complexes led to a paradoxical narrowing of the QRS complex, a previously undocumented observation.

Implications:

• This finding expands the understanding of complex arrhythmias post-myocardial infarction reperfusion.
• It highlights the importance of comprehensive ECG interpretation in identifying rare simultaneous arrhythmias.
• Clinicians should consider AIVR and LBBB co-occurrence when observing paradoxical QRS narrowing after reperfusion.