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Right bundle branch block-induced Q waves simulating anterior myocardial infarction extension
J Ortega-Carnicer1, M L Gómez-Grande, A Ambrós
1Coronary Care Unit, Hospital Alarcos, Ciudad Real, Spain.
Journal of Electrocardiology
|December 1, 2000
Summary
Right bundle branch block (RBBB) can alter initial QRS complex, mimicking anterior myocardial infarction (MI) by replacing R waves with Q waves. These changes resolved when RBBB disappeared, highlighting RBBB
Area of Science:
- Clinical Electrocardiography
- Cardiac Electrophysiology
- Cardiology
Background:
- Standard electrocardiography (ECG) assumes right bundle branch block (RBBB) minimally affects the initial QRS complex.
- Normal septal activation (left-to-right) is expected with an intact left bundle branch during RBBB.
Observation:
- A patient with acute anterior myocardial infarction (MI) initially showed small R waves in leads V1 and V4.
- Development of RBBB with PR-interval prolongation led to the replacement of these R waves with Q waves.
Findings:
- The electrocardiographic signs of anterior MI resolved as the RBBB disappeared.
- This case demonstrates that RBBB can transiently obscure or mimic anterior MI findings.
Implications:
- RBBB can significantly alter the QRS complex, potentially leading to misinterpretation of acute myocardial infarction.
- Understanding RBBB's effect on ECG morphology is crucial for accurate diagnosis and patient management.
- Further electrophysiologic studies are needed to fully elucidate the mechanisms involved.