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Right bundle-branch block unmasking a myocardial infarction
1Department of Internal Medicine, University of Florida College of Medicine, Gainesville 32610-0277, USA.
Clinical Cardiology
|May 23, 2002
Summary
Right bundle-branch block can mask or reveal Q waves in myocardial infarction patients. This condition aids in diagnosing anteroseptal infarcts by preventing right ventricular free wall activation.
Area of Science:
- Cardiology
- Electrocardiography
- Cardiac Electrophysiology
Background:
- Anteroseptal myocardial infarction diagnosis often relies on characteristic Q waves in ECG leads.
- Right bundle-branch block (RBBB) can alter the typical ECG presentation of cardiac events.
Observation:
- A patient presented with acute anteroseptal myocardial infarction and intermittent right bundle-branch block.
- Abnormal Q waves indicative of infarction were only visible during episodes of RBBB.
Findings:
- The depolarization of the right ventricular free wall in the absence of RBBB masked the Q waves.
- RBBB prevented early right ventricular free wall activation, thereby unmasking the diagnostic Q waves.
Implications:
- Intermittent RBBB can be crucial for the accurate diagnosis and localization of anteroseptal myocardial infarction.
- Understanding ECG changes during RBBB is vital for interpreting infarct patterns.