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Transient right axis deviation during acute anterior wall infarction or ischemia: electrocardiographic and
Insights
Transient right axis deviation during myocardial infarction indicates significant right coronary artery obstruction. This electrocardiographic pattern is linked to specific coronary artery disease, aiding diagnosis.
Area of Science:
- Cardiology
- Electrophysiology
- Diagnostic Imaging
Background:
- Acute myocardial infarction (MI) and ischemia can present with various electrocardiographic (ECG) changes.
- Right axis deviation (RAD) with left posterior hemiblock is an uncommon ECG pattern.
- Understanding the correlation between ECG patterns and coronary anatomy is crucial for diagnosis and management.
Purpose of the Study:
- To investigate the correlation between transient right axis deviation with left posterior hemiblock and coronary angiographic findings in patients with acute myocardial infarction or ischemia.
- To compare the coronary artery disease (CAD) patterns in patients with and without this specific ECG abnormality.
Main Methods:
- Retrospective analysis of 11 patients with acute anterior MI/ischemia and transient RAD with left posterior hemiblock (study group).
- Comparison with 24 control patients with acute anterior MI/ischemia but without this ECG pattern.
- Coronary angiography was performed to assess coronary artery anatomy and disease severity.
Main Results:
- The study group showed a significantly higher incidence of severe right coronary artery (RCA) obstruction (100% vs. 25%) compared to the control group.
- Collateral circulation from the left coronary system to the posterior descending artery was more frequent in the study group (73% vs. 0%).
- No significant differences in left anterior descending or circumflex artery disease were observed between the groups.
Conclusions:
- Transient right axis deviation with left posterior hemiblock during acute MI/ischemia is strongly associated with significant RCA obstruction.
- This ECG pattern may indicate specific coronary anatomy, including collateral supply to the posterior descending artery.
- The findings can aid in identifying patients with critical RCA disease based on their ECG presentation.
Abstract:
Eleven patients, three with acute anterior myocardial infarction and eight with anterior ischemia, who developed transient right axis deviation with a left posterior hemiblock pattern during the acute phase of myocardial infarction or ischemia are described (study group). A correlation between their electrocardiographic pattern and the angiographic findings was made. The arteriographic findings were compared with those of a group of 24 patients with acute anterior myocardial infarction or ischemia without transient right axis deviation (control group). The main electrocardiographic characteristics of the right axis deviation pattern were: an average shift of the mean frontal axis to the right of 42 degrees (10 degrees to 94 degrees); increased voltage of R waves in leads II, III and a VF and appearance of small Q waves or decreased voltage of Q waves if previously present in the same leads; decreased voltage of R waves and appearance of deep S waves in lead aVL; and inverted T waves and isoelectric ST segments in leads II, III and aVF. Coronary angiography revealed that the study group had a higher incidence of significant right coronary artery obstruction and collateral circulation between the left coronary system and the posterior descending artery than did the control group (100 versus 25% and 73 versus 0%, respectively; p less than 0.01). There were no differences between the groups regarding left anterior descending and circumflex artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)