Prediction of isolated first diagonal branch occlusion by 12-lead electrocardiography: ST segment shift in leads I
Insights
Electrocardiogram (ECG) abnormalities in leads I and aVL, with a normal V1 lead, can help differentiate first diagonal branch occlusion from left anterior descending coronary artery occlusion.
Area of Science:
- Cardiology
- Diagnostic Electrocardiography
Background:
- ECG findings for first diagonal branch obstruction are not well-defined.
- Comparison with left anterior descending coronary artery obstruction is lacking.
Purpose of the Study:
- To identify specific ECG features distinguishing first diagonal branch occlusion from left anterior descending coronary artery occlusion.
- To enhance diagnostic accuracy for coronary artery occlusions.
Main Methods:
- Compared ECG findings in 34 patients with isolated diagonal branch occlusion (group 9) against 20 patients with left anterior descending occlusion at site 6 (group 6) and 20 at site 7 (group 7).
- Utilized American Heart Association classification for occlusion sites.
- Statistical analysis with >80% power to detect a 50% difference.
Main Results:
- Group 9 showed ST elevation in leads I and aVL (100%), abnormal Q waves, and inverted T waves more frequently than groups 6 and 7.
- Group 9 had significantly less ST elevation, abnormal Q waves, and inverted T waves in lead V1 compared to groups 6 and 7.
- Multivariate analysis identified leads I, aVL, and V1 abnormalities as key discriminators.
Conclusions:
- Isolated diagonal branch occlusion causes distinct ECG changes in leads I and aVL.
- Precordial lead changes are less common in diagonal branch occlusion compared to LAD occlusion.
- Leads I and aVL reflect the myocardial territory supplied by the diagonal branch.
Objectives:
This study was performed to determine electrocardiographic (ECG) features that could distinguish first diagonal branch occlusion from left anterior descending coronary artery occlusion.
Background:
The ECG findings associated with first diagonal branch obstruction have not previously been compared with those of left anterior descending coronary artery obstruction.
Methods:
The ECG findings in 34 patients with isolated diagonal branch occlusion (group 9) were compared with those in 20 patients with occlusion at site 6 (group 6) and 20 with occlusion at site 7 (group 7), according to American Heart Association classification. This study had a power > 80% to detect a 50% difference between groups at a probability value of 0.05.
Results:
ST segment elevation was observed in leads I and aVL for all group 9 patients, in 80% (p < 0.05) of group 6 patients for lead I and 90% for lead aVL and in 50% (p < 0.01) of group 7 patients for lead I and 55% (p < 0.01) for lead aVL. Similarly, there was a higher incidence of abnormal Q waves and inverted T waves in leads I and aVL in group 9 than in groups 6 and 7. In contrast, group 9 showed a significantly lower incidence of ST segment elevation (3.4%), abnormal Q waves (3.0%) and inverted T waves (0%) in lead V1 than group 6 (80%, 40% and 90%, respectively) and group 7 (75%, 60% and 70%, respectively) (p < 0.01 for each). Multivariate analysis revealed that abnormalities in leads I and aVL, combined with a normal lead V1 (and V6), provided good criteria for distinguishing isolated diagonal branch occlusion from left anterior descending coronary artery occlusion.
Conclusions:
Isolated diagonal branch occlusion more frequently caused ECG abnormalities in leads I and aVL and less frequently caused changes in the precordial leads compared with left anterior descending coronary artery obstruction, indicating that leads I and aVL represent myocardium perfused by the diagonal branch.
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