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[The relationship between conventional ECG and the culprit coronary artery in acute myocardial infarct]
L A César1, M A Moretti, J A Ramires
1Instituto do Coração, Hospital das Clínicas, FMUSP, San Paulo.
Insights
Electrocardiograms (ECGs) can detect acute myocardial infarction (AMI), but left circumflex artery occlusions often lead to false negatives. These occlusions commonly cause posterior or inferior wall myocardial infarctions on ECG.
Area of Science:
- Cardiology
- Diagnostic Imaging
Context:
- Acute myocardial infarction (AMI) diagnosis relies heavily on electrocardiogram (ECG) interpretation.
- Early and accurate detection of AMI is crucial for timely intervention and improved patient outcomes.
- Identifying the culprit coronary artery aids in guiding treatment strategies.
Purpose:
- To evaluate the accuracy of electrocardiogram (ECG) in detecting acute myocardial infarction (AMI) within the initial 12 hours of symptom onset.
- To assess the relationship between specific ECG findings and the culprit coronary artery in patients with AMI.
Summary:
- This study analyzed ECGs from 68 patients with confirmed AMI, correlating ECG findings with cinecoronariography results.
- Electrocardiograms showed high accuracy for right coronary artery (RCA) and left anterior descending (LAD) artery occlusions.
- Left circumflex (LC) artery occlusions were frequently associated with false-negative ECGs, often presenting as posterior or inferior wall infarctions.
Impact:
- Findings highlight the limitations of early ECG in diagnosing AMI due to left circumflex artery occlusions.
- Emphasizes the need for considering posterior and inferior wall changes on ECG for LC-related AMIs.
- Improves understanding of ECG patterns in relation to specific coronary artery territories in AMI.
Purpose:
To evaluate electrocardiogram (ECG) in detecting acute myocardial infarction (AMI) during the first 12 hours of symptoms and its relationship to the culprit coronary artery.
Methods:
We studied 68 patients aged 55.6 (30 to 76) years, 61 males, with AMI confirmed by elevated CKMB isoenzyme and cinecoronariography (CINE). In all of them we obtained two ECG: first (i), with < 12 hours of symptoms and a second, > or = 5 days during evolution. ECG were analyzed in order to disclose up and downward ST-T segments > or = 1 mm, new Q waves > or = 0.04 s and R/S > or = 1 plus downward ST-T segment in leads V1 and V2. Then we have done correlation between these and the culprit coronary lesions at CINE.
Results:
The culprit coronary lesions were: right coronary artery (RCA) in 16, left circumflex (LC) in 26 and left anterior descending (LAD) in 31 cases. According to the ECG, the RCA determined inferior AMI in all patients and the LC only in 62% of cases. Posterior AMI due to LC was seen in 81% of cases at ECG and, associated with lateral AMI, in 52%. Lone lateral AMI was seen in 5% and true posterior in 14% of cases, all of them due to LC.
Conclusion:
False negative ECG (i) in AMI is in fact due to LC occlusion which, frequently, causes posterior wall more then inferior wall myocardial infarction at ECG.