|Year : 2016 | Volume
| Issue : 1 | Page : 10-12
Prediction of totally occluded culprit artery from presenting electrocardiogram in acute coronary syndrome
Rupesh George1, Arun George2, Alwin Treesa George2, K Jayaraj2, TP Antony2
1 Department of Cardiology, Amala Institute of Medical Sciences, Thrissur, Kerala, India
2 Department of Medicine, Amala Institute of Medical Sciences, Thrissur, Kerala, India
|Date of Web Publication||4-Mar-2016|
Department of Cardiology, Amala Institute of Medical Sciences, Thrissur - 680 555, Kerala
Source of Support: None, Conflict of Interest: None
Background: Revascularization strategy in acute coronary syndrome is based on the ST segment deviation in the presenting ECG. ST segment elevation denotes total occlusion of culprit vessel and mandates early revascularization. Aim: To study the correlation of totally occluded coronary vessel with ST segment elevation in presenting 12 lead ECG. Material and Methods: The present study was conducted in 89 consecutive patients with chestpain and angiogram evidence of at least one totally occluded epicardial coronary vessel. Culprit artery prediction was attempted according to the available algorithms and correlated with the angiogram finding. Results: Out of 89 cases 47 patients had left anterior descending artery (LAD), 27 had right coronary artery (RCA) and 15 had left circumflex artery (LCX) as culprit vessel. All patients with total occlusion of LAD and RCA had ST segment elevation, while only 50% of patients with circumflex artery occlusions had classical ST segment elevation. Conclusion: In our study we found that half of total circumflex artery occlusions were classified as non-ST elevation acute coronary syndrome when using the current 12-lead ECG criteria. This emphasizes the need for the incorporation of routine posterior leads in cases of suspected acute coronary syndrome if classical ST elevation is not present in 12-lead ECG .Otherwise many patients with totally occluded culprit arteries may be denied, the revascularization procedures in their golden hour.
Keywords: Acute coronary syndrome, culprit artery, electrocardiogram (ECG)
|How to cite this article:|
George R, George A, George AT, Jayaraj K, Antony T P. Prediction of totally occluded culprit artery from presenting electrocardiogram in acute coronary syndrome. Heart India 2016;4:10-2
|How to cite this URL:|
George R, George A, George AT, Jayaraj K, Antony T P. Prediction of totally occluded culprit artery from presenting electrocardiogram in acute coronary syndrome. Heart India [serial online] 2016 [cited 2020 Jan 22];4:10-2. Available from: http://www.heartindia.net/text.asp?2016/4/1/10/178122
| Introduction|| |
The total occlusion of epicardial coronary artery leads to myocardial infarction (MI). It is being manifested in electrocardiogram (ECG) as ST segment elevation in the leads records electrical activity from that region. Because there can be topographic variations in blood supply of the three major epicardial coronary arteries from person-to-person and the predilection of involvement of particular sites of conduction system with different coronary arteries, the clinical presentation, morbidity, and mortality vary with the artery involved, in cases of acute MI. Hence, early identification of the culprit artery gives a bird's-eye view for the clinician in managing the life-threatening disease. The 12-lead ECG is a simple noninvasive tool used for diagnosing the acute MI. By adding algorithm to identify the culprit artery in ECG, it will empower it into a more efficient modality. The American College of Cardiology/American Heart Association (ACC/AHA) recommends implementation of reporting the culprit artery in acute MI ECG.
| Materials and Methods|| |
We conducted a prospective, descriptive study of 89 consecutive patients who had chest discomfort, ECG changes, and angiograms within 24 h showing thrombotic total occlusion of at least one major epicardial coronary artery. The study was conducted from October 2013-March 2014. We excluded patients with a history of old MI and those who were not willing for a coronary angiogram and revascularization. The algorithm we tested to detect the culprit artery has been shown in [Figure 1].,, Binomial logistic regression analysis was done to assess the positive and negative predictive values of the algorithms.
| Results|| |
Our study population mainly belonged to the age group of 40-60 years and majority of the population were males (72% males versus 28% females). Out of 89 cases, 47 had left anterior descending artery (LAD) and 27 had right coronary artery (RCA) as the culprit artery and 15 had left circumflex artery (LCx) as the culprit artery. All patients with total occlusion of LAD and RCA had ST elevation in representing leads. While only 50% patients of LCx occlusion had a classical ST elevation. The culprit artery prediction of RCA involvement in inferior wall MI with the criteria of ST elevation more in LIII than LII had 63.8% sensitivity and 92.4% specificity, with a positive predictive value of 85% and negative predictive value of 79.03% [Figure 2].
|Figure 2: Sensitivity and Specificity of culprit artery prediction of RCA with ST segment elevation in LIII>LII|
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When comparing the magnitude of ST depression in LI and aVL for RCA involvement, more ST depression in aVL than in L1 gives 57.9% sensitivity and 77% specificity and 87% negative predictive value.
Identification of proximal LAD occlusion in acute anterior wall MI, ST elevation in V1, V2, V3 with ST depression in LI and aVL shows 57.8% sensitivity and 88.5% specificity with 87.5% positive predictive value [Figure 3].
|Figure 3: Sensitivity and specificity of culprit artery prediction of LAD with right bundle branch block with ST segment elevation in V1-V4|
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Using the criteria of ST elevation in LII more than LIII for LCx had high specificity of 81.3% but very low sensitivity of 7.14% [Figure 4].
|Figure 4: Sensitivity and Specificity of ST depression in V1-V3 for circumflex occlusion|
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| Discussion|| |
Current of injury of acute MI draws the repolarization vector toward that site. So the lead facing the infarcted region records the maximum ST elevation while leads in obtuse angle to the lead facing the infarcted region records maximal ST depression as the reciprocal changes. Because the RCA supplies region in the axis of LIII and LCx supplies the myocardium in LII axis, in RCA involvement LIII ST elevation will be more than LII, while in circumflex occlusion it is the vice versa. Similarly, lead aVL is more obtuse than LI; aVL will show more ST depression than LI when the RCA is the culprit. In ostioproximal LAD occlusion the basal septal infarction is manifested as ST elevation in V1-V4 and aVR, while ST depression will be seen in the rest of the leads. In our study, the sensitivity and specificity of RCA and the proximal LAD prediction as the culprit artery is similar to other studies. The criteria for identifying circumflex artery occlusion had very low sensitivity. The reason for this may be that we analyzed ECGs of patients with ongoing chest pain and immediate angiogram that showed occlusion of at least one major vessel. With RCA and LAD occlusion, all patients had a classical ST elevation, while half of LCx occlusion did not have the classical ST elevation or significant ST depression in V1-V4 in 12-lead ECG. Many of our patients had only subtle ECG changes and initial diagnosis before angiogram was a non-ST elevation acute coronary syndrome. This finding emphasizes the importance of adding posterior leads and high lateral leads to identify LCx total occlusion for reperfusion strategies if the patient is not taken for early coronary angiogram. Our study shows the limitation of 12-lead ECG in detecting LCx total occlusions. If early angiogram has not been done, majority of these cases will be managed as unstable angina, instead of ST elevation MI. This reiterates the need for additional posterior leads and high lateral leads in cases of classical chest pain with minimal ECG changes.
Limitation of our study is the small sample size.
| Conclusion|| |
Culprit artery identification of RCA and proximal LAD by current ECG algorithm has high specificity and high sensitivity. However, majority of circumflex occlusions do not show significant ST changes in conventional 12-lead ECG. Hence, high lateral leads and posterior leads can be useful in patients with minimal ECG changes and chest discomfort in addition to conventional 12-lead ECG for the detection of acute total occlusion of circumflex artery.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]