ST-segment Depression In Leads Research Articles

Characteristics and mechanism of reciprocal ST-segment depression in acute ST segment elevation myocardial infarction: Reciprocal ST-segment depression and ST segment elevation myocardial infarction.

At present, the mechanism of reciprocal ST-segment depression (RSTD) is unclear. ST-segment changes may be caused by the potential difference between the positive and negative electrodes, although this requires further investigation. The characteristics of RSTD and their relationship with ST-segment elevation in acute ST segment elevation myocardial infarction (STEMI) patients were analyzed. We replaced the negative electrode of the precordial leads of an inferior wall myocardial infarction patient and observed the changes in the ST-segment of the precordial leads. A total of 85 patients were included, of which 75 were patients with RSTD. All 45 patients with inferior myocardial infarction had limb lead RSTD, and 37 had anterior lead ST-segment depression. All ST-segment changes in STEMI can be explained by the proposed mechanism, and the value of ST segment depression in limb leads can be calculated by the value of ST segment elevation. In summary, the mechanism of RSTD in acute myocardial infarction may be that the action potential (AP) of the negative electrode of the lead weakens or disappears and the AP of the positive electrode may not be completely offset, resulting in ST-segment depression. Animal experimental studies are needed for further confirmation. When the negative electrode of the precordial lead is changed in acute inferior wall myocardial infarction patient, the ST-segment of the precordial lead changes accordingly. All the changes are consistent with our analysis.

When Positive Ischemic Response on Treadmill Test Implies Otherwise: One Overlooked Pitfall on TMT

When Positive Ischemic Response on Treadmill Test Implies Otherwise: One Overlooked Pitfall on TMT
 
 Background:
 Particular ischemic process that portrayed in Electrocardiogram (ECG) changes bear similar depiction to different conditions, one of them is hypokalemia. On the other hand, Treadmill Test (TMT) has been used for decades for risk stratifying and diagnosing coronary artery disease as a non-invasive, safe and affordable screening test. However, using ECG changes as interpretation, TMT could have incidence of false positive results reported in various conditions, one of which is hypokalemia. The aim is to report a case of positive ischemic response resemblance in TMT of patient with severe hypokalemia.
 
 Case Illustration:
 A-43-years-old female with history of unstable angina pectoris with risk factors of diabetes mellitus and hypertension underwent several examinations. Computed Tomography Coronary Angiography (CTCA) showed a 60% stenosis lesion in Left Anterior Descending (LAD) coronary artery. Within 3 minutes of TMT the ECG showed ST-segment depression in lead II, III, aVF, V1-V6 and prominent elevation in lead aVR. Fear of left main coronary artery occlusion, the test was terminated and the patient was immediately planned for urgent Percutaneous Coronary Intervention (PCI). The result indicated non-significant coronary lesion. Potassium concentration of 1.87 mmol per liter and troponin levels were normal. Unbeknownst before, the patient had multiple episodes of vomiting for a whole day and felt dehydrated prior to the TMT. Patient then treated for potassium implementation and discharged uneventfully.
 
 Conclusion:
 Hypokalemia could induce widespread ST-Segment depression or ST-Segment elevation in right limb lead. Peculiarly in context of stress testing or accompanied with chest pain, it is difficult to differentiate ECG changes in hypokalemia with true myocardial ischemia. Hypokalemia should be considered when TMT result is not concordance with true myocardial ischemia.

The Relationship Between ST-Segment Depression in Lead aVR and Coronary Microvascular Function in Acute Inferior Myocardial Infarction

Aim: The aim of this study was to investigate the relationship between ST-segment depression in the aVR lead and coronary microvascular function in acute inferior myocardial infarction undergoing primary percutaneous intervention.
 Methods: 287 patients with inferior myocardial infarction confirmed by coronary angiography were divided into two groups with and without ST-segment depression in lead aVR ≥ 0.1 mV on the 12 lead ECG. Electrocardiographic recordings were made for the evaluation of ST-segment resolution before and after primary PCI. Angiographic assessment in the infarct-related artery was performed by using the myocardial blush grade and thrombolysis in myocardial infarction flow. 
 Results: Overall, 51 of 287 patients had ST-segment depression in lead aVR. The number of patients with RCA-induced infarction was higher in the group with ST-segment depression in lead aVR. RCA involvement was present in 44 patients. Peak troponin was higher in the group with ST-segment depression in lead aVR compare to the other group (P <0.001). The MBG was more impaired, and the STR was less regressed in patients with ST depression in lead aVR (p<0,001). The ejection fraction of patients with ST-segment depression in lead aVR was lower.
 Conclusion: We found that ST-segment depression in lead aVR was associated with impaired myocardial perfusion in patients with inferior myocardial infarction.

Acute Occulusion of Diagonal Branch:Triad of Severe Pain,Small Infarct & Specific Ekg Pattern

A 59 years female, known case of Non-Insulin Dependent Diabetes Mellitus (NIDDM) for 10 years with a strong family history of coronary artery disease (both parents & siblings have CAD), presente with severe agonizing precordial chest discomfort, radiating to left shoulder associated with profuse sweating for last 3 hours.In emergency room,patient was restless,pulse=100/min.,BP=170/100mm Hg,O2 saturation 98%.There was no sign of cardiac failure.ECG recorded in emergency room revealed ST elevation of 5to 6 mm in lead I,aVL, 4 mm ST elevation in lead II, V2 and shuttle ST segment sagging in lead II, 4 mm ST segment depression in lead III & Avf (South African Flag Sign) (Fig 1).

EKG-gyöngyszem: acut coronaria szindrómát utánzó sinuscsomó-betegség – az aVR-jel

The aVR-sign can indicate left main or multivessel coronary disease, but the sign is not STEMI eqvivalent and is not a sensitive sign for coronary disese. The following case is an example of this. An 89-year-old woman was admitted with chest pain, atrial fibrillation and multiple lead ST-segment depression but ST-segment elevation in lead aVR. The aVR-sign indicated urgent angiography with negative result. A spontaneous sinus conversion was observed with repolarization normalisation. Later the ECG demonstrated SA-blocks, and sinus arrest. Sick sinus syndrome was diagnosed and the patient was treated with pacemaker and oral anticoagulant. Orv Hetil. 2020; 161(11): 434-436.

Differences in initial electrocardiographic findings between ST-elevation myocardial infarction due to left main trunk and left anterior descending artery lesions

BackgroundEarly discrimination of ST-elevation myocardial infarction (STEMI) due to a left main trunk (LMT) lesion provided by straightforward electrocardiographic criteria is useful for prompt treatment. The purpose of this study is to investigate differences in electrocardiographic findings between STEMI due to lesions of LMT and those of left anterior descending artery (LAD).MethodsInitial electrocardiogram (ECG) recordings of 435 patients with analyzable ECGs from a cohort of 940 consecutive STEMI patients were analyzed retrospectively for presence of LMT lesions (LMT, n = 39), proximal (pLAD, n = 224) and distal LAD lesions (dLAD, n = 172). ST-segment deviations in 12 leads were assessed among 3 groups without bundle branch block (n = 17 in LMT, n = 180 in pLAD, and n = 159 in dLAD).ResultsMagnitudes of ST-segment deviations showed significant differences in leads II, III, aVR aVL, aVF, and V2–V6 across the three groups. This difference suggested two possible characteristic findings in the LMT group, allowing it to be distinguished from the pLAD or dLAD group; (A) larger magnitude of ST-segment depression in lead II than that of ST-segment elevation in lead V2 (47.1% in LMT vs. 0.6% in pLAD vs. 1.3% in dLAD, P < 0.0001), and (B) ST-segment depression in lead V5 (58.8% in LMT vs. 6.7% in pLAD vs. 2.5% in dLAD, P < 0.0001). These findings exhibited superior negative predictive value over conventional ST-segment elevation in lead aVR.ConclusionsA large reciprocal ST-segment depression in inferior leads and ST-segment depression in lead V5 are useful ECG findings allowing determination of STEMI due to an LMT lesion.

New ST-segment algorithms to determine culprit artery location in acute inferior myocardial infarction

ObjectivesIn acute inferior ST-segment elevation myocardial infarction (STEMI), multiple criteria have been proposed to predict the culprit artery based on the 12-lead electrocardiogram (ECG). We assessed the utilities of 11 traditional and 2 new criteria to devise a new ECG algorithm to localize the culprit artery in acute inferior STEMI. MethodsWe analyzed electrocardiographic and angiographic findings of 194 consecutive patients with acute inferior STEMI to devise a new ECG algorithm, further validated in another cohort of 80 patients with acute inferior STEMI. ResultsIn derivation cohort, the 2 new criteria including (1) ST-segment depression in lead I equal to half of that in lead aVL and (2) equal ST-segment elevation in leads II, III, and aVF did not prove useful. The most powerful electrocardiographic criteria were (1) the ratio of ST elevation in lead III to that in lead II, (2) the ratio of ST depression in lead I to that in lead aVL, and (3) ST changes in lead I; these formed a 3-step algorithm. Application of this algorithm suggested the location of the culprit artery in 192 of 194 patients (nearly 99%) in the derivation cohort. In validation cohort, the algorithm possessed a sensitivity and specificity of 100% and 89%, respectively, for predicting the right coronary artery and 89% and 100%, respectively, for predicting the left circumflex artery. ConclusionsA new 3-step algorithm based on 12-lead ECG is proposed to localize the culprit artery at the bedside of acute inferior STEMI patients before primary percutaneous coronary intervention, allowing immediate decisions about therapy.

Value of electrocardiogram (ECG) in identifying acute occlusion sites of right coronary artery

Clinical data of 151 patients with acute occlusion of right coronary artery were retrospectively analyzed. Coronary angiography and electrocardiography (EEG) were performed in all 151 patients, angiography showed proximal-middle segment occlusion in 114 cases and distant segment occlusion in 37 cases. The correlation of ECG findings with coronary artery occlusion sites was analyzed. Results showed that EEG findings related to proximal-middle segment occlusion were: ST segment elevation in lead V4R ≥0.05 mV, Ⅲ degree atrioventricular block, ST segment depression in lead Ⅰ>0.1 mV, ST segment depression in lead AVL≥0.2 mV, ST segment elevation in lead Ⅲ≥0.25 mV, the total ST depression in lead V2,V3 and V4 ≥0.4 mV , the total ST depression in lead I and aVL ≥0.25 mV; among which ST depression of Lead Ⅰ>0.1 mV, ST elevation of Lead V4R≥0.05 mV and Ⅲ degree atrioventricular block were used to predict occlusion of proximal-middle segment of right coronary artery with 100% specificity. ECG findings related to distal segment occlusion were: ST depression in lead Ⅰ≤0.1 mV, ST segment depression in lead AVL<0.2 mV, ST elevation in lead Ⅲ≤0.25 mV, the total ST depression in lead V2,V3 and V4 <0.4 mV, ST segment were not depression in lead V1-V5,the total ST depression in lead I and aVL<0.25 mV. Based on a 4-step flow method, ECG might be adopted to identify the acute occlusion sites in proximal-middle segment and distal segment of right coronary. Key words: Coronary occlusion; Inferior wall myocardial infarction; Electrocardiography

Electrocardiographic prediction of lateral involvement in acute non-anterior wall myocardial infarction

PurposeRecent research has established that a tall R-wave in V1 indicates lateral wall involvement in non-anterior wall myocardial infarction (MI). The objective of this study was to assess the value of the admission electrocardiogram (ECG) to predict R-waves and consequently lateral wall damage in the late phase of non-anterior MI. MethodsECGs of 69 patients were analyzed. ST-segment changes in representative leads for lateral wall infarction such as V1, V2, V6 and I were correlated with the extent of QRS-wave changes in V1 and V6. ResultsST-segment elevation in V6 showed correlations with R/S ratio in V1 (r=0.802, B=0.440, P=<0.001) and with the depth of Q-waves in V6 (r=0.671, B=0.441, P=0.007). This correlation was higher in a small subgroup where the left circumflex branch (Cx) was the culprit vessel (r=0.888, B=1.469 and P=0.018). ST-segment depression in lead I correlated with the height of R and the surface of R in V1 (height times width of R) (r=0.542, B=−0.150, P=0.005 and r=0.538, B=−0.153, P=0.005 respectively), especially in the subgroup without proximal occlusions of RCA (r=0.711 and r=0.699). ST-segment depression in lead I also predicted Q-waves in V6 (r=0.538, B=0.114, P=0.006). ST-segment changes in V2 showed no significant correlation with either R- or Q-wave measurements. ConclusionsST-segment elevation in V6 in the acute phase of non-anterior MI predicts lateral involvement as expressed by the R/S ratio in V1 in the post reperfusion phase. A subgroup with Cx occlusion showed especially strong correlations, although the size of the group was small. In lead I ST-segment depression is correlated to height and surface of R in V1 and Q-waves in V6.

Unusual Cause of STEMI: An Intramyocardial Metastasis

A 66-year-old patient was admitted to the emergency unit for chest pain. The electrocardiogram showed a ST-segment elevation in leads V2-V4 and a slight STsegment depression in lead III. The coronary angiography was normal but CMR imaging and CT scan revealed a tumor surrounding the left anterior artery. Finally, further investigations disclosed a metastasis of squamous cell carcinoma lung cancer.

Oxaliplatin-induced acquired long QT syndrome with torsades de pointes and myocardial injury in a patient with dilated cardiomyopathy and rectal cancer

A 67-year-old woman presented with a history of dilated cardiomyopathy with congestive heart failure since 2003, who subsequently developed lower rectal cancer (adenocarcinoma) with liver, bone, and lymph node metastasis. Abdominoperineal resection and hepatectomy were performed. The patient received two rounds of intravenous chemotherapy, including 12 and six courses of FOLFOX4 (5-fluorouracil, leucovorin, and oxaliplatin; 85 mg/m2 per cycle). She underwent a third round of intravenous FOLFOX4 because of tumor progression. During the 21st course of FOLFOX4 regimen, the patient developed ST segment depression in lead II and prolongation of QT interval with polymorphic ventricular tachycardia, torsades de pointes right after the start of oxaliplatin infusion. Immediate defibrillation and cardiopulmonary resuscitation were administered, and the patient regained spontaneous circulation and consciousness. Twelve-lead electrocardiogram showed ST segment elevation in III, aVF, and ST segment depression in V4–6 after resuscitation. To our knowledge, prolongation of QT interval with torsades de pointes and coronary spasm with myocardial injury that were stabilized in one patient following oxaliplatin infusion has not been reported. We present a patient with these rare complications.

Life-threatening early saphenous vein graft stenosis after left main artery replacement

A 42-year-old woman with a past medical history of i.v. drug abuse and endocarditis presented in our emergency department with severe and persisting chest pain. Cardiac markers were elevated (hsTrop T 1.210 µg/L; CK 800 U/L; CK-MB 100 U/L) and ECG revealed descending ST-segment depression in lead I and aVL with negative T waves and horizontal ST-segment depression in lead V4–V6. Inflammatory parameters were negative. Three months before, the patient was referred to our institution because of antibiotic-resistant fever, chills, elevated inflammatory parameters, and splenomegaly. Following microbiological analysis, Staphylococcus aureus was verified and transoesophageal echocardiography (TEE) demonstrated aorto-ventricular disconnection caused by a circumferential partly thrombosed aortic annulus abscess ( Panel A ). Surgery was performed, replacing …

Recurrent Severe Acute Pulmonary Edema Caused by Transient Left Ventricular Insufficiency With Mitral Regurgitation Related to Severe Coronary Artery Spasm

A 64-year-old diabetic and dyslipidemic woman was admitted to our hospital with a history of 3 episodes of acute pulmonary edema in the past 4 months, without evidence of organic heart disease. She was affected by a hypopituitarism and was treated with levothyroxine and desmopressin. She had atypical chest pain 1 year before, but 2 exercise stress tests were negative. In the past 4 months, she had been admitted 3 times for severe dyspnea at rest of sudden onset without chest pain, requiring endotracheal intubation because of severe acute pulmonary edema. Basal physical examination was normal. ECGs and serial troponin levels were normal. Clinical treatment was successful with early extubation. Echocardiography (echo) at rest was completely normal with normal left ventricular systolic and diastolic function and no valvular regurgitations. Coronary angiography revealed normal coronary arteries and normal global and regional left ventricular systolic motion. Thoracoabdominal computerized tomography was normal; and pulmonary thromboembolism, aortic disease, and suprarenal tumor were ruled out. Pulmonary biopsy also was normal. Laboratory tests including hemoglobin, electrolytes, autoantibodies, catecholamine, and thyroid hormones were also normal. Holter and telemetry did not reveal arrhythmias. Gated single-photon emission computed tomography and stress echo were negative for ischemia. Most of …

The ECG in localizing the culprit lesion in acute inferior myocardial infarction: a plea for lead V4R?

This editorial refers to ‘Distinguishing the right coronary artery from the left circumflex coronary artery as the infarct-related artery in patients undergoing primary percutaneous coronary intervention for acute inferior myocardial infarction’ by N.J. Verouden et al., on page 1517 The electrocardiogram (ECG) is being used for decades as a reliable and inexpensive tool to diagnose acute myocardial infarction in the patient with chest pain. More recently, an emphasis has been made on ECG features that allow better identification of the coronary occlusion site and thereby better estimation of the size of the area at risk, which is important for selection of the preferred type of reperfusion. On average the left anterior descending coronary artery supplies 50% of blood flow and the right coronary artery (RCA) and circumflex (Cx) coronary artery each supply 25% of blood flow to the left ventricular myocardium. In addition, RCA irrigates most of the right ventricle. The closer the occlusion site to the origin of the coronary artery, the larger the ischaemic area and the greater the necessity of a rapid reperfusion attempt. The ECG findings considered to be helpful to localize the occlusion site in the culprit coronary artery have been described by several authors and are summarized elsewhere. 1 In the current issue of the journal, Verouden et al. looked at the value of the standard 12-lead ECG to distinguish the RCA from the Cx coronary artery as an infarct-related vessel in a large series of patients with acute inferior MI undergoing primary percutaneous coronary intervention shortly thereafter. 2 ST-segment elevation in lead III more than in lead II, combined with ST-segment depression in lead I or aVL was used as a marker, suggesting that the culprit lesion was located in RCA. The study is important because of the large number of patients and the short time interval between the 12-lead ECG and the coronary angiogram. The findings can be summarized that using this ECG algorithm a correct diagnosis as to the coronary occlusion site did not reach a pre-specified sensitivity threshold of 90% in the whole group. Of interest is that when the authors applied algorithms published by other investigators using ST-segment deviation in the extremity leads, even lower sensitivity was observed. Only in the case of a total 12-lead ST-segment deviation score of more than 18.5 mm, a sensitivity of more than 90% was found. We are not informed about the accuracy of the algorithm in relation to the degree of ST-segment deviation. Is there a critical threshold of

Distinguishing the right coronary artery from the left circumflex coronary artery as the infarct-related artery in patients undergoing primary percutaneous coronary intervention for acute inferior myocardial infarction

Aim of this study was to investigate the diagnostic accuracy of the conventional electrocardiogram (ECG) algorithm [ST-segment elevation (STE) in lead III exceeding that in lead II combined with ST-segment depression in lead I or aVL] for identification of the infarct-related artery (IRA) in a large cohort of patients undergoing primary percutaneous coronary intervention (PCI) for inferior wall STE myocardial infarction (STEMI). We included 1131 patients with inferior STEMI, who underwent primary PCI between 2000 and 2007 and of whom a pre-procedural 12-lead ECG was available, recorded immediately prior to PCI. The IRA was determined during emergency angiography. Coronary angiography confirmed the right coronary artery (RCA) as the IRA in 895 patients (79%) with inferior wall STEMI. Application of the ECG algorithm resulted in 624 true positive cases of acute RCA obstruction (sensitivity: 70%, 95% CI: 67 -73%) and 170 cases with true negative result (specificity: 72%, 95% CI: 66-77%). Sensitivity of >90% was established in patients with cumulative ST-segment deviation above median (>18.5 mm). The conventional ECG algorithm showed a low sensitivity for the non-invasive diagnosis of RCA occlusion in an all-comer, inferior STEMI cohort undergoing primary PCI. Sensitivity was only sufficient in patients with extensive ST-segment deviation.

Electrocardiographic prediction of short-term prognosis in patients with acute myocardial infarction associated with the left main coronary artery

Purpose The purpose of this study was to assess the usefulness of electrocardiogram on admission to predict short-term prognosis in patients with acute myocardial infarction (AMI) associated with left main coronary artery (LMCA). Methods Electrocardiogram was obtained on admission in 41 patients with AMI associated with LMCA who underwent reperfusion therapy. Electrocardiographic findings were compared between nonsurvivors and survivors. Results There were 24 nonsurvivors and 17 survivors during 30-day follow-up. Nonsurvivors had ST-segment elevation in both leads aVR and aVL (54% vs 18%, P < .05), left anterior fascicular block (83% vs 41%, P < .05), and right bundle-branch block (54% vs 18%, P < .05) more frequently, and ST-segment depression in lead V 5 (17% vs 59%, P < .05) less frequently than survivors among patients with AMI associated with LMCA. Conclusions Our data suggested that electrocardiogram on admission might be useful to predict short-term prognosis in patients with AMI associated with LMCA.

Inverted Takotsubo contractile pattern caused by pheochromocytoma with tall upright T-waves, but not typical deep T-wave inversion

We describe a 36-year-old woman with inverted Takotsubo cardiomyopathy caused by pheochromocytoma crisis. In the acute phase, her electrocardiogram showed ST segment depression in lead II, III, aVF and V2 through V5. On day 14, tall upright T-waves were observed in leads V2 through V5 despite heart failure and basal to midventricular ballooning improved on day 4, and all electrocardiographic abnormalities finally normalized after surgical removal of the pheochromocytomas. This is the first report of electrocardiographic course of inverted Takotsubo cardiomyopathy, and these findings seem as if the inverted electrocardiographic findings are contrary to those of apical ballooning.

Acute Right Ventricular Myocardial Infarction: A Very Specific Entity

It was a pleasure to read the recent electrocardiographic report on ST-segment changes (1). Indeed, one of the features of electrocardiograms indicating that the right coronary artery, rather than the left circumflex artery, is the culprit is ST-segment depression in lead I. The first author who underlined ST-segment depression in lead I was J. Willis Hurst (2). We also had a similar observation (3, 4). In addition, we described right ventricular (RV) acute myocardial infarction (AMI) “in extension” (5). Recurrent AMI within 10 days of inferior wall AMI is considered to be RV AMI “in extension” only if ST-segment elevation ≥1 mm in V4R is present as well as hypotension and/or bradycardia but RV AMI is absent at admission. RV AMI “in extension” may be the result of proximal thrombus extension or spasm (6). Heparin-rebound phenomenon contributes to such a scenario (7).

Electrocardiographic features and prognosis in acute diagonal or marginal branch occlusion

The aim of our study was to analyze electrocadiographic changes in patients with acute myocardial infarction related to the occlusion of diagonal (DG) or marginal (MG) branch. We selected 13 cases with DG and 12 with MG occlusion on angiography and evaluated their electrocardiogram (ECG) patterns on admission obtained in emergency department (ED) of university hospital with catheterization laboratory serving everyday interventional cardiology duty for ACS. Most characteristic ECG changes in acute occlusion of DG observed in 12 patients (92.3%) included ST-segment elevation in leads V 2 and V 3 (mean, 1.2 ± 0.5 mm; maximum, 1.7 mm) and ST-segment depression in leads II and III (mean, 0.9 ± 0.4 mm; maximum, 1.5 mm). Most characteristic ECG changes for acute occlusion of MG were ST-segment depression in leads V 5 and V 6 (mean, 0.9 ± 0.4 mm; maximal, 1 mm) observed in 11 (91.7%) patients, ST-segment depression in lead II (mean, 0.7 ± 0.2 mm; maximal, 0.8 mm) in 10 (83.3%,) and in leads V 2 and V 3, and aVF in 8 (66.7%) of cases. Risk of complications including cardiogenic shock and death was high in both groups especially during acute phase of myocardial infarction. Prevalence of borderline ECG changes in patients with acute coronary occlusion confirms how important is precise ECG interpretation usually initially done by ED physician.

Differentiating the Infarct-Related Artery on Initial Electrocardiogram in Single or Multi-Vessel Disease in Acute Inferior Myocardial Infarction and Evaluating Involvement of Vessels Using Correspondence Analysis

Initial electrocardiography changes were compared prospectively with the findings of coronary angiography to predict the infarct-related artery (IRA) in cases of single- and multi-vessel disease and to demonstrate the relationship between other coexisting coronary involvements and IRA in patients who presented with acute inferior myocardial infarction (AMI). ST elevations or depressions of at least 1 mm (0.1 mV) were evaluated in the leads I, aVL, and V1-V6. Of the 160 patients hospitalized due to inferior AMI, 153 (96%) underwent coronary angiography using standard methods. The angiograms were screened for stenotic lesions using quantitative coronary angiography to confirm significance, which was considered >50% vessel lumen diameter reduction. Among single-vessel involvements, the IRA was either the circumflex artery (Cx) or right coronary artery (RCA). In conditions in which IRA was detected as either Cx or RCA, 1-, 2-, and 3-vessel involvements were also detected. Correspondence analysis was performed to show the vessel involvements accompanying IRA. Compared with patients with IRA as RCA, the presence of ST depressions in the leads V1 or V2 and aVL were more frequently seen in patients with IRA as Cx (p=0.000, p=0.015, respectively). Among all vessel involvements in which IRA was either Cx or RCA, a ST-segment depression in leads V1 or V2 (p=0.000) and aVL (p=0.000) and a ST-segment elevation in lead I (p=0.005) were considered to be significant for Cx, and a ST-segment depression in lead I for RCA involvement (p=0.010). According to correspondence analysis, the most frequent single-vessel involvement seen in inferior AMI was RCA; when IRA was RCA, a multi-vessel involvement included RCA and Cx; and when IRA was Cx, a single-vessel involvement included the left anterior descending (LAD) artery most frequently, and RCA+LAD less frequently (p=0.000). In inferior AMI, RCA was the most common IRA; however, the possibility of multi-vessel disease is increased when Cx is found to be the IRA. In patients presenting with inferior AMI, the presence of ST-depression in the leads aVL and V1-2 is a sensitive finding that indicates Cx stenosis rather than RCA stenosis and is not affected by coexisting other coronary artery involvements.