Electrocardiographic discrimination of infarct-related artery between left circumflex and right coronary artery: comparison of ST elevation between leads II and III

OBJECTIVES: Admission electrocardiography was evaluated to discriminate left circumflex artery (LCX) versus right coronary artery (RCA) as the cause of acute myocardial infarction. METHODS: Electrocardiographic findings were assessed in patients with RCA (n = 60) and LCX (n = 60) occlusion. RESULTS: ST segment elevation in the inferior leads or right precordial leads was more common in the RCA group. ST segment depression or negative T wave was more common in leads I, aVL in the RCA group. ST segment elevation was more common in leads V5, V6 in the LCX group. ST segment was elevated in inferior leads in 55 patients in the RCA group and 27 patients in the LCX group. Mean ST level was higher in lead III than in lead II in the RCA group, but not in the LCX group. The ST level was higher in lead III than in lead II in 78% of the RCA group, but only 44% of the LCX group (p < 0.01). CONCLUSIONS: Comparison of ST levels between leads II and III, and a three-dimensional analysis in 12-lead electrocardiography is useful for discriminating the left circumflex artery from the right coronary artery as the cause of acute myocardial infarction.     

Microvascular angina accompanied by epicardial coronary artery spasm

A case of microvascular angina accompanied by coronary artery spasm is described. A 54-year-old woman had anginal pain at rest and during exercise. Both exercise testing and rapid atrial pacing caused significant ST depression in the inferior and all precordial leads. Exercise thallium myocardial scintigraphy was negative despite similar ST depressions. Coronary angiography revealed insignificant stenoses of the left anterior descending coronary artery after the injection of nitrate. Intracoronary acetylcholine provoked diffuse spasm of the artery with concurrent myocardial lactate production. Coronary flow reserve assessed with papaverine was 2.75. The combined use of amlodipine and high-dose nicorandil was effective for the treatment of angina.     

Transesophageal Doppler echocardiographic detection of intramyocardial collateral flow to the right coronary artery and changes in the flow to the inferior left ventricular wall immediately after coronary artery bypass grafting

This study examined the feasibility of Doppler transesophageal echocardiography (TEE) to detect collateral flow to the myocardium supplied by the right coronary artery (RCA) in the inferior left ventricular wall. Forty-four patients who underwent elective coronary artery bypass grafting (CABG) were prospectively studied. Presence of collateral flow to the RCA was diagnosed on preoperative angiography using the Rentrop score and by intraoperative Doppler TEE. Agreement of the 2 methods was analyzed by calculating the kappa coefficient. Collateral flow was present on preoperative angiography in 19 patients and absent in 25 patients. Intraoperative TEE detected collateral flow in the inferior wall in 15 patients (79%) with and 3 patients (12%) without angiographic collaterals, resulting in a kappa coefficient for agreement of 0.67 (95% confidence interval 0.45 to 0.90). Baseline collateral flow disappeared after CABG in 12 of 14 patients with grafting of the RCA but persisted in all patients without such grafting. Physiologic flow in the inferior wall was detected by TEE in a total of 27 patients at baseline and in 38 patients after CABG (p = 0.0018); its peak velocity increased after surgery only in the subgroup of patients with grafting of the RCA. In conclusion, these findings indicate that Doppler TEE may detect collateral flow in the inferior left ventricular wall, and that there are typical changes in collateral and physiologic flow after CABG.     

A case in which stent insertion is considered to have triggered contrast medium-induced coronary vasospasm.

A Gianturco-Roubin II (GR-II) stent was inserted in a 75-year-old man who developed restenosis of the right coronary artery (RCA) after percutaneous transluminal coronary angioplasty (PTCA). Although the vessel became partially occluded after 7 months, it was redilated by PTCA. Follow-up angiography of the RCA and left coronary artery (LCA) was performed 3 months later. Chest pain with bradycardia and hypotension occurred immediately after this examination, and ST elevation appeared in ECG leads II, III, and aVF. Repeat angiography of the RCA confirmed complete occlusion due to a spasm at a site proximal to the GR-II stent. The spasm was resolved by intracoronary infusion of isosorbide dinitrate (ISDN), and PTCA was carried out for extensive recurrent restenosis of the RCA; however, vascular dissection developed at the distal end of the GR-II stent. Therefore, a Palmaz-Schatz (P-S) stent was placed such that its proximal end overlapped the distal end of the GR-II stent. Follow-up angiography 3 months later showed no restenosis, but an episode of vasospasm similar to the previous one occurred immediately after left ventriculography. The RCA was completely occluded proximal to the GR-II stent because of spasm. Although this spasm was gradually relieved by intracoronary infusion of ISDN, marked spasm was also observed distal to the P-S stent; complete relief was achieved by infusion of additional ISDN.     

The significance of a persistent precordial ST segment greater than or equal to 0.1 mV depression in acute inferior myocardial infarction (coronary angiographic and ventriculographic findings)

40 patients with acute inferior myocardial infarction (MI) associated with persistent precordial ST segment depression greater than or equal to 0.1 mV underwent coronary arteriography and left ventriculography within 5-6 days of their admission. The inferior MI was the result of complete occlusion of the right coronary artery (RCA) in 38 patients and the result of complete occlusion of the posterior descending artery (PDA) coming off the circumflex artery (Cx) in two patients. 36 (90%) of the 40 patients showed one or more severe stenoses in the left anterior descending artery (LAD). 12 of the 36 patients had severe triple vessel disease. The 36 patients whose coronary arteriograms showed significant LAD stenosis had an emergency coronary artery by pass graft (CABG) operation. Soon afterwards the precordial leads were normal and the patients free of angina till their discharge from hospital. We conclude that a persistent precordial ST segment greater than or equal to 0.1 mV depression in acute inferior MI is highly predictive of significant LAD disease.     

Vasospastic total occlusion at the left main tract in a single coronary artery.

A 64-year-old man was admitted to hospital under the suspicion of unstable angina pectoris. Coronary angiography showed that he has a single coronary artery originating from the right coronary artery (RCA) without significant fixed stenosis. Acetylcholine was superselectively infused into the left main coronary artery (LMCA), and confirmed the coronary vasospastic occlusion associated with chest pain and elevation of the ST-segment in the precordial leads. This is the first report of the induction of a totally occlusive spasm of the LMCA of a patient with a RCA type single coronary artery, and this case suggests that spasm of the aberrant coronary artery is a potential mechanism for sudden death in patients with a single coronary artery.     

Correlation of coronary artery stenosis site with anterior or inferior projection of ST changes induced by treadmill exercise using a newly devised 9-lead Holter method.

A 9-lead Holter monitor using the lead-switching technique (9-lead DCG) and conventional 12-lead electrocardiograph (12-lead ECG) were simultaneously used for recording during treadmill exercise testing (Td-test) in 140 patients with coronary artery disease. Coronary arteriography was performed in 118 of the 140 patients, and the correlation between coronary stenosis and anterior or inferior projection of ST depressions occurring during the Td-test was investigated. Additionally, 10 patients with acute myocardial infarction (AMI) were studied to test ST elevation detection by the 9-lead DCG. The CM5 lead demonstrated ST depressions in 92 of the 109 patients showing ST depressions in one or more leads. High lateral (HL) and/or low lateral leads detected all ST depressions occurring in the I and aVL leads of the 12-lead ECG. Leads CM1, CM2 and CM3 exhibited low sensitivity (0-32%) and high specificity (56-100%), while leads CM4, CM5, and CM6 provided greater sensitivity (66-95%), but less specificity (3-32%) in detecting diseases of the left anterior descending artery, left circumflex artery and/or right coronary artery (RCA). In contrast, the low back (LB) lead demonstrated high sensitivity (88%) and high specificity (86%) in detecting RCA disease. Lead CM3 detected ST elevations in all 6 patients with anterior AMI, while the LB lead did so in all 4 patients with inferior AMI. With a Holter monitor, 4 leads are needed: CM5 like, CM3 like, lateral (such as HL) and inferior (such as LB). The LB lead is useful in detecting inferior ischemia.     

Hypertrophic obstructive cardiomyopathy and coronary artery spasm.

Three patients had hypertrophic obstructive cardiomyopathy and coronary artery spasm. The clinical diagnosis of hypertrophic obstructive cardiomyopathy, in all patients, was confirmed by echocardiography and angiography. Significant spasm of the right coronary artery was demonstrated in each patient by selective coronary arteriography. One patient had atherosclerotic obstructive three vessel disease, while the other two showed no evidence of any fixed organic narrowing of the coronary arteries. ST segment elevation in the inferior ECG leads was documented in two of the patients in association with coronary spasm.     

Acute myocardial infarction showing total occlusion of right coronary artery and thrombus formation of left anterior descending artery

A 33-year-old Japanese man had an attack of chest pain associated with ST-segment elevation in the inferolateral leads on his electrocardiogram. Emergency coronary angiography showed total obstruction in the mid right coronary artery (RCA) and a movable thrombus in the proximal left anterior descending artery (LAD). We performed emergency percutaneous transluminal coronary angioplasty (PTCA) for the RCA lesion. The operation was successful and we then conducted intracoronary thrombolysis (ICT) with tisokinase 6,400,000 IU for the LAD thrombus. Its size was reduced by ICT. He had an uneventful hospital course. After 1 month, repeat coronary angiography showed no significant stenosis in the RCA nor thrombus in the LAD. A coronary spasm provocation test was performed using acetylcholine. Coronary spasm in the LAD was induced by an intracoronary injection of 100 microg acetylcholine. In this case, we observed a unique condition suggesting simultaneous double coronary artery occlusion.     

急性下壁心肌梗死患者心电图胸前导联ST段改变的临床意义

目的探讨急性下壁心肌梗死患者心电图胸前导联ST段改变与冠状动脉造影(CAG)所见冠状动脉病变部位的关系及其临床意义。方法 187例急性下壁心肌梗死患者,按入院时18导心电图胸前导联ST段改变分为3组,ST段无变化组(47例),ST段抬高组(16例),ST段压低组(124例);所有患者均行CAG。结果急性下壁心肌梗死伴胸前导联ST段抬高时多为右冠状动脉(RCA)近段闭塞(14例,82.3%),尤其是伴圆锥支动脉闭塞,与RCA中远端闭塞(2例,5.9%)比较差异有统计学意义(P0.01),且14例(73.7%)伴有右心功能不全和血流动力学障碍。下壁心肌梗死胸前导联ST段压低者可见于RCA、回旋支(LCX)闭塞及RCA、LCX闭塞与前降支(LAD)、对角支(D)病变的不同组合,其中LCX闭塞伴RCA病变者多表现为朐前ST V_4～V_6的压低,RCA闭塞伴LAD近端病变多有胸前ST V_1～V_6的压低,RCA伴D病变胸前ST V_1～V_3压低,与对照组比较差异有统计学意义(P0.05)。结论急性下壁心肌梗死合并胸前导联ST段抬高表明为RCA近段或丌口闭塞且多伴右心室心肌梗死和心功能不全;下壁心肌梗死伴胸前导联ST段压低提示为多支病变,ST V_1～V_3压低多伴有对角支严重狭窄,STV_1～V_6压低多伴有前降支的严重狭窄。     

Induced coronary spasm: immediate revascularization by the opposite coronary artery. Use of myocardial scintigraphy

The case reported analyses the instantaneous revascularisation distal to a coronary spasm by electrocardiography and thallium scintigraphy. The patient, a 48 year old man, had an 18 months history of spontaneous anginal chest pain sensitive to trinitrin. No electrocardiogrammes had been recorded during an attack. Coronary angiography was normal apart from a slight reduction in calibre of a dominant right coronary artery. Injection of 0.4 mg methylergometrine provoked an occlusive spasm of this artery after 4 minutes. At the same time the patient experienced angina and 4,5 mm depression of the ST segment, without ST changes in D3 and AVF, was observed. Opacification of the left coronary artery during spasme of the right showed retrograde revascularisation of the posterior interventricular artery which was reversed when the coronary spasm was terminated with trinitrin. Thallium scintigraphy was performed during another spasm provocation test four days later which gave identical clinical and electrical changes. A zone of hypofixation with blurred limits over the inferior myocardial wall was demonstrated. In the absence of ST elevation and of lacuna on myocardial scanning, the myocardial ischaemia induced by this occlusive spasm could not be considered to be total. Therefore the immediate revascularisation of the coronary artery in spasm seemed to have played the role of an effective collateral circulation.     

Clinical characteristics of coronary artery spasm: electrocardiographic, hemodynamic and arteriographic assessment

We studied the clinical characteristics of 153 patients with angina pectoris associated with coronary artery spasm (CAS). The study was designed to investigate the relationship of CAS to ST segment deviation and to the site of fixed stenosis, and hemodynamic alteration during a spastic event. Analysis of coronary arteriograms and multilead electrocardiograms obtained simultaneously from 170 events of CAS by the use of radioluscent carbon-fiber electrodes resulted in 58 events with ST elevation which were related to total occlusion of major coronary arteries due to CAS; another 54 events with ST depression, in which the affected coronary arteries demonstrated severe but incomplete occlusion, or total occlusion but were visualized via collateral vessels; and remaining 58 events without ST deviation showing mild occlusion. The results indicate a close correlation between magnitude of CAS and ST segment deviation. CAS occurred at the site of pre-existing fixed stenosis including minor plaque defect in 133 patients and at apparently normal site in 20 patients. In the former group, only four patients had triple vessel disease, while 95 had nonsignificant fixed lesion. In the latter group, 10 patients had minor lesion distant from the site of CAS. Thus, CAS is closely related to fixed stenosis, which may have but a limited role as a cause of CAS. Hemodynamic measurements during spastic events were obtained from 49 patients including 41 events with spasm of the left anterior descending artery (LAD) and 21 events with spasm of the right coronary artery (RCA). The onset of an increase in left ventricular (LV) filling pressure and a reduction in LV dP/dt preceded ST segment deviation in all events. The first hemodynamic variable manifested in the spastic event was the reduction of LV contraction dP/dt in the majority of patients. The increase of LV filling pressure was greater in LAD spasm than RCA spasm (11 +/- 6 mmHg vs 7 +/- 4 mmHg, P less than 0.0125) and in events with ST elevation than with ST depression (11 +/- 5 mmHg vs 6 +/- 5 mmHg, p less than 0.001). Right ventricular functional impairment was mild in most patients during CAS. The study indicates that mechanical impairment precedes electrical impairment during CAS and that LAD spasm with ST elevation represents the most severe LV dysfunction.     

Transient QRS axis shift to the right during right coronary artery and/or left circumflex artery spasms

The QRS axis was measured in 24 patients during ergonovine malate provocation test (EM test). Of 12 patients with significant spasm of the right coronary artery (RCA) and/or left circumflex artery (LCX), the QRS axis shifted to the right in 7 patients after the EM test (mean 8.2 degrees), and the axis shifted back to the left in 9 patients after nitroglycerin administration (mean -9.1 degrees). The sensitivity of right axis shift for RCA and LCX spasm was 58% and the specificity was 80%. Thus, right axis shift seems to be associated with myocardial ischemia due to RCA and LCX spasm and to be useful for the detection of RCA and/or LCX spasms.     

急性下壁ST段抬高心肌梗死直接冠脉内支架置入术靶血管判定及预后评估

目的 总结急诊介入治疗（PCI）的急性下壁心肌梗死患者心电图及临床资料,分析其对急性下壁心肌梗死患者罪犯血管判定及预后评估的作用.方法 选择2007年1月到2010年7月进行急诊PCI的急性下壁心肌梗死患者280例,根据冠脉造影结果分为右冠状动脉（RCA）梗死组及左冠回旋支（LCX）梗死组;根据临床结果分为高危急性下壁心梗组（高危组）及低危组.分析各组的心电图表现、危险因素及预后.结果 RCA组与LCX组比较,STⅢ＞STⅡ、STavL或STⅠ＞1 mm下移更多见于RCA梗死.高危组年龄比低危组偏大,糖尿病患者更多,更多出现心肌梗死溶栓治疗（TIMI）分级中的0级（无灌注）及1级（渗透而无灌注）,RCA近端闭塞及双支、三支病变患者,心电图出现STV3R-5R↑、STV7-V9↑、STV4-6↓、STV1↑、STAVR↓的比例更高.结论 心电图在急性下壁心肌梗死进行急诊PCI的患者诊断及预后判断中有重要作用,对进行急诊PCI靶血管判定有一定的协助作用.冠脉造影TIMI 0、1级,RCA近端闭塞,双支、三支病变患者,年龄偏大患者和糖尿病患者整体预后均较差.     

Localization of coronary artery disease with exercise induced ST segment depression: coronary angiographic correlation

Abnormalities of the 12 lead electrocardiogram (ECG) are often used to localize the anatomic site of myocardial ischemia and vessel involvement in patients (pts) with coronary artery disease. This study is to determine if ischemia of specific vascular segments can be identified by exercise induced ST segment depression (STD) on 12-lead ECG. One hundred and forty three pts with a positive treadmill stress testing (TST) who had coronary arteriography within one month of TST were reviewed. There were 114 men and 29 women, aged 34-74 years (mean 55 years). The Bruce protocol was used for TST. Significant coronary stenosis was defined as obstruction of 70% or greater of the luminal diameter. The pattern of STD on 12 lead ECG during exercise was similar in pts with single vessel disease involving the left anterior descending artery (LAD), right coronary artery (RCA) or circumflex artery (Cx). This pattern of STD in single vessel disease was also comparable to 2-vessel, 3-vessel or left main stem disease. Twenty-two percent of pts with LAD disease had isolated STD in inferior leads. Twenty-five and 29% of pts with RCA and Cx disease respectively had STD in the anterior leads alone during exercise testing. It is concluded that exercise induced STD in 12 lead ECG can not predict ischemia of specific vascular segments or specific vessel involvement.     

Multivessel coronary vasospasm mimicking triple-vessel obstructive coronary artery disease

Spontaneous coronary artery spasm is an important cause of morbidity both in patients with atherosclerotic coronary artery disease and in those with Prinzmetal's angina. Coronary vasospasm tends to occur in focal areas in the coronary tree and can be readily induced by the use of various agents. Spontaneous severe multivessel spasm, mimicking severe obstructive coronary artery disease, has been infrequently described. The therapeutic dilemma in such a clinical situation is highlighted in our current case where an unnecessary coronary artery bypass graft surgery (CABG) was performed due to the lack of clinical suspicion of spasm. This patient presented 5 years after triple-vessel CABG with an episode of rest angina, and was initially found to have severe obstruction of all three native coronary arteries with patent grafts to the right coronary and left anterior descending arteries. After nitroglycerin injection, all three native vessels appeared large and normal. This report raises the question of whether the routine use of intracoronary nitroglycerin, largely abandoned over the past 20 years, should be revisited, at least for certain patient populations such as those with rest angina.     

Repeated epicardial coronary artery endothelial injuries lead to a global spontaneous coronary artery spasm

OBJECTIVES: This study was conducted to develop a spontaneous coronary spasm model. MATERIALS AND METHODS: Balloon endothelial denudation was carried out in the epicardial left anterior descending coronary artery (LAD) every 2 weeks, for a total of four times, in 12 pigs. Changes in the denuded site diameter and LAD blood flow caused by acetylcholine or serotonin were assessed before each denudation and at week 8. Blood pressure, electrocardiogram (ECG) from the LAD area and LAD blood flow were monitored continuously in conscious and unrestrained pigs. RESULTS: Spontaneous ECG ST depression with a decrease in LAD blood flow appeared at around 2 weeks. In accordance with this, 0.5 microg/kg acetylcholine induced similar ECG and LAD blood flow changes without denuded site narrowing, suggesting microvascular spasm. Thereafter, ECG ST depression or elevation by serotonin via a denuded site spasm was found after 6 weeks and spontaneous ECG ST changes due to epicardial coronary artery spasm were observed. CONCLUSION: Epicardial coronary artery endothelial injury may induce spontaneous vasospasticity in the downstream coronary microvessels as well as in the denuded portion, suggesting functional abnormality through the entire coronary arterial tree.     

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.     

The mystery of the lost and found right coronary artery

Most coronary artery anomalies are discovered only incidentally during coronary angiography. Recognition and identification of these anomalies especially during coronary intervention procedures are of importance because of their occasional association with symptoms due to atherosclerotic coronary disease. Anomalous origin of the right coronary artery (RCA) from the left anterior descending coronary artery (LAD) is one of the most uncommon coronary anomalies. We report an extremely interesting case of anomalous RCA from the LAD presenting as acute inferior ST elevation MI, with ostial total block of the RCA, precluding its visualization during coronary angiography. Interventional Cardiologists need to be aware of such anatomical variations, as occasionally, this can lead to a diagnostic dilemma, as in our case. © 2010 Wiley‐Liss, Inc.     

多排螺旋CT冠脉成像与冠脉造影对冠心病诊断的对比研究

目的初步评价多排螺旋CT（MSCT）在冠状动脉成像中的临床应用价值。方法18例疑诊冠状动脉狭窄患者行MSCT扫描,利用影像曲面重建,3D重建,了解冠状动脉病变情况,并与冠状动脉造影（CAG）对比。结果18例76支血管同时经MSCT和CAG成像。CAG发现狭窄27支,其中左前降支（LAD）病变11支,回旋支（LCA）病变3支,左主干（LMA）2支,右冠（RCA）病变9支,桥支病变2支。MSCT发现狭窄24支,其中LAD病变11支,LCA病变3支,LMA病变1支,RCA病变7支,桥支病变2支。MSCT与CAG结果相符的病变血管22支,MSCT成像的敏感性为82%（22/27）,特异性96%（47/49）。结论在控制心率的情况下MSCT可作为冠状动脉狭窄的一种无创筛选检查方法。