Blood flow velocity in donor coronary artery depends on the degree and pattern of collateral vessel development: a study using thrombolysis in myocardial infarction frame count method.

To understand the influence of collateral vessels on the coronary flow, TIMI frame count (TFC) method was applied as a measure of mean coronary blood flow velocity in artery giving collateral blood supply to the other artery in angiograms of 76 patients with single occluded coronary artery: RCA giving collaterals to occluded LAD or LAD giving collaterals to occluded RCA. As a control group, TFC was applied in angiograms of 30 patients with mild or no coronary artery disease. TFC was lower (faster blood flow) in LAD giving collaterals to occluded RCA (43 patients) than in LAD in control group (21.8 +/- 10.5 vs. 33.9 +/- 20.8 frames; P < 0.01). Higher degree of collateral vessels (Rentrop classification) and mixed- and distal-type collaterals (through the interventricular septum and heart apex) was associated with lower TFC. There was no difference in TFC in the RCA giving collaterals to an occluded LAD (33 patients) compared to the TFC in RCA in control group (16.6 +/- 9.0 vs. 18.5 +/- 6.0; P = NS), even in angiograms with higher degree of collateral vessel development. TFC was lower (faster blood flow) only in subgroups with mixed (proximal and distal types together in the same patient) and distal (through the interventricular septum and the apex of the heart) collateral types. A delayed contrast appearance in occluded LAD compared to occluded RCA has been found (35.1 +/- 16.1 vs. 20.2 +/- 7.3 frames; P < 0.001) with earlier contrast appearance in occluded LAD when proximal collateral vessels (through the conal and acute marginal branches of RCA) were presented. The coronary flow in donor arteries depends not only on the degree but also on the pattern of collateral vessels. The simple TFC method may facilitate the study of collateral filling pattern and offer insight into the influence of collaterals on the ventricular function.     

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。     

Contribution of the electrocardiogram to the diagnosis of localization and extension of coronary lesions in patients with acute myocardial infarct]

With the purpose of evaluating the contribution of the ECG to the localization and extension of coronary artery lesions, 85 patients with the first acute myocardial infarction treated with thrombolysis, 79 males and 6 females (mean age 53.9 years), were studied, and the ECG changes at 3.5 and 24 hours correlated with the coronary angiographic findings before discharge. Patients were divided in two groups--Group A with anterior infarction (48 pts) and Group B with inferior infarction (37 pts). RESULTS: A) Returning of the ST downslope to baseline in inferior and anterior leads, respectively in anterior and inferior infarction at 24 h ECG, excluded associated LAD or RCA/CX lesions with a sensitivity (S) of 93% and 87% and aspecificity (E) of 60% and 58%, with a positive predictive value (PPV) of 62% and 77% and a negative predictive value of 86% and 85% respectively. All patients with anterior infarction had LAD stenosis. B) ST upslope bigger than 5 mm in V2-V3 or its presence in D-I or aVL associated to any precordial leads, diagnosed proximal LAD lesions with S of 82% and 73% and E of 75% and 73% respectively. The left axis deviation was present in 6 of 7 patients and pointed to proximal lesion. C) In Group B patients, RCA lesion was related to ST downslope in D-I, S = 77%, E = 37.5%, PVV = 80% and NPV = 33.5%, and the proximal localization (ratio between ST downslope in V2 and ST upslope in aVF) inferior to 0.5 mm with S and NPV = 80% and E and PPV = 100%. The presence of an isoelectrical ST in D-I in association with ST upslope in V5-V6 is related to CX with S and NPV = 100%, E = 85% and PPV = 25%. In conclusion, these results suggest that a careful analysis of ECG changes in patients with first acute myocardial infarction, can provide important information regarding the infarct related artery, localization of the stenosis and the presence of associated coronary artery disease, with implications in the risk stratification before hospital discharge.     

93例急性心肌梗死患者的心电图及冠脉造影分析

目的探讨急性心肌梗死患者心电图sT改变的导联与冠状动脉罪犯血管的关系。方法对93例急性心肌梗死患者心电图ST段改变与选择性冠状动脉造影结果进行对比分析。结果心电图V1-V4sT抬高伴Ⅱ、Ⅲ、aVFST段下移的罪犯血管主要为左前降支（LAD）,少数前壁心肌梗死伴下壁sT段抬高;Ⅱ、Ⅲ、aVFST抬高伴V1-V4 ST段下移的主要罪犯血管为右冠状动脉（RCA）,少部分为左回旋支（LCX）,极少部分为LAD;胸前导联T高尖与ST抬高导联不一致可排除LAD;高侧壁Ⅰ、AVLST段抬高多数罪犯血管为LCX。结论心电图ST改变的导联对急性心肌梗死罪犯血管能进行初步预测。     

Transthoracic echocardiography in the detection of chronic total coronary artery occlusion

Aims: The aim of our study was to detect chronic total occlusion ofthe left anterior descending coronary artery (LAD), circumflexcoronary artery (Cx), and right coronary artery (RCA) usingtransthoracic echocardiography (TTE) in 110 consecutive patientswho underwent coronary angiography for investigation of angina. Methods and results: Coronary blood flow direction was assessed in the epicardialcollaterals [distal LAD (dLAD), obtuse marginal branches andright posterior descending artery (PDA)] and intramyocardialcollaterals [LAD septal branch (SB LAD) and RCA septal branch(SB RCA)]. The sensitivity and specificity of retrograde flowfor identification of the occluded LAD by TTE in the dLAD onlywere 78 and 96%, respectively, and those in both dLAD and SBLAD were 89 and 96%, respectively. The retrograde SB LAD flowdetects proximal LAD occlusion with 88% sensitivity and 75%specificity. The sensitivity and specificity of retrograde flowfor identification of the occluded RCA by TTE in the PDA onlywere 79 and 97%, respectively, and those in both PDA and SBRCA were 89 and 97%, respectively. The retrograde SB RCA flowdoes not allow us to differentiate between proximal and non-proximalRCA occlusion. Transthoracic echocardiography is not a methodfor diagnosing Cx occlusions as the success in visualizing theCx epicardial collaterals was achieved in 31% of cases only. Conclusion: TTE is a sensitive and highly specific non-invasive method fordiagnosis of LAD and RCA occlusions, based on the detectionof the coronary blood flow direction in the epicardial and intramyocardialcollaterals.     

ST segment response to acute coronary occlusion: coronary hemodynamic and angiographic determinants of direction of ST segment shift

To assess the relationship between the direction of ST segment response to transient coronary occlusion and collateral function, we studied 25 patients with diagnostic ST segment changes during transient occlusion of the proximal left anterior descending artery (LAD). Electrocardiographic leads I, II, V2, and V5; left ventricular filling, aortic, and distal coronary pressures; and great cardiac vein flow were measured during percutaneous transluminal coronary angioplasty (PTCA) of the LAD. During a 1 min LAD balloon occlusion, 16 patients had reversible ST elevation (group I) and nine patients had ST depression (group II). The ST responses in individual patients were consistent during repeated occlusions, and ST depression never preceded ST elevation. Angiography before PTCA showed less severe LAD stenosis in group I (69 +/- 15%) than in group II (88 +/- 10%; p less than .01) and collateral filling of the LAD in no group I patient but in six of nine patients in group II (p less than .01). During LAD occlusion, determinants of myocardial oxygen demand (left ventricular filling pressure, aortic pressure, heart rate, and double product) were similar in both groups. Group I patients, however, had lower distal coronary pressure (25 +/- 8 vs 41 +/- 16 mm Hg) and residual great cardiac vein flow (33 +/- 14 vs 51 +/- 22 ml/min) and higher coronary collateral resistance (3.1 +/- 2.1 vs 1.5 +/- 0.8 mm Hg/ml/min) than group II patients (all p less than .05). In patients with ST elevation during LAD occlusion, stenosis before PTCA was less severe, visible collaterals were not present, and hemodynamic variables during LAD occlusion reflected poorer collateral function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Out-of-hospital ventricular fibrillation in patients with acute myocardial infarction: coronary angiographic determinants

OBJECTIVES: The study intended to compare the acute coronary anatomy of patients with acute myocardial infarction (AMI) complicated by out-of-hospital ventricular fibrillation (VF) versus patients with AMI without this complication. BACKGROUND: More than half of the deaths associated with AMI occur out of the hospital and within 1 h of symptom onset. The angiographic determinants of out-of-hospital VF in patients with AMI have not been investigated in detail. METHODS: Acute coronary angiographic findings of 72 consecutive patients with AMI complicated by out-of-hospital VF were compared with findings from 144 matched patients with AMI without this complication. RESULTS: Patients with an acute occlusion of the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) had a higher risk for out-of-hospital VF compared with patients with an acute occlusion of the right coronary artery (RCA) (odds ratio and 95% confidence interval, respectively, 4.82 [2.35 to 9.92] and 4.92 [2.34 to 10.39]). With regard to extent of coronary artery disease (CAD), the location of the culprit lesion in the coronary arteries (proximal vs. mid or distal), the flow in the infarct related artery (IRA), the presence or absence of collaterals to the IRA and chronic occlusions, there were no differences between the two groups. CONCLUSIONS: Acute myocardial infarction due to occlusion in the left coronary artery (LCA) is associated with greater risk for out-of-hospital VF compared to the RCA. The location of occlusion within LCA (LAD, LCx, proximal or distal), amount of myocardium at risk for necrosis and extent of CAD are not related to out-of-hospital VF.     

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.     

Precordial ST segment elevation in acute ischemia caused by right coronary artery occlusion.

The purpose of this study is to determine why precordial ST elevation (V1 lead) occurs during acute occlusion of the right coronary artery (RCA). Nineteen patients with vasospastic angina, in whom ergonovine administration into RCA provoked spasms, were divided into 2 groups by precordial ST change during spasms. Group I (n = 6) had precordial ST elevation; group II (n = 13) had no precordial ST elevation. A subgroup, IIA was comprised 6 patients in group II with spasms in the RCA proximal segment (segment number less than 2 of AHA coronary classification). None had left coronary dominancy. There was no difference in collateral flow during spasms. Location of spasms in group I was in the RCA proximal segment, and was significantly more proximal compared to group II. There was no difference in sigma ST in II, III, aVF between group I and II or IIA. Max ST elevation time by which duration of ischemia was estimated was significantly longer in group I than in group IIA. Three patients in group I displayed precordial ST depression before elevation, in all of whom in sigma ST in II, III, aVF was higher during precordial ST elevation than during depression. During acute occlusion in the RCA proximal segment, precordial ST elevation is caused by ischemia of the right ventricular anterior wall. Furthermore, precordial ST elevation can occur in a patient with RCA dominance, even if ischemic injury in the left ventricular infero-posterior wall increases progressively.     

Coronary collateral vessel development after acute myocardial infarction

OBJECTIVE

The aim of the present study was to assess the factors affecting collateral vessel development in patients with acute myocardial infarction.METHODS AND RESULTS: Between May 2001 and April 2004, coronary angiography was performed on 74 patients following myocardial infarction. Only patients with total proximal occlusion in the left anterior descending coronary artery (LAD) or right coronary artery (RCA) in angiography were included in the study. Patients were separated into two groups according to the development of coronary collateral circulation (CCC). In group 1, CCC was inadequate (Rentrop 0, 1 and 2); and in group 2, CCC was adequate (Rentrop 3). Although CCC was adequate in 20 of 28 (71%) patients who had RCA occlusion (P=0.015), it was adequate in only 14 of 46 (30%) patients who had LAD occlusion (P>0.05). The presence of angina pectoris was positively correlated with the development of CCC (P=0.03). Diabetes mellitus (DM) was present in 14 of 40 (35%) patients with inadequate CCC and four of 34 (11%) patients with adequate CCC. The presence of DM was significantly higher in the group with inadequate development of CCC (P=0.017).

CONCLUSIONS

While DM was associated with an inadequate development of CCC, the presence of angina pectoris and RCA occlusion were associated with an adequate development of CCC.     

Regional coronary hemodynamic effects of diltiazem in man

We evaluated the changes in regional coronary hemodynamics induced by diltiazem, 0.25 mg/kg intravenously, in nine patients with 75% to 90% diameter stenosis of the left anterior descending coronary artery (LAD) (group 1) and in 10 patients with 100% occlusion of the LAD and collaterals to the distal LAD (group 2). Although diltiazem induced similar changes in systemic hemodynamics in the two groups, a decrease in anterior coronary vascular resistance (ACVR) and an increase in great cardiac vein flow (GCVF) were observed after administration of diltiazem in all patients in group 1 but in only 6 of 10 patients in group 2 (subgroup 2B). ACVR increased and GCVF decreased after administration of diltiazem in 4 of 10 patients in group 2 (subgroup 2A). Clinico-angiographic characteristics, origin of collaterals, and diltiazem-induced changes in systemic hemodynamics were similar in subgroups 2A and 2B. Thus diltiazem increases coronary flow distal to a stenotic coronary artery but can decrease regional coronary flow and increase regional coronary resistance in a minority of patients with an occluded coronary artery supplied by collaterals, probably through a steal mechanism.     

Proximal coronary artery intervention: Stent thrombosis,restenosis and death

Background

Percutaneous coronary intervention (PCI) of lesions in the proximal left anterior descending coronary artery (LAD) may confer a worse prognosis compared with the proximal right coronary artery (RCA) and left circumflex coronary artery (LCX).

Methods

From May 2005, to May 2011 we identified all PCIs for proximal, one-vessel coronary artery disease in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). We evaluated restenosis, stent thrombosis (ST) and mortality in the LAD as compared to the RCA and LCX according to stent type, bare metal (BMS) or drug-eluting stents (DES).

Results

7840 single vessel proximal PCI procedures were identified. Mean follow-up time was 792 days. No differences in restenosis or ST were seen between the LAD and the RCA. The frequency of restenosis and ST was higher in the proximal LAD compared to the proximal LCX (restenosis: hazard ratio (HR) 2.28, confidence interval (CI) 1.56–3.34 p < 0.001; ST: HR 2.32, CI 1.11–4.85 p = 0.024). We found no difference in mortality related to coronary artery. In the proximal LAD, DES implantation was associated with a lower restenosis rate (HR 0.39, CI 0.27–0.55 p < 0.001) and mortality (HR 0.58, CI 0.41–0.82 p = 0.002) compared with BMS. In the proximal RCA and LCX, DES use was not associated with lower frequency of clinical restenosis or mortality.

Conclusions

Following proximal coronary artery intervention restenosis was more frequent in the LAD than in the LCX. Solely in the proximal LAD we found DES use to be associated with a lower risk of restenosis and death weighted against BMS.     

急性前壁心肌梗死伴不同下壁导联ST段改变的临床特点

目的探讨ST段抬高急性前壁心肌梗死(简称心梗)伴不同下壁导联ST段改变患者的梗死相关血管以及梗死面积及心功能情况。方法73例急性前壁心梗患者,根据入院时心电图下壁导联ST段改变情况将患者分为3组:A组为Ⅱ、Ⅲ、aVF中至少两个导联ST段抬高;B组为Ⅱ、Ⅲ、aVF中至少两个导联ST段压低,C组为Ⅱ、Ⅲ、aVF中少于两个导联ST段有改变。比较三组CK最大值,左室射血分数以及梗死相关血管(IRCA)。结果CK最大值3组比较A组最低(1280±531IU/Lvs2034±911,1677±630IU/L,P<0.01);左室射血分数A组最高(0.54±0.09vs0.48±0.07,0.47±0.08,P<0.01);三组IRCAA组中85.7%的患者位于“绕过心尖的左前降支(LAD)”的中远段,有14.3%的患者位于右冠状动脉(RCA)的近段;B组的患者中全部为非“绕过心尖的LAD”,其中有70.4%的患者位于非“绕过心尖的LAD”的近段;C组中有96.7%的患者为非“绕过心尖的LAD”,其中有73.3%的患者位于非“绕过心尖的LAD”的近中段,三组比较差异有显著性(P<0.01)。结论IRCA为LAD的急性前壁心梗时下壁ST段改变可能与LAD长度和病变部位有关;前壁合并下壁ST段同时抬高的患者若IRCA为“绕过心尖的LAD”,其梗死面积较小,心功能较好。     

Coronary anatomy and left ventricular function in the first 12 hours of acute myocardial infarction: the Western Washington Randomized Intracoronary Streptokinase Trial

The relationships among clinical variables, coronary anatomy, and left ventricular function during the early hours of acute myocardial infarction (AMI) were evaluated from data acquired in the Western Washington Intracoronary Streptokinase Trial. All patients had symptoms and electrocardiographic changes typical of AMI. All data were obtained before treatment with streptokinase. Mean time to catheterization was 4.1 hr after onset of symptoms. Coronary angiograms (n = 245) were analyzed for location of infarct-related occlusion and collateral flow to the infarct bed. Left ventricular ejection fraction and regional left ventricular function were quantitated in 227. Sixty-two percent of occlusions were in the most proximal segment of the involved coronary artery. Collateral circulation was seen in 42% overall, in 31% with left anterior descending artery (LAD) occlusion, and in 52% with right coronary artery (RCA) occlusion (p less than .005). Left ventricular ejection fraction was lowest and regional function was most abnormal in the group with proximal LAD occlusion. Hyperkinesis was present in 32%; in those with hyperkinesis, hyperkinetic segment length was longest in those with RCA or circumflex occlusion. Multivariate analysis identified proximal LAD occlusion as the factor most closely associated with left ventricular ejection fraction and with measures of left ventricular regional hypofunction. We conclude that (1) AMI is usually caused by occlusion or subtotal occlusion in the most proximal portion of the involved coronary artery, (2) collateral circulation is more frequent with RCA than with LAD occlusion, and (3) location of the infarct-related occlusion is the most important determinant of global and regional left ventricular function in the early hours of AMI.     

冠心病伴束支传导阻滞患者冠状动脉病变特点研究

目的 :探讨冠心病伴束支传导阻滞患者冠状动脉血管病变特点。方法 :回顾性分析冠心病伴束支传导阻滞患者 (束支阻滞组 ,39例 )及无束支阻滞的冠心病患者 (对照组 ,35 1例 )心电图束支阻滞有无与冠状动脉病变的对应关系。结果 :与对照组比较 ,束支阻滞组左主干、左回旋支 (LCX)及三支血管 [左前降支 (LAD)、LCX、右冠状动脉 (RCA)同时存在病变 ]发生病变比率增加 (P <0 .0 1,P <0 .0 5 ,P <0 .0 5 )。右束支传导阻滞(RBBB)者LAD及RCA发病率高 ,RBBB并发左前分支阻滞 (LAFB)者三支血管病变发生率增高 ,左束支传导阻滞 (LBBB)者LAD、LCX病变发生率高 ,LAFB者LAD病变发生率高 ,房室传导阻滞伴束支阻滞患者多为三支血管病变。结论 :冠心病伴束支阻滞预示冠状动脉病变广泛而严重 ,LBBB提示冠状动脉血管病变以左冠状动脉为主 ,RBBB提示冠状动脉血管病变多累及RCA及LAD ,如存在 2种以上阻滞 ,特别是并发有左前分支或房室阻滞时 ,多提示存在三支血管病变及左主干病变     

Dobutamine stress echocardiography as a predictor of coronary lesion severity on coronary angiography.

In order to evaluate the capacity of dobutamine stress echocardiography (stress echo) to predict the severity of atherosclerotic lesions observed on coronary angiography in patients with coronary artery disease, we performed a retrospective study at Instituto Nacional de Cardiologia and Universidade Federal Fluminense, Brazil. The health records of 40 patients who underwent both stress echo and coronary angiography within a period of less than 14 days were assessed. For the stress echo analysis, the heart was divided into 16 segments and the different types of response assessed: biphasic, ischemic, viable or unchanged. The main arteries - left anterior descending artery (LAD), left circumflex coronary artery (LCx) and right coronary artery (RCA) and their branches - were studied by coronary angiography to assess the degree of obstruction (in %), the type of lesion (A, B1, B2 or C), and the presence or absence of collateral circulation. The following results were obtained: patients showing an altered response on stress echo (ischemic) presented a higher degree of coronary obstruction as well as more complex lesions in the anterior descending artery on coronary angiography. A higher degree of obstruction was associated with more complex lesions (in LAD, LCx and RCA) and collateral circulation (in LAD and RCA). The presence of more complex lesions also correlated with collateral circulation in the LAD. Based on these results, we concluded that dobutamine stress echocardiography is a non-invasive test capable of predicting the severity of coronary lesions in patients with chronic ischemic cardiopathy.     

Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1).

OBJECTIVES: We sought to determine the electrocardiographic (ECG) features associated with acute left main coronary artery (LMCA) obstruction. BACKGROUND: Prediction of LMCA obstruction is important with regard to selecting the appropriate treatment strategy, because acute LMCA obstruction usually causes severe hemodynamic deterioration, resulting in a less favorable prognosis. METHODS: We studied the admission 12-lead ECGs in 16 consecutive patients with acute LMCA obstruction (LMCA group), 46 patients with acute left anterior descending coronary artery (LAD) obstruction (LAD group) and 24 patients with acute right coronary artery (RCA) obstruction (RCA group). RESULTS: Lead aVR ST segment elevation (>0.05 mV) occurred with a significantly higher incidence in the LMCA group (88% [14/16]) than in the LAD (43% [20/46]) or RCA (8% [2/24]) groups. Lead aVR ST segment elevation was significantly higher in the LMCA group (0.16 +/- 0.13 mV) than in the LAD group (0.04 +/- 0.10 mV). Lead V(1) ST segment elevation was lower in the LMCA group (0.00 +/- 0.21 mV) than in the LAD group (0.14 +/- 0.11 mV). The finding of lead aVR ST segment elevation greater than or equal to lead V(1) ST segment elevation distinguished the LMCA group from the LAD group, with 81% sensitivity, 80% specificity and 81% accuracy. A ST segment shift in lead aVR and the inferior leads distinguished the LMCA group from the RCA group. In acute LMCA obstruction, death occurred more frequently in patients with higher ST segment elevation in lead aVR than in those with less severe elevation. CONCLUSIONS: Lead aVR ST segment elevation with less ST segment elevation in lead V(1) is an important predictor of acute LMCA obstruction. In acute LMCA obstruction, lead aVR ST segment elevation also contributes to predicting a patient's clinical outcome.     

Proximal RCA occlusion producing anterior ST segment elevation,Q waves,and T wave inversion

An ST segment elevation myocardial infarction (STEMI) that produces anterior ST segment elevation (STE) is typically caused by acute occlusion of the left anterior descending (LAD) artery. Anterior STE, however, may also be caused by acute occlusion of either the proximal right coronary artery (RCA) or the right ventricular marginal branch (RVB). It has been thought that, in contrast to occlusions of the LAD, proximal RCA/RVB occlusion rarely causes Q waves in the right precordial leads. We present a case where a proximal RCA occlusion produced not only anterior STE, but also anterior T wave inversions and anterior Q waves.     

246例回旋支不同节段闭塞的心电图特点

目的探讨回旋支闭塞中不同节段,不同优势型,多支病变对心电图变化的影响。方法本研究共入选246例发生急性LCX闭塞的患者（其中男187例,女59例）,根据冠脉造影结果将患者根据冠脉优势型、单支、多支、合并LAD、RCA分组,结合年龄、性别及相关危险因素,对比分析心电图改变与冠脉造影结果及临床特点的关系。结果回旋支闭塞心电图变化受不同冠脉优势型影响,Ⅱ、Ⅲ、aVF、V7~V9导联ST段抬高常见于左优势型的LCX闭塞。V1~V3导联ST段压低常见于均衡型的LCX闭塞,Ⅰ、aVL导联ST段抬高在各优势型中无特异性。在单支LCX闭塞中,V1~V3导联ST段压低常见于近段闭塞,Ⅱ、Ⅲ、aVF导联ST段抬高常见于远段闭塞,V7~V9导联ST段抬高与Ⅰ、aVL导联ST段抬高在各节段闭塞的心电图中无特异性。合并多支病变时LCX心电图变化与单纯LCX闭塞存在差异,在LCX近段闭塞中,合并多支病变的患者更易出现V7~V9导联ST段抬高,单支病变者心电图易出现V1~V3导联ST段压低,在LCX中段闭塞的患者中,单支病变与多支病变的心电图改变大致相同。在LCX远段闭塞的患者中,多支病变患者出现V1~V3导联ST段压低可能性较大。OM闭塞在单支及合并多支病变时的心电图差异无明显统计学意义。在合并LAD或RCA病变的LCX闭塞患者中,心电图改变无明显差异。结论心电图对诊断梗死相关动脉为回旋支的急性心肌梗死有重要的预测价值,结合病史及相关一般资料可对急性心肌梗死患者的预后进行评估。     

Value of the electrocardiogram in localizing the occlusion site in the left anterior descending coronary artery in acute anterior myocardial infarction.

OBJECTIVES: The study assessed the value of the electrocardiogram (ECG) as predictor of the left anterior descending coronary artery (LAD) occlusion site in relation to the first septal perforator (S1) and/or the first diagonal branch (D1) in patients with acute anterior myocardial infarction (AMI). BACKGROUND: In anterior AMI, determination of the exact site of LAD occlusion is important because the more proximal the occlusion the less favorable the prognosis. METHODS: One hundred patients with a first anterior AMI were included. The ECG showing the most pronounced ST-segment deviation before initiation of reperfusion therapy was evaluated and correlated with the exact LAD occlusion site as determined by coronary angiography. RESULTS: ST-elevation in lead aVR (ST elevation(aVR)), complete right bundle branch block, ST-depression in lead V5 (ST depression(V5)) and ST elevation(V1) > 2.5 mm strongly predicted LAD occlusion proximal to S1, whereas abnormal Q-waves in V4-6 were associated with occlusion distal to S1 (p = 0.000, p = 0.004, p = 0.009, p = 0.011 and p = 0.031 to 0.005, respectively). Abnormal Q-wave in lead aVL was associated with occlusion proximal to D1, whereas ST depression(aVL) was suggestive of occlusion distal to D1 (p = 0.002 and p = 0.022, respectively). For both the S1 and D1, inferior ST depression > or = 1.0 mm strongly predicted proximal LAD occlusion, whereas absence of inferior ST depression predicted distal occlusion (p < or = 0.002 and p < or = 0.020, respectively). CONCLUSIONS: In anterior AMI, the ECG is useful to predict the LAD occlusion site in relation to its major side branches.