右心室梗死的心电图与临床

1资料与方法1.1一般资料63例均为我院1995年9月～2004年9月诊断为右室梗死(RVMI)患者。其中男39例,女24例,年龄47～82(62.2±4.5)岁。所有病例符合WHO急性心肌梗死(AMI)诊断标准。1.2心电图表现1.2.1RVMI心电图诊断标准[1～3]①V4R导联ST段抬高≥1mm,若ST段抬高的程度为V4R>V3R>V1则诊断更有价值;②未合并前壁AMI时,STV1～V5导联抬高≥1mm,抬高幅度从V1～V5导联逐渐降低;③STV2压低与STaVF抬高之比≤50%[3];④CR4R(右锁骨中线第5肋间)导联ST段抬高≥1mm;⑤右心前导联(V3R～V6R)QRS波可呈QS型;⑥多与下壁或后壁MI同时…     

急性下壁心肌梗死ST段抬高STⅢ/Ⅱ＞1对右室梗死的诊断价值

目的　探讨ST段抬高STⅢ /Ⅱ >1在急性下壁心肌梗死并发右室梗死的诊断价值。方法　描记常规 12导联和V3R～V7R,以连续 2个QRS波群的TP连线为基线 ,测量Ⅱ ,Ⅲ ,V3R V7R导联J点后 80ms处ST段抬高的幅度。结果　Ⅲ导联ST段抬高 >0 1mv ,且STⅢ /Ⅱ >1者占 2 4例 ,其中 18例 (75 % )并发右室梗死 ;而STⅢ /Ⅱ≤ 1者 2 4例中仅 2例 (8 3% )并发右室梗死 ,二者之间差异显著 (P <0 0 0 1)。其敏感性 ,特异性和准确率分别为 90 %、78%、77%。结论　急性下壁心肌梗死的早期 ,ST段抬高 ,STⅢ /Ⅱ >1,是心电图早期识别合并右室梗死的可靠指标。该指标对诊断右室梗死的敏感性同STV4R段抬高相当     

下壁急性心肌梗死患者心电图对梗死相关动脉定位的再评价

目的探讨ST段抬高型下壁急性心肌梗死(AMI)患者心电图对梗死相关动脉(IRA)定位的价值。方法分析76例ST段抬高型急性下壁心肌梗死患者心电图改变并与冠状动脉造影结果进行回顾性对比分析。结果①梗死相关动脉多为右冠状动脉(RCA),其次为左回旋支(LCX),分别为56例(73.7%)、20例(26.3%)。②患者心电图STⅢ↑/STⅡ↑>1、STaVL↓/STI↓>1对判断梗死相关动脉在RCA敏感性分别为87.5%、96.4%,特异性分别为85.0%、85.0%。STV3↓/STⅢ↑>1.2对判断梗死相关动脉为LCX的特异性为94.6%。③心电图STaVF↑+STV2↓>0对于判断梗死相关动脉为RCA的特异性、阳性预测值分别为90.0%、95.8%。④心电图V1～V3导联ST段压低之和与下壁导联ST段抬高之和的比值ST(V1～V3)↓/ST(inf)↑≤0.5对于判断相关动脉为RCA的敏感性、阳性预测值分别为78.6%、91.7%。⑤心电图STV3↓/STⅢ↑≤0与心电图STV1↑预测梗死动脉在RCA近端的敏感性分别为54.5%、86.4%,特异性分别为29.4%、88.2%。结论心电图STⅢ↑/STⅡ↑>1、STaVL↓/STI↓>1,STV3↓/STⅢ↑>1.2,STaVR↓≥0.05 mV预测IRA为RCA或LCX特异性较高;STV1↑预测IRA为RCA近段的敏感性、特异性较高;而STV3↓/STⅢ↑≤0预测RCA近段闭塞结果不理想。     

急性右室心肌梗死的心电图分析

目的　探讨急性右室心肌梗死 (ARVI)的心电图特征。方法　选择急性心肌梗死 (AMI) 5 0例 ,进行心电图回顾性分析。结果　 5 0例AMI中合并ARVI 18例 ,发生率为 3 6%。下壁、正后壁AMI 2 3例中合并ARVI 12例 ,发生率 5 2 2 %。V3R～V5R导联QRS波呈QS型 ,其后ST T有动态改变。部分病例有Ⅰ、aVL、V5、V6 导联Q波消失 ,STⅢ /Ⅱ 抬高 >1,STⅡ 抬高≥ 1mm ,V1 ～V5导联ST段抬高呈递减性 ,STV2 ↓ /STaVF↑≤ 5 0 %等表现。结论　AVRI多合并下壁、正后壁AMI。右胸导联异常Q波 ,动态ST T改变是ARVI诊断依据 ,常规 12导联心电图上述改变可作为ARVI诊断线索     

下壁并右室心肌梗死心电图诊断指标分析

目的:评价下壁合并右心室梗死(RVMI)心电图各诊断指标的准确性和实用性。方法:根据Andersen等心电图诊断指标对照分析46例下壁心肌梗死患者的心电图及冠状动脉造影结果。结果:按心电图标准诊断合并右心室梗死15例(31.6%),其中冠脉造影检出右冠状动脉阻塞者14例(93%),RCA在近端闭塞者13例(86.6%)。下壁+右室梗死心电图诊断主要敏感指标顺序是STV3R-V5R≥1mm(STV4R↑>STV3R↑),STV3↓/ST↑<0.5,I、aVL、V5、V6导联Q波消失。结论:下壁合并RVMI的心电图改变多为RCA近端阻塞所致,以上3条标准为下壁合并右室梗死的主要诊断标准。     

42例急性右室梗死的心电图分析

目的探讨急性右室心肌梗死（ARVI）的心电图诊断价值。方法对42例确诊ARVI的心电图进行回顾性分析。结果V4R导联ST抬高≥0．1mV是ARVI早期诊断的最佳指标;下壁急性心肌梗死（AMI）时,ST抬高幅度STⅢ〉STU、STV2Ⅱ、STV2↓/STaVF↑≥0．5强烈提示合并ARVI;ARVI易伴发缓慢心律失常。结论体表心电图对ARVI早期诊断简便、实用,且有价值。     

急性后间壁心肌梗死心电图诊断标准商榷

目的　对 4例下壁急性心肌梗死 (AMI)伴V1 3 和V3R 5R导联ST段抬高入院诊断为下壁、右室合并前间壁AMI的梗死部位进行探讨 ,藉以商榷急性后间壁心肌梗死诊断标准。方法　根据心电图及核素心肌灌注显像和冠状动脉造影资料进行分析。结果　 4例患者心电图表现为Ⅱ、Ⅲ、aVF、V1 3 和V3R 5RST段抬高 ,其中V1导联ST段抬高最显著 ,放射性核素99mTc MIBI心肌灌注缺损部位在下壁和后间壁 ,4例患者梗死相关动脉均为右冠状动脉。结论　根据以上发现我们提出后间壁AMI的心电图诊断标准如下 :①下壁AMI同时伴V1导联ST段明显抬高≥ 2mm ;②ST段抬高的幅度呈V1>V2 >V3 和V1>V3R>V4R,同时具备以上两个条件即可诊断为下壁、后间壁AMI。     

心电图在右冠病变所致急性下壁心肌梗死时的预测价值

目的通过体表心电图探讨右冠状动脉(RCA)病变及判断RCA是否为优势血管对ST段抬高型急性下壁心肌梗死时的预测价值。方法对84例经冠状动脉造影证实RCA为梗死相关动脉患者的18导联心电图进行回顾性分析。结果 RCA近段病变的62例,RCA远段病变的22例。RCA近段病变患者中,STV4R抬高≥1 mm为56例,阳性率为90.3%,STV1-V2抬高≥2 mm的为52例,阳性率为83.9%。RCA远段病变的22例患者中,出现STV4R抬高≥1 mm的为0例,出现STV1-V2抬高≥2 mm的为1例,阳性率为4.5%。RCA优势型为56例,非RCA优势型为28例,RCA优势型的56例患者中,STV5-V6抬高≥1 mm为50例,阳性率为89.3%。非RCA优势型的28例患者中,STV5-V6抬高≥1 mm为0例。结论对于RCA病变所致ST段抬高型急性下壁心肌梗死患者,心电图STV4R抬高≥1 mm、STV1-V2抬高≥2 mm对RCA近段闭塞的识别有较大的价值,如同时合并有STV5-V6抬高≥1 mm,常提示患者为RCA优势型,其诊断的特异性、敏感性均较高。     

心电图对急性下壁心肌梗死患者梗死相关血管及闭塞部位的预测价值

目的:探讨急性下壁心肌梗死患者的体表心电图对梗死相关血管及闭塞部位的预测价值。方法:对62例急性下壁心肌梗死患者的体表心电图和冠状动脉造影资料进行回顾性对比分析。结果:梗死相关血管为右冠状动脉者50例(80.65%),左回旋支者12例(19.35%)。单纯急性下壁心肌梗死多发生在右冠状动脉中远段(62.07%);并发右室梗死者均发生在右冠状动脉,且多发生在右冠状动脉近段(70.00%)。STⅢ抬高/STⅡ抬高>1、STaVL压低≥0.5mm、STV1抬高≥0.5mm、STV3压低/STⅢ抬高≤1.2提示梗死相关血管为右冠状动脉的灵敏度分别为88.00%、90.00%、66.00%、72.00%,特异度分别为58.33%、75.00%、83.33%、66.67%。STⅢ抬高/STⅡ抬高≤1、STaVL呈等电位线或抬高、STV1压低≥0.5mm、STV3压低/STⅢ抬高>1.2提示梗死相关血管为左回旋支的灵敏度分别为58.33%、75.00%、66.67%、66.67%,特异度分别为88.00%、90.00%、80.00%、72.00%。结论:急性下壁心肌梗死时,体表心电图对梗死相关血管及闭塞部位有重要的预测价值。     

急性下壁心肌梗死心电图对右冠状动脉病变的诊断价值

目的探讨心电图在ST段抬高型急性下壁心肌梗死(IWAMI)时右冠状动脉(RCA)病变位置的诊断价值。方法对109例经冠状动脉造影证实右冠状动脉为梗死相关动脉患者的18导联心电图进行回顾性分析。结果心电图STV1抬高≥2mm、STV4R抬高≥1mm、STV3压低/STⅢ抬高<0.5对右冠状动脉近段闭塞的判断有较大的价值,其阳性率与右冠状动脉远段闭塞组有显著性差异,其诊断的特异性、敏感性均较高。结论ST段抬高型急性下壁心肌梗死时体表心电图与右冠状动脉闭塞位置有明显相关性。     

Significance of right precordial ST elevation in experimental right ventricular infarction

We produced experimental isolated right ventricular infarction (RVI) with closed chest method, and examined ECG changes of right precordial leads and changes of cardiac output (C. O) in 19 dogs. As a result, ECG showed ST depressions in leads, II, III, aVF and V2-V6 and ST elevations in a VR lead in all 15 cases of the proximal occlusion of right coronary artery (RCA). In 10 of 15 dogs ST elevations in some right precordial leads occurred, and the sensitivity of ST elevation in single right precordial lead was 60% (V5R), 53% (V4R) and 47% (V3R and V1), respectively for the detection of RVI. When left circumflex artery (LCX) was occluded, ST elevation in V4R lead after RCA occlusion was blocked. Therefore, it is thought that the sensitivity of ST elevation in right precordial lead may be lower than expectation in identifying RVI. Concerning anterior chest leads, none of 15 dogs with RVI showed ST elevations in leads V2-V6 in this study. If ST elevations in right precordial leads did not appear, variation of C.O was small and C.O reduced in proportion to the extension of ST elevations in right precordial leads.     

头胸导联右胸心电图诊断急性右室梗塞的价值

选择急性下壁合并右室梗塞（依据血液动力学诊断）患者３４例，比较其同部位、同时间右胸Ｗｉｌｓｏｎ导联（Ｖ３Ｒ～Ｖ７Ｒ）和头胸导联（ＨＶ３Ｒ～ＨＶ７Ｒ）的心电图，探讨后者诊断急性右室梗塞的价值。首次记录心电图的时间为发病１０（平均４±２．８）ｈ２４例（Ａ组），超过１０（平均３１±１６．８）ｈ１０例（Ｂ组），两组Ｖ５Ｒ～Ｖ７Ｒ、ＨＶ５Ｒ～ＨＶ７Ｒ导联病理性Ｑ波出现率均为１００％。Ｖ４Ｒ（ＨＶ４Ｒ）或Ｖ７Ｒ（ＨＶ７Ｒ）ＳＴ段抬高≥０．１ｍＶ者，Ａ组为１００％，Ｂ组Ｗｉｌｓｏｎ导联为６０％、头胸导联为１００％。头胸导联ＳＴ段抬高幅度高于Ｗｉｌｓｏｎ导联０．０５～０．１５ｍＶ；头胸导联不仅ＱＲＳ－Ｔ波群呈现急性损伤期向充分发展期的衍变与ａＶＦ导联一致，并且ＳＴ段抬高持续的时间也与ａＶＦ导联一致，此特征有利于急性右室梗塞的诊断。     

11例急性单纯后壁心肌梗死心电图及梗死相关动脉特点分析

目的 分析急性单纯后壁心肌梗死（不包括同时合并下壁及右室心肌梗死）的心电图及冠状动脉造影特点。方法 总结自2001年至2006年门、急诊收治的急性单纯后壁心肌梗死患者11例,随访心电图特点,并行冠状动脉造影确定梗死相关动脉。结果 11例患者除了V7-V9导联ST段有典型的弓背向上抬高1．0—2．0mm外,9例（81．8％）V1-V2导联R／S≥1,5例（45．5％）V1-V4导联ST段压低1．0—2．0mm,4例（36．4％）Ⅰ、aVL导联ST段抬高0．5-1．5mm,5例（45．5％）V5-V6导联ST段抬高0．5—1．5mm。冠状动脉造影显示梗死相关动脉均为左回旋支（LCX）。梗死部位1例在第一钝缘支（OM1）发出前,为95％管状狭窄;6例（54．5％）在OM1发出后,其中4例为100％闭塞,1例为99％次全闭塞,1例为90％长段狭窄;4例（36．4％）在OM1,其中2例为100％闭塞,1例为99％次全闭塞,1例为95％局限性狭窄。单支病变3例（27．3％）,合并左前降支（LAD）病变4例（36．4％）,合并右冠状动脉（RCA）病变2例（18．2％）,同时合并LAD及RCA病变2例（18．2％）。结论12导联心电图,如有V1-V2导联R／S≥1,V1-V4导联ST段压低等特点时,结合临床与心肌酶学改变,高度怀疑急性后壁心肌梗死,需做后壁导联和冠状动脉造影加以证实,而梗死相关动脉多为左回旋支。     

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。     

Electrocardiographic identification of the culprit coronary artery in inferior wall ST elevation myocardial infarction

BACKGROUND:

Electrocardiograms (ECGs) are essential in identifying the type and location of acute myocardial infarction. In the setting of inferior wall myocardial infarction (IWMI), identification of the right coronary artery (RCA) as the culprit artery is important because of the potential complications associated with its involvement.

OBJECTIVES:

To evaluate previous ECG criteria used for the identification of RCA involvement and validate them in the Assessment of the Safety and Efficacy of a New Treatment Strategy with Percutaneous Coronary Intervention (ASSENT 4 PCI) cohort; and to develop an improved simplified score to identify RCA involvement.

METHODS:

ASSENT 4 PCI patients with IWMI (n=710) were included in the present study. A literature review was conducted to identify previously published criteria to detect RCA involvement. Logistic regression was used to develop a new simplified algorithm for identifying RCA involvement.

RESULTS:

The sensitivities and specificities of six previous ECG criteria were substantially lower when applied to the ASSENT 4 PCI population. A new algorithm found that ST segment depression in leads I, aVL and V6, and ST segment elevation of greater than 1 mm in lead aVF was associated with a higher likelihood of RCA involvement, and any ST segment depression in V1 and V3 was associated with a lower likelihood of RCA involvement. A simplified risk score found a prevalence of RCA involvement of over 90% among patients with scores of greater than two.

CONCLUSIONS:

The ECG is useful in identifying RCA involvement in IWMI before angiography. Previously published criteria appear to be inadequate, and the simple algorithm presented in the current study may be a useful tool in identifying RCA involvement at the bedside.     

Early diagnosis of the site of infarction and the infarct-related coronary artery in patients with acute inferior myocardial infarction.

We evaluated the relationship between the site of infarction and the infarct-related coronary arteries from electrocardiograms (ECGs) recorded early after the onset of chest pain in patients with an initial acute inferior myocardial infarction (IMI). The subjects were 80 patients (mean age 57 +/- 12 years) with IMI admitted within 6 hours from the onset of chest pain. This was prior to the thrombolytic era. We analyzed the ECGs on admission, at 24 hours and at 4 weeks. All patients underwent left ventriculography and coronary angiography at 4-6 weeks from the onset of the IMI. Left ventricular ejection fraction (EF) and regional area changes were measured. The infarct-related coronary artery was determined by the site of the asynergy. Patients were allocated into 2 groups according to the infarct-related artery, i.e. right (RCA, n = 52) and left circumflex (LCX, n = 28). Parameters measured were ST elevation, amplitude and width of R wave and R/S ratio in leads V1 and V2, and amplitude of U waves in leads V1 to V3. We defined the U wave as a prominent positive U wave (PPU) if it was > 0.5 mm (50 microV) in height. A significantly greater number of patients with PPU showed asynergy in posterolateral segments compared to those without PPU. The EF was significantly lower in patients with PPU than in those without (46 +/- 12% vs 54 +/- 13%, p < 0.05). Patients with PPUs eventually showed ECG evidence of posterior infarction (increased R wave duration and R/S ratio > or = 1 in lead V1 or V2) by 4 weeks compared to those without PPUs. Also a significantly greater number of patients with PPUs developed posterior infarction shown by left ventriculograms than those without PPUs. As to the infarct-related coronary arteries, a significantly greater number of patients with LCX disease showed concomitant posterior infarction than those with RCA disease. Also, a significantly greater number of LCX patients showed PPUs and ST elevations in leads V5 and V6 than those with RCA disease. The sensitivity of PPUs and ST elevations in leads V5 and V6 suggesting LCX disease was 60% and the specificity was 98% with a predictive accuracy of 87%. Therefore, we conclude that PPUs in leads V1-3 and ST elevations in leads V5 and V6 are specific markers for the diagnosis of LCX-related infarction in the setting of evolving IMI.     

心电图对老年急性下壁心肌梗死冠状动脉病变部位的预测价值

目的　探讨急性下壁心肌梗死心电图与冠状动脉病变的关系 ,以揭示体表心电图对梗死相关动脉及病变节段的预测价值。方法　对 15 6例老年急性下壁心肌梗死患者的体表心电图和冠状动脉造影资料进行对比分析。结果　梗死相关动脉为右冠状动脉占 79.5 % ,左回旋支占 2 0 .5 %。单纯急性下壁心肌梗死病变节段多发生在第一右心室支开口以远 (77.6 % ) ,合并右心室心肌梗死病变节段多发生在第一右心室支开口前 (87% )。STⅢ 抬高 /STⅡ 抬高 >1,STⅠ、aVL下移≥ 1mm ,提示右冠状动脉为梗死相关动脉的敏感性分别为 87.9%、89.5 % ,特异性分别为 84 .4 %、81.2 % ,阳性预告值分别为 95 .6 %、94 .8% ,两者差异无显著性意义 (P >0 .0 5 )。ST段V1、V2 下移≥ 1mm ,提示左回旋支为梗死相关动脉的敏感性 ,特异性和阳性预告值分别为 84 .4 %、91.9%、73.0 %。结论　急性下壁心肌梗死时心电图对判断梗死相关动脉及病变节段有重要的预测价值     

∑ST_(V1-V3) ↓/∑ST_(Ⅱ、Ⅲ、aVF) ↑指标在识别急性下壁心肌梗死罪犯血管中的价值

目的分析∑STV1-V3↓/∑STⅡ、Ⅲ、aVF↑指标识别急性下壁心肌梗死(简称心梗)罪犯血管的价值。方法60例急性下壁心梗明确诊断单支冠状动脉闭塞[右冠状动脉(RCA)或左回旋支(LCX)]的患者,分析罪犯血管开通前心电图。比较∑STV1-V3↓/∑STⅡ、Ⅲ、aVF↑指标与常用指标(Ⅱ导联和Ⅲ导联ST段抬高程度的比较)预测价值的差异。结果①∑STV1-V3↓/∑STⅡ、Ⅲ、aVF↑≤1在预测RCA闭塞中敏感度高于STⅢ↑﹥STⅡ↑(91.3%vs 87.0%)。②预测LCX闭塞∑STV1-V3↓/∑STⅡ、Ⅲ、aVF↑>1有相对高的特异度、敏感度、阳性预测值、阴性预测值(91.3%、57.1%、66.7%、87.5%)。结论∑STV1-V3↓/∑STⅡ、Ⅲ、aVF↑指标在识别急性下壁心梗的罪犯血管中有重要价值。     

Electrocardiographic algorithm for assignment of occluded vessel in acute myocardial infarction

BACKGROUND: This study was performed to elaborate an electrocardiographic (ECG) algorithm enabling assignment of an occluded coronary artery in acute myocardial infarction (AMI). PATIENTS AND INTERVENTIONS: In 109 patients (age, 59+/-12 years) with AMI (pain onset, 3.6+/-1.7 h), coronary angiography with PTCA/stenting of the culprit lesion was performed. The diagnosis of AMI was confirmed by emergency coronary angiography and laboratory analyses. Admission ECG parameters (amplitude of R-wave, ST-segment deviation, presence of Q-wave, deflection of T-wave) in standard 12-lead ECG plus extended (V(3)R to V(6)R and V(7-9)) leads were subjected to classification and regression tree (CART) analysis. RESULTS: Continuous CART analysis assessed ST-segment deviations in V(2) and V(5)R. AMI of the left anterior descending (LAD), right coronary artery (RCA) and left circumflex coronary artery (CX) were correctly classified in 94, 64, and 91% of cases, respectively. Dichotomised CART analysis assessed ST-segment deviations in V(2), V(5)R, and aVF. True classification rates for LAD, RCA, and CX amounted to 84, 74, and 71%, respectively. CONCLUSIONS: Dichotomised CART analysis is a simple means of differentiation of CX from RCA occlusion during AMI.     

Value of electrocardiographic algorithm based on "ups and downs" of ST in assessment of a culprit artery in evolving inferior wall acute myocardial infarction

Acute myocardial infarction (AMI) of the inferoposterior wall is due to occlusion of the right coronary artery (RCA) or the left circumflex (LCx) coronary artery. The outcome of patients depends mainly on the culprit artery. Therefore, the presumptive prediction of a culprit artery based on the electrocardiogram recorded at admission is of clinical importance. The aim of this study was to develop a sequential algorithm based on the "ups and downs" of the ST segment in different leads to predict the culprit artery (RCA vs LCx) in cases of inferoposterior AMI. We analyzed electrocardiographic and angiographic findings of 63 consecutive patients with an evolving AMI with ST elevation in the inferior leads (II, III, and aVF) and a single-vessel occlusion. Specificity, sensitivity, and positive and negative predictive values of different electrocardiographic criteria (ups and downs of the ST segment) were studied individually and in combination to find an algorithm that would best predict the culprit artery. The following electrocardiographic criteria were included in the 3-step algorithm: (1) ST changes in lead I, (2) the ratio of ST elevation in lead III to that in lead II, and (3) the ratio of the sum of ST depression in precordial leads to the sum of ST elevation in inferior leads [( summation operator downward arrow ST in leads V(1) to V(3))/( summation operator upward arrow ST in leads II, III, and aVF)]. Application of this sensitive algorithm suggested the location of the culprit coronary artery (RCA vs LCx) in 60 of 63 patients (>95%). The few patients in whom this algorithm did not work were those with a very dominant LCx that presented ST depression of > or =0.5 mm in lead I. In conclusion, careful sequential analysis of an electrocardiogram of an inferoposterior AMI with ST elevation may lead to the identification of a culprit artery.