Comparison of optimal scalar electrocardiographic,orthogonal electrocardiographic and vectorcardiographic criteria for diagnosing inferior and anterior myocardial infarction

A scalar electrocardiogram (ECG), orthogonal ECG and vectorcardiogram (VCG) were recorded in 46 normal persons, 38 patients with inferior myocardial infarction (MI) and 22 patients with anterior MI proved at cardiac catheterization. The diagnostic information provided by the scalar ECG, orthogonal ECG and VCG was quantitatively analyzed and the optimal criteria for diagnosing inferior and anterior MI exhibited by each method were identified. The optimal scalar electrocardlographic, orthogonal electrocardiographic and vectorcardiographic criteria, respectively, are: For inferior MI: initial superior duration in lead aVF >30 ms (sensitivity 63%, specificity 100%), superior/inferior amplitude ratio in lead Y ≥0.2 (sensitivity 63%, specificity 96%), initial superior duration >29 ms or initial superior distance >0.4 mV in the frontal plane loop (sensitivity 68%, specificity 100%). For anterior MI: initial anterior duration in lead V₂ <20 ms or initial anterior duration in lead V₃ < 25 ms (sensitivity 91%, specificity 100%), anterior/posterior duration ratio in lead Z <0.3 (sensitivity 73%, specificity 98%), initial anterior duration <15 ms in the transverse plane loop (sensitivity 64%, specificity 98%). There were no significant differences among the performances of the optimal scalar ECG, orthogonal ECG and the VCG for diagnosing inferior MI. However, the performance of the optimal scalar ECG was superior to that of the optimal orthogonal ECG and the optimal VCG for diagnosing anterior MI (chi-square = 5.20, p <0.02 and chi-square = 7.14, p >0.01, respectively).     

Extent of the inferior myocardial infarction assessed by the frontal plane of the vectorcardiogram.

A correlation was made between the vectorcardiographic changes and the peak value of the L.D.H. in the serum of 21 patients with acute inferior (diafragmatic) M.I. The following vectorcardiographic variables showed changes proportional to the increase in serum L.D.H. The correlation was found to be statistically significant. The direction of the 0.025 sec vector (r = 0.63, P less than 0.005). The duration of the initial superior forces of the QRS loop (r = 0.87, P less than 0.001). The maximal leftward deviation of the initial superior QRS loop forces (r = 0.65, P less than 0.005). The maximal superior deviation of the initial QRS loop forces (r = 0.68, P less than 0.05). The ratio of the maximal superior deviation over the maximal inferior deviation of the QRS loop "QY/RY" (r = 0.76, P less than 0.001). The area under the initial superior forces of the QRS loop and over 0 degrees +/- 180 degrees axis in squared milimeters (r = 0.88, P less than 0.001). It is suggested that V.C.G. is a usefull means in assessing the extent of inferior M.I.     

起源于右室流出道间隔部特发性室性早搏心电图及心电向量图研究

目的：探讨经射频消融证实的起源于右室流出道间隔部的特发性室性早搏（室早）的心电图特征及心电向量图特征。方法采用 CARDIO-View 心电工作站收集并分析14例经射频消融术证实为右室流出道间隔部特发性室早患者的12导联心电图及 Frank 导联心电向量图参数。结果起源于右室流出道间隔部的特发性室早呈类左束支阻滞图形。12导联心电图胸导联移行指数≥0的有12例（85．7％）,V2导联 R 波时限指数＜50％的14例（100％）, V2导联 R／S 波振幅指数＜30％的有13例（92．9％）,SV2／RV3指数＞1．5的有12例（85．7％）。心电向量图特征为：QRS 环运行方向在 F 面呈 CW 和 CCW 的各有5例（35．7％）,H 面呈 CCW的有10例（71．4％）,S 面均呈 CW（100％）;起始0．04 s,QRS 环振幅逐渐增大,QRS 环方位大部分指向左前下;0．01～0．04 s 向左向量逐渐增加,向前向量逐渐减少;QRS 环最大向量及大部分面积位于左下后。结论心电图对起源于右室流出道间隔部的室早定位诊断具有较高的准确率。起源于右室流出道间隔部的室早有典型的心电向量特征。     

A study on vectorcardiographic criteria for evaluating right ventricular hypertrophy in chronic obstructive pulmonary disease.

Vectorcardiographic analysis was mainly made on the basis of hemodynamic findings through right heart catheterization in COPD. From the results obtained in the present study, the authors proposed the following quantitative VCG criteria as a mean for clinical recognition of right ventricular overload in patients with COPD. (I) Individual parameters of the criteria are: i) The QRS loop; (a) P/A (posterior force/anterior force) greater than or equal to 2.8 (b) R/L (rightward force/leftward force) greater than or equal to 0.6 (c) P/6 (posterior force/leftward force) greater than or equal to 1.8 ii) The P loop; Ap/Pp (anterior force/posterior force) greater than or equal to 1.8 (II) Criteria i) "RVH (right ventricular hypertrophy)" should satisfy more than 3 of the above individual parameters. ii) "RVH suspected" should satisfy 1 or 2 of them. iii) "RVH negative" should not satisfy any of them. The recognition rate for RVH by the present VCG criteria was higher than the conventional ECG criteria and there was good correspondence with autopsy findings.     

Diagnostic value of electrocardiogram and vectorcardiogram in postinfarction ventricular asynergy

The ability of ECG-VCG to predict the severity of postinfarction LV asynergy was evaluated in 152 patients with previous myocardial infarction who underwent left cineventriculography in the right anterior oblique view. Various ECG and VCG signs were examined in order to predict the existence of severe asynergy in general (dyskinesia or akinesia or severe hypokinesia) and of dyskinesia in particular. In patients with inferior myocardial infarction (Group A) persistent ST segment elevation was the only specific ECG sign (100%) of severe asynergy; it had a poor sensitivity (6.2%). Four frontal VCG signs (presence of terminal bite, y- greater than 0.18 mV, maximum early superior vector along x axis = MESV greater than or equal to 1.3 mV, duration of initial superior forces = DISF greater than 50 msec) increased the sensitivity of the ECG-VCG method to 75.8% while maintaining a 100% specificity. Regarding the diagnosis of dyskinesia, only the ECG sign of persistent ST segment elevation and the VCG sign of y- greater than or equal to 0.3 mV had a 100% specificity. The sensitivity of the ECG-VCG method was 33.3% (16.6% ECG and 16.6% VCG). In patients with anterior myocardial infarction (Group B), concerning the diagnosis of severe asynergy, the ECG signs of sigma ST greater than 3 mm in anterior leads; pathologic Q wave in four or more anterior leads (including D1 and aVL); and the presence of LAH or LAH + RBBB, had a 100% specificity and a good sensitivity (60.5%). The VCG sign of a narrow horizontal QRS loop increased the sensitivity of the ECG-VCG method to 71% while maintaining a 100% specificity. As for the diagnosis of dyskinesia, the ECG signs with a 100% specificity were sigma ST greater than or equal to 5 mm in anterior leads, a pathologic Q wave in more than five anterior leads (including I and a VL) and RBBB + LAH; these variables had a sensitivity of 48.3%. The VCG sign of a narrow horizontal QRS loop increased the sensitivity of the ECG-VCG method to 79.3% while maintaining a 100% specificity. In patients with inferior plus anterior myocardial infarction (Group A + B) the signs mentioned above for each group were evaluated, confirming a 100% specificity. Regarding the diagnosis of severe asynergy, the ECG signs had a sensitivity of 61.3%, while VCG increased the sensitivity of the ECG-VCG method to 90.3%.(ABSTRACT TRUNCATED AT 400 WORDS)     

Assessment of left ventricular hypertrophy by ECG and VCG in patients with inferior and posterior myocardial infarction. A comparison with echocardiographic data

Electrocardiographic (ECG) and vectorcardiographic (VCG) QRS voltage criteria have been analyzed in 26 patients with inferior and 17 with posterior myocardial infarction (MI) in comparison with left ventricular (LV) mass and global and regional wall motion as assessed by M-mode and two-dimensional (2D) echocardiography. Transverse plane QRS maximal vector correlated significantly with LV mass in patients with both inferior and posterior MI (r = 0.65 and 0.87, respectively, p less than 0.01). A transverse plane QRS maximal vector greater than 1.5 mV correctly recognized 12 of 15 (80%) and 9 of 12 (75%) patients with respectively inferior and posterior MI and LV mass greater than 221 gm. Of the ECG measurements, S V1-2 + R V5-6 correlated moderately with LV mass in patients with inferior MI (r = 0.47), and R V1-2 + R V5-6 correlated moderately with LV mass in those with posterior MI (r = 0.67). ECG and VCG QRS voltage data did not correlate with global and regional LV function as assessed by M-mode and 2D echocardiography. We conclude that: ECG and VCG QRS voltage parameters can be utilized for assessing non-invasively LV enlargement in patients with postero-inferior MI; ECG and VCG QRS voltage parameters should be utilized with caution for analyzing LV function or MI size in postero-inferior MI.     

Vectorcardiographic and epicardial activation studies on experimentally-induced subdivision block of the left bundle branch

The functional significance of the septal Purkinje network (SEP) in the left ventricular conduction system was examined by measuring changes of the activation sequence and vectorcardiogram (VCG) after inducing experimental blocks of the left anterior subdivision (LA) and the SEP. A discrete block of the SEP (10 dogs) resulted in a slight delay of the epicardial activation in the apical area. In lead of the McFee system of VCG, the antero-posterior ratio was increased significantly, and in 3 of 10 cases (30%) major QRS loops were deviated anteriorly on the horizontal plane. In the discrete block of the LA (10 dogs), epicardial mapping revealed a slight activation delay in the anterior basal area. There were no significant changes on VCG, except for a superior and leftward deviation of the terminal QRS vector. In the combined block of the LA + SEP (9 dogs), an activation delay of the greater area and magnitude was observed from the anterior basal area to the apical area, and the direction of the maximum QRS vector on the frontal plane showed a significant displacement to the left and superiorly. These results suggest that the SEP block itself may produce an electrocardiographic change and that this network also plays an important role in the so-called hemiblock, producing axis changes on the frontal plane of a VCG, in association with the blocks of the left anterior and posterior subdivisions.     

The effect of the localization of Q wave myocardial infarction on ventricular electromechanics

BACKGROUND: The exact location of a Q wave myocardial infarction has an important effect on overall left ventricular function. OBJECTIVES: To assess the effect of localization of Q wave infarction on left ventricular minor and long axis function, with particular reference to electromechanical disturbances. METHODS: We studied 72 patients with Q wave myocardial infarction; 35 anterior, age 61+/-15 years and 37 inferior, age 62+/-12 years. ECG intervals were automatically measured by Hewlett-Packard Pagewriter and LV dimension and filling velocities studied by transthoracic echocardiography and simultaneous phonocardiogram. Findings were compared with 21 controls of similar age. RESULTS: Heart rate and all ECG intervals were similar in the two patient groups and controls. QRS axis was more to the left in patients with inferior MI. Normal septal q wave was absent in lead V5 and V6 in 33/35 (94%) patients with anterior MI and in only 3/37 (8%) with inferior MI, p<0.001. LV minor axis dimensions were enlarged vs. normal (p<0.001) in the two patient groups and to a greater extent in anterior MI compared with inferior MI, p<0.05. Isovolumic relaxation time was prolonged only in-patients with an inferior MI, p<0.01. Long axis amplitude was globally reduced (p<0.001) in the two patient groups as were shortening and lengthening velocities (p<0.001). The onset of septal long axis shortening with respect to the q wave was delayed by 30 and 40 ms in inferior MI and anterior MI and that of lengthening with respect to A2 by 20 and 30 ms, respectively, compared to normal (p<0.001 for both). Post ejection shortening was localized to the septal long axis in 32/35 patients with anterior MI but was generalized involving all three LV long axes in inferior MI, p<0.001. Transmitral Doppler flow velocities and the frequency of mild mitral regurgitation were similar in the two groups. CONCLUSION: These results confirm a close association between anterior Q wave infarction, septal incoordination and absent septal q waves. The global incoordinate long axis behaviour in inferior Q wave MI may be due to significant papillary muscle dysfunction, and results in significant shape change in early diastole. This disturbance in electromechanical behaviour might play an important role in the differing outcomes between the two different sites of myocardial infarction.     

Electro-vectorcardiographic behavior of right bundle branch block in endocardial cushion defects. Its probable relation to the so-called left anterior fascicular hemiblock

We have investigated the possible ECG signs of incomplete Left Anterior Hemiblock (LAH). As an experimental model we chose the endocardial cushion defect, which is proved to have a ventricular activation correspondent to different degrees of LAH due to the particular disposition of the AV node and the His bundle. The VCG of 50 patients with endocardial cushion defect were divided into 5 groups according to the entity of the left and superior deviation of the maximum left vector. Comparison with the ECG signs shows that: a) minimal degrees of LAH occur with simple counterclockwise rotation of the frontal loop without a significant left axis deviation; b) there is no linear correlation between the importance of the left axis deviation and the signs of left ventricular activation asincronism. We conclude that, with the exception of this particular congenital heart disease, minimal LAH degrees can only be suspected on the basis of a counterclockwise VCG frontal loop, because the ECG diagnosis is possible only when the left axis deviation becomes important.     

心电向量图和心肌断层显象对比评价心肌梗塞范围

为探讨心电向量图评价心肌梗塞范围的准确性,采用铊—201心肌断层显象参数—缺损心肌容积百分比(%DV)为标准,分析了63例心肌梗塞患者的心电向量指标与%DV间的相关性.结果:在前间壁梗塞,20ms向量的Z轴投影值与%DV相关性良好(r=0.832,P<0.001);在前间壁+侧壁梗塞,30ms向量的水平面角度和X轴投影值与%DV呈负相关;在下壁和下后壁梗塞,30ms向量的额面角度和Y轴投影值与%DV显著相关.本文表明:心电向量图可简便而且准确地评价心肌梗塞范围.     

Vectorcardiography in inferior infarction associated with left bundle-branch block

The authors report a series of 13 patients, 8 men and 5 women, with an average age of 68 years (range 39 to 87 years) presenting with documented inferior infarction with anteroseptal extension in 2 cases. These patients developed LBBB (complete in 9 cases, incomplete in 4 cases). This complications occurred in the acute phase in 8 cases and 4 months to 9 years later (average 4,5 years) in the other 5 cases. The block was intermittent in 4 patients and became permanent in all cases. The diagnosis of inferior infarction with LBBB was made by vectorcardiography (VCG) in 5 out of the 13 patients (38,4 p. 100) on the criteria suggested by Starr. 3 of the 8 false negative results were directly related to the block which masked the ECG and VCG signs of inferior infarction. The VCG signs observed were an upwards displacement of the QRS loop with preservation of the superior orientation of the initial forces (5 cases). Atypical appearances of LBBB were observed in 2 cases with a posterior and right-sided shift of the efferent loop following the anterior and left-sided orientations of the initial forces. The sensitivity of the VCG and ECG is mediocre in inferior infarction with LBBB because the block may mask the electrical signs of inferior infarction. The specificity of the VCG could not be assessed because of the mode of selection of the patients and the small number of cases.     

Ventricular arrhythmias. A guide to their localisation.

An electrocardiographic atlas of ventricular tachycardias was produced by pacing 27 epicardial sections of the heart and the mitral papillary muscles to simulate focal ventricular arrhythmias and simultaneously recording their 12 lead electrocardiographic appearances. One hundred and twenty nine patients undergoing cardiac surgery were studied. In five patients all 27 epicardial sites were paced at operation and in 124 individual sections were paced postoperatively with temporary epicardial wires and the electrocardiograms analysed in terms of frontal and horizontal plan QRS axis, maximum limb lead QRS amplitude, and QRS duration. Each ventricular region paced produced a distinctive 12 lead electrocardiographic pattern. Simulated right ventricular arrhythmias had either inferior frontal plane QRS axes (from the anterobasal region) or superior frontal plane QRS axes (from the apical and posterior right ventricular sections). Horizontal plane QRS axes were directed leftwards, with some posterior shift in the anteroapical regions. Simulated arrhythmias from the base of the left ventricle (anteriorly and laterally) had inferior frontal plane QRS and anterorightward horizontal plane QRS axes. Left ventricular arrhythmias with a superior frontal plane QRS axis were readily distinguished by their horizontal plane QRS axes: posterorightwards from the anterior and anterorightwards from the posterior left ventricular sections. Standard errors of the paced QRS axes for the various epicardial sections paced postoperatively ranged from 3.0 degrees to 6.0 degrees using the frontal plane axis. The electrocardiogram was most accurate in localising ventricular arrhythmias from the anterior left ventricle and least accurate for those arising from the inferior right ventricle. The appearance of the paced electrocardiograms was slightly modified by underlying disease such as myocardial infarction and left ventricular hypertrophy. This atlas may be useful in comparing the localisation of ventricular tachycardia with the site of underlying cardiac disease and may facilitate mapping in patients with refractory ventricular tachycardia requiring ablation (either surgical or by high energy impulses).     

Electrocardiographic tall R waves in the right precordial leads. Comparison of recently proposed ECG and VCG criteria for distinguishing posterolateral myocardial infarction from prominent anterior forces in normal subjects

Electrocardiographic tall R waves in the right precordial leads may be present in patients with posterior myocardial infarction, right ventricular hypertrophy, various conduction disturbances, and some forms of cardiomyopathy and in clinically otherwise normal subjects with prominent anterior electromotive forces. Clinical uncertainty most often arises in distinguishing possible prior posterolateral myocardial infarction (PMI) from the unusual normal variant (PAF). The ECGs and VCGs of 15 subjects with posterolateral infarction were compared with tracings from 12 subjects with no evidence of cardiac disease, all individuals demonstrating tall R waves (R/S greater than 1.0 in V1 and/or V2) in the right precordial leads on surface ECG. By standard ECG, the infarction group was characterized by taller T waves in leads V1 and V2, shorter T waves in V6, greater T2-T6 index, and a more negative two variable function as described by Nestico. By VCG, the infarction group was characterized by a more anteriorly oriented T loop, more leftward maximal frontal plane QRS vector and a lower calculated -45 degrees/ab, as described by Suzuki. An algorithm was proposed that permitted proper classification (PAF vs. PMI) based on ECG criteria in 75% of subjects with 90% accuracy. This compared favorably with performance of the Frank vectorcardiogram, including using more recently proposed criteria. Routine use of the VCG, therefore, in this clinical setting may no longer be justified.     

Diagnosis of posterior infarction. Value of vectorcardiography. Apropos of 108 cases, 31 of which had exclusively posterior necrosis]

An analysis of the vectorcardiogram results (VCG) in 77 cases with a posterior extension of an infarct and 31 cases with an exclusively posterior infarction (EPI) has allowed us to distinguish some diagnostic criteria relative to the extension, or localisation, of an infarct in the posterior segment. The maximum anterior vector (MAV) appears late (36.5 ms +/- 5), and the amplitude of its projection onto Z is increased; the maximum vector (V max) appears early (41.5 ms +/- 4.5), and its orientation is anterior (+ 24 degrees +/- 11); the interval separating MAV from V max is reduced to 5 ms; the transition from before backwards is late (50 ms +/- 6); the ratio of anterior surface to posterior surface is increased (1.45); there is a terminal delay, most frequently occuring in the right posterior quadrant in 78 percent of cases; and finally, the T loop approaches the Z axis. Repeat electrocardiograms in patients with EPI show the most frequent changes to be represented (in 25 cases out of 31) by the following formula: AQRS " 0 degrees, R/S greater than or equal to 1 in V2, RV2 greater than RV6. The diagnosis of an exclusively posterior infarction can therefore be made with a high degree of certainty when these electrocardiographic abnormalities are associated with the clinical picture of coronary insufficiency.     

计算机心电图与计算机心向量图的联合应用

本研究利用两个计算机自动诊断系统，一个对心电图，一个对心电向量图进行分析，完成了对国际标准心电图库的联合诊断，产观察了单独诊断之间，单独诊断与联合诊断之间的差异，以进一步探讨心电图与心电向量图在诊断上的互补效应，以及ＣＳＥ研究中关于联合诊断优于单独诊断的机制。国际标准心电图库由１２２０个病例构成，其中正常者３８２例，左室肥大１８３例，右室肥大５５例，双室肥大５３例，前壁心梗１７０例，下壁心梗２７３     

Lack of superiority of the vectorcardiogram over the electrocardiogram in detecting inferior wall myocardial infarction regardless of time since infarction

Using more recent VCG and ECG criteria, the relative accuracy of these two tests in detecting inferior wall MI over time was evaluated in 38 of 236 patients undergoing elective left ventriculographic and coronary angiographic studies who had clinical plus angiographic evidence of inferior wall myocardial infarction. The overall sensitivity and specificity of the ECG criteria of the New York Heart Association and Warner did not differ from that of the VCG criteria of Starr and Takatsu. There was a trend toward decreased sensitivity in both VCG criteria and the ECG criterion of Warner in detecting inferior wall myocardial infarction greater than or equal to 18 months, although the difference did not reach statistical significance. Changing the age of infarction to greater than or equal to 3, greater than or equal to 6, greater than or equal to 12, or greater than or equal to 24 months did not yield a different result. It is concluded that VCG is not superior to ECG in the diagnosis of inferior wall MI regardless of time since occurrence of infarction.     

Ventricular arrhythmias. A guide to their localisation

An electrocardiographic atlas of ventricular tachycardias was produced by pacing 27 epicardial sections of the heart and the mitral papillary muscles to simulate focal ventricular arrhythmias and simultaneously recording their 12 lead electrocardiographic appearances. One hundred and twenty nine patients undergoing cardiac surgery were studied. In five patients all 27 epicardial sites were paced at operation and in 124 individual sections were paced postoperatively with temporary epicardial wires and the electrocardiograms analysed in terms of frontal and horizontal plan QRS axis, maximum limb lead QRS amplitude, and QRS duration. Each ventricular region paced produced a distinctive 12 lead electrocardiographic pattern. Simulated right ventricular arrhythmias had either inferior frontal plane QRS axes (from the anterobasal region) or superior frontal plane QRS axes (from the apical and posterior right ventricular sections). Horizontal plane QRS axes were directed leftwards, with some posterior shift in the anteroapical regions. Simulated arrhythmias from the base of the left ventricle (anteriorly and laterally) had inferior frontal plane QRS and anterorightward horizontal plane QRS axes. Left ventricular arrhythmias with a superior frontal plane QRS axis were readily distinguished by their horizontal plane QRS axes: posterorightwards from the anterior and anterorightwards from the posterior left ventricular sections. Standard errors of the paced QRS axes for the various epicardial sections paced postoperatively ranged from 3.0 degrees to 6.0 degrees using the frontal plane axis. The electrocardiogram was most accurate in localising ventricular arrhythmias from the anterior left ventricle and least accurate for those arising from the inferior right ventricle. The appearance of the paced electrocardiograms was slightly modified by underlying disease such as myocardial infarction and left ventricular hypertrophy. This atlas may be useful in comparing the localisation of ventricular tachycardia with the site of underlying cardiac disease and may facilitate mapping in patients with refractory ventricular tachycardia requiring ablation (either surgical or by high energy impulses).     

Wolff-Parkinson-White VCG patterns that mimic other cardiac pathologies: a correlative study with the preexcitation pathway localization

Vectorcardiograms (VCGs) of 44 patients with a Wolff-Parkinson-White (WPW) syndrome have been analyzed with the aim to correlate the QRS loop patterns with specific preexcitation sites. The VCG QRS loops were analyzed to determine whether conduction abnormalities and myocardial infarction (MI)-like patterns observed in the WPW syndrome could be related to specific preexcitation sites identified by surgery as well as by body surface potential mapping (BSPM). Left bundle branch block pattern was observed with anteroseptal (AS) preexcitation, anterior MI pattern was seen with lateral right ventricle (LRV) preexcitation, left anterior fascicular block was observed with posterior right ventricle (PRV) preexcitation, inferoposterior and strictly posterior MI pattern was found with posteroseptal (PS) and posterior left ventricle (PLV) preexcitation, right bundle branch block was seen in lateral left ventricle (LLV) preexcitation, and right bundle branch block was observed with left posterior fascicular block in anterior left ventricle (ALV) preexcitation. These VCG criteria seem to identify accurately the preexcitation sites as observed by delta wave BSPM and at surgery investigations. Consequently, they could be useful in localizing the preexcitation site in cases of ambiguous delta vector orientation.