High reliability rates of spatial pattern analysis by vectorcardiogram in assessing the severity of eccentric left ventricular hypertrophy.

In 33 patients, including 12 control subjects and 21 with eccentric LVH, LV mass determined by angiocardiogram was correlated to 26 VCG measurements (Frank system) calculated from the scalar X, Y, and Z leads. The results demonstrated that the most reliable indices of VCG in assessing the severity of eccentric LVH determined by angiocardiogram were the magnitude of the spatial mean QRS vector and the time of the spatial maximal QRS vector ("spatial VAT"), of which correlation coefficients were 0.93 and 0.93, respectively. Such high correlation coefficients have never been obtained with the usual ECG analysis. These findings strongly suggest that (1) increased QRS voltage and usual prolonged QRS duration in eccentric LVH are due to an increase in LV mass, and (2) prolonged VAT observed in eccentric LVH is closely related to an anatomic alteration, namely, the greater distance of intra-ventricular conducting pathways as the result of LV dilatation, as an increase in LV mass is usually paralleled by the grade of the chamber enlargement in this type of LVH. Regarding the T loop, correlations between the LV mass and the VCG measurements were less as compared to those of the QRS loop. In general, T changes in moderate or severe LVH may be also related to a certain altered cardiac muscle state, in addition to an increase in LV mass. Angiocardiographic and light microscopic findings of a patient with eccentric LVH in whom a widened QRS-T angle was demonstrated to an extent much more than that expected with an increase in LV mass are presented and discussed. The spatial pattern analysis by VCG is very useful and reliable in assessing the severity of eccentric LVH.     

Increase in electrocardiographic R-waves after revascularization in patients with acute myocardial infarction.

BACKGROUND: The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated. METHODS AND RESULTS: One hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (SigmaR) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in SigmaR and the absolute increase in LV ejection fraction from the acute to the subacute phase (DeltaEF) were also calculated. The SigmaR in the subacute phase was significantly greater than that in the acute phase (p<0.0001). The % increase in SigmaR significantly correlated with the DeltaEF (r=0.57, p<0.0001). The % increase in SigmaR also correlated with the % defect-discordance (r=0.68, p<0.0001). CONCLUSIONS: The increase in the ECG R-wave voltage reflects not only the improvement in myocardial perfusion but also the presence of salvaged myocardium after revascularization in acute MI patients.     

Improved diagnostic performance on the severity of left ventricular hypertrophy with body surface mapping

To improve the diagnostic usefulness of electrocardiography (ECG) in determining the severity of left ventricular hypertrophy (LVH) with body surface mapping, 87 unipolar ECGs were recorded from 57 patients with left ventricular (LV) concentric hypertrophy and 30 with LV dilatation. Body surface ECG features due to LVH were evaluated by increase of QRS voltage and delayed local activation. We measured for each lead R voltage, net area of QRS (AQRS), ventricular activation time (VAT), and departure index (DI) of AQRS and VAT (DI = mean/SD). From these measurements, seven parameters were calculated for each patient: Rmax, the maximal R wave voltage; AQRSmax, the maximal AQRS; AQRS-Dmax, the maximal AQRS DI; AQRS-Darea, the area size where DIs of AQRS are more than 2; VATmax, the maximal VAT; VAT-Dmax, the maximal VAT DI; and VAT-Darea, the area size where DIs of VAT are more than 2. Among these parameters, the most effective for diagnosis of LVH were selected by stepwise multiple regression analysis. In the concentric hypertrophy group, the combination of VAT-Darea and Rmax was determined to be the best for estimating wall thickness. The regression equation determined from them correlated well to wall thickness (r = 0.73). In the LV dilatation hypertrophy group, only AQRSmax was selected for estimating LV dilatation. A good correlation between AQRSmax and LV internal dimension was observed (r = 0.73). With the body surface distribution of VAT prolongation, septal hypertrophy was separated from the other LVH. These were superior to the conventional method of 12-lead ECGs. ECG diagnosis of LVH severity improved by incorporating a mapping study. Also, prolongation of VAT and increase in QRS voltage were shown to be important when determining the severity of LVH.     

Electrocardiographic characteristics and metabolic risk factors associated with inappropriately high left ventricular mass in patients with electrocardiographic left ventricular hypertrophy: the LIFE Study

BACKGROUND: To investigate electrocardiographic (ECG) and metabolic abnormalities associated with left ventricular (LV) mass inappropriately high for workload and body size (termed 'inappropriate left ventricular mass'; ILVM) in hypertensive patients with ECG left ventricular hypertrophy (LVH). METHODS: In patients enrolled in the Losartan Intervention for Endpoint Reduction (LIFE) Echocardiographic Substudy, LV structure and functions were assessed by echocardiography; Sokolow-Lyon and Cornell voltage, QRS duration, Cornell voltage-duration product and ST strain pattern in leads V5-V6 were evaluated on standard ECG tracings. ILVM was defined as observed LV mass greater than 128% of that predicted by sex, body size and stroke work. RESULTS: In univariate analysis, compared with subjects with appropriate LV mass (n = 593), ILVM (n = 348) was associated with older age, diabetes, higher body mass index, lower systolic blood pressure, higher serum creatinine and urinary albumin/creatinine levels, higher LV mass index and greater prevalence of wall motion abnormalities (all P < 0.05). ILVM was associated with higher Cornell voltage and voltage-duration product but not higher Sokolow-Lyon voltage, with longer QRS and higher prevalences of ECG ST strain and echocardiographic wall motion abnormalities, independent of covariates including echocardiographically defined LVH or LV geometry. In separate logistic models, the likelihood of ILVM was significantly related to prolonged QRS duration, higher Cornell voltage, and greater Cornell voltage-duration independently (all P < 0.01). CONCLUSION: In hypertensive patients with ECG LVH, ILVM was associated with prolonged QRS duration and higher Cornell voltage, with ECG ST strain pattern, and with echocardiographic wall motion abnormalities independent of traditionally defined LVH.     

Left ventricular mass and hypertrophy assessment by means of the QRS complex voltage-independent measurements

ECG QRS-complex voltage-based criteria are relatively insensitive for detection of increased left ventricular mass (LVM). We developed and evaluate a new ECG index for LV hypertrophy (LVH) detection regardless of the QRS voltage. METHODS: Study population consisted of 106 patients (73 m, 33 f, aged 60 +/- 10 years) with established coronary artery disease (CAD). All patients had LVM assessed echocardiographically and indexed to BSA (LVMI(ECHO)). LVH was diagnosed if LVMI(ECHO) >117 g/m2 in men and >104 g/m2 in women. LV geometry was also determined. Analysed ECG variables, obtained from 12 leads recorded simultaneously, were: the QRS complex duration (QRSd, ms), the average 12-lead time to maximal deflection (TMD, ms), the average 12-lead QRS complex voltage (12QRSV, mV), the average product of 12 lead QRS voltage and duration (12QRSVd, mV ms), Sokolow-Lyon voltage and V-d product (SLV, SLVd), Cornell voltage and V-d product (CV, CVd). A newly developed index, LVM(ECG), was calculated, as LVM(ECG) = [(2 x TMD+QRSd/pi)3-(QRSd/pi)3]*0.0001 (ms3), and indexed to BSA (LVMI(ECG), ms3/m2). RESULTS: Means of the QRS voltage-related parameters were similar in patients with LVH and normal LVM. Greater differences existed between both groups when the QRS voltage-duration products were compared. LVMI(ECG) was most powerful in distinguishing between groups (130 +/- 33 LVH vs 91 +/- 21 normal LVM, p < 0.001). LVMI(ECG) correlated with LVMI(ECHO) better (r = 0.77, p < 0.001) than other indices (r coefficients between 0.24 for SLV and 0.49 for CVd). None of the examined indices allowed for distinction between eccentric and concentric LVH. The new index showed better statistical performance (area under ROC = 0.861) compared to the other indices (AUC range 0.545-0.697, p<0.001 vs LVMI(ECG)). At the specificity level of 92%, the value of LVMI(ECG) > 120 ms3/m2 had the sensitivity of 64% for detection of increased LVM. The sensitivities of the other parameters were significantly lower (sensitivity range 18-42%). Relative intra- and interobserver errors and correlation coefficients for LVMI(ECG) calculation were 0.4% and 1.6% and r = 0.94 and 0.98, respectively. CONCLUSIONS: In patients with CAD an assessment of LV mass and detection of hypertrophy using the QRS complex time-dependent index is feasible. The new index correlated well with echocardiographically-determined LVM and showed better statistical performance than indices which include QRS-voltage measurements. The results are promising and warrant further studies to evaluate the utility of the new index as a risk predictor.     

Inaccuracy of various proposed electrocardiographic criteria in the diagnosis of apical myocardial infarction--a critical review

The diagnostic accuracy of the standard electrocardiogram (ECG) in apical myocardial infarction (MI) was evaluated in 112 consecutive patients with recent MI and wall-motion abnormalities limited to the left ventricular (LV) apex on two-dimensional echocardiography, performed at rest 21 to 84 days after MI. The following patterns of abnormal (greater than or equal to 30 ms) Q waves were found: anteroseptal (Q V1-V4) in 44 patients (39.3%), anterolateral (Q V1-V6 and/or I, aVL) in 22 (19.6%), inferior (Q III, aVF or II, III, aVF) in five (4.5%), lateral (Q I, aVL and/or V5-V6) in five (4.5%), anteroinferior in six (5.3%); non-Q MI was present in 30 patients (26.8%). By applying various proposed ECG criteria, the presence of apical MI was correctly identified in very few (24, 21%) patients. LV apex was extensively asynergic in 85 patients (76%) and partially asynergic in 27 (24%). All the patients with Q waves in lateral leads and 47% of the patients with non-Q MI had partially asynergic LV apex, while in the other ECG patterns, extensively asynergic LV apex was predominant. The presence of both greater than or equal to 30 ms Q waves and loss of R in left precordial leads and I strongly suggests extensive apical asynergy; normal QRS in the same leads, however, does not exclude extensive apical involvement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Precordial ST-segment mapping: 6. Evaluation of serial changes in ST-segment elevations and QRS complexes of precordial maps and standard ECGs in patients with acute myocardial infarction

A total of 21 patients, 10 with anterior and 11 with inferior myocardial infarction (MI) had serial precordial 49-lead ECG maps or standard ECGs on admission, and 2, 6, 12, 24 hours, and 7 days thereafter, to evaluate the natural course of ST-segment elevation (index of ischemic injury) and QRS changes (index of necrosis), and their relationship. ECG parameters used included the sum of ST-segment elevations, number of sites showing such changes, the sum of R waves from all leads with ST-segment elevations, and a QRS score of all leads showing ischemic injury on admission. Sums of ST-segment elevations either did not show statistically significant change throughout the study or showed unexplained re-elevation (anterior MI), or completed their downward course in 6 hours (inferior MI). The number of sites showing ST-segment elevations either remained unchanged (inferior MI), or declined at 2 hours without further change. However changes in the sum of R waves or QRS scores were gradual and completed most of their overall course within 24 hours. Decline of sums of R waves correlated well with sums of ST-segment elevations on admission (inferior MI), and the number of sites showing changes (anterior MI). The course of changes in QRS complexes is more reliable than the alterations of ST-segment elevations for the monitoring of evolution of MI. The former, assessed frequently in the first 24 hours, should be useful in the evaluation of therapies for patients with MI.     

High-frequency analysis of the signal-averaged ECG. Correlation with left ventricular mass in rabbits.

Standard electrocardiographic (ECG) criteria have exhibited poor correlation with left ventricular mass and poor sensitivity for left ventricular hypertrophy at acceptable levels of specificity. To assess the ability of the high-frequency filtered signal-averaged ECG to improve ECG correlation with left ventricular mass, signal-averaged orthogonal lead recordings in 29 normal rabbits and seven rabbits with left ventricular hypertrophy due to chronic aortic regurgitation were compared with left ventricular mass corrected for body weight. Voltage of the vector QRS complex was integrated over the total duration of the QRS after separate filtering with standard frequency (0-100 Hz) low-pass and high-frequency (44 Hz) high-pass filters. Measurement of individual X, Y, and Z lead R and S wave voltage was performed on averaged, standard frequency filtered complexes, and the maximal spatial vector magnitude was determined from the standard frequency filtered vectors. Voltage of the 44 Hz high-pass filtered vector QRS complex integrated over the total duration of the QRS (high-frequency vector integral) correlated closely with indexed left ventricular mass (r = 0.84, p less than 0.0001), significantly better than the correlation of standard frequency vector integral or maximal spatial vector magnitude voltages (r = 0.35 and r = 0.61, each p less than 0.01 vs high-frequency vector integral) and the correlation of orthogonal lead X R wave or lead Y S wave voltages (r = 0.55 and r = 0.37, respectively, each p less than 0.01 vs high-frequency vector integral).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular hypertrophy: relationship of anatomic, echocardiographic and electrocardiographic findings

Anatomic, echocardiographic and ECG findings of left ventricular hypertrophy (LVH) were compared in 34 subjects. Echocardiographic LV mass correlated weel with postmortem LV weight (r = 0.96) and accurately diagnosed LVH (sensitivity 93%, specificity 95%). In contrast, Romhilt-Estes (RE) point score and Sokolow-Lyon (SL) voltage criteria for ECG LVH were insensitive (50% and 21%, respectively) but specific (both 95%). RE correlated weakly with LV weight (r = 0.64), but SL did not. Echocardiographic LV mass was then compared with RE and SL in an unselected clinical series of 100 subjects, in 28 subjects with severe aortic stenosis (AS) and in 14 with severe aortic regurgitation (AR). Results in the clinical series were comparable to those in the necropsy series. In the AS and AR groups, with a high prevalence of LVH, the low sensitivity of RE point score and Sl criteria led to poor overall results. Analysis of individual ECG variables showed that most voltage information is contained in leads aVL and V1. Correction of voltage for distance from the left ventricle did not substantially improve results. Individual nonvoltage criteria were each nearly as sensitive as RE point score. We could not devise new ECG criteria that improved diagnostic results. We conclude that the ECG is specific but insensitive in recognition of LVH. Moreover, when true LVH prevalence is less than 10%, more false-positive than true-positive diagnoses will be obtained. M-mode echocardiographic LV mass is superior to ECG criteria for clinical diagnosis of LVH.     

Geometric determinants of electrocardiographic left ventricular hypertrophy

Experimental studies have suggested that electrocardiographic recognition of left ventricular hypertrophy depends on geometric relationships involving wall thickness and chamber size. To determine the clinical significance of these observations, we studied the effects of echocardiographic LV mass (LVM), posterior wall thickness (PWT), interventricular septal thickness (IVST) and internal dimension (LVID) on ECG voltage in 360 patients. Standard voltage and nonvoltage manifestations of LVH correlated modestly with LVM (r = 0.33-0.44, p less than 0.001). Sokolow-Lyon precordial voltage (SLV) (SV1 + RV5 or V6) correlated moderately with LVM (r = 0.41, p less than 0.001), but correlated less well with IVST (r = 0.26), PWT (r = 0.24) or LVID (r = 0.22). Stepwise regression revealed that there was no relation, independent of LVM, between SLV and IVST (r = 0.03), PWT (r = 0.03) or LVID (r = 0.01). The 90 patients with increased LVM (greater than 215 g) but without LVH by SLV (false negatives) were compared with the 48 identified by SLV (true positives). False negatives differed from true positives in LVM (298 +/- 72 vs 339 +/- 98 g, p less than 0.01), age (55 +/- 18 vs 44 +/- 19 years, p less than 0.001), weight (70 +/- 16 vs 63 +/- 14 kg, p less than 0.02), and distance from skin to the interventricular septum (42 +/- 10 vs 38 +/- 8 mm, p less than 0.02). Thus, for a given LVM, ECG voltage criteria of LVH are independent of LV chamber dilatation or other geometric variables, but depend on age, weight and LV depth in the chest, suggesting that stratification of subjects by clinical variables has promise for improved electrocardiographic recognition of LVH.     

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.     

Racial differences in electrocardiograms and vectorcardiograms between black and white adolescents

In a previous study of 244 normal children, we detected higher leftward, posterior and inferior voltages in blacks than in whites in two groups: 6- to 10-year-old children and in 11- to 14-year-old boys; no difference was found in 3-to-5-year-old children, or 11- to 14-year-old girls. The purpose of this study was to determine if such race-related voltage differences are also present in 15- to 19-year-old adolescents. Biographic data, blood pressure and hemoglobin values, electrocardiogram (ECG), Frank vectorcardiogram (VCG) and echocardiogram were obtained in 59 normal 15- to 19-year-olds (28 blacks and 31 whites); 144 measured parameters and 57 computed variables were analyzed. Many sex-related differences (p less than 0.05 to 0.001) were seen in both races. R in leads I, AVL and V6, S in V1, and sum of SV1 and RV6 in the ECG and X to left, terminal X to right and Y inferior in the VCG were higher (p less than 0.05 to 0.01) in black males than in white males. However, no such differences (p greater than 0.05) were observed between black and white females. To understand the causes of these differences, comparison of the biographic data, blood pressure, hemoglobins and echocardiograms were made. The height, weight, body surface area, chest circumference, AP diameter of the chest, diastolic and systolic blood pressure and left ventricular (LV) dimension were similar (p greater than 0.1) in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

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).     

Reliability of standard electrocardiogram in detecting left ventricular asynergy in 315 patients with recent myocardial infarction

The relationship between asynergy of the left ventricular wall detected by two-dimensional echocardiography and ECG signs of necrosis (number of Q waves greater than or equal to 40 ms, Wagner's score) was evaluated in 315 patients (NYHA I-II) 23-90 days after a first Q-wave myocardial infarction (MI). Poor correlations were found between asynergy and ECG parameters. An ECG anterior MI is an apicoseptal MI by echo (independently of the ECG extent of Q waves) and the ECG is of little or no help in predicting the extent of asynergy to the inferior wall and proximal segments of the septum. An ECG inferior MI is inferoposterior by echo and the ECG has very limited value in predicting the extent of asynergy to the apex and septum. Patients with Q waves in leads II, III, and aVF had more extensive asynergy than those with either 2Q or greater than 3Q. R/S greater than or equal to 1 in V1 and/or V2 was present in 44% of patients with inferior MI while asynergy of at least one segment of the posterior wall was observed in 94%. In conclusion, standard ECG is sensitive in identifying anterior versus inferior infarct but it is unreliable in predicting the real extent of asynergy of the left ventricle, particularly in inferior infarcts.     

Assessment of right ventricular overload in patients with chronic pulmonary disease by 12-lead electrocardiography, vectorcardiography, and body surface electrocardiographic mapping

Twenty-eight patients with chronic pulmonary diseases were examined with standard 12-lead electrocardiogram (ECG), vectorcardiogram (VCG), and body surface ECG mapping (MAP). The electrocardiographic findings were compared with results of 99 mTc radionuclide right ventriculography or T1-201 myocardial scintigraphy. In a stepwise multiple regression analysis between the electrocardiographic parameters and right ventricular ejection fraction, only the amplitude of the negative P wave in V2 (r = 0.69), the posterior force of P loop in VCG (r = 0.71), and the size of -2SD area at 50 msec QRS potential departure map (r = 0.55) were selected as the parameters in standard ECG, VCG, and MAP, respectively. On the radionuclide ventriculography and myocardial scintigraphy, 14 patients were judged to have right ventricular overload. The criteria by VCG, and MAP had better sensitivity and specificity for right ventricle overload than those by 12-lead ECG. VCG criteria of Chou et al had sensitivity of 93% and specificity of 71%. MAP criteria, departure index of F3 or F4 less than or equal to -2, had sensitivity of 86% and specificity of 79%. The electrocardiographic findings by standard 12-lead ECG, VCG and body surface ECG mapping are useful parameters for the noninvasive detection of right ventricular overload in patients with chronic pulmonary diseases.     

Electrocardiographic diagnosis of left ventricular hypertrophy accompanied by complete right bundle branch block]

The new electrocardiographic criteria for diagnosing left ventricular hypertrophy (LVH) were evaluated in patients with complete right bundle branch block (CRBBB) based on the relationships between left ventricular mass and multiple electrocardiographic variables obtained from 12-lead electrocardiograms. The subjects consisted of 88 patients with CRBBB, whose ages ranged from 18 to 86 years. Patients with histories of myocardial infarction, moderate to severe pericardial effusion and an undetermined axis were excluded from the study. LVH was defined as left ventricular mass (LVmass) > or = 215 g calculated from the Penn method using standard M-mode echo measurements. All electrocardiograms were interpreted by one investigator who had no knowledge of the echocardiographic results. Items calculated were the amplitude of Q, R, and S waves and their A/R, R/S, and S/A ratios, the mean frontal QRS axis, ventricular activation time in lead V5, the Morris' index, ST-T segment depression in leads V5,6, and negative U waves in leads V5,6. We selected 22 items for our criteria according to their sensitivity and specificity, and added to the 11 previously reported ones determined. LV wall thickness correlated best with R I (r = 0.57, p < 0.01), LV diastolic dimension with RV5 (r = 0.48, p < 0.01), and LV mass with R I+S III (r = 0.60, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

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.     

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of left bundle branch block: an echocardiographic study

This study tests the electrocardiographic diagnosis of left ventricular (LV) hypertrophy in the presence of left bundle branch block (BBB). The LV mass of 125 patients with left BBB was estimated by echocardiography. M-mode echocardiography was technically adequate in 80% of patients. LV mass was calculated using previously validated M-mode formulas and then indexed to body surface area. The known shifts in the QRS voltage and axis with the onset of left BBB led to the selection of 4 electrocardiographic parameters for the diagnosis of LV hypertrophy: R in aVL 11 or more; QRS axis -40 degrees or less (or SII greater than RII); SV1 + RV5 to RV6 40 or more; SV2 30 or more and SV3 25 or more; these parameters were used in cumulative fashion. This cumulative approach was superior to using single conventional criterion such as the SV1 + RV5 or RV6. When LV hypertrophy was defined as an M-mode index of at least 115 g/m2, the sensitivity was 75% and specificity 90%. Using an M-mode mass of at least 215 g as the standard, the sensitivity was 73% and the specificity 66%. LV hypertrophy can be diagnosed by electrocardiographic criteria in the presence of left BBB at least as reliably as in normal conduction.     

A quantitative relationship of electrocardiographic criteria of left ventricular hypertrophy with echocardiographic left ventricular mass: a multivariate approach

The purpose of this study was to evaluate the sensitivity of various electrocardiographic (EKG) criteria of left ventricular hypertrophy (LVH) in relation to echocardiographic left ventricular mass (LVME) and to assess the relative strength of various EKG variables used in the diagnosis of LVH by multivariate analysis. An attempt was also made to determine if a new combination of precordial and T-wave voltage could improve the sensitivity of EKG. In 89 patients, M-mode echocardiograms and standard EKGs were studied. Correlation of Romhilt-Estes point-score system with LVME was r = 0.621, sensitivity and specificity was 57 and 81%, respectively. Other voltage criteria had lower sensitivity. Various combinations of precordial and T-wave voltage were not superior. The quantitative relationship of individual EKG variable, QRS duration, S V1-3, R V4-6, strain T wave, left atrial abnormality, intrinsicoid deflection and axis, with LVM was, r = 0.661, 0.595, 0.429, 0.42, 0.347, and 0.225, respectively. By multivariate analysis, QRS duration, S V1-3, T-wave and R V4-6 voltage had F-value (relative strength) of 27.95, 27.15, 22.02, and 4.03, respectively, other variables were statistically insignificant. In conclusion, the most important EKG variables predictive of LVH are QRS duration, S V1-3, strain T-wave and lateral voltage in decreasing value. Rescoring these variables in accordance to their correlation to LVM may improve EKG sensitivity for the diagnosis of LVH.