Electrocardiographic observations in clinically isolated, pure, chronic, severe aortic regurgitation: analysis of 30 necropsy patients aged 19 to 65 years

Certain electrocardiographic findings are described in 30 necropsy patients with clinically isolated pure, chronic, severe aortic regurgitation. They were 19 to 65 years old (mean 45). The hearts of the 22 men ranged in weight from 430 to 1,110 g (mean 717) and of the 8 women, from 375 to 950 g (mean 638). Four had grossly visible left ventricular (LV) scars. All but 1 patient was in sinus rhythm. The PR interval was greater than 0.20 second in 8 patients (28%) and the QRS duration was greater than or equal to 0.12 second in 6 patients (20%). Only 5 patients (17%) had 1 or more ventricular premature complexes recorded on the resting electrocardiogram analyzed. The mean QRS amplitude for each of the 12 leads averaged 23 mm. The highest mean QRS voltage occurred in leads V2 and V3 (each 38 mm), and the lowest in lead aVR (11 mm). The mean QRS voltage in V5 was higher than in V6 (33 vs 28 mm) and in 22 patients (73%) the QRS voltage in V5 was higher than in V6. The sum of the S wave in V1 plus the larger of the R wave in V5 or V6 (Sokolow-Lyon index) averaged 51 mm and in only 22 patients (73%) was it greater than 35 mm. The Romhilt-Estes voltage criteria for LV hypertrophy was fulfilled even less frequently, despite the severe degrees of LV hypertrophy in the patients studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrocardiographic criteria of left ventricular hypertrophy in left bundle-branch block.

In order to determine whether the electrocardiographic criteria of left ventricular hypertrophy apply in the presence of left bundle-branch block we studied 79 cases of intermittent left bundle-branch block and compared the QRS voltage and axis before and after its onset. Cases of incomplete left bundle-branch block were excluded. There was a statistically significant correlation between pre- and post-left bundle-branch block values of R or S wave voltage in leads I, V1, V2, V5, and V6, the Sokolow index (R V5 or V6 + S V1), and the QRS axis. There was a statistically significant reduction in R wave voltage in leads I, V5, and V6, an increase in S wave voltage in V1 and V2, and leftward shift of QRS axis, but the Sokolow index remained unchanged, after the onset of left bundle-branch block. The Sokolow criteria for left ventricular hypertrophy apply satisfactorily even in the presence of left bundle-branch block, though specificity is low, but QRS axis is unhelpful.     

Electrocardiographic criteria of left ventricular hypertrophy in left bundle-branch block.

In order to determine whether the electrocardiographic criteria of left ventricular hypertrophy apply in the presence of left bundle-branch block we studied 79 cases of intermittent left bundle-branch block and compared the QRS voltage and axis before and after its onset. Cases of incomplete left bundle-branch block were excluded. There was a statistically significant correlation between pre- and post-left bundle-branch block values of R or S wave voltage in leads I, V1, V2, V5, and V6, the Sokolow index (R V5 or V6 + S V1), and the QRS axis. There was a statistically significant reduction in R wave voltage in leads I, V5, and V6, an increase in S wave voltage in V1 and V2, and leftward shift of QRS axis, but the Sokolow index remained unchanged, after the onset of left bundle-branch block. The Sokolow criteria for left ventricular hypertrophy apply satisfactorily even in the presence of left bundle-branch block, though specificity is low, but QRS axis is unhelpful.     

The electrocardiogram in morbid obesity

Electrocardiographic variables that occurred with significantly higher frequency in morbidly obese patients than in lean controls were low QRS voltage, leftward shift of the P, QRS, and T axes and multiple electrocardiographic criteria for left ventricular hypertrophy and left atrial enlargement. P-terminal force, RaVL, SaVR, and R/S ratio in lead V1 values were significantly higher in morbidly obese than in lean subjects.     

Electrocardiographic detection of left ventricular hypertrophy using echocardiographic determination of left ventricular mass as the reference standard. Comparison of standard criteria, computer diagnosis and physician interpretation

Electrocardiographic findings of left ventricular hypertrophy were compared with echocardiographic left ventricular mass in 148 patients to assess performance of standard electrocardiographic criteria, the IBM Bonner program and physician interpretation. On echocardiography, 43% of the patients had left ventricular hypertrophy (left ventricular mass greater than 215 g). Sokolow-Lyon voltage-(S in V1 + R in V5 or V6) and Romhilt-Estes point score correlated modestly with left ventricular mass (r = 0.40, p less than 0.001 and r = 0.55, p less than 0.001, respectively). Sensitivity of Sokolow-Lyon voltage greater than 3.5 mV for left ventricular hypertrophy was only 22%, but specificity was 93%. Point score for probable left ventricular hypertrophy (greater than or equal to 4 points) had 48% sensitivity and 85% specificity, whereas definite hypertrophy (greater than or equal to 5 points) had 34% sensitivity and 98% specificity. Computer analysis resulted in 45% sensitivity and 83% specificity. Overall diagnostic accuracy of the IBM Bonner program (67%) was better than that of Sokolow-Lyon voltage (62%), but worse than the Romhilt-Estes point score (69% for greater than or equal to 4 points or 70% for greater than or equal to 5 points). Three cardiologists interpreted electrocardiograms independently and in a blinded fashion. Physician sensitivity was 56%, specificity 92% and accuracy 76%. Correlation with left ventricular hypertrophy was good (r = 0.70, p less than 0.001). It is concluded that: 1) computer diagnosis of left ventricular hypertrophy by the IBM Bonner program is no more accurate than diagnosis by Sokolow-Lyon or Romhilt-Estes criteria, and 2) physician recognition of left ventricular hypertrophy is more accurate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of left bundle branch block: a wasted effort

We assessed the reliability of multiple electrocardiographic variables for detecting left ventricular hypertrophy in 100 patients (aged 23 to 92 years, mean age 39 +/- 14) with complete left bundle branch block and different underlying cardiac diseases. Left ventricular hypertrophy, defined as an echocardiographically evaluated left ventricular mass greater than 241 g, was present in 66 of the 100 patients. The electrocardiographic parameters with the highest sensitivity were both the Cornell voltage criteria (RaVL + SV3 greater than 28 mm in men and greater than 20 mm in women) and the combination of criteria proposed by Kafka (any of these four indexes: RaVL greater than or equal to 11 mm, QRS axis -40 degrees or less, SV1 + RV5 or RV6 greater than or equal to 40 mm, SV2 greater than or equal to 30 mm and SV3 greater than or equal to 25 mm), with a sensitivity of 77%. Both criteria had a very low specificity (32 and 35%, respectively). The high specificities (greater than or equal to 88%) of several electrocardiographic criteria were accompanied by ineffective low sensitivities (less than 35%). Moreover, the cumulative parameters of Kafka and Cornell voltage criteria achieved a sensitivity of 84 and 89%, respectively, in hypertensive patients and in those with valvar diseases. None of the electrocardiographic indexes tested showed a significant difference in sensitivity when applied in categories of patients with left ventricular hypertrophy and different left ventricular geometry (cavity dilation or concentric hypertrophy). These data indicate that both conventional and recently proposed electrocardiographic criteria for left ventricular hypertrophy in the presence of left bundle branch block poorly recognize an augmented left ventricular mass.     

The usefulness of the electrocardiogram in the diagnosis of left ventricular hypertrophy in essential arterial hypertension]

The aim of the study is to analyse the usefulness of electrocardiographic criteria of left ventricular hypertrophy in essential hypertension. Seventy four patients (27 males, 47 females), 49 +/- 11 years--old with mild--moderate systemic hypertension (blood pressure greater than or equal to 140/90 mmHg) have been prospectively studied. A 12-lead electrocardiogram and an echocardiogram (M and 2D mode) have been performed after the basic clinical study. A left ventricular mass index (Devereux's method) greater than 131 g/square meters (males) or greater than 110 g/square meters (females) has been considered as left ventricular hypertrophy. Sensitivity, specificity and accuracy of 11 current electrocardiographic criteria of left ventricular hypertrophy have been determined. Sensitivity of these criteria was very low (0-0.35), while specificity was high (0.71-1). Total QRS voltage showed the best accuracy (0.51), while V5 or V6 R wave amplitude greater than 26 mm showed the best sensitivity (0.35). Current electrocardiographic criteria of left ventricular hypertrophy are not very useful in the diagnosis of left ventricular hypertrophy in essential hypertension.     

Cardiac changes induced by deconditioning in athletes: an echocardiographic and electrocardiographic study]

The relationships between echocardiographic and electrocardiographic variations and the sensibility of three different electrocardiographic criteria of left ventricular (LV) hypertrophy were assessed during deconditioning in 18 top-level oarsmen (mean age 23 +/- 4 years). After seven months of training and on the 7th and 21st deconditioning days the oarsmen underwent clinical examination, electrocardiogram (ECG) and echocardiogram with Doppler evaluation. The following ECG measurements were obtained: heart rate (HR), QTc, QRS and T waves axes, QRS and T wave angular gradients, R, S and T wave amplitude and T wave area. Moreover, the sums of S wave in lead V1 plus R wave in lead V5 or V6, of S wave in lead V1 or V2 plus R wave in lead V5 or V6, and of R wave in lead aVL plus S wave in lead V3 were calculated as indices of left ventricular hypertrophy. The following echocardiographic parameters were also analyzed: intraventricular septal (IVST) and posterior wall thickness (PWT), LV internal diameter (LVID), left ventricular mass (LVM) and volumes, LV endocardial/epicardial diastolic surface area ratio, peak systolic meridional wall stress (PSS), end-systolic stress (ESS) and mean systolic wall stress (MWSI), LV ejection fraction (EF) and total peripheral resistances (TPR); early (E) and late (A) transmitral peak flow velocity, E/A ratio. Systolic blood pressure was reduced after 3 deconditioning weeks, while diastolic blood pressure and HR were unchanged. Left ventricular mass and end-systolic volume were reduced after 1 week, while LV end-diastolic volume only after 3 weeks; therefore, EF improved at the end of the first week when TPR were lower. End-systolic stress always remained unchanged; PSS increased at 1 week and then returned to previous values. In addition, the endocardial-epicardial area ratio increased after 1 week and then returned to starting values after 3 weeks. Doppler parameters were in the normal range and remained unchanged during the study. Amplitudes of R wave in aVL, V5, V6 and of S wave in V2 did not change, while S wave amplitude in V1 and V3 decreased after three weeks and one week, respectively. The most sensible criterion for LV hypertrophy was the sum of S wave in V1 or V2 plus R wave in V5 or V6 (range from 33.3% to 22.2%); the sum of S in V1 plus R in V5 or V6 performed better than the sum of R in aVL plus S in V3.(ABSTRACT TRUNCATED AT 400 WORDS)     

QRS voltage of the electrocardiogram and Frank vectorcardiogram in relation to ventricular volume.

Left ventricular volumes were estimated in 59 patients, who were investigated by single plane ventriculography and coronary arteriography. The relation of the left ventricular end-diastolic volumes to the QRS voltage of the 12-lead electrocardiograms and Frank vectorcardiograms was examined. It was found that the maximum spatial QRS voltage and the R wave voltage of leads V5 and V6 in patients without left ventricular hypertrophy were inversely correlated with end-diastolic volume. This inverse relation of QRS voltage and left ventricular volume may explain loss of QRS voltage with dilatation of the heart. In patients with left ventricular hypertropy QRS voltage is usually positively correlated with the degree of hypertrophy, but there is no significant correlation in the presence of cardiac dilatation. If the results of this study are extrapolated to patients with left ventricular hypertrophy and cardiac dilatation, then the inverse correlation of volume and QRS voltage may reduce the diagnostic sensitivity of unipolar chest lead and vectorcardiographic criteria of left ventricular hypertrophy.     

QRS voltage of the electrocardiogram and Frank vectorcardiogram in relation to ventricular volume.

Left ventricular volumes were estimated in 59 patients, who were investigated by single plane ventriculography and coronary arteriography. The relation of the left ventricular end-diastolic volumes to the QRS voltage of the 12-lead electrocardiograms and Frank vectorcardiograms was examined. It was found that the maximum spatial QRS voltage and the R wave voltage of leads V5 and V6 in patients without left ventricular hypertrophy were inversely correlated with end-diastolic volume. This inverse relation of QRS voltage and left ventricular volume may explain loss of QRS voltage with dilatation of the heart. In patients with left ventricular hypertropy QRS voltage is usually positively correlated with the degree of hypertrophy, but there is no significant correlation in the presence of cardiac dilatation. If the results of this study are extrapolated to patients with left ventricular hypertrophy and cardiac dilatation, then the inverse correlation of volume and QRS voltage may reduce the diagnostic sensitivity of unipolar chest lead and vectorcardiographic criteria of left ventricular hypertrophy.     

Reevaluation of electrocardiographic criteria for left, right and combined cardiac ventricular hypertrophy

Cardiac chamber weight was determined at necropsy in 323 men to develop correlative studies of electrocardiographic criteria for ventricular hypertrophy. Thirty recommended criteria for left ventricular (LV) hypertrophy, 10 for right ventricular (RV) hypertrophy, and combinations of both criteria for combined hypertrophy were evaluated. Four methods for electrocardiographic diagnosis of LV hypertrophy were derived: (1) a modification of the Romhilt-Estes point system; (2) the presence of any 1 of 3 criteria: (a) S V1 + R V5 or V6 greater than 35 mm, (b) left atrial abnormality, or (c) intrinsicoid deflection in lead V5 or V6 greater than or equal to 0.05 second; (3) a combination of any 2 criteria or of 1 criterion (above) plus at least 1 of the following 3 additional criteria: (a) left-axis deviation greater than -30 degrees, (b) QRS duration greater than 0.09 second, or (c) T-wave inversion in lead V6 of 1 mm or more; and (4) the use of a single criterion--left atrial abnormality. Sensitivity varied from 57 to 66% and specificity from 85 to 93% among these 4 methods. Myocardial infarction increased sensitivity of the foregoing methods, but the specificity was reduced. Method 2 is preferred for the electrocardiographic diagnosis of LV hypertrophy. Two methods were useful for right ventricular (RV) hypertrophy: (1) the use of any 1 of 4 criteria: (a) R/S ratio in lead V5 or V6 less than or equal to 1; (b) S V5 or V6 greater than or equal to 7 mm; (c) right-axis deviation of more than +90 degrees, or (d) P pulmonale; and (2) use of any 2 combinations of the foregoing criteria. Sensitivity ranged from 18 to 43% and specificity from 83 to 95%. Combined hypertrophy was best diagnosed using left atrial abnormality as the sole criteria of LV hypertrophy, plus any 1 of 3 criteria of RV hypertrophy: (a) R/S ratio in lead V5 or V6 less than or equal to 1, (b) S V5 or V6 greater than or equal to 7 mm, or (c) right axis deviation greater than +90 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrocardiographic criteria for diagnosis of left ventricular hypertrophy in the presence of complete right bundle branch block

The usual electrocardiographic criteria recommended for left ventricular (LV) hypertrophy may be unreliable in the presence of complete right bundle branch block (BBB). Thirty-six standard electrocardiographic criteria for LV hypertrophy were evaluated in 100 patients (mean age +/- standard deviation 67 +/- 11 years) with right BBB and technically satisfactory echocardiograms. Eight additional electrocardiographic criteria derived from this study also were evaluated. LV mass index was determined from the echocardiogram using the Penn method. LV hypertrophy defined as LV mass index greater than 132 g/m2 in men and 109 g/m2 in women was present in 56 of the 100 patients. Electrocardiographic criteria with the highest sensitivity were SIII + (R + S) maximal precordial lead greater than or equal to 30 mm (sensitivity 68%), specificity 66%), left axis deviation of -30 degrees to -90 degrees (sensitivity 59%, specificity 71%) and combination of left axis deviation and SIII + (R + S) maximal precordial lead greater than or equal to 30 mm (sensitivity 52%, specificity 84%). The electrocardiographic criteria with the highest sensitivity and specificity greater than 90% were left axis deviation of -30 degrees to -90 degrees and SV1 greater than 2 mm (sensitivity 34%), point-score system, RaVL greater than 12 mm and RI + SIII greater than 25 mm (each with a sensitivity of 27%). In general, limb lead voltage criteria such as RaVL greater than 11 mm (sensitivity 29%, specificity 86%) had higher sensitivities than criteria using right precordial lead S-wave voltage criteria such as SV1 + RV5, V6 greater than 35 mm (sensitivity 2%, specificity 100%).(ABSTRACT TRUNCATED AT 250 WORDS)     

QRS voltage measurements in autopsied men free of cardiopulmonary disease: a basis for evaluating total QRS voltage as an index of left ventricular hypertrophy

Use of total 12-lead QRS electrocardiographic voltage as a criterion for left ventricular (LV) hypertrophy has been of recent interest. Although upper and lower limits of QRS voltage for individual electrocardiographic leads have been reported in clinically healthy men and women, the upper limit of total 12-lead QRS voltage has not been established in adults free of cardiopulmonary disease by clinical and necropsy criteria. Therefore, the total QRS voltage from all 12 electrocardiographic leads was determined in 30 autopsied men known to be free of cardiopulmonary disease by clinical assessment and by a special cardiac examination using postmortem coronary angiography and chamber partition determination of LV weight. Gross heart weight, LV weight and total QRS voltage are reported. Comparisons were made between disease-free patients and previously reported patients with aortic valve stenosis, aortic regurgitation and cardiac amyloidosis with respect to total QRS voltage and gross heart weight. Total QRS voltage and gross heart weight were significantly greater in patients with severe aortic stenosis (mean 245 mm) and severe aortic regurgitation (mean 274 mm) than in our patients (mean 127 mm). Total QRS voltage was significantly less, whereas gross heart weight was significantly greater in patients with cardiac amyloidosis (mean 101 mm) than in our normal subjects (mean 127 mm). These data provide a basis for evaluating the total 12-lead QRS voltage as a criterion for LV hypertrophy.     

Cardiac involvement in Friedreich's ataxia: a clinical study of 75 patients

To establish the prevalence and to characterize the types of cardiac involvement in Friedreich's ataxia, 75 consecutive patients (39 male and 36 female), aged 10 to 66 years (mean 24) were prospectively studied. Electrocardiograms were performed in all patients, vectorcardiograms in 34 and echocardiograms in 58. Electrocardiographic and vectorcardiographic abnormalities occurred in 69 (92%) of the 75 patients. Electrocardiograms revealed ST-T wave abnormalities in 79%, right axis deviation in 40%, short PR interval in 24%, abnormal R wave in lead V1 in 20%, abnormal inferolateral Q waves in 14% and left ventricular hypertrophy (voltage and repolarization criteria) in 16%. Echocardiograms revealed concentric left ventricular hypertrophy in 11%, asymmetric septal hypertrophy in 9% and globally decreased left ventricular function in 7%. Progression from a normal echocardiogram to concentric left ventricular hypertrophy, asymmetric septal hypertrophy or globally decreased left ventricular function was identified in one patient in each category, although the study was not designed for longitudinal follow-up. Two patients died, and necropsy revealed in both a minimally dilated but flabby left ventricle. On the basis of electrocardiographic and vectorcardiographic and echocardiographic data, 95% of patients had one or more disorders. The most common abnormality was segmental myocardial "dystrophy" (electrocardiographic QRS initial force abnormalities), but global left ventricular hypokinesia occurred more often than previously recognized.(ABSTRACT TRUNCATED AT 250 WORDS)     

The orthogonal electrocardiogram in normal women. Implications of sex differences in diagnostic electrocariodgraphy.

Normal limits of the orthogonal electrocardiogram and vectorcardiogram in adult women, ranging in age from 18 to 90 years, are presented. A comparison of results is made with those of normal age-matched men, and sex differences are analyzed from a total of 960 normal records (510 men and 450 women). For the majority of scalar and vectorial items, significant sex differences were found which in women included shorter QRS duration, smaller vector loops, and decreased P, Q, R, S, and T deflections. The upper normal limits of R_x, R_y, and R_z amplitudes were 11 per cent, 20 per cent, and 30 per cent less, respectively, in women than in men.The sensitivity and specificity of electrocardiographic criteria, for high and low voltage, were significantly affected by these sex differences in amplitudes. For example, as a discriminator between normals and subjects with left ventricular hypertrophy, the upper normal limit of R_x + R_z amplitude sum was 3.10 millivolts in men but 2.50 millivolts in women. Hence, the use of the limit derived from males in a female population would decrease its sensitivity drasticially. Similar discrepancies existed in the sensitivity and specificity of electrocardiographic criteria for low voltage. Since the lower normal limit of R_x amplitude was 0.51 millivolt in men but only 0.35 millivolt in women, a substantial number of normal women would be misclassified as having right ventricular hypertrophy or chronic obstructive pulmonary disease if the limit derived from males was used as a criterion.The absence of Q waves in Leads x and y was a common finding in each age and sex group and carries no diagnostic significance. While initial anterior QRS forces in Lead z were present in all normal men, they were smaller and even absent in 1 per cent of normal women. Hence, greater difficulties in electrocardiographic diagnosis of anteroseptal myocardial infarction in women may be encountered.Mean vectors at the end of QRS (point J) and early part of the ST segment were more inferiorly and anteriorly directed in men than in women. T waves in Lead z were always negative in men, but flat or positive T waves were observed in some of the normal women. Sex differences in the level of point J and the ST segment may have important bearings on the interpretation of exercise electrocardiograms.The shorter QRS duration in women signified the importance of sex-specific limits for ventricular conduction delays.     

Sex Differences in the Relationships Between Electrocardiographic Abnormalities and the Extent of Left Ventricular Hypertrophy by Echocardiography

Background: Several criteria have been proposed for the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). However, their diagnostic accuracy is questionable. Furthermore, the diagnostic accuracy of abnormalities in ST‐T patterns for LVH is known to be uncertain, especially in women. We examined the relationship between electrocardiographic abnormalities and the extent of LVH. Methods: We studied 76 men and 48 women who satisfied electrocardiographic voltage criteria for LVH (RV₅ or RV₆≥ 2.6 mV, SV₁+ RV₅ or SV₁+ RV₆≥ 3.5 mV) . They were classified into three groups based on ST‐T pattern: normal, early strain, and strain. We defined echocardiographic evidence of LVH as an LV wall thickness ≥ 12 mm. Results: LVH was identified by echocardiography in 55.3% of men and in 47.9% of women. In strain and early strain groups, the prevalence of echocardiographic LVH was significantly higher in men than in women (strain group: 100 vs 75%, P < 0.05, early strain group: 81.8 vs 42.1%, P < 0.05), it did not differ significantly between men and women in normal group. In men, QRS voltage values were significantly correlated with echocardiographic indices. In group strain of men, significant good correlations were observed between QRS voltage values and echocardiographic indices. However, in women, there were no significant correlation between QRS voltage values and echocardiographic indices even in strain group. Conclusions: The combined criteria of both QRS voltage and ST‐T classification could provide a greater accuracy in diagnosing LVH compared to the criteria using QRS voltage alone in men rather than in women.     

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)     

Improved prediction of left ventricular mass by regression analysis of body surface potential maps

Electrocardiographic left ventricular (LV) hypertrophy involving ST-T abnormalities, in addition to high QRS voltages, is associated with increased risk of cardiovascular disease mortality. Unfortunately, conventional electrocardiographic criteria have limited utility in the quantitative assessment of LV hypertrophy. Body surface potential maps, which contain diagnostic information not present in commonly used lead systems, were recorded from 117 thoracic sites and 3 limb electrodes in 72 normal subjects and 84 patients with LV hypertrophy. Multiple regression analysis was performed separately for 54 women and 102 men on 120-lead data, using as features instantaneous voltages on time-normalized P, PR, QRS and ST-T waveforms. Leads and features for optimal prediction of echocardiographically determined LV mass were selected. A total of 6 features from 3 torso sites in men, and from the same 3 sites plus 2 others in women, yielded correlations between echocardiographic and electrocardiographic estimates of LV mass of 0.89 and 0.88, respectively. The standard errors of the estimate (SEE), or average errors in predicting LV mass from the regression equations, were 31 and 22 g, respectively. The single most potent predictor in both sexes was a mid-QRS voltage measured on a lead positioned 10 cm below V1; QRS duration, late QRS and early-to-mid T-wave amplitudes recorded in the lower left flank contributed significantly to the performance of both regression models. The optimal electrode sites for electrocardiographic prediction of LV mass were outside the conventional lead locations.(ABSTRACT TRUNCATED AT 250 WORDS)     

aVR导联临床应用的新视点

aVR导联是一个经常被忽略的导联,但是,近几年的研究显示aVR导联在诸多方面都发挥着重要的作用。aVR导联经典的临床应用包括窦性心律的确认、电轴的确定、右位心和左右手反联及心室肥厚的诊断。其临床应用的新发现包括:急性冠脉综合征时,aVR导联ST段抬高提示左主干、左前降支近端或三支病变;在ST段抬高型心肌梗死中aVR导联ST段抬高或下移是住院患者死亡率的独立预测因子,可用于危险分层;分析心律失常时,aVR导联可用于鉴别宽QRS型、窄QRS型心动过速;体表心电图的aVR导联结合V1、V2导联可以估算右房房颤周长,并且aVR导联P波振幅是心脏手术术后房颤发生的强有力的预测因子;Brugada综合征时出现"aVR征"有助于危险分层;右室负荷过重时,aVR导联ST段抬高是急性肺栓塞的死亡预测因子(单变量回归分析)和并发症的预测因子;aVR导联R波延迟是慢性右室压力负荷过重的独立预测因子且多见于肺动脉狭窄患者;特发性肺动脉高压的患者中,aVR导联R波>4mm,结合V1导联R波>6mm、R/SV1>1,R/SV5与R/SV1比值<0.04,Ⅱ导联P波>2.5mm可以诊断右室肥厚;当疑似预激综合征时,利用体表心电图同时出现PR间期≤120ms和PR离散度≥20ms、aVR导联缺少初始正向波(间隔R波)和V1导联水平面QRS移行提前这3步可识别心室预激,且具有较高的特异性和敏感性;连续监测aVR导联R波和R/S比例有助于预测三环类抗抑郁药物中毒时意识的恢复;急性心包炎时,aVR导联ST段压低、PR段抬高形成了急性心包炎的特征性表现,即"关节征",并且可能是急性心包炎最早甚至是唯一的心电图改变,具有早期诊断价值。     

Vectorcardiographic diagnosis of right ventricular hypertrophy in the presence of right bundle branch block in young subjects.

Two groups of young patients, one with right bundle branch block complicated by right ventricular hypertrophy due to congenital heart disease, the other with right bundle branch block and no right ventricular hypertrophy, could be separated on the basis of a few quantitative vectorcardiographic and electrocardiographic criteria. Vectorcardiographic criteria proved better than electrocardiographic criteria in detecting right ventricular hypertropy in individual patients with complete right bundle branch block. Criteria based on the configuration of the QRS loop were also specific but much less sensitive for the diagnosis of this association. In a similar population, that is, young patients with postoperative right bundle branch block, the existence of a residual right ventricular overload would be strongly suggested by the presence of any one of the following criteria: (1) a clockwise rotation of the QRS loop in the horizontal plane, (2) a ratio of the magnitude of the R wave to that of the S wave (R/S ratio) in lead X at less than 2.0, (3) a mean QRS vector in lead X more negative than--10 mv.msec, or (4) a maximal QRS vector located between 90 degrees and 270 degrees in the horizontal plane. In contrast, an R/S ratio in lead X that was equal or superior to 2.0 or an azimuth angle of the mean spatial QRS vector that was not between 90 degrees and 180 degrees would indicate that the right ventricular conduction defect is probably uncomplicated.