Ethnic differences in electrocardiographic criteria for left ventricular hypertrophy: the LIFE study. Losartan Intervention For Endpoint

BACKGROUND: African Americans have greater precordial QRS voltages than whites, with concomitant higher prevalences of electrocardiographic (ECG) left ventricular hypertrophy (LVH) and lower specificity of ECG LVH criteria for the identification of anatomic hypertrophy. However, the high mortality associated with LVH in African American patients makes more accurate ECG detection of LVH in these patients a clinical priority. METHODS: Electrocardiograms and echocardiograms were obtained at study baseline in 120 African American and 751 white hypertensive patients enrolled in the Losartan Intervention For Endpoint (LIFE) echocardiographic substudy. The ECG LVH was determined using Sokolow-Lyon, 12-lead sum, and Cornell voltage criteria. Echocardiographic LVH was defined by LV mass indexed to height(2.7) >46.7 g/m(2.7) in women and >49.1 g/m(2.7) in men. RESULTS: After adjusting for ethnic differences in LV mass, body mass index, sex, and prevalence of diabetes, mean Sokolow-Lyon and 12-lead sum of voltage were significantly higher, but Cornell voltage was lower, in African Americans than in whites. As a consequence of these differences, when identical partition values were used in both ethnic groups, Sokolow-Lyon and 12-lead voltage criteria had lower specificity in African Americans than whites (44% v 69%, P = .007 and 44% v 59%, P = .10) but had greater sensitivity in African Americans (51% v 27%, P < .001 and 62% v 45%, P = .003). In contrast, Cornell voltage specificity was higher (78% v 62%, P = .09) but sensitivity was slightly lower (49% v 57%, P = 0.16) in African Americans. However, when overall test performance was compared using receiver operating curve analyses that were independent of partition value selection, ethnic differences in test performance disappeared, with no differences in accuracy of any of the ECG voltage criteria for the identification of LVH between African American and white hypertensive individuals. CONCLUSIONS: When standard, non-ethnicity-specific thresholds for the identification of LVH are used, Sokolow-Lyon and 12-lead voltage overestimate and Cornell voltage underestimates the presence and severity of LVH in African American relative to white individuals. However, these apparent ethnic differences in test performance disappear when ethnic differences in the distribution of ECG LVH criteria are taken into account. These findings demonstrate that ethnicity-specific ECG criteria can equalize detection of anatomic LVH in African American and white patients.     

Comparison of electrocardiographic versus echocardiographic detection of left ventricular mass changes over time and evaluation of new onset left ventricular hypertrophy

We assessed the value of 3 electrocardiographic (EKG) voltage criteria in detecting variations of left ventricular mass (LVM) over time, taking echocardiographic (ECHO) LVM as reference, in the Pressioni Arteriose Monitorate E Loro Associazioni study. In 927 subjects (age 47 ± 13 years on entry, 49.9% men) an ECHO evaluation of LVM and EKG suitable for measurement of EKG-LVH criteria (Sokolow-Lyon voltage, Cornell voltage and R-wave voltage in aVL) were available at baseline and at a 2^nd evaluation performed 10 years later. Δ (delta) LVM, Δ LVMI, and Δ EKG parameters values were calculated from 2^nd evaluation to baseline. The sensitivity of the EKG criteria in the diagnosis of LVH, poor at baseline, becomes even worse after 10 years, reaching very low values. Only the sensitivity of R-wave amplitude exhibited slight increase over time but with unsatisfactory absolute values. Despite the prevalence of ECHO-LVH at the 2^nd evaluation was threefold increased compared to baseline (29.3% and 33.7% for LVM indexed to BSA and height^2.7, respectively), the prevalence of EKG-LVH was unchanged when evaluated by Sokolow-Lyon criteria, significantly reduced when assessed by Cornell voltage index, while significantly increased using R-wave voltage in aVL criteria. Despite an ECHO-LVM increase over the time, mean EKG changes were of opposite sign, except for R-wave amplitude in aVL. Our study highlights the discrepancy between ECHO and EKG in monitoring LVM changes over the time, especially for Sokolow-Lyon and Cornell voltage. Thus, EKG is an unsuitable method for the longitudinal evaluation of LVM variations.     

Ethnic differences in the identification of left ventricular hypertrophy in the hypertensive patient.

Left ventricular hypertrophy (LVH) is more prevalent in black than white hypertensives, but this difference is greater when identified by electrocardiography (ECG) than by echocardiography. We evaluated the proposal that current ECG criteria for LVH are less specific, and therefore, less useful, in blacks than whites. In a retrospective cross-sectional study, 408 subjects (271 white, 137 black) referred to a hypertension clinic for assessment of hypertension underwent measurement of blood pressure, ECG voltages (Sokolow-Lyon and Cornell sex-specific), and echocardiographic left ventricular mass index (LVMI). Black subjects had greater ECG voltages than whites, even when closely matched for LVMI. In black subjects, current ECG criteria were twice as sensitive as in whites (Sokolow-Lyon: 44.9% v 22.5%, P = .003. Cornell: 30.4% v 15.7%, P = .03). They were less specific in blacks using the Sokolow-Lyon criteria (73.5% v 86.8%, P = .02) but this failed to reach significance using the Cornell criteria (83.8% v 91.8%, P = .07). When voltage criteria were adjusted to give matched sensitivities and specificities, respectively, differences in specificity and sensitivity were no longer apparent. Receiver operating characteristic curve analyses confirmed no significant differences in overall performance of either ECG criteria between blacks and whites. In conclusion, ECG detection of LVH is insensitive in both ethnic groups. Sensitivity is higher in blacks due to higher LVMI in those with LVH. Apparent differences in specificity are due to ethnic differences in ECG voltages that are unrelated to differences in LVMI. When these differences are taken into account, there are no overall differences in test accuracy. However, given the prognostic importance of the detection of LVH, currently accepted ECG voltage criteria for the detection of LVH remain of equal or greater value in black hypertensives compared with whites.     

Race- and sex-specific ECG models for left ventricular mass in older populations. Factors influencing overestimation of left ventricular hypertrophy prevalence by ECG criteria in African-Americans

The validity of the reported high prevalence of left ventricular hypertrophy (LVH) among African-American men and women has been questioned owing to conflicting echocardiographic evidence. We used echocardiographic left ventricular mass (LVM) from M-mode measurements to evaluate associations between LVM, body size, and electrocardiographic (ECG) variables in 3,627 white and African-American men and women 65 years of age and older who were participants of the Cardiovascular Health Study (CHS), a multicenter cohort study of risk factors for coronary heart disease and stroke. ECG amplitudes used in LVH criteria were substantially higher in African-Americans, with apparent LVH prevalence 2 to 3 times higher in African American men and women than in white men and women, although there was no significant racial difference in echocardiographic LVM. The higher apparent LVH prevalence by Sokolow-Lyon criteria in African-American men is in part owing to smaller lateral chest diameter. In women, reasons for racial differences in ECG LVH prevalence remain largely unexplained although a small part of the excess LVH in African-American women by the Sokolow-Lyon criteria appears to be owing to a larger lateral chest semidiameter in white women. ECG variables alone were too inaccurate for LVM prediction, and it was necessary to incorporate in all ECG models body weight that was properly adjusted for race and sex. This resulted in modest LVM prediction accuracy, with R-square values ranging from .22 to .36. Race- and sex-specific ECG models introduced for LVM estimation with an appropriate adjustment for body size differences are expected to facilitate evaluation of LVH status in contrasting racial population groups.     

Performance of classic electrocardiographic criteria for left ventricular hypertrophy in an African population

ECG criteria for left ventricular hypertrophy (LVH) have been almost exclusively elaborated and calibrated in white populations. Because several interethnic differences in ECG characteristics have been found, the applicability of these criteria to African individuals remains to be demonstrated. We therefore investigated the performance of classic ECG criteria for LVH detection in an African population. Digitized 12-lead ECG tracings were obtained from 334 African individuals randomly selected from the general population of the Republic of Seychelles (Indian Ocean). Left ventricular mass was calculated with M-mode echocardiography and indexed to body height. LVH was defined by taking the 95th percentile of body height-indexed LVM values in a reference subgroup. In the entire study sample, 16 men and 15 women (prevalence 9.3%) were finally declared to have LVH, of whom 9 were of the reference subgroup. Sensitivity, specificity, accuracy, and positive and negative predictive values for LVH were calculated for 9 classic ECG criteria, and receiver operating characteristic curves were computed. We also generated a new composite time-voltage criterion with stepwise multiple linear regression: weighted time-voltage criterion=(0.2366R(aVL)+0.0551R(V5)+0.0785S(V3)+ 0.2993T(V1))xQRS duration. The Sokolow-Lyon criterion reached the highest sensitivity (61%) and the R(aVL) voltage criterion reached the highest specificity (97%) when evaluated at their traditional partition value. However, at a fixed specificity of 95%, the sensitivity of these 10 criteria ranged from 16% to 32%. Best accuracy was obtained with the R(aVL) voltage criterion and the new composite time-voltage criterion (89% for both). Positive and negative predictive values varied considerably depending on the concomitant presence of 3 clinical risk factors for LVH (hypertension, age >/=50 years, overweight). Median positive and negative predictive values of the 10 ECG criteria were 15% and 95%, respectively, for subjects with none or 1 of these risk factors compared with 63% and 76% for subjects with all of them. In conclusion, the performance of classic ECG criteria for LVH detection was largely disparate and appeared to be lower in this population of East African origin than in white subjects. A newly generated composite time-voltage criterion might provide improved performance. The predictive value of ECG criteria for LVH was considerably enhanced with the integration of information on concomitant clinical risk factors for LVH.     

Relation of echocardiographic left ventricular mass and hypertrophy to persistent electrocardiographic left ventricular hypertropy in hypertensive patients: the LIFE study

Background: The Losartan Intervention For Endpoint Reduction in Hypertension (LIFE) trial used left ventricular hypertrophy (LVH) on a screening ECG to identify patients at high risk for morbid events. Because of regression to the mean, not all patients who met screening criteria had persistent ECG LVH on the ECG performed at study baseline.Methods: The relationship of echocardiographic LV mass and LVH to persistence or loss of ECG LVH between screening and baseline evaluation was examined in 906 hypertensive patients in the LIFE study, who had echocardiograms and additional ECG performed at study baseline. Patients were categorized according to the presence or absence of ECG LVH by Cornell voltage-duration product criteria or Sokolow-Lyon voltage criteria; echocardiographic LVH was defined by LV mass index (LVMI) > 104 g/m² in women and > 116 g/m² in men.Results: A total of 678 patients (75%) had persistent ECG LVH at baseline evaluation. Compared with the 228 patients without ECG LVH on the second ECG by either criterion, the 106 patients with LVH by both Cornell product and Sokolow-Lyon criteria had significantly higher LVMI (140 ± 31 v 114 ± 21 g/m², P < .001) and a higher prevalence of echocardiographic LVH (86% v 55%, P < .001). Patients with ECG LVH on the baseline ECG by either Cornell product criteria (n = 410) or Sokolow-Lyon voltage criteria (n = 162) had intermediate values of LVMI (125 ± 25 and 121 ± 21 g/m²) and prevalences of echocardiographic LVH (78% and 62%). After controlling for possible effects of age, sex, ethnicity, systolic blood pressure, and body mass index, persistence of ECG LVH on the baseline ECG was associated with an increased risk of echocardiographic LVH: compared with patients with neither ECG criteria for LVH, patients with only Sokolow-Lyon voltage criteria had a 1.2-fold increased risk of echocardiographic LVH, those with only Cornell product criteria had a 2.7-fold increased risk, and patients with both ECG criteria had a 4.1-fold increased risk of echocardiographic LVH (P < .001).Conclusions: Persistent ECG LVH between screening and LIFE study baseline identified patients with greater LV mass and a higher prevalence of echocardiographic LVH, suggesting that these patients may be at higher risk for subsequent morbid and mortal events.     

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.     

The determinants of left ventricular hypertrophy defined by Sokolow-Lyon criteria in untreated hypertensive patients

Left ventricular hypertrophy (LVH) measured by electrocardiography (ECG LVH) in hypertensive patients has been shown to be associated with an increased risk of cardiovascular sequelae. Analysis of the determinants predisposing to ECG LVH may be helpful in the prevention of LVH. The Department of Health and Social Security Hypertension Care Computer Project studied 2994 hypertensive patients in whom an electrocardiogram was recorded while not on treatment. LVH was determined as the voltage sum SV1+RV5 or RV6>or=35 mm using Sokolow-Lyon voltage criteria. The relations were determined between the presence of LVH or voltage sum and different variables. Untreated systolic (SBP) and diastolic (DBP) blood pressure and pulse pressure were positively related to the increasing ECG voltage, while body mass index (BMI) and serum cholesterol were inversely related. Blood glucose and age did not correlate significantly. Patients with the presence of ECG LVH were more often men, black people, smokers and users of alcohol. In multiple logistic regression analyses, SBP, DBP, male gender and black race were positively, whereas BMI was negatively related to the presence of LVH. The positive relation of smoking and negative relation of serum cholesterol concentration to the presence of ECG LVH were apparent in men but not in women. This study confirms the adverse association between ECG LVH and SBP and DBP, male gender, black race and decreased BMI. It also addresses the less well-known associations of blood glucose, cholesterol, smoking and alcohol consumption.     

老年男性心电图Cornell电压标准及其应用价值

目的 探讨老年男性心电图Comell电压标准及其诊断老年男性左室肥厚的价值.方法 回顾性分析北京医院自1990年来进行尸体解剖的老年男性患者资料,排除心电图ORS波时限≥0.12 s及起搏心电图的患者.测量死亡前3个月内标准12导联心电图QRS波振幅,分析老年男性Comell、Sokolow-Lyon电压值与左室前壁厚度的相关性.计算老年男性无器质性心脏病组Comell电压值的均数及其97.5%的上限值,分析老年男性心电图Comell电压标准诊断老年男性左室肥厚的敏感性、准确性.结果 老年男性心电图Comell、Sokolow-Lyon电压值与左室前壁厚度相关.老年男性无器质性心脏病组心电图Sv3+RaVL平均值为(1.32±0.79)mV,以其97.5%的上限值2.9 mV为Comell标准诊断老年男性左室肥厚的敏感性、准确性分别为34.3%、77.5%,高于Sokolow-Lyon标准.结论 心电图Comell电压标准诊断中国老年男性左室肥厚的界值可采用2.9 mV,其诊断老年男性左室肥厚的敏感性、准确性高于Sokolow-Lyon标准.     

Genome-wide linkage analysis of electrocardiographic and echocardiographic left ventricular hypertrophy in families with hypertension.

AIMS: To localize chromosomal regions (or quantitative trait loci) that harbour genetic variants influencing the variability of electrocardiographic (ECG) and echocardiographic left ventricular hypertrophy (LVH). METHODS AND RESULTS: We evaluated genetic linkage to ECG Sokolow-Lyon voltage, ECG Cornell voltage product, ECG left ventricular (LV) mass, and to echocardiographic septal wall thickness, LV cavity size, and LV mass in 868 members of 224 white British families. A genome-wide scan was performed with microsatellite markers that covered the genome at 10-cM intervals and linkage was assessed by variance components analysis. We identified chromosomal regions suggestive of linkage for Sokolow-Lyon voltage on chromosome 10q23.1 [log(10) of the odds (LOD = 2.21, P = 0.0007)], for ECG Cornell voltage product on chromosome 17p13.3 (LOD = 2.67; P = 0.0002), and for ECG LV mass on chromosome 12q14.1 (LOD = 2.19; P = 0.0007). There was a single region of possible linkage for echocardiographic LV mass on chromosome 5p14.1 (LOD = 1.6; P = 0.003). CONCLUSION: Stronger genetic signals for LVH were found using electrocardiographic than echocardiographic measurements, and the genetic determinants of each of these appear to be distinct. Chromosomes 10, 12, and 17 are likely to harbour genetic loci that exert a major influence on electrocardiographic LVH.     

Electrocardiographic left ventricular hypertrophy has low diagnostic accuracy in middle-aged subjects

Objective. To evaluate the usefulness of electrocardiographic left ventricular hypertrophy (ECG LVH) as a marker of LVH in middle-aged subjects. Methods. LVH was determined by cardiovascular magnetic resonance imaging (MRI) in 188 apparently healthy middle-aged [97 men (45±7 years) and 91 women (47±6 years)]. Receiver operating characteristic (ROC) curves, test sensitivity, specificity, positive and negative predictive values for identifying LVH at different ECG criteria were calculated. Results. Systolic and diastolic blood pressures were 142±13 mmHg and 90±8 mmHg in men and 139±10 mmHg and 90±8 mmHg in women, respectively. LVMI was 78±17 g/m² in men and 67±12 g/m² in women, and 14% of men and 22% of women had LVH in cardiac MRI. Only Sokolow-Lyon and Sokolow-Lyon product had the area under the ROC curve over 0.70. Sokolow-Lyon product had the highest sensitivity (47%). All ECG criteria had high negative predictive values, but the positive predictive values were below 46%. Conclusions. Commonly used ECG criteria of LVH have low discrimination ability in middle-aged subjects. ECG LVH alone should not be used as a marker of target organ damage in middle-aged, never treated and apparently healthy hypertensives.     

Baseline characteristics in relation to electrocardiographic left ventricular hypertrophy in hypertensive patients: the Losartan intervention for endpoint reduction (LIFE) in hypertension study. The Life Study Investigators

The Losartan Intervention For Endpoint (LIFE) reduction in hypertension study is a double-blind, prospective, parallel group study designed to compare the effects of losartan with those of atenolol on the reduction of cardiovascular morbidity and mortality. A total of 9194 patients with hypertension and ECG left ventricular hypertrophy (LVH) by Cornell voltage-duration product and/or Sokolow-Lyon voltage criteria were enrolled in the study, with baseline clinical and ECG data available in 8785 patients (54% women; mean age, 67+/-7 years). ECG LVH by Cornell voltage-duration product criteria was present in 5791 patients (65.9%) and by Sokolow-Lyon voltage in 2025 patients (23.1%). Compared with patients without ECG LVH by Cornell voltage-duration product criteria, patients with ECG LVH by this method were older; more obese; more likely to be female, white, and to have never smoked; more likely to be diabetic and have angina; and had slightly higher systolic, diastolic, and pulse blood pressures. In contrast, patients with ECG LVH by Sokolow-Lyon criteria were slightly younger; less obese; more likely to be male, black, and current smokers; less likely to have diabetes; more likely to have angina and a history of cerebrovascular disease; and had higher systolic and pulse blood pressure but slightly lower diastolic blood pressure than patients without ECG LVH by this method. By use of multivariate logistic regression analyses, presence of ECG LVH by Cornell voltage-duration product criteria was predominantly associated with higher body mass index, increased age, and female gender, whereas presence of ECG LVH by Sokolow-Lyon voltage criteria was predominantly related to lower body mass index, male gender, and black race. Thus, hypertensive patients who meet Cornell product and Sokolow-Lyon voltage criteria are associated with different, but potentially equally adverse, risk factor profiles.     

New gender-specific partition values for ECG criteria of left ventricular hypertrophy: recalibration against cardiac MRI

ECG criteria for left ventricular hypertrophy (LVH) were mostly validated using left ventricular mass (LVM) as measured by M-mode echocardiography. LVM as measured by cardiac MRI has been demonstrated to be much more accurate and reproducible. We reevaluated the sensitivity and specificity of 4 ECG criteria of LVH against LVM as measured by cardiac MRI. Patients with systemic hypertension (n=288) and 60 normal volunteers had their LVM measured using a 1.5-Tesla MRI system. A 12-lead ECG was recorded, and 4 ECG criteria were evaluated: Sokolow-Lyon voltage, Cornell voltage, Cornell product, and Sokolow-Lyon product. Based on a cardiac MRI normal range, 39.9% of the hypertensive males and 36.7% of the hypertensive females had elevated LVM index. At a specificity of 95%, the Sokolow-Lyon product criterion had the highest sensitivity in females (26.2%), the Cornell criterion had the highest sensitivity in males (26.2%), and the Cornell product criteria had a relatively high sensitivity in both males and females (25.0% and 23.8%). Receiver operating characteristic curves showed the Cornell and Cornell product criteria to be superior for males whereas the Sokolow-Lyon product criterion was superior for females. Comparing the mean LVM index values of the subjects who were ECG LVH positive to the normal volunteers indicated that the ECG LVH criteria detect individuals with an LVM index substantially above the normal range. We have redefined the partition values for 4 different ECG LVH criteria, according to gender, and found that they detect subjects with markedly elevated LVM index.     

Correlation of electrocardiographic left ventricular hypertrophy criteria with left ventricular mass by echocardiogram in obese hypertensive patients

Introduction

Left ventricular hypertrophy (LVH) and obesity are important cardiovascular risk factors. This study evaluates the influence of obesity on the diagnostic performance of the most used electrocardiographic criteria for LVH in hypertensive patients.

Methods

One thousand two hundred four outpatients from the Hypertensive Unit of the Hospital São Paulo, São Paulo, SP, Brazil, were studied. All underwent 12-lead electrocardiogram and echocardiogram. The most known electrocardiographic criteria for LVH were assessed and compared with the left ventricular mass index obtained by echocardiogram in obese and nonobese groups of hypertensive patients.

Results

The population's mean age was 57.4 ± 4.7 years; 351 were men (29.1%) and 853 women (70.8%). Cornell voltage, Cornell duration, Sokolow-Lyon voltage, Romhilt-Estes criteria, and R wave in aVL 11 mm or higher showed a positive correlation with left ventricular mass index (P < .05). Notwithstanding, there were no changes regarding specificity for obese or nonobese characteristics. However, sensitivity had a statistically significant decrease in obese patients in regard to Sokolow-Lyon voltage and Romhilt-Estes criteria and strain pattern (P < .05).

Conclusion

Cornell voltage and Cornell duration criteria, Perugia score, R wave in aVL, and QTc variable had no significant changes in diagnostic sensitivity in the obese patients.     

Validity of electrocardiographic classification of left ventricular hypertrophy across adult ethnic groups with echocardiography as a standard

Aims

To assess the validity of the electrocardiogram (ECG) as a diagnostic tool for left ventricular hypertrophy (LVH) for different ethnic groups with echocardiography as a standard.

Methods

Systematic review of the literature using the Cornell and Sokolow-Lyon voltage criteria for LVH.

Results

Five studies were identified. Pooled data from these studies demonstrated low sensitivity using both types of ECG criteria for white and African-origin groups, but with slightly higher sensitivity values for the African-origin group (Cornell, 31.2%; 95% confidence interval [CI], 28%-34.8%; Sokolow-Lyon, 32.9%; 95% CI, 29.5%-36.4%) compared with the white group (Cornell, 26.5%; 95% CI, 25.2%-27.8%; Sokolow-Lyon, 18.2%; 95% CI, 17.2%-19.3%). Specificity was high using both types of criteria in the white group (Cornell, 87.4%; 95% CI, 86.4%-88.4%; Sokolow-Lyon, 88.9%; 95% CI, 88%-90%) but was much lower in the African-origin group using the Sokolow-Lyon criteria (72.1%; 95% CI, 68.7%-75.3%). Specificity was high however for the African-origin group using the Cornell criteria (86.2%, 95% CI, 83.4%-88.5%).

Conclusions

Both types of criteria are more sensitive in African-origin populations. The Sokolow-Lyon criteria are less specific for LVH in people of African origin. The evidence favors the Cornell criteria in research and service contexts involving African-origin and white populations. Further research is needed to adapt ECG criteria to take into account ethnicity to a greater degree. The issue needs to be studied in a broader range of ethnic groups.     

QT intervals and QT dispersion as measures of left ventricular hypertrophy in an unselected hypertensive population

Electrocardiographic (ECG) QT intervals and dispersion correlate with echocardiographic left ventricular mass index (LVMI) in groups of selected essential hypertensives. We tested the strength of this relationship in a large group of unselected hypertensives to assess whether QT measurements may be a simple screening test for LVH in clinical practice. In a cross-sectional study of 386 unselected hypertensive subjects, maximal QT intervals (QT_max), QT dispersion (QT_disp), and ECG voltages (Sokolow-Lyon and Cornell sex-specific voltages) were measured from 12-lead ECG. The LVMI correlated most strongly with Cornell voltage (linear regression r = 0.44, P < .001). The strongest relationship between LVMI and QT parameters was with QT_max, (r = 0.25, P < .001). This relationship weakened using heart rate-corrected QT_max. Correlations between LVMI and QT_disp were weak, whether or not they were corrected for heart rate. Sokolow-Lyon voltages, Cornell voltage and QT_max, but not QT_disp, were independently predictive of LVMI after adjustment for age, sex, race, and the other ECG parameters. Receiver operating characteristic (ROC) curve analyses demonstrated that no QT parameter performed better than simple ECG voltage criteria in the detection of LVH. In conclusion, QT_max, the QT parameter most strongly associated with LVMI, was independently associated with LVMI after adjustment for standard ECG voltage criteria. However, as an isolated measure it was no better than simple ECG voltage criteria as a screening test for LVH in clinical practice.     

Magnetocardiographic indices of left ventricular hypertrophy

OBJECTIVE: We tested the hypothesis that multichannel magnetocardiographic (MCG) mapping can detect and quantify the degree of left ventricular hypertrophy (LVH). DESIGN: A cross-sectional study. SETTING: Helsinki University Central Hospital, a tertiary referral center. PARTICIPANTS: Forty-two patients with pressure overload induced LVH by gender-specific echocardiographic criteria (LVH group), and 12 healthy middle-aged controls. MAIN OUTCOME MEASURES: MCG QRS-T area integrals and QRS-T angle in magnetic field maps in relation to echocardiographic LVH as well as left ventricular (LV) mass and structure. Conventional 12-lead electrocardiographic (ECG) LVH indices (Sokolow-Lyon voltage, Cornell voltage, Cornell voltage duration product) were assessed for comparison. RESULTS: MCG QRS- and T-wave integrals provided complementary information of echocardiographic LV mass. Their combination, the QRS-T integral, and the QRS-T angle were increased in patients with LVH and, in those patients, correlated significantly with LV mass indexed to body surface area (r = 0.455;P = 0.002 and r= 0.379; P= 0.013, respectively). A QRS-T integral 16000 fT.s had identical sensitivity of 62% at 92% specificity as the gender-adjusted Cornell voltage duration product of 240 micro V.s for the detection of LVH. CONCLUSIONS: The MCG method can detect patients with LVH and also quantify the degree of LVH in patients with increased LV mass.     

V_1、V_2、V_3的S波及Ⅰ、Ⅱ、aVL的R波之和在诊断左室肥大中的价值

目的探讨诊断左室肥大(LVH)新的心电图指标。方法以超声心动图测定的左室重量(LVM)及重量指数(LVMI)为对照,其诊断LVH的标准为>125g/m2(男),120g/m2(女),对100例正常健康人及111例患者进行了观察,对12导联QRS总振幅(∑QRS)、V1～V3导联的S波之和(∑SV1～V3)、Ⅰ、Ⅱ、aVL导联的R波之和(∑RⅠ、Ⅱ、aVL)及后两者之和(Z表示),分别进行了测定。寻找新指标的正常值范围以及以此标准为依据,诊断LVH的灵敏度、特异度、准确率。结果正常组中,∑QRS、∑SV1～V3、∑RⅠ、Ⅱ、aVL及Z值正常范围分别为77～175,11～38,5～23及22～54mm,以大于这些指标的正常值上限为标准,其诊断LVH灵敏度、特异度及准确率较传统指标明显提高,其中Z值>54mm灵敏度最高(86.54%),准确率最高(90.09%),而特异度仍保持在93.22%。结论LVH新的心电图指标具有一定诊断价值,其中Z>54mm最好。     

Left ventricular hypertrophy in relation to systolic blood pressure and the angiotensin converting enzyme I/D polymorphism in Chinese

Objective There is little population-based data on the prevalence and the environmental or genetic determinants of left ventricular hypertrophy （LVH） in China. The purpose of this paper is to study LVH in relation to systolic blood pressure and the angiotensin converting enzyme （ACE） insertion/deletion（I/D） polymorphism in Chinese. Methods We recorded 12- lead ECG （CardioSoft, v4.2） in 1365 residents in the Jingning County, Zhejiang Province, China. LVH was defined according to the gender-specific Sokolow-Lyon and Cornell product ECG criteria. Results Regardless of whether the Sokolow-Lyon or Cornell product ECG criteria was used, the prevalence of LVH （20.7% and 4.8%, respectively） significantly （P〈0.0001） increased with male gender （odds ratio [OR] 2.33 and 7.15） and systolic blood pressure （per 10 mm Hg increase, OR 1.46 and 1.33）. If the Sokolow-Lyon criteria was used, the prevalence of LVH was also influenced by alcohol intake （OR 1.44, P=-0.03） and body mass index （OR 0.83, P=0.0005）. The association between the Sokolow-Lyon voltage amplitude and the ACE I/D polymorphism was dependent on antihypertensive therapy （P=0.01）. In 1262 untreated subjects, but not 103 patients on antihypertensive medication, the ACE DD compared with II subjects had significantly higher Sokolow-Lyon voltage amplitudes （29.8：-0.6 vs. 28.0-3：0.5 mV, P=-0.02） and higher risk of LVH （OR 1.74, 95% CI： 1.12-2.69, P=-0.01）. Conclusion LVH is prevalent in Chinese, and is associated with systolic blood pressure and the ACE D allele. The genetic association might be modulated by antihypertensive therapy（J Geriatr Cardio12009; 6：131-136）.     

S_(aVR)与R_(aVL)+S_(V_3)标准诊断左室肥大的价值

目的探讨SaVR与RaVL+SV3电压标准诊断左室肥大(LVH)的价值。方法以超声心动图结果为诊断标准,测量有LVH者100例(A组)及无LVH者100例(B组)的心电图(ECG)SaVR和RaVL+SV3电压。计算B组SaVR和RaVL+SV3电压的均数及标准差,获取诊断LVH的ECG新标准,并与传统标准比较,检验不同标准对诊断LVH的敏感度、特异度及准确度。结果①SaVR诊断LVH的灵敏度低(36%),特异度高(100%),准确度为68%;传统标准及RaVL+SV3诊断LVH的灵敏度提高(52%及58%),但特异度明显下降(70%及84%),准确度60%及71%。②两者联用诊断LVH的灵敏度及准确度提高,特异度无明显降低,分别为68%、76%、84%;③两者联用对诊断LVH伴电轴左偏者的灵敏度显著提高,为77.9%,准确度与特异度相近,分别为78.8%、82.3%;④两者联用在成人各年龄组中及不同体型中诊断LVH的价值无差异。结论SaVR及RaVL+SV3标准诊断LVH具有临床实用价值,两者联用则更为理想,可弥补单用的不足。