T-wave Axis Research Articles

T-wave axis deviation, metabolic syndrome and estimated cardiovascular risk – In men and women of the MOLI-SANI study

AimWe aimed at investigating the association between T-wave axis deviation, metabolic syndrome (MetS), its components and estimated risk of cardiovascular disease (CVD) at 10 years in an adult Italian population. Methods11,143 women (54 ± 11 years) and 9742 men (55 ± 11 years) were analyzed from the Moli-sani cohort, randomly recruited from the general population. MetS was defined using the ATPIII criteria. T-wave axis deviation was measured from the standard 12-lead resting electrocardiogram. CVD risk in ten years was estimated by the CUORE score. Results29% of men and 27% of women with MetS showed borderline or abnormal T-wave as compared to 24% and 17% without MetS (p < 0.0001 for both genders).Among components of MetS, elevated waist and blood pressure were strongly associated with T-wave axis deviation, whereas glucose, HDL and triglycerides were only marginally. The odds of having borderline or abnormal T-wave axis deviation in multivariable regression analysis, was 1.38 (95% CI:1.25–1.53) in MetS men and 1.68 (95% CI:1.51–1.87) in MetS women compared to those without. Further adjustment for MetS components completely abolished the associations. Abnormal T-wave axis deviation was associated with an increased risk of CVD in 10 years in men (OR = 4.4; 95% CI:1.10–17.9). ConclusionT-wave axis deviation is strongly associated with components of the MetS, in particular high waist circumference and blood pressure and with an increased CVD risk, particularly in men. ECG monitoring to identify T-wave axis deviation in obese, hypertensive or MetS subjects can be an early indicator of vascular disease and help in reducing cardiac events.

T-wave axis deviation, metabolic syndrome and cardiovascular risk: results from the MOLI-SANI study

Early recognition of patients at increased cardiovascular risk is a major challenge. The surface electrocardiogram provides a useful platform and it has been used to propose several indexes. T wave axis abnormality is associated with an increased risk of cardiovascular mortality, independently of other risk factors and can be associated with the presence of the metabolic syndrome (MetS). We assessed the prevalence of T axis abnormalities and its relationship with MetS and its components in a large population of Italian adults. Data concerning 11,143 women (54±11years) and 9742 men (55±11years) randomly recruited from a general population (Moli-sani cohort) were analyzed. After excluding subjects with incomplete data and with history of cardiac disease or left ventricular hypertrophy, T-wave axis was normal in 74.5% of men and 80.9% of women, borderline in 23.6% and 17.3% and abnormal in 1.9% and 1.8%. In subjects with MetS, the prevalence of borderline or abnormal T-wave axis deviation was higher than in subjects without MetS (in men: 26.6% vs. 22.1% and 2.5% vs. 1.7%; in women: 25% vs. 15% and 2.4% vs. 1.6%, respectively for borderline and abnormal levels, p<0.0001). Each component of MetS increased the odds of having borderline or abnormal T-wave axis deviation by 1.21 in men and 1.31 in women. T wave axis deviation is associated with MetS and its individual components. These findings confirm previous reported results, expanding them to a large and representative sample of European population of Caucasian ethnicity.

C-reactive protein level is linked to T-wave axis deviation in a healthy Italian population: results from the MOLI-SANI project

Corresponding 12-lead ECGs were simulated for the 20 combinations (Table). The ECGs were classified into strict LBBB (terminal negative deflection in V1, QRS duration ≥140ms with mid-QRS notching), LVH (Sokolow–Lyon or Cornell criteria) or no confounders (non-LVH, non-strict LBBB). ECGs meeting conventional LBBB criteria (terminal negative deflection in V1, QRS duration ≥120ms and notched R wave in leads I, aVL, V5, V6) were also noted. Results: Complete LBBB was diagnosed correctly by strict and conventional LBBB criteria in all cases (normal anatomy, LV dilation and LVH). However, conventional ECG LBBB criteria falsely diagnosed LBBB in all cases with combined LVH+LV dilation and the case with 10-mm LV dilation combined with 18-ms LV activation delay.

The association between urinary cadmium and frontal T wave axis deviation in the US adults

The association between environmental cadmium exposure and frontal T wave axis deviation, a valuable and easily detected subclinical marker of ventricular arrhythmias in individuals without heart disease is unexplored and unknown. The objective of the study was to test the hypothesis that cadmium exposure predicts frontal T-wave axis deviation. US adults 40 years of age or older from NHANES III were included in the analysis. The participants' creatinine-corrected urinary cadmium concentrations expressed as micrograms per gram were determined. Frontal T-wave axis deviations were measured from the standard 12-lead electrocardiogram. Multivariable regression analyses adjusting for age, race, smoking, metabolic syndrome, left ventricular mass, QRS duration and heart rate were performed. The odds ratio of borderline and abnormal frontal T wave axis deviations due to cadmium exposure and their corresponding 95% confidence intervals (CIs) were 1.25 (1.10-1.54) and 1.64 (1.27-2.12), respectively. This study documents a positive graded relationship between environmental cadmium exposure and the risk for frontal T-wave axis deviation. Screening individuals with large body burden of cadmium to identify frontal T-wave axis deviation is warranted.

QRS-T angle as a predictor of sudden cardiac death in a middle-aged general population

Spatial QRS-T angle measured from a 12-lead electrocardiogram (ECG) has been shown to predict cardiac mortality. However, there is a paucity of studies on the prognostic significance of frontal QRS-T angle, which is more readily available from the standard 12-lead ECG. The purpose of the present study was to investigate the importance of wide frontal QRS-T angle, QRS-axis, and T-wave axis as cardiac risk predictors in general population. We evaluated the 12-lead ECGs of 10 957 Finnish middle-aged subjects from the general population recorded between 1966 and 1972, and followed them for 30 ± 11 years. QRS-T angle 0 to 90°, QRS-axis -30 to 90°, and T-wave axis 0 to 90° were considered normal. The primary endpoint was death from arrhythmia, and the secondary endpoints were all-cause mortality and non-arrhythmic cardiac mortality. QRS-T angle ≥ 100° was present in 2.0% of the subjects, and it was associated with an increased risk of sudden arrhythmic death [relative risk (RR) 2.26; 95% confidence interval (CI) 1.59-3.21; P< 0.001) and all-cause mortality (RR 1.57; CI 1.34-1.84; P< 0.001), but not with non-arrhythmic cardiac mortality (RR 1.34; CI 0.93-1.92; P= 0.13). The prognostic significance of wide QRS-T angle was mainly due to abnormal T-wave axis, which predicted death from arrhythmia (RR 2.13; CI 1.63-2.79; P< 0.001), all-cause mortality (RR 1.39; 1.24-1.55; P< 0.001), and non-arrhythmic cardiac death (RR 1.87; CI 1.50-2.34; P< 0.001). Frontal QRS-T angle ≥ 100° increases the risk of arrhythmic death, this being mainly the result of an altered T-wave axis.

Electrocardiographic consequences of cardiac iron overload in thalassemia major

Iron cardiomyopathy is a leading cause of death in transfusion-dependent thalassemia major (TM) patients and MRI (T2*) can recognize preclinical cardiac iron overload, but, is unavailable to many centers. We evaluated the ability of 12-lead electrocardiography to predict cardiac iron loading in TM. 12-lead electrocardiogram and cardiac T2* measurements were performed prospectively, with a detectable cardiac iron cutoff of T2*less than 20 ms. Patients with and without cardiac iron were compared using two-sample statistics and against population norms using age and gender-matched Z-scores. 45/78 patients had detectable cardiac iron. Patients having cardiac iron were older and more likely female but had comparable liver iron burdens and serum ferritin. Increased heart rate (HR) and prolonged corrected QT interval (QT(c)) were present, regardless of cardiac iron status. Repolarization abnormalities were the strongest predictors of cardiac iron, including QT/QT(c) prolongation, left shift of T-wave axis, and interpretation of ST/T-wave morphology. Recursive partitioning of the data for females using T-axis and HR and for males using QT, HR, and T-axis produced algorithms with AUROC's of 88.3 and 87.1, respectively. Bradycardia and repolarization abnormalities on 12-lead electrocardiography were the most specific markers for cardiac iron in thalassemia major. Changes in these variables may be helpful to stratify cardiac risk when cardiac MRI is unavailable. However, diagnostic algorithms need to be vetted on larger and more diverse patient populations and longitudinal studies are necessary to determine reversibility of the observed abnormalities.

Electrocardiographic indices in a rural pregnant Nigerian women population.

Background: The aim of the present study was to assess the resting electrocardiograms (ECG) in apparently healthy pregnant women in a Northern Nigerian rural settlement, and to compare with a control group comprising of non – pregnant women in their reproductive ages.Methods: Electrocardiogram (ECG) recordings at rest of 238 women in their reproductive ages, comprising of 123 pregnant subjects and 115 non- pregnant controls were obtained. The study was cross-sectional in design and carried out at Kura Comprehensive Health Center, Kura Local Government in Kano State, Nigeria.Results: Significant differences in some of the electrocardiogram (ECG) variables and baseline characteristics were observed when the pregnant subjects were compared with the controls: lower systolic blood pressure (115.20± 8.13 Vs 120.43±9.02 mmHg), diastolic blood pressure (73.65±9.24 vs 80.44±4.85mmHg), QRS duration (71.87±13.99 vs 78.61±13.71ms), and P-wave, mean QRS T-wave axes (p

Characterization of the electrocardiographic pattern of individuals with cerebral palsy

Background Dentists of Lar São Francisco observed during dental treatment that children with cerebral palsy (CP) had increased heart rate (HR) and lower production of saliva. Despite the high prevalence of CP found in the literature (2.08-3.6/1000 individuals), little is known about the electrocardiographic (ECG) characteristics, especially HR, of individuals with CP. Objective This study aimed to investigate the hypothesis that individuals with CP have a higher HR and to define other ECG characteristics of this population. Methods Ninety children with CP underwent clinical examination and 12-lead rest ECG. Electrocardiographic data on rhythm, HR, PR interval, QRS duration, P/QRS/T axis, and QT, QTc and T peak-end intervals (minimum, mean, maximum, and dispersion) were measured and analyzed then compared with data from a control group with 35 normal children. Fisher and Mann-Whitney U tests were used, respectively, to compare categorical and continuous data. Results Groups cerebral palsy and control did not significantly differ in age (9 ± 3 × 9 ± 4 years) and male gender (65% × 49%). Children with CP had a higher HR (104.0 ± 20.6 × 84.2 ± 13.3 beats per minute; P < .0001), shorter PR interval (128.8 ± 15.0 × 138.1 ± 15.1 milliseconds; P = .0018), shorter QRS duration (77.4 ± 8.6 × 82.0 ± 8.7 milliseconds; P = .0180), QRS axis (46.0° ± 26.3° × 59.7° ± 24.8°; P = .0024) and T-wave axis (34.3° ± 28.9° × 42.9° ± 17.1°; P = .034) more horizontally positioned, and greater mean QTc (418.1 ± 18.4 × 408.5 ± 19.4 milliseconds; P = .0110). All the electrocardiogram variables were within the reference range for the age group including those with significant differences. Conclusion Children with CP showed increased HR and other abnormal ECG findings in the setting of this investigation. Further studies are needed to explain our findings and to correlate the increased HR with situations such as dehydration, stress, and autonomic nervous disorders.

Cystatin C estimated renal dysfunction predicts T wave axis deviation in US adults: results from NHANES III

Patients with impaired kidney function are at increased risk of ventricular arrhythmia and sudden death. The association between chronic kidney disease and frontal T wave axis deviation, a cardiovascular risk factor, in individuals without heart disease is unexplored and unknown. To test the hypothesis that chronic kidney disease predicts frontal T-wave axis deviation, American participants 40years of age or older from NHANES III, were categorized as having and not having chronic kidney disease based on glomerular filtration rates estimated by both serum cystatin C and serum creatinine and serum creatinine alone. Frontal T-wave axis deviation was measured from the standard 12-lead electrocardiogram. Multivariable adjustments for age, ace, smoking, metabolic syndrome, albuminuria, left ventricular mass, QRS duration and heart rate were performed. In multivariable weighted regression analysis, the odds ratio for abnormal frontal T wave axis deviations and their corresponding 95% CIs in patients with decreased glomerular filtration rate determined by an equation included cystatin and creatinine was 1.90 (1.20-3.32). The odds ratio of frontal T wave axis deviation due to decreased kidney function, determined using an equation included serum creatinine alone, was 1.65 (1.10-2.90). This study suggests that abnormal frontal T wave axis deviation abnormalities occur in subjects with chronic kidney disease. Those with decline in renal function should be considered at risk for potentially serious T-wave associated arrhythmias and thus carefully monitored.

Abnormal T-wave axis is associated with coronary artery calcification in older adults

Objective. To determine whether T-wave axis on the resting electrocardiogram (ECG) is associated with coronary artery calcification (CAC) score, a measurement of coronary atherosclerosis, in older adults. Methods. The sample consisted of 2004 adults aged 66 and over participating in the prospective, population-based Age-Gene/Environment Susceptibility-Reykjavik Study. The cohort was divided into gender-stratified quartiles based upon Agatston CAC score derived from computerized tomography. Frontal T-axis deviation from 45° was assessed using surface ECG. Statistical analysis was performed with Tobit regression models adjusted for demographic and cardiovascular risk factors. Results. In the entire study population, T-axis deviation from 45° was significantly associated with increasing CAC score in men (p<0.001) and women (p=0.03). In men without clinically recognized coronary heart disease (CHD), the association with CAC score remained statistically significant (p=0.02). This association was significant among women without CHD once male CAC cut points were used (p=0.05). Conclusion. An abnormal T-wave axis is associated with an increasing CAC score in this population of Icelandic older adults. This association remains in the subgroup of subjects without clinical CHD.

The Association of the Metabolic Syndrome with T-wave Axis Deviation in NHANES III

We sought to study the association between metabolic syndrome (MetS) and abnormal T-wave axis deviation. A representative sample of the adult U.S. population, 3810 individuals 40 years of age or older, was categorized as having metabolic syndrome and not having the syndrome as defined by Adult Treatment Panel III. T-wave axis deviation was measured from the standard 12-lead electrocardiogram. The odds of having abnormal T-wave axis deviation was calculated for those with metabolic syndrome versus those without after multivariable adjustment for age, race, daily alcohol consumption, body mass index categories, left ventricular hypertrophy, and heart rate. In multivariable weighted regression analysis, the odds were 2.03 times greater in those persons with MetS compared to those without (odds ratio, 1.79; 95% confidence interval, 1.04-3.11). The population-attributable risk percentage of abnormal T-wave axis deviation associated with MetS was 23.94%. Additionally, a graded relationship was observed between the number of MetS components and the odds ratio of abnormal T-wave axis (p trend < 0.01). These data indicate that MetS is independently associated with an abnormal T-wave axis shift. This study calls for careful electrocardiographic monitoring among persons with MetS for early detection of abnormal T-wave axis in clinical practice to prevent severe and often fatal arrhythmias.

Recent Ventricular Repolarization Markers in Resistant Hypertension: Are They Different from the Traditional QT Interval?

Two electrocardiographic markers of ventricular repolarization abnormalities have been recently proposed: spatial T-wave axis deviation and T(peak)-T(end)-interval duration. The aim of this study was to evaluate these markers in patients with resistant hypertension, particularly their relationships with left ventricular mass (LVM) and geometric patterns, in comparison with the more traditional marker, the QTc interval. In a cross-sectional study, 810 resistant hypertensive patients were evaluated. Clinical, laboratory, electrocardiographic, 24-h blood pressures and echocardiographic variables were obtained. Maximum T(peak)-T(end)-interval duration (Tpe(max)) was considered prolonged if it was beyond the upper quartile value (120 ms), and the spatial T-wave axis on the frontal plane was considered abnormally deviated if >105 degrees or < 15 degrees . Statistical analysis involved bivariate tests, multivariate logistic regression and analysis of covariance. Tpe(max)-interval prolongation, like QTc-interval prolongation, was found to be associated with body mass index, 24-h systolic blood pressure (SBP), indexed LVM, serum potassium, and heart rate. Abnormal T-axis deviation was associated with male gender, presence of coronary heart disease, serum creatinine, 24-h SBP, LVM, and serum potassium. All three repolarization parameters were shown to be associated with increased LVM, after adjustment for possible confounders. However, when included together into the same model, only abnormal T-axis and QTc-interval prolongation remained independently associated with LVM. All three parameters were also increased in patients with concentric hypertrophy geometric pattern. Both the recently proposed repolarization parameters are associated with increased LVM and hypertrophy in patients with resistant hypertension, but only abnormal T-wave axis deviation appears to have distinct and additive relationships to the more classic marker, the QTc interval. Their prognostic values should be addressed in prospective studies .

Cardiac Memory Induced by QRS Widening due to Propafenone Toxicity

Propafenone toxicity can cause significant QRS widening and markedly abnormal ventricular activation pattern. Aberrant ventricular activation upon its resolution is known to produce persistent T-wave changes known as "cardiac memory" (CM). A 74-year-old woman presented with a severely abnormal electrocardiogram consistent with propafenone toxicity. As her QRS complex narrowed, T-wave inversions developed with the T-wave axis and resolution kinetics consistent with CM. Abnormal ventricular activation due to propafenone toxicity can result in CM development.

Comparison of the Prognostic Significance of the Electrocardiographic QRS/T Angles in Predicting Incident Coronary Heart Disease and Total Mortality (from the Atherosclerosis Risk In Communities Study)

Spatial QRS/T angle and spatial T-wave axis were shown to be strong independent predictors of incident coronary heart disease (CHD) and total mortality, but they are not routinely available. We evaluated whether frontal plane QRS/T angle, easily obtained as the difference between frontal plane axes of QRS and T, provides a suitable substitute for spatial QRS/T angle as a risk predictor. Our study consisted of 13,973 participants from the ARIC Study. Outcome variables were incident CHD and total mortality during a median follow-up of 14 years. Electrocardiographic variables were categorized as abnormal (>/=95th percentile), borderline (>/=75th and <95th percentile), and normal (<75th percentile) separately for men and women. Cox regression was used to assess the effect of electrocardiographic variables on risk of each outcome. The normal category was considered the reference cell. With adjustment for demographic and clinical characteristics, both QRS/T angles were approximately equally strong predictors of total mortality with >50% increased risk. Spatial QRS/T angle was a stronger predictor of incident CHD in women, with a 114% increased risk, but it was not significantly associated with risk of incident CHD in men. Similarly, frontal plane QRS/T angle was statistically significant for only women with a 74% increased risk of incident CHD. In conclusion, frontal plane QRS/T angle as an easily derived risk measure is a suitable clinical substitute for spatial QRS/T angle for risk prediction.

Short-term repeatability of electrocardiographic spatial T-wave axis and QT interval

Although ventricular repolarization abnormalities reflect arrhythmic susceptibility, few reliable tools exist to identify their presence. We investigated the repeatability of the spatial T-wave axis and QT interval from standard 12-lead electrocardiograms in 63 asymptomatic volunteers. Certified technicians used a standardized protocol to digitally record 2 electrocardiograms per participant at each of 2 visits separated by 1 to 2 weeks. Absolute paired differences within and between visits were 0.19° and 0.90° for the T-wave axis and 1.08 and 1.55 milliseconds for the QT interval, respectively. The intraclass correlation coefficients for the T-wave axis and QT interval were 0.87 and 0.86, respectively. The impact of repeated measurements on the precision of the QT-interval measurements was evaluated for a hypothetical clinical trial aimed at detecting a drug-induced QT prolongation. We conclude that the spatial T-wave axis is as repeatable a measure of ventricular repolarization as the QT interval.

T-Vector Direction Differentiates Postpacing From Ischemic T-Wave Inversion in Precordial Leads

Postpacing precordial T-wave inversion (TWI), known as cardiac memory (CM), mimics ischemic precordial TWI, and there are no established ECG criteria that adequately distinguish between the two. On the basis of CM properties (postpacing sinus rhythm T vector approaching the direction of the paced QRS vector), we hypothesized that CM induced by right ventricular pacing would manifest a TWI pattern different from that of precordial ischemic TWI, thereby discriminating between the two. T-wave axis, polarity, and amplitude on a 12-lead ECG during sinus rhythm were compared between CM and ischemic patients. The CM group incorporated 13 patients who were paced in DDD mode with short atrioventricular delay for 1 week after elective pacemaker implantation. The ischemic group consisted of 47 patients with precordial TWI identified among 228 consecutive patients undergoing percutaneous coronary intervention for an acute coronary syndrome. The combination of (1) positive T(aVL), (2) positive or isoelectric T(I), and (3) maximal precordial TWI>TWI(III) was 92% sensitive and 100% specific for CM, discriminating it from ischemic precordial TWI. CM induced by right ventricular pacing results in a distinctive T-vector pattern that allows discrimination from ischemic precordial T-wave inversions regardless of the coronary artery involved.

T-wave axis deviation as an independent predictor of mortality in chronic Chagas' disease

The T-wave axis shift has been reported to represent a general marker of ventricular repolarization abnormalities and a potential indicator of increased risk for cardiovascular mortality. We assessed the prognostic importance of the T-wave axis deviation for mortality rate in patients with chronic Chagas' disease. In a long-term follow-up prospective study, 738 adult outpatients in the chronic phase of Chagas' disease were enrolled. The frontal plane T-wave axis was estimated from 12-lead electrocardiograms obtained on admission and categorized as normal (15° to 75°), borderline (75° to 105° or 15° to −15°), and abnormal (>105° or < −15°). Clinical and radiologic data, 2-dimensional echocardiographic data, and other electrocardiographic data were also recorded. Primary end points were all-cause, those related to Chagas' disease, and sudden cardiac deaths. Statistical analyses included Kaplan-Meier estimation of survival curves and multivariate Cox's proportional hazards models. During a follow-up of 58 ± 39 months, 62 patients died, 54 from causes related to Chagas' disease and 40 due to sudden cardiac death. Kaplan-Meier survival curves showed that the 3 categories of T axis had significantly different prognoses. Multivariate Cox's survival analysis demonstrated that an abnormal T axis increases the risk of death threefold and sudden death nearly sixfold after adjustment for other covariates, including left ventricular systolic function and other electrocardiographic abnormalities. Borderline T-wave axis also indicated a worse prognosis, particularly in the subgroup of patients with abnormal baseline electrocardiograms. These results indicate that T-wave axis deviation is an easily quantified, strong, and independent mortality risk predictor in patients with chronic Chagas' disease.

Effect of Weight Loss on the ECG of Normotensive Morbidly Obese Patients

Morbid obesity produces a variety of ECG alterations, including leftward shifts of the P-wave, QRS, and T-wave axes; disproportionately high frequencies of low QRS voltage; left ventricular hypertrophy and left atrial abnormality; and a high frequency of T-wave flattening in the inferior and lateral leads. This study was designed to assess the effects of substantial weight loss on the ECG in morbid obesity. We performed a resting 12-lead ECG on 60 normotensive patients (48 women and 12 men; mean +/- SD age, 37 +/- 7 years), whose body weight was twice their ideal body weight prior to and at the time of maximum weight loss after bariatric surgery. Mean weight decreased from 136 +/- 7 to 85 +/- 3 kg. Weight loss produced significant decreases in the frequencies of low QRS voltage; Romhilt-Estes point score > or = 5 points; SV(1) + RV(5) or V(6) > 35 mm; RV(5) or V(6) > 26 mm; RaVL > 11 mm; RaVL > or = 7.5 mm; SaVR > 14 mm; P-terminal force more negative than - 0.04 mm.s in lead V(1); and T-wave flattening in the inferior, lateral, and inferolateral leads. Weight loss significantly shifted the mean P-wave, QRS, T-wave axes rightward, and significantly reduced mean RaVL and mean SaVR voltage. Substantial weight loss is capable of reversing many of the ECG alterations associated with morbid obesity.

QT interval is linked to 2 long-QT syndrome loci in normal subjects.

The rate-corrected QT interval (QTc) is heritable, and the discovery of quantitative trait loci that influence the QTc would be an important step in identifying the genes responsible for life-threatening arrhythmias in the general population. We studied 66 pairs of unselected normal dizygotic (DZ) twin subjects and their parents in a sib-pair analysis. We tested for linkage of gene loci harboring genes known to cause the long-QT syndrome (LQT) to the quantitative trait QTc. We found genetic variance on QRS duration, QRS axis, T-wave axis, and QTc. Women had a longer QTc than men. Microsatellite markers were tested in the vicinity of the gene loci for the 5 known LQT genes. We found significant linkage of QTc with the loci for LQT1 on chromosome 11 and LQT4 on chromosome 4 but not to LQT2, LQT3, or LQT5. We also found linkage of the QRS axis with LQT2 and LQT3. We suggest that these quantitative trait loci may represent the presence of variations in LQT genes that could be important to the risk for rhythm disturbances in the general population.

Accuracy of the EASI 12-lead electrocardiogram compared to the standard 12-lead electrocardiogram for diagnosing multiple cardiac abnormalities

This study was performed to compare a derived 12-lead electrocardiogram (ECG) using a simple 5-electrode lead configuration (EASI 12-lead) with the standard ECG for multiple cardiac diagnoses. Accurate diagnosis of arrhythmias and ischemia often require analysis of multiple (ideally, 12) ECG leads; however, continuous 12-lead monitoring is impractical in hospital settings. EASI and standard ECGs were compared in 540 patients, 426 of whom also had continuous 12-lead ST segment monitoring with both lead methods. Independent standards relative to a correct diagnosis were used whenever possible, for example, echocardiographic data for chamber enlargement-hypertrophy, and troponin levels for acute infarction. Percent agreement between the 2 methods were: cardiac rhythm, 100%; chamber enlargement-hypertrophy, 84%–99%; right and left bundle branch block, 95% and 97%, respectively; left anterior and posterior fascicular block, 97% and 99%, respectively; prior anterior and inferior infarction, 95% and 92%, respectively. There was very little variation between the 2 lead methods in cardiac interval measurements; however, there was more variation in P, QRS, and T-wave axes. Of the 426 patients with ST monitoring, 138 patients had a total of 238 ST events (26, acute infarction; 62, angioplasty-induced ischemia; 150, spontaneous transient ischemia). There was 100% agreement between the 2 methods for acute infarction, 95% agreement for angioplastyinduced ischemia, and 89% agreement for transient ischemia. EASI and standard 12-lead ECGs are comparable for multiple cardiac diagnoses; however, serial ECG changes (eg, T-wave changes) should be assessed using one consistent 12-lead method.