Natural History of Early Repolarization in the Inferior Leads

Aims: Though early repolarization (ER) in the inferior leads has been associated with increased cardiovascular risk, its natural history is uncertain. We aimed to study the serial electrocardiographic behavior of inferior ER and understand factors associated with that behavior. Methods: We selected electrocardiograms (ECGs) from patients with the greatest amplitude of ER in AVF from ECGs of 29,281 ambulatory patients recorded between 1987 and 1999 at the Palo Alto Veterans Affairs Hospital. Starting from the highest amplitude, we reviewed the ECGs and medical records from the first 85%. From this convenience sample, 36 were excluded for abnormal patterns similar to ER. The remaining 257 patients were searched for another ECG at least 5 months later, of whom, 136 satisfied this criteria. These ECGs were paired for comparison and coded by four interpreters. Results: The average time between the first and second ECGs was 10 years. Of the 136 subjects, 47% retained ER while 53% no longer fulfilled the amplitude criteria. While no significant differences were found in initial heart rate (HR) or time interval between ECGs, those who lost the ER pattern had a greater difference in HR between the ECGs. There was no significant difference in the incidence of cardiovascular events or deaths. Conclusions: In conclusion, the ECG pattern of ER was lost over 10 years in over half of the cohort. The loss of ER was partially explained by changes in HR, but not higher incidence of cardiovascular events or death, suggesting the entity is a benign finding.     

Natural history of the electrocardiographic pattern of early repolarization in ambulatory patients

Although it is known that the electrocardiographic pattern of early repolarization (ER) occurs most commonly in healthy young bradycardic men, its natural history is uncertain. We considered initial electrocardiograms (ECGs) at rest from 29,281 ambulatory patients recorded from 1987 through 1999 at Veterans Affairs Palo Alto Hospital. With PR interval as the isoelectric line and amplitude criterion as >0.1 mV ER was identified when any of the following fulfilled the amplitude criterion: ST-segment elevation at the end of the QRS duration, J waves as an upward deflection, and slurs as delay on the R wave downstroke. The first 250 ECGs with the greatest ER increase were selected and the database was searched for an ECG >5 months later. Of the 250 patients selected with the greatest amplitude of ER 6 were excluded for electrocardiographic abnormalities, leaving 244 subjects, of whom 122 had another ECG ≥5 months later. Their average age was 42 ± 10 years and average time from the first to second ECG was 10 years. Of the 122 patients 47 (38%) retained ER, whereas most (62%) no longer fulfilled the amplitude criterion. There were no significant differences in heart rate or time interval between ECGs. In conclusion, the electrocardiographic pattern of ER was lost over 10 years in more than half of this young clinical cohort and the loss was not caused by higher heart rate, longer time between ECGs, decrease in R-wave amplitude, death, acute disease, or alterations in electrocardiographic diagnostic characteristics.     

T‐Wave Abnormalities Are a Better Predictor of Cardiovascular Mortality than ST Depression on the Resting Electrocardiogram

Background: ST depression and T‐wave amplitude abnormalities are known to be independent predictors of cardiovascular (CV) death, but a direct comparison between them has not been described. Methods: Analyses were performed on the first electrocardiogram (ECG) digitally recorded on 46,950 consecutive patients at the Palo Alto Veterans Affairs Medical Center since 1987. Females and patients with electrocardiograms exhibiting bundle branch block, left ventricular hypertrophy, electronic pacing, diagnostic Q waves, or Wolff–Parkinson–White syndrome were excluded, leaving 31,074 male patients for analysis (mean age 55 ± 14). There were 1878 (6.0%) cardiovascular deaths (mean follow‐up of 6 ± 4 years). Electrocardiograms were classified using Minnesota code according to the degree of ST depression and T‐wave abnormality, and the nine possible combinations of ST segment and T‐wave abnormalities were recoded for analysis. Results: The combination of major abnormalities in ST segments and T‐waves carried the greatest hazard [3.2 (CI 2.7–3.8)]. Minor ST depression combined with more severe T‐wave abnormalities carried a hazard of 3.1 (CI 2.5–3.7), whereas minor T‐wave abnormalities combined with more severe ST depression carried a hazard of only 1.9 (CI 1.6–2.3). Conclusion: While both ST segment depression and abnormal T‐wave amplitude are clinically important, T‐wave abnormalities appear to be greater predictors of cardiovascular mortality.     

Secondary and primary repolarization changes in left ventricular hypertrophy: a model study

The contributions of reduced conduction velocity (CV) and prolonged action potential duration (APD) to QT interval prolongation and T wave and T vector loop morphology in left ventricular hypertrophy (LVH) were studied using an analytical computer model. Three types of anatomic LVH were simulated: concentric and eccentric hypertrophy, and left ventricular dilatation. In each LVH type, depolarization changes were simulated by CV slowing and primary repolarization changes by APD prolongation. Both CV slowing and APD prolongation prolonged the QT interval; however, the secondary and primary repolarization changes differed in additional electrocardiogram (ECG) characteristics creating specific vectorcardiographic/ECG patterns. The secondary repolarization changes were characterized by prolonged QT interval, accompanied by pronounced QRS changes, including increased maximum spatial QRS vector magnitude, prolonged QRS duration, QRS morphology consistent with intraventricular conduction delay, lower values of the T/QRS duration ratio, increased maximum spatial T vector magnitude, narrow and prolonged discordant T vector loops, and discordant tall T waves creating a pattern of ST strain in the precordial ECG leads. QT prolongation in primary repolarization changes was accompanied with inconsiderable changes of QRS amplitude and duration, higher values of the T/QRS duration ratio, widened rounded T loops, and notched or bifid T waves in left precordial leads of the 12-lead ECG. These simulation data are consistent with the accumulated evidence suggesting that LVH induces changes in CV and APD. Our results emphasize the need for simultaneous consideration of morphologic QRS and T wave patterns together with QT prolongation in clinical evaluation of LVH.     

Prognostic Significance of T‐Wave Amplitude in Lead aVR in Heart Failure Patients with Narrow QRS Complexes

Background: Prolonged duration of the QRS complex is a prognostic marker in patients with heart failure (HF), whereas electrocadiographic markers in HF with narrow QRS complex remain unclear. We evaluated the prognostic value of the T‐wave amplitude in lead aVR in HF patients with narrow QRS complexes. Methods: We examined 331 patients who were admitted to our hospital for worsening HF (68 ± 15 years, mean ± standard deviation) from January 2000 to October 2004 who had sinus rhythm and QRS complex <120 ms. The patients were categorized into three groups according to the peak T‐wave amplitude from baseline in lead aVR: negative (<–0.1 mV; n = 209, 63%), flat (–0.1–0.1 mV; n = 64, 19%), and positive (>0.1 mV; n = 58, 18%). Results: During a mean follow‐up of 33 months, 113 (34%) patients had all‐cause death, the primary end point. After adjusting for clinical covariates, flat T wave (hazard ratio [HR] 1.86, 95% confidence interval [CI] 1.42–2.46), and positive T wave (HR 6.76, 95% CI 3.92–11.8) were independent predictors of mortality, when negative T wave was considered a reference. Conclusions: As the peak T‐wave amplitude in lead aVR becomes less negative, there was a progressive increase in mortality. The T wave in lead aVR provides prognostic information for risk stratification in HF patients with narrow QRS complexes. Ann Noninvasive Electrocardiol 2011;16(3):250–257     

Prediction of cardiovascular death and myocardial infarction by the QRS-T angle and T vector loop morphology after angioplasty in stable angina pectoris: an 8-year follow-up

Reliable cardiovascular (CV) risk assessment by a noninvasive tool would be of great value for CV event prevention.The present study consists of 187 coronary artery disease patients with 8 years of follow-up. Eight vectorcardiographic parameters characterizing different aspects of ventricular repolarization were analyzed at baseline: (1) the ST-segment (ST-VM), (2) the T vector angles (QRS-T angle, Televation, and Tazimuth), (3) the T vector loop morphology (Tavplan and Teigenvalue), and (4) Tarea and Tpeak-end. Cardiovascular death, myocardial infarction (MI), and repeated revascularization were traced via national registries.There were 16 CV deaths and 19 MIs; 89 patients remained free from CV events and revascularization. Ventricular repolarization parameters independently predicted CV death (widened QRS-T angle) and new MI (increased Tavplan) during follow-up.CV mortality was associated with increased divergence between depolarization and repolarization waves (widened QRS-T angle). Increased Tavplan, presumably reflecting heterogeneous repolarization, predicted future MI, which is a novel finding.     

下壁导联心电图异常改变:Brugada综合征患者预后不良的信号?

目的寻找评估和预测Brugada综合征猝死风险的手段。方法使用维普全文数据库检阅文献,获取87例Brugada综合征原始文献,符合入选标准的Brugada综合征25例,根据患者有无死亡及其家族中有无猝死病史,分为猝死组(n=10)和非猝死组(n=15),比较两组肢体导联QRS波电压和形态变化。结果猝死组Ⅱ、aVF和aVR导联QRS波电压显著低于非猝死组。猝死组下壁导联1型(至少一个导联T波宽而平坦,升支僵直及ST段不可辩认)和/或2型(至少一个导联QRS波矮小,连同T波和P波形成老鹰飞翔样)变化显著高于非猝死组。结论Brugada综合征患者的体表肢导联,特别是下壁导联心电图可能包含着患者的预后信息。     

The long-term prognostic value of the ST depression criteria for ischemia recommended in the universal definition of myocardial infarction in 43,661 veterans

Background

The third Universal Definition of Myocardial Infarction (UDMI) includes electrocardiographic criteria for ischemia, specifying horizontal or down-sloping ST depression ≥ 0.05 mV in two contiguous electrocardiogram (ECG) leads. We used the surrogate of cardiovascular (CV) death to evaluate the criteria.

Methods

We collected computerized ST amplitude measurements, in different lead groupings, from the resting ECGs of 43,661 patients collected between 1987 and 1999 at the Palo Alto VA. There were 3929 (9.0%) cardiac deaths over a mean follow-up of 7.6 (SD 3.8) years.

Results

We found that horizontal or down-sloping ST depressions in contiguous leads, depending upon the lead groupings, had sensitivities ranging from 1% to 5%, specificities exceeding 99%, and relative risks for CV death ranging from 3.1 to 7.0 (p < 0.001 for each individual relative risk) while horizontal or down-sloping ST depressions in a single lead had comparable values. We found that up-sloping ST depressions had greater sensitivities than horizontal or down-sloping ST depressions. Additionally, we found that ST depressions isolated to the inferior or anterior leads, without concomitant lateral depressions, were poor predictors of CV death.

Conclusion

These findings reinforce and further characterize the value of ST depressions for predicting CV death. Furthermore, if these findings can be reproduced in the acute setting, they would undermine the requirement for contiguous lead depressions with slope assessment as well as prioritize ST depression in V4, V5, and V6 when assessing for myocardial ischemia.     

Prognostic value of ECG findings for total, cardiovascular disease, and coronary heart disease death in men and women

OBJECTIVE: To study abnormalities in the resting ECG as independent predictors for all cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in a population based random sample of men and women, and to explore whether their prognostic value is different between sexes. DESIGN AND SUBJECTS: An age and sex stratified random sample was selected from the total Belgian population aged 25 to 74 years. Baseline data were gathered and resting ECGs were classified according to Minnesota code criteria. The sample was then followed for at least 10 years with respect to cause specific death. Results are based on observations from 5208 men and 4746 women free from prevalent CHD at the start of the follow up period. RESULTS: Although the prevalence of major abnormalities in general was comparable between sexes, women had more ischaemic findings, ST segment changes, and abnormal T waves on their baseline ECG, while men showed more arrhythmias, bundle branch blocks, and left ventricular hypertrophy. Fitting the multiplicative effect on subsequent mortality between all ECG classifications under study and sex indicated that the prognostic value of ECG changes was equal in women and men. Independently of other risk factors and other major ECG changes, almost all ECG classifications were significantly related to all cause, CVD, and CHD mortality. The most predictive ECG findings for CVD death were ST segment depression (risk ratio (RR) 4.71), major ECG findings (RR 3.26), left ventricular hypertrophy (RR 2.79), bundle branch blocks (RR 2.58), T wave flattening (RR 2.47), ischaemic ECG findings (RR 2.35), and arrhythmias (RR 2.15). The prognostic value of major ECG findings for CVD and CHD death was more powerful than well established cardiovascular risk factors. CONCLUSIONS: Abnormalities in the baseline ECG are strongly associated with subsequent all cause, CVD, and CHD mortality. Their predictive value was similar for men and women.     

Repolarization abnormalities in survivors of out-of-hospital ventricular fibrillation.

Survivors of out-of-hospital ventricular fibrillation (VF) are at high risk for recurrent VF, probably reflecting continued myocardial electrical instability. In this study 12-lead ECGs of 125 VF survivors with coronary heart disease were examined and compared to those of 98 ambulatory post-MI patients. The study was part of an effort to define clinical identifiers of patients likely to develop sudden cardiac death. Ventricular fibrillation survivors were commonly had premature ventricular complexes (PVCs):30% versus 13% (P less than 0.01). In addition, ECGs of VF survivors showed a significantly greater prevalence of ST-segment depression (46% versus 10%), T wave flattening (52% versus 26%), and QTc prolongation (35% versus 18%). It is proposed that these repolarization abnormalities represent asynchronous repolarization, which together with frequent PVCs, may set the stage for re-entrant ventricular dysrhythmias and ultimately VF. It is also possible that repolarization abnormalities together with premature ventricular contractions might serve as markers of patients with coronary heart disease who are at increased risk for sudden cardiac death.     

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Objectives: Elevated beat‐to‐beat QT interval variability (QTV) has been associated with increased cardiovascular morbidity and mortality.The aim of this study was to investigate interlead differences in beat‐to‐beat QTV of 12‐lead ECG and its relationship with the T wave amplitude. Methods: Short‐term 12‐lead ECGs of 72 healthy subjects (17 f, 38 ± 14 years; 55 m, 39 ± 13 years) were studied. Beat‐to‐beat QT intervals were extracted separately for each lead using a template matching algorithm. We calculated the standard deviation of beat‐to‐beat QT intervals as a marker of QTV as well as interlead correlation coefficients. In addition, we measured the median T‐wave amplitude in each lead. Results: There was a significant difference in the standard deviation of beat‐to‐beat QT intervals between leads (minimum: lead V₃ (2.58 ± 1.36 ms), maximum: lead III (7.2 ± 6.4 ms), ANOVA: P < 0.0001). Single measure intraclass correlation coefficients of beat‐to‐beat QT intervals were 0.27 ± 0.18. Interlead correlation coefficients varied between 0.08 ± 0.33 for lead III and lead V₁ and 0.88 ± 0.09 for lead II and lead aVR. QTV was negatively correlated with the T‐wave amplitude (r =–0.62, P < 0.0001). There was no significant affect of mean heart rate, age or gender on QT variability (ANOVA: P > 0.05). Conclusions: QTV varies considerably between leads in magnitude as well as temporal patterns. QTV is increased when the T wave is small.     

Ventricular activation and recovery measured in electrocardiographic limb leads correlate with measurements from specific areas in body surface mapping.

AIMS: Dispersion of ventricular depolarization-repolarization in 12-lead electrocardiograms (ECGs) has been reported to provide noninvasive information on arrhythmogenicity. However, there are two methods to calculate the dispersion from ECGs including and excluding limb leads. The aim of this study was to examine whether temporal parameters from limb leads represent activation and repolarization of a particular part of the body surface. METHODS AND RESULTS: We compared the temporal parameters of activation time (AT), activation-recovery interval (ARI), and recovery time (RT) from limb leads of ECGs with those from an 87-lead body surface maps. The study population consisted of 50 normal subjects (25 men and 25 women, 19.4 +/- 1.6 years). The temporal parameters in leads I, II, and III were highly (r > 0.9) correlated with those in unipolar leads over the left lateral, left lower, and right lower chest, respectively. The temporal parameters in leads aVR, aVL, and aVF showed a significant correlation (r > 0.8) with those in unipolar leads over the right upper, left upper, and lower anterior chest, respectively. The mean AT, ARI, and RT from each limb lead of ECG were almost the same as those of unipolar leads over the corresponding areas of the body surface. CONCLUSIONS: These findings suggest that ATs, ARIs, and RTs from limb leads may represent those from unipolar leads of particular areas over the body surface in normal subjects. The temporal parameters from limb leads of ECGs may provide information on activation and repolarization as well as the precordial leads of ECGs.     

Choice of an alternative lead for QT interval measurement in serial ECGs when Lead II is not suitable for analysis

IntroductionConventionally, QT interval is measured in lead II. There are no data to select an alternative lead for QT measurement when it cannot be measured in Lead II for any reason.Methods and resultsWe retrospectively analyzed ECGs from 1906 healthy volunteers from 41 phase I studies. QT interval was measured on the median beat in all 12 leads. The mean difference in QT interval between lead aVR and in Lead II was the least, followed by aVF, V5, V6 and V4; lead aVL had maximum difference. The T wave was flat (<0.1 mV) in Lead II in 6.9% of ECGs; it was also flat in 20% of these ECGs (1.4% of all ECGs) in Leads aVR, aVF and V5.ConclusionsWhen QT interval cannot be measured in Lead II, the best alternative leads are aVR, aVF, V5, V6 and V4 in that sequence. It differs maximally from that in Lead II in Lead aVL.     

肥厚型心肌病体表心电图特征

目的 探讨肥厚型心肌病（HCM）患者体表心电图（ECG）特征。 方法 选取2015年5月~2017年4月期间住院治疗的HCM患者60例，同时选取本院同期查体的正常人60例，作为对照组，要求两组人员性别、年龄、体质量指数匹配。分析ECG各导联QRS波时限和R波、S波振幅，异常q波情况，QTC时限，R/S比值， ST段下移与抬高，T波低平、倒置，P波时限等指标。 结果 ①HCM组的V2、V3导联QRS波时限；Ⅱ、V4导联异常Q波比例；QTC时限；P波时限；左心室肥厚ECG诊断公式SV1+RV5/V6及（SV3+RaVL）×QRS波时限均显著高于正常对照组。②HCM组的I、aVR、aVL、aVF导联QRS波时限；aVR导联Q波所占比例； I、Ⅱ、Ⅲ、aVL、aVF、V3、V4、V5、V6导联QRS波主波与T波方向一致性； V4、V5、V6导联R/S比值均显著低于正常对照组。 结论 ECG诊断HCM首先要满足左心室肥厚的诊断标准，再结合上述ECG导联的特异性参数进行综合判断。     

Interobserver Reproducibility of QT Interval Measurement and QT Dispersion in Patients After Acute Myocardial Infarction

Background: The study evaluated interobserver differences in the classification of the T-U wave repolarization pattern, and their influence on the numerical values of manual measurements of QT interval duration and dispersion in standard predischarge 12-lead ECGs recorded in survivors after acute myocardial infarction. Methods: Thirty ECGs recorded at 25 mm/s were measured by six independent observers. The observers used an adopted scheme to classify the repolarization pattern into 1 of 7 categories, based on the appearance of the T wave, and/or the presence of the U wave, and the various extent of fusion between these. In each lead with measurable QRST(U) pattern, the RR, QJ, QT-end, QT-nadir (i.e., interval between Q onset and the nadir or transition between T and U wave) and QU interval were measured, when applicable. Based on these measurements, the mean RR interval, the maximum, minimum, and mean QJ interval, QT-end and/or QT-nadir interval, and QU interval, the difference between the maximum and minimum QT interval (QT dispersion [QTD]), and the coefficient of variation of QT intervals was derived for each recording. The agreement of an individual observer with other observers in the selection of a given repolarization pattern were investigated by an agreement index, and the general reproducibility of repolarization pattern classification was evaluated by the reproducibility index. The interobserver agreement of numerical measurements was assessed by relative errors. To assess the general interobserver reproducibility of a given numerical measurement, the coefficient of variance of the values provided by all observers was computed for each ECG. Statistical comparison of these coefficients was performed using a standard sign test. Results: The results demonstrated the existence of remarkable differences in the selection of classification patterns of repolarization among the observers. More importantly, these differences were mainly related to the presence of more complex patterns of repolarization and contributed to poor interobserver reproducibility of QTD parameters in all 12 leads and in the precordial leads (relative error of 31%–35% and 34%–43%, respectively) as compared with the interobserver reproducibility of both QT and QU interval duration measurements (relative error of 3%–6%, P < 0.01). This observation was not explained by differences in the numerical order between QT interval duration and QTD, as the reproducibility of the QJ interval (i.e., interval of the same numerical order as QTD was significantly better (relative error of 7.5%–13%, P < 0.01) than that of QTD. Conclusions: Poor interobserver reproducibility of QT dispersion related to the presence of complex repolarization patterns may explain, to some extent, a spectrum of QT dispersion values reported in different clinical studies and may limit the clinical utility in this parameter.     

Hypothermia-induced J waves

A 36 years old woman with acquired immunodeficiency syndrome was admitted to the hospital for pulmonary Mycobacterium Avis Complex infection. Seventy-two hours after the admission she became hypothermic and bradycardic. The ECG showed sinus bradycardia, J waves in leads II, III, aVF, aVR, aVL, V5 and V6 along with QT prolongation and T wave abnormalities. After rewarming the J waves and repolarization abnormalities disappeared. The proposed cellular basis of hypothermia-induced J waves is the accentuation of the spike-and-dome morphology of the action potential of M and epicardial cells.     

Upright T waves in lead aVR are associated with cardiac death or hospitalization for heart failure in patients with a prior myocardial infarction

The aim of the present study was to clarify the prognostic significance of upright T waves (amplitude > 0 mV) in lead aVR in patients with a prior myocardial infarction (MI). We retrospectively examined 167 patients with a prior MI. The primary end point was cardiac death or hospitalization for heart failure. During a follow-up period of 6.5 ± 2.8 years, 34 patients developed the primary end point. A Kaplan-Meier analysis showed a lower primary event-free rate in patients with upright T waves in lead aVR than in those with nonupright T waves in lead aVR (P = 0.001). Univariate Cox proportional hazards regression analyses showed that age, gender, chronic kidney disease, anterior wall MI, upright T waves in lead aVR, left ventricular ejection fraction, loop diuretic use, and spironolactone use were significantly associated with the primary end point. A multivariate Cox proportional hazards regression analysis selected age [hazard ratio (HR) 1.10, 95% confidence interval (CI) 1.05-1.16, P < 0.001], upright T waves in lead aVR (HR 3.10, 95% CI 1.23-7.82, P = 0.017), and loop diuretic use (HR 4.61, 95% CI 1.55-13.67, P = 0.006) as independent predictors of the primary end point. In conclusion, the presence of upright T waves in lead aVR is an independent predictor of cardiac death or hospitalization for heart failure in patients with a prior MI. The analysis of T-wave amplitude in lead aVR provides useful prognostic information in patients with a prior MI.     

Prognosis following acute myocardial infarction in patients with ST-T abnormalities on electrocardiograms obtained before myocardial infarction

BACKGROUND: Many studies have examined the relationship between prognosis after myocardial infarction (MI) and electrocardiographic (ECG) findings at the time of or after the onset of MI. However, little work has been done concerning the association between ECG findings obtained before the onset of MI (pre-MI) and the prognosis after MI. HYPOTHESIS: The study was undertaken to determine whether ST-T segment and T-wave morphology on pre-MI ECGs provides useful information for prognosis after acute MI. METHODS: Pre-MI ECGs of 212 patients recorded within the 6-month period before MI were studied for the presence of high-voltage R waves, ST-segment depression, and negative T waves. The Kaplan-Meier method and multivariate analysis were used to determine the relationship between these ECG findings and in-hospital cardiac death. RESULTS: In-hospital cardiac death occurred in 32 (15.1%) patients. The in-hospital mortality rate was 38.5% (5/13) for the patients with high-voltage R waves, 54.5% (6/11) for patients with ST-segment depression, and 45.6% (15/33) for patients with negative T waves. The in-hospital mortality rate was 13.6% (27/199) for patients without high-voltage R waves, 12.9% (26/201) for patients without ST-segment depression, and 9.5% (17/179) for those without negative T waves. Multivariate analysis identified age and negative T waves as independent risk factors for cardiac death, with a hazard ratio for negative T waves of 3.1. CONCLUSION: Negative T waves on pre-MI ECGs represent an independent predictor of in-hospital cardiac death in patients with MI.     

Relation of positive T wave in lead aVR to risk of cardiovascular mortality

We examined the prevalence and prognostic impact of a positive T wave in lead aVR (aVRT+) on a standard electrocardiogram in the general population. Data were collected from a large nationally representative (random sample) health examination survey conducted in Finland from 2000 through 2001. The survey consisted of 6,354 subjects (2,876 men and 3,478 women) ≥30 years who participated in the field health examination including standard electrocardiographic (ECG) recording at rest. The prevalence of aVRT+ (defined as positive or isoelectric T wave in lead aVR) was 2.2%. During the median follow-up of 98.5 months (interquartile range 96.6 to 99.6), there were 214 (3.5%) cardiovascular (CV) deaths. In Cox regression analysis after adjustment for age and gender, relative risks for CV and total mortalities associated with aVRT+ were 3.24 (95% confidence interval [CI] 2.32 to 4.54, p <0.001) and 1.91 (95% CI 1.47 to 2.49, p <0.001), respectively. In the fully adjusted model controlling for other risk factors, CV morbidity, and ECG findings, the relative risk for CV mortality for aVRT+ was 2.94 (95% CI 2.07 to 4.18, p <0.001). In conclusion, aVRT+, an easily recognized ECG finding, predicts risk for CV mortality in the general population. This finding could aid in screening for risk of total and CV mortalities.     

Spatial Properties of QT and the T‐Wave Morphology

Objective: To describe the relation between the QT interval and the T‐wave morphology. Material and methods: Frank orthogonal leads X, Y, Z of one subject and resting 12‐lead ECG of 40 subjects. QT was measured by the tangent method. The QT values are organized according to the anatomic orientation of the leads: I, ‐aVR, II, aVF, III, ‐aVL, ‐I, aVR, ‐II, ‐aVF, ‐III, aVL. and: V₁, V₂, V₃, V₄, V₅, V₆, ‐V₁ ‐V₂, ‐V₃, ‐V₄, ‐V₅, ‐V₆. The T‐wave amplitudes and QT were categorized according to QT into four groups with increasing mean QT. Results: Kruskal‐Wallis nonparametric test showed that the shortest and longest QT values are measured on the T wave with the smallest amplitudes (P < 0.001). Inspection of plots of QT and T waves reveals that the shortest and longest QT values are usually measured in leads with a small difference in orientation (neighbor leads). The mechanism behind these characteristics is mainly that the shortest and longest QT values are measured on T waves that are close to a lead orientation, whereas the T waves are flat or biphasic. We also observed an almost significant (P = 0.057) decrease in the T‐wave amplitude with increasing dispersion. Conclusion: The relation between T‐wave morphology and QT in the same cardiac plane is highly organized. The shortest and longest QT values are measured on the T wave with the smallest amplitudes (P < 0.001).