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

Clinical utility of aVR lead T-wave in electrocardiogram of patients with ST-elevation myocardial infarction

Background

aVR lead is often neglected in routine clinical practice largely because of its undefined clinical utility specifications. Nevertheless, positive T-wave in aVR lead has been reported to be associated with poor clinical outcomes in some cardiovascular diseases. This study aimed to prospectively investigate the prognostic value and clinical utility of T-wave amplitude in aVR lead in patients with acute ST-elevation myocardial infarction (STEMI).

Methods

A total of 340 STEMI patients admitted to a tertiary heart center were consecutively included. Patients were categorized into four strata, based on T wave amplitude in aVR lead in their admission ECG (i.e. < − 2, − 1 to − 2, − 1 to 0, and ≥ 0 mV). Patients’ clinical outcomes were also recorded and statistically analyzed.

Results

In-hospital mortality, re-hospitalization, and six-month-mortality significantly varied among four T wave strata and were higher in patients with a T wave amplitude of ≥ 0 mV (p 0.001–0.002). The groups of patients with higher T wave amplitude in aVR, had progressively increased relative risk (RR) of in-hospital mortality (RRs ≤ 0.01, 0.07, 1.00, 2.30 in four T wave strata, respectively). T wave amplitude in the cutoff point of − 1 mV exhibited a sensitivity and specificity of 95.83 (95% CI 78.88–99.89) and 49.68 (95% CI 44.04–55.33).

Conclusion

Our study demonstrated a significant association of positive T wave in aVR lead and adverse clinical outcomes in STEMI patients. Nevertheless, the clinical utility of T-wave amplitude at aVR lead is limited by its low discriminative potential toward prognosis of STEMI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02335-5.

Relationship between resting 12-lead electrocardiogram and all-cause death in patients without structural heart disease: Shinken Database analysis

Background

Resting 12-lead electrocardiography is widely used for the detection of cardiac diseases. Electrocardiogram readings have been reported to be affected by aging and, therefore, can predict patient mortality.

Methods

A total of 12,837 patients without structural heart disease who underwent electrocardiography at baseline were identified in the Shinken Database among those registered between 2010 and 2017 (n = 19,170). Using 438 electrocardiography parameters, predictive models for all-cause death and cardiovascular (CV) death were developed by a support vector machine (SVM) algorithm.

Results

During the observation period of 320.4 days, 55 all-cause deaths and 23 CV deaths were observed. In the SVM prediction model, the mean c-statistics of 10 cross-validation models with training and testing datasets were 0.881 ± 0.027 and 0.927 ± 0.101, respectively, for all-cause death and 0.862 ± 0.029 and 0.897 ± 0.069, respectively for CV death. For both all-cause and CV death, high values of permutation importance in the ECG parameters were concentrated in the QRS complex and ST-T segment.

Conclusions

Parameters acquired from 12-lead resting electrocardiography could be applied to predict the all-cause and CV deaths of patients without structural heart disease. The ECG parameters that greatly contributed to the prediction were concentrated in the QRS complex and ST-T segment.

Effects of upright T-wave in lead aVR on left ventricular volume and function derived from ECG-gated SPECT in patients with advanced chronic kidney disease

BACKGROUND

Numerous studies have shown the association between chronic kidney disease (CKD) and adverse cardiac events. We investigated whether or not the upright T-wave in lead aVR (TaVR) could predict left ventricular (LV) volume and function derived from ECG-gated SPECT in patients with advanced CKD.

METHODS

Two hundred and sixty-one patients with advanced CKD [estimated glomerular filtration rate (eGFR) < 45 ml/min/1.73 m2] were enrolled. Upright TaVR was defined as a wave with a positive deflection of > 0 mV. Enlarged LV end-diastolic volume (LVEDV) was defined as LVEDV index of > 76 ml/m2 in men and > 57 ml/m2 in women. Reduced LV ejection fraction (LVEF) was defined as LVEF of < 40%.

RESULTS

Forty-six patients (18%) had upright TaVR, and 215 patients (82%) had negative TaVR. Summed redistribution score (SRS) [ 6 (1-12) vs. 2 (0-5), p < 0.001] and summed difference score (SDS) [4 (1-6) vs. 2 (0-4), p = 0.004] were significantly larger in patients with upright TaVR than those with negative TaVR. Patients with upright TaVR had larger LVEDV index (75 ± 33 ml/m2 vs. 50 ± 18 ml/m2, p < 0.001) and lower LVEF (43 ± 14% vs. 58 ± 11%, p < 0.001) compared to those with negative TaVR. After adjusted for other variables including SRS and SDS, upright TaVR remained a significant predictor of enlarged LVEDV (odds ratio 5.45; 95% CI 2.16-14.22; p < 0.001) and reduced LVEF (odds ratio 4.54; 95% CI 1.70-12.23; p = 0.003).

CONCLUSIONS

Our data suggested that upright TaVR could predict LV volume and function derived from ECG-gated SPECT in patients with advanced CKD.

Association of the positive T wave in lead aVR with short-term mortality in patients with acute pulmonary embolism

Background: Lead aVR provides prognostic information in various settings for patients with cardiovascular diseases. The present study aimed to investigate the prognostic value of a positive T wave in lead aVR (TaVR) for patients with acute pulmonary embolism (APE).Methods: We screened a total of 412 consecutive patients who were hospitalised with a diagnosis of APE between 2008 and 2018. We investigated electrocardiograms (ECGs) for the presence of a positive TaVR and classified other abnormal ECG findings. Additionally, clinical data, such as echocardiographic findings were recorded, and pulmonary embolism severity index (PESI) scores were calculated. The predictors of mortality at 30 days were investigated as the clinical outcome by logistic regression analysis.Results: In our study population, 54 patients (13.1%) died within 30 days. The prevalence of female gender, congestive heart failure, chronic obstructive pulmonary disease, and mean PESI scores were significantly higher in patients with a positive TaVR compared to those without it. Systolic blood pressure of patients with positive TaVR was significantly lower than that of patients without positive TaVR. In multivariate regression analysis; PESI scores (OR: 1.03; 95% CI: 1.01-1.04, p < .01), Right ventricular end-diastolic diameter (RVEDD) (OR: 1.07 95% CI: 1.01-1.13, p = .02), and a positive TaVR (OR: 4.41; 95% CI: 1.63-11.96, p < .01) were independently correlated with mortality.Conclusion: Positive TaVR, PESI scores, and RVEDD at hospital admission may have prognostic value in patients with APE. Positive T wave in lead aVR could be a useful marker in early risk stratification of pulmonary embolism.

Importance of lead aVR on predicting adverse cardiac events in patients with noncompaction cardiomyopathy

Background

Noncompaction cardiomyopathy (NCCM) is a relatively rare cardiac abnormality with high rates of mortality and morbidity. T‐wave amplitudes during ventricular repolarization in lead aVR (TaVR) have been reported to be associated with the prognosis of various cardiovascular diseases. This study sought to investigate the prevalence and prognostic role of positive TaVR in patients with NCCM.

Methods

We evaluated consecutive 161 patients with NCCM (65.8% men, mean age 42.5 ± 15.2 years old). Presentation electrocardiogram was assessed regarding classical parameters as well as T‐wave amplitudes in lead aVR. The primary endpoint was defined as composite lethal arrhythmic events, including sudden cardiac death, ventricular fibrillation, or sustained ventricular tachycardia or appropriate implantable cardioverter–defibrillator shock. Heart failure requiring hospitalization, cardiovascular death, and all‐cause mortality were also investigated as secondary endpoints.

Results

Patients with positive TaVR showed higher rates for arrhythmic events, hospitalization for heart failure, and death compared with patients without it. In multivariate Cox model, after adjusting for other known clinical and electrocardiographic risk factors, the positive TaVR was found to be a strong independent predictor of primary endpoint (HR: 4.8, 95% CI: 1.2–19.3; p = .025) and all‐cause death (HR: 3.5, 95% CI: 1.0–12.1; p = .045).

Conclusion

Our findings revealed that positive TaVR is significantly and independently associated with adverse outcomes in NCCM patients. This unique ECG criterion in the often ignored lead provides incremental information beyond what is available with other traditional risk factors.

The prognostic significance of a positive or isoelectric T wave in lead aVR in patients with acute coronary syndrome and ischemic ECG changes in the presenting ECG - Long-term follow-up data of the TACOS study

BACKGROUND

A positive T wave in lead aVR (aVRT+) is an independent prognostic predictor of cardiovascular mortality in the general population as well as in cardiovascular disease.

SUBJECTS AND METHODS

We evaluated the prognostic impact of aVRT+ in an ECG recorded as close to hospital discharge as possible in acute coronary syndrome patients (n = 527). We divided the patients into three categories based on the findings in the admission ECG: ST elevation, global ischemia and other ST/T changes.

RESULTS

In the whole study population, and in all the three ECG subgroups, the 10-year all-cause mortality rate was higher in the aVRT+ group than in the aVRT- group. In Cox regression analysis, the age and gender adjusted hazard ratio (HR) for aVRT+ to predict all-cause mortality in the whole study population was 1.43 (95% confidence interval [CI] 1.12-1.83; p = 0.004). To predict cardiovascular mortality, the age and gender adjusted HR for aVRT+ was 1.54 (95% CI 1.14-2.07; p = 0.005) in the whole study population and 2.07 (95% CI 1.07-4.03; p = 0.032) in the category with other ST/T changes.

CONCLUSION

In ACS patients with or without ST elevation, but with ischemic ST/T changes in their presenting ECG, a positive or isoelectric T wave in lead aVR in an ECG recorded in the subacute in-hospital stage is associated with all-cause and cardiovascular mortality during long-term follow-up. Clinicians should pay attention to this simple ECG finding at hospital discharge.

Usefulness of positive T wave in lead aVR in predicting arrhythmic events and mortality in patients with hypertrophic cardiomyopathy

BACKGROUND

Positive T wave in lead aVR (TaVR) has been associated with increased risk of adverse events in patients with various cardiovascular diseases.

OBJECTIVE

The purpose of this study was to investigate the prevalence and prognostic significance of positive TaVR in patients with hypertrophic cardiomyopathy (HCM).

METHODS

This study investigated 421 consecutive patients with HCM (177 women; age 51.1 ± 14.9 years). Admission electrocardiogram was examined for the presence of a positive TaVR. The primary endpoint was defined as a composite of major arrhythmic events (MAEs), which included sudden cardiac death, sustained ventricular tachycardia or fibrillation, or appropriate implantable cardioverter-defibrillator therapy. Cardiovascular mortality and all-cause death were evaluated as secondary endpoints.

RESULTS

During median follow-up period of 6.0 years (interquartile range 4.0-11.6 years), 53 patients (12.6%) experienced the primary endpoint. On multivariable competing analysis, after adjusting for other confounding factors, the presence of positive TaVR was found to be an independent and strong predictor of the primary composite endpoint. Time-dependent receiver operating characteristic analysis, net reclassification index, and integrated discrimination improvement showed that the addition of positive TaVR to conventional HCM risk factors improved prediction of arrhythmic events. However, in subgroup analysis, a positive TaVR lost statistical significance in patients with apical HCM but remained significant in patients with all other hypertrophy patterns.

CONCLUSION

Positive TaVR is associated with MAE in HCM patients, independent of and incremental to traditional risk factors.

Electrocardiographic associations with myocardial fibrosis among sudden cardiac death victims

OBJECTIVE

A major challenge in reducing the incidence of sudden cardiac death (SCD) is the identification of patients at risk. Myocardial fibrosis has a substantial association with SCD risk but is difficult to identify among general populations. Our aim was to find electrocardiographic (ECG) markers of myocardial fibrosis among SCD victims.

METHODS

Study population was acquired from the Fingesture study, which has gathered data from 5869 consecutive autopsied SCD victims in Northern Finland between 1998 and 2017. The degree of fibrosis was determined in histological samples taken from the heart during autopsy and was categorised into four groups: (1) no fibrosis, (2) scattered mild fibrosis, (3) moderate patchy fibrosis and (4) substantial fibrosis. We were able to collect ECGs from 1100 SCD victims.

RESULTS

The mean age of the study subjects was 66±13 years and 75% were male. QRS duration in ECG correlated with the degree of fibrosis (p<0.001, β=0.153). Prevalence of fragmented QRS complex, pathological Q waves and T wave inversions correlated with increased degree of fibrosis (p<0.001 in each). Depolarisation abnormalities were observed both in ischaemic and non-ischaemic heart disease. Repolarisation abnormalities reached statistical significance only among ischaemic SCD victims. An abnormal ECG was observed in 75.3% of the subjects in group 1, 73.7% in group 2, 88.5% in group 3 and 91.7% in group 4 patients (p<0.001).

CONCLUSIONS

Myocardial fibrosis was associated with QRS prolongation, deep Q waves, T wave inversions and QRS fragmentation. The results provide potentially useful non-invasive early recognition of patients with fibrotic cardiomyopathy and risk of SCD.

The prognostic value of positive T wave in lead aVR: A novel marker of adverse cardiac outcomes in peripartum cardiomyopathy

BACKGROUND

Peripartum cardiomyopathy (PPCM) is an uncommon complication of pregnancy. Clinical courses of PPCM are markedly heterogeneous. Positive T waves in lead aVR (TaVR) are shown to be associated with adverse cardiac events in several cardiovascular diseases. We aimed to investigate the prevalence and prognostic role of positive TaVR in patients with PPCM.

METHODS

A total of 82 patients (mean age 29.1 ± 6.3 years) with the diagnosis of PPCM were enrolled. Presentation electrocardiogram (ECG) was investigated for presence of a positive TaVR. The median follow-up duration was 67.0 months. The primary endpoint was defined as composite cardiac events, including cardiac death, arrhythmic events, or persistent left ventricular systolic dysfunction.

RESULTS

Patients with positive T wave in lead aVR showed higher rates for persistent left ventricular systolic dysfunction, arrhythmic events, and cardiac death compared to patients without it. In multivariate logistic regression analysis, after adjusting for other confounding factors, the presence of positive TaVR was found to be as an independent and strong predictor of primary composite endpoint (odds ratio 6.21, 95% CI 1.45-26.51; p = 0.014). In Kaplan-Meier survival analysis, both primary and secondary endpoints occurred more frequently in the positive TaVR group. Using the cut-off level of 0.25 mV, T-wave amplitude in lead aVR predicted primary endpoint with a sensitivity of 100% and specificity of 100%.

CONCLUSION

Positive T wave in lead aVR, as a simple and feasible electrocardiographic marker, seems to be a novel predictor of adverse cardiovascular outcomes in patients with PPCM.

Usefulness of upright T wave in lead aVR for predicting short-term prognosis of patients with ischemic stroke

Background

Upright T wave in lead aVR (TaVR) has recently been reported to be associated with cardiovascular death and mortality in general population and in patients with prior cardiovascular disease (CVD). However, the evidence for the predictive ability of TaVR in patients with ischemic stroke (IS) is lacking.

Methods

A total of 625 consecutive patients with IS (mean age: 66 ± 12 years; 379 male) were enrolled in this study between January 2013 and December 2014. Patients were divided into upright TaVR (≥0 mV; n = 201) and negative TaVR (<0 mV; n = 424) groups. All patients were evaluated with respect to clinical features and in-hospital clinical results.

Results

Overall, the prevalence of upright TaVR was 32.2% at baseline. Patients with an upright TaVR were older, had a higher percentage of CVD and hypertension, higher level of MB isoenzyme of creatine kinase (CKMB), faster heart rate, higher rate of QT prolongation > 450 ms, higher rate of negative T in lead II, higher rate of negative T in lead V6, higher rate of ST depression, and longer QTc duration. During the mean follow-up period of 20.0 ± 5.8 months, 29 (4.6%) patients experienced all-cause death and 12 (1.9%) patients experienced cardiovascular death, the primary end point. Concomitantly, 94 (15%) patients experienced recurrence of IS, the secondary end point. After adjusting for clinical covariates, upright TaVR was independently associated with all-cause death [hazard ratio (HR): 2.88, 95% confidence intervals (CI): 1.07–7.73], cardiovascular death (HR: 3.04, 95% CI: 1.07–8.64), and IS recurrence (HR: 1.86, 95% CI: 1.08–3.20).

Conclusions

Upright TaVR in patients with IS is associated with increased mortality and recurrence of IS.

Prognostic value of positive T wave in lead aVR in patients with non-ST segment myocardial infarction

BACKGROUND

Lead aVR provides prognostic information in various settings in patients with ischemia. We aim to investigate the role of a positive T wave in lead aVR in non-ST segment myocardial infarction (NSTEMI).

METHODS

In a prospective cohort study, we included 400 patients with NSTEMI. Presentation electrocardiogram (ECG) was investigated for presence of a positive T wave as well as ST segment elevation (STE) in aVR and study variables were compared. Predictors of primary outcome defined as hospital major adverse cardiovascular events (MACE) and secondary outcome, defined as three-vessel coronary disease and/or left main coronary artery stenosis (3VD/LMCA) stenosis in angiography, were determined in multivariate logistic regression analysis.

RESULTS

Patients with a positive T wave in aVR were significantly older and were more likely to be female. Left ventricular ejection fraction was significantly lower in patients of positive T group. Positive T group was more likely to have 3VD/LMCA stenosis (58.3% vs. 19.8%, p < .001). The prevalence of a positive T wave in aVR was significantly higher in MACE group (54.9 % vs. 24.8%, p < .001). However, in multivariate analysis, it was not an independent predictor of MACE (OR: 1.083 95% CI: [0.496-2.365], p: .841). Though, it was independently associated with presence of 3VD/LMCA stenosis (OR: 3.747 95% CI: [2.058-6.822], p < .001).

CONCLUSION

Though positive T wave in lead aVR was more common in patients with MACE; it was not an independent predictor. Additionally, a positive T wave in aVR was an independent predictor of 3VD/LMCA stenosis in NSTEMI.

Association of Lead aVR T-wave Amplitude With Cardiovascular Events or Mortality Among Prevalent Dialysis Patients

In dialysis patients, electrocardiogram (ECG) abnormalities are common. However, the associations between the T-wave of the lead aVR (aVRT) amplitude and cardiovascular (CV) events or total mortality are unknown. We performed a prospective, observational cohort study of prevalent hemodialysis patients (N = 474), followed for 4 years. Outcomes were composite CV events and all-cause mortality. Predictors were baseline aVRT and other ECG findings. ECG parameters were analyzed in three models: model 1, univariate; model 2, basic adjustments; and model 3, model 2 plus serum albumin, C-reactive protein level, and NT-proBNP. By Cox analysis, aVRT was best associated with both endpoints through model 1 to 3 compared to other ECG findings. Patients categorized according to aVRT amplitude showed a step-by-step increase in hazard ratios for both endpoints. The aVRT amplitude level was significantly associated with not only composite CV events but also with all-cause mortality in prevalent dialysis patients.

Twenty-eight genetic loci associated with ST-T-wave amplitudes of the electrocardiogram

The ST-segment and adjacent T-wave (ST-T wave) amplitudes of the electrocardiogram are quantitative characteristics of cardiac repolarization. Repolarization abnormalities have been linked to ventricular arrhythmias and sudden cardiac death. We performed the first genome-wide association meta-analysis of ST-T-wave amplitudes in up to 37 977 individuals identifying 71 robust genotype–phenotype associations clustered within 28 independent loci. Fifty-four genes were prioritized as candidates underlying the phenotypes, including genes with established roles in the cardiac repolarization phase (SCN5A/SCN10A, KCND3, KCNB1, NOS1AP and HEY2) and others with as yet undefined cardiac function. These associations may provide insights in the spatiotemporal contribution of genetic variation influencing cardiac repolarization and provide novel leads for future functional follow-up.

The prognostic value of positive T-wave in lead aVR in hemodialysis patients

BACKGROUND

Given that cardiac disease is the leading cause of mortality in hemodialysis (HD) patients, identification of patients at risk for cardiac mortality is crucial. The aim of this study was to determine if positive T-wave amplitude in lead aVR (TaVR) was predictive of cardiovascular (CV) mortality and sudden cardiac death (SCD) in a group of HD patients.

METHODS AND RESULTS

After exclusion, 223 HD patients were prospectively followed-up for 25.43 ± 3.56 months. Patients were divided into TaVR negative (n = 186) and TaVR positive (n = 37) groups. Myocardial infarction, diabetes and beta-blocker therapy were more frequent in positive TaVR patients. Patients with upright TaVR were older, had higher left ventricular mass index, lower ejection fraction, higher calcium × phosphate product, higher troponin T level, higher prevalence of ST-T abnormalities, and increased width of QRS complex and QT interval, compared with patients with negative TaVR. A Kaplan-Meier analysis showed that the cumulative incidences of CV mortality as well as SCD were higher in patients with positive TaVR compared with those with negative TaVR (log-rank, p < 0.001 in both cases). A multivariate analysis selected age [hazard ratio (HR) 1.71, p < 0.001], heart rate (HR 1.42, p = 0.016), and positive TaVR (HR 2.21, p = 0.001) as well as age (HR 1.88, p < 0.001), and positive TaVR (HR 1.53, p = 0.014) as independent predictors of CV mortality and SCD, respectively.

CONCLUSION

In HD patients, positive TaVR is an independent and powerful predictor of CV mortality as well as SCD. This simple ECG parameter provides additional information beyond what is available with other known traditional risk factors and allows the identification of patients most at risk of CV events.

T-wave reversal in the augmented unipolar right arm electrocardiographic lead is associated with increased risk of sudden death

BACKGROUND

Repolarization abnormalities are associated with ventricular arrhythmias, and published studies report that a reversal of T wave polarity (positive or flat T wave) in lead aVR may be linked to increased cardiovascular mortality. We evaluated whether a positive or flat T wave in aVR is a risk marker for sudden cardiac death (SCD).

METHODS

SCD cases from the Oregon Sudden Unexpected Death Study (catchment population ~1 million) were compared to geographic controls with coronary artery disease and no history of SCD. Archived electrocardiograms performed prior and unrelated to the SCD event were evaluated.

RESULTS

SCD cases (n = 691, 67.6 ± 14.9 years, 69% male) were more likely than controls (n = 663, 66.2 ± 11.6 years, 67% male) to have diabetes (40 vs 32%; p < 0.01), left ventricular ejection fraction (LVEF) ≤35% (27 vs 11 %; p < 0.01), prolonged QTc (≥450 ms; 54 vs 28%; p < 0.01) and positive (19 vs 13%; p < 0.01) or flat T wave (14 vs 7%; p < 0.01) in aVR. On multivariable analysis, a positive/flat T wave in aVR was independently associated with SCD (OR 1.9, 95% CI 1.3-2.8, p < 0.01). However, a positive T wave alone lost statistical significance in patients with LVEF ≤ 35% and QTc ≥ 450 ms. In a subgroup analysis among patients with normal LVEF, QTc, and no diabetes, a positive T wave in aVR (but not a flat T wave) remained associated with SCD (OR 2.8, 95% CI 1.2-6.1, p < 0.01).

CONCLUSIONS

A positive or flat T wave in lead aVR was associated with SCD in subsets of patients. This simple ECG marker in this often-ignored lead may contribute to enhancement of SCD risk stratification, and warrants further evaluation.

Usefulness of an Upright T-Wave in Lead aVR for Predicting the Short-Term Prognosis of Incident Hemodialysis Patients: A Potential Tool for Screening High-Risk Hemodialysis Patients

BACKGROUND/AIMS

An upright T-wave in lead aVR (aVRT) has recently been reported to be associated with cardiovascular death and mortality among the general population and patients with prior cardiovascular disease (CVD). However, evidence for the predictive ability of aVRT in patients with chronic kidney disease is lacking. Therefore, a hospital-based, prospective, cohort study was conducted to evaluate the predictive ability of an upright aVRT for the short-term prognosis in incident hemodialysis patients.

METHODS

Among 208 patients who started maintenance hemodialysis, 79 with preexisting CVD (CVD cohort) and 129 with no history of CVD (non-CVD cohort), were studied. An upright and non-upright aVRT were defined as a wave with a positive deflection in amplitude of ≥0 mV and a negative deflection in amplitude of <0 mV, respectively. The endpoint was all-cause death.

RESULTS

Overall, the prevalence of an upright aVRT was 22.6% at baseline. During the mean follow-up period of 2.1 ± 1.0 years, 33 deaths occurred. Cumulative survival rates at 3 years after starting dialysis in patients with an upright and non-upright aVRT were 50.0 and 80.7%, respectively, in the CVD cohort and 92.0 and 91.3%, respectively, in the non-CVD cohort. In the CVD cohort, multivariate Cox regression analysis showed that an upright aVRT was an independent predictor of death after adjusting for confounding variables.

CONCLUSION

Among Japanese hemodialysis patients at high risk for CVD, an upright aVRT seems to be useful for predicting death.

The prognostic value of discordant T waves in lead aVR: A simple risk marker of sudden cardiac arrest in ischemic cardiomyopathy

BACKGROUND

Simple and reliable ECG marker(s) for sudden cardiac arrest (SCA) could be very useful in assessing high-risk populations. Since ischemic repolarization abnormalities in the left ventricular (LV) apex are strongly correlated with discordant T waves in lead aVR, we sought to evaluate the clinical and prognostic significance of this feature in ischemic cardiomyopathy.

METHODS

The PAREPET trial enrolled patients with ischemic cardiomyopathy eligible for a primary prevention implantable cardiac defibrillator (ICD). Those with persistent pacing or left bundle branch block were excluded. Amplitudes of T/aVR were automatically computed from median ECG beats at enrollment and endpoints were blindly adjudicated.

RESULTS

The sample was mainly composed of older men (n=138, age 65±12, 91% male, EF 29±9%). At enrollment, amplitude of T/aVR significantly correlated with EF, indexed LV end-diastolic volume, B-type natriuretic peptide (BNP), regional scar volume, and PET-quantified denervated myocardium. After a median follow up of 4.2years, there were 23 (17%) adjudicated SCA. In multivariate analysis, the presence of discordant T/aVR (>0mm, n=42, 30%) was a significant and independent predictor of SCA (hazard ratio 2.0 [95% CI 1.0-4.9]) and cardiac death (hazard ratio 1.9 [95% CI 1.0-3.7]).

CONCLUSIONS

In subjects with ischemic cardiomyopathy, discordant T waves in lead aVR are associated with high-risk clinical parameters including lower ejection fraction, greater ventricular volume, higher BNP, and more denervated myocardium. Furthermore, discordant T/aVR remained an independent predictor of SCA and cardiovascular mortality even after accounting for these prognostic factors.

The classical versus the Cabrera presentation system for resting electrocardiography: Impact on recognition and understanding of clinically important electrocardiographic changes

The classical system for presentation of the 12-lead electrocardiogram (ECG) reflects the electrical activity of the heart as viewed in the transverse plane by 6 leads with a single anatomically ordered sequence, V1-V6; but in the frontal plane by 6 leads with dual sequences, I, II, and III, and aVR, aVL, and aVF. However, there is also a single anatomically ordered sequence of leads, called the Cabrera display that presents the six frontal plane leads in their anatomically ordered sequence of: aVL, I, -aVR, II, aVF, and III. Although it has been recognized that the Cabrera system has clinical diagnostic advantages compared to the classical display, it is currently only used in Sweden. The primary explanation of why the Cabrera system has not been adopted internationally has been that analog ECG recorders had technical limitations. Currently, however, the classical system is most often seen as a historical remnant that prevails because of conservatism within the cardiology community.

Usefulness of electrocardiographic QRS/T angles with versus without bundle branch blocks to predict heart failure (from the Atherosclerosis Risk in Communities Study)

Repolarization abnormalities in the setting of bundle branch blocks (BBB) are generally ignored. We used Cox regression models to determine hazard ratios (HRs) with 95% confidence intervals (CIs) for incident heart failure (HF) associated with wide spatial and frontal QRS/T angle (upper twenty-fifth percentile of each) in men and women with and without BBB. This analysis included 14,478 participants (54.6% women, 26.4% blacks, 377 [2.6%] with BBB) from the Atherosclerosis Risk in Communities Study who were free of HF at baseline. Using No-BBB with normal spatial QRS/T angle as the reference group, the risk for HF in multivariable adjusted models was increased 51% for No-BBB with wide spatial QRS/T angle (HR 1.51, 95% CI 1.37 to 1.66), 48% for BBB with normal spatial QRS/T angle (HR 1.48, 95% CI 1.17 to 1.88), and the risk for incident HF was increased more than threefold for BBB with wide spatial QRS/T angle (HR 3.37, 95% CI 2.47 to 4.60). The results were consistent across subgroups by gender. Similar results were observed for the frontal plane QRS/T angle. In the pooled BBB group excluding right BBB, a positive T wave in lead aVR and heart rate 70 bpm and higher were also potent predictors of incident HF similar to the QRS/T angles. In conclusion, both BBB and wide QRS/T angles are predictive of HF, and concomitant presence of both carries a much higher risk than for either predictor alone. These findings suggest that repolarization abnormalities in the setting of BBB should not be considered benign or an expected consequence of BBB.

Electrocardiographic repolarization-related variables as predictors of coronary heart disease death in the women's health initiative study

BACKGROUND

We evaluated 25 repolarization-related ECG variables for the risk of coronary heart disease (CHD) death in 52 994 postmenopausal women from the Women's Health Initiative study.

METHODS AND RESULTS

Hazard ratios from Cox regression were computed for subgroups of women with and without cardiovascular disease (CVD). During the average follow-up of 16.9 years, 941 CHD deaths occurred. Based on electrophysiological considerations, 2 sets of ECG variables with low correlations were considered as candidates for independent predictors of CHD death: Set 1, Ѳ(Tp|Tref), the spatial angle between T peak (Tp) and normal T reference (Tref) vectors; Ѳ(Tinit|Tterm), the angle between the initial and terminal T vectors; STJ depression in V6 and rate-adjusted QTp interval (QTpa); and Set 2, TaVR and TV1 amplitudes, heart rate, and QRS duration. Strong independent predictors with over 2-fold increased risk for CHD death in women with and without CVD were Ѳ(Tp|Tref) >42° from Set 1 and TaVR amplitude >-100 μV from Set 2. The risk for these CHD death predictors remained significant after multivariable adjustment for demographic/clinical factors. Other significant predictors for CHD death in fully adjusted risk models were Ѳ(Tinit|Tterm) >30°, TV1 >175 μV, and QRS duration >100 ms.

CONCLUSIONS

Ѳ(Tp|Tref) angle and TaVR amplitude are associated with CHD mortality in postmenopausal women. The use of these measures to identify high-risk women for further diagnostic evaluation or more intense preventive intervention warrants further study.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00000611.

Significance of lead aVR in acute coronary syndrome

The 12-lead electrocardiogram (ECG) is a crucial tool in the diagnosis and risk stratification of acute coronary syndrome (ACS). Unlike other 11 leads, lead aVR has been long neglected until recent years. However, recent investigations have shown that an analysis of ST-segment shift in lead aVR provides useful information on the coronary angiographic anatomy and risk stratification in ACS. ST-segment elevation in lead aVR can be caused by (1) transmural ischemia in the basal part of the interventricular septum caused by impaired coronary blood flow of the first major branch originating from the left anterior descending coronary artery; (2) transmural ischemia in the right ventricular outflow tract caused by impaired coronary blood flow of the large conal branch originating from the right coronary artery; and (3) reciprocal changes opposite to ischemic or non-ischemic ST-segment depression in the lateral limb and precordial leads. On the other hand, ST-segment depression in lead aVR can be caused by transmural ischemia in the inferolateral and apical regions. It has been recently shown that an analysis of T wave in lead aVR also provides useful prognostic information in the general population and patients with prior myocardial infarction. Cardiologists should pay more attention to the tracing of lead aVR when interpreting the 12-lead ECG in clinical practice.

ST-T wave abnormality in lead aVR and reclassification of cardiovascular risk (from the National Health and Nutrition Examination Survey-III)

Electrocardiographic lead aVR is often ignored in clinical practice. The aim of this study was to investigate whether ST-T wave amplitude in lead aVR predicts cardiovascular (CV) mortality and if this variable adds value to a traditional risk prediction model. A total of 7,928 participants enrolled in the National Health and Nutrition Examination Survey (NHANES) III with electrocardiographic data available were included. Each participant had 13.5 ± 3.8 years of follow-up. The study sample was stratified according to ST-segment amplitude and T-wave amplitude in lead aVR. ST-segment elevation (>8 μV) in lead aVR was predictive of CV mortality in the multivariate analysis when not accounting for T-wave amplitude. The finding lost significance after including T-wave amplitude in the model. A positive T wave in lead aVR (>0 mV) was the strongest multivariate predictor of CV mortality (hazard ratio 3.37, p <0.01). The addition of T-wave amplitude in lead aVR to the Framingham risk score led to a net reclassification improvement of 2.7% of subjects with CV events and 2.3% of subjects with no events (p <0.01). Furthermore, in the intermediate-risk category, 20.0% of the subjects in the CV event group and 9.1% of subjects in the no-event group were appropriately reclassified. The absolute integrated discrimination improvement was 0.012 (p <0.01), and the relative integrated discrimination improvement was 11%. In conclusion, T-wave amplitude in lead aVR independently predicts CV mortality in a cross-sectional United States population. Adding T-wave abnormalities in lead aVR to the Framingham risk score improves model discrimination and calibration with better reclassification of intermediate-risk subjects.

Electrocardiographic predictors of coronary heart disease and sudden cardiac deaths in men and women free from cardiovascular disease in the Atherosclerosis Risk in Communities study

Background

We evaluated predictors of coronary heart disease (CHD) death and sudden cardiac death (SCD) in the Atherosclerosis Risk in Communities (ARIC) study.

Methods and Results

The study population included 13 621 men and women 45 to 65 years of age free from manifest cardiovascular disease at entry. Hazard ratios from Cox regression with 95% confidence intervals were computed for 18 dichotomized repolarization‐related ECG variables. The average follow‐up was 14 years. Independent predictors of CHD death in men were TaVR‐ and rate‐adjusted QTend (QT_ea), with a 2‐fold increased risk for both, and spatial angles between mean QRS and T vectors and between Tpeak (T_p) and normal R reference vectors [θ(R_m|T_m) and θ(T_p|T_ref), respectively], with a >1.5‐fold increased risk for both. In women, independent predictors of the risk of CHD death were θ(R_m|T_m), with a 2‐fold increased risk for θ(R_m|T_m), and θ(T_p|T_ref), with a 1.7‐fold increased risk. Independent predictors of SCD in men were θ(T_p|T_ref) and QT_ea, with a 2‐fold increased risk, and θ(T_init|T_term), with a 1.6‐fold increased risk. In women, θ(T_init|T_term) was an independent predictor of SCD, with a >3‐fold increased risk, and θ(R_m|T_m) and TV1 were >2‐fold for both.

Conclusions

θ(R_m|T_m) and θ(T_p|T_ref), reflecting different aspects of ventricular repolarization, were independent predictors of CHD death and SCD, and TaVR and TV1 were also independent predictors. The risk levels for independent predictors for both CHD death and SCD were stronger in women than in men, and QT_ea was a significant predictor in men but not in women.