Determinants of discrepancies in detection and comparison of the prognostic significance of left ventricular hypertrophy by electrocardiogram and cardiac magnetic resonance imaging

Electrocardiography versus Echocardiography in Severe Aortic Stenosis with the Consideration of Coexistent Coronary Artery Disease

(1) Background: Coexistent coronary artery disease (CAD) might influence the ability of electrocardiogram (ECG) to identify echocardiographic left ventricular hypertrophy (ECHO-LVH) in patients with aortic stenosis (AS). We aimed to assess the relation between ECG-LVH (by the Sokolov-Lyon or Cornell criteria) and ECHO-LVH considering coexistent CAD. (2) Methods: We retrospectively analyzed the medical records of 74 patients (36 males) with severe AS who were hospitalized in the University Hospital in Cracow from 2021 to 2022. (3) Results: ECHO-LVH was present in 49 (66%) patients, whereas 35 (47.3%) patients had ECG-LVH. There was no difference between the rate of ECG-LVH in patients with vs. without ECHO-LVH. Single-vessel and multi-vessel CAD were diagnosed by invasive coronary angiography in 18% and 11% of patients, respectively. The sensitivity of the classical ECG-LVH criteria with regard to ECHO-LVH was low, reaching at best 41% for the Sokolov-Lyon and Cornell criteria. The results were similar and lacked a pattern when considering patients without significant stenosis, with single- and multi-vessel disease separately. Correlations between the left ventricular mass index and ECG-derived parameters were weak and present solely for the Lewis index (r = 0.31), R wave's amplitude >1.1 mV in aVL (r = 0.36), as well as the Cornell (r = 0.32) and Sokolov-Lyon (r = 0.31) voltage criteria (p < 0.01). The presence, location of stenoses, and CAD extent were not associated with the presence of either ECHO-LVH or ECG-LVH, irrespective of individual ECG-LVH criteria. (4) Conclusions: The sensitivity of classical ECG criteria for echocardiographic LVH in severe AS is low, regardless of coexistent CAD or its angiographic extent.

ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Electrocardiographic and genetic characteristics in first degree relatives of hypertrophic cardiomyopathy probands: A descriptive cross-sectional study from Vietnam

Objectives

In order to study the phenotype-genotype relationship and to better understand the early consequences of the mutation, we would report the spectrum of electrocardiographic and genetic features in the relatives of hypertrophic cardiomyopathy (HCM) patients.

Methods

Participants underwent a comprehensive clinical assessment, electrocardiography, standardized and echocardiography and genetic testing. In probands, next-generation sequencing was performed using the gene panel associated with HCM, while in relatives, Sanger sequencing was used to screen for mutations identified in their individual probands.

Results

A total of 84 participants were included in this study. The interventricular septal and posterior wall thickness was highest in the G+/LVH+ group, followed by the G+/LVH- group, and was lowest in G-/LVH- group. Compared to the normal control group, the pathologic Q wave was statistically more prevalent in the G+/LVH- group. The prevalence of repolarization abnormalities and major abnormalities was highest in the G+/LVH+ group, followed by the G+/LVH- group, and lowest in G-/LVH- group.

Conclusion

Our results suggested that sarcomere mutations have early consequences on myocardial biology. These findings suggest the possibility of implementing a mutation carrier detection model within families affected by HCM, where ECG could play a central role when combined with other relevant clinical factors. Longitudinal studies on a cohort of G+/LVH- patients are required.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Diastology with Cardiac MRI: A Practical Guide

Diastolic filling of the ventricle is a complex interplay of volume and pressure, contingent on active energy-dependent myocardial relaxation and myocardial stiffness. Abnormal diastolic function is the hallmark of the clinical entity of heart failure with preserved ejection fraction (HFpEF), which is now the dominant type of heart failure and is associated with significant morbidity and mortality. Although echocardiography is the current first-line imaging modality used in evaluation of diastolic function, cardiac MRI (CMR) is emerging as an important technique. The principal role of CMR is to categorize the cause of diastolic dysfunction (DD) and distinguish other entities that manifest similarly to HFpEF, particularly infiltrative and pericardial disorders. CMR also provides prognostic information and risk stratification based on late gadolinium enhancement and parametric mapping techniques. Advances in hardware, sequences, and postprocessing software now enable CMR to diagnose and grade DD accurately, a role traditionally assigned to echocardiography. Two-dimensional or four-dimensional velocity-encoded phase-contrast sequences can measure flow and velocities at the mitral inflow, mitral annulus, and pulmonary veins to provide diastolic functional metrics analogous to those at echocardiography. The commonly used cine steady-state free-precession sequence can provide clues to DD including left ventricular mass, left ventricular filling curves, and left atrial size and function. MR strain imaging provides information on myocardial mechanics that further aids in diagnosis and prognosis of diastolic function. Research sequences such as MR elastography and MR spectroscopy can help evaluate myocardial stiffness and metabolism, respectively, providing additional insights on diastolic function. The authors review the physiology of diastolic function, mechanics of diastolic heart failure, and CMR techniques in the evaluation of diastolic function. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

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

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

Incremental prognostic value of positron emission tomography derived left ventricular mass

BACKGROUND

Left ventricular hypertrophy has been shown to be an independent predictor of outcomes in patients with coronary artery disease (CAD). We aimed to determine the incremental prognostic value of positron emission tomography (PET) derived left ventricular mass (LVM) to clinical variables and myocardial flow reserve (MFR).

METHODS

We included consecutive patients who had clinically indicated PET myocardial perfusion imaging for suspected or established CAD. Patients were followed from the date of PET imaging for major adverse cardiovascular events (MACE, inclusive of all-cause death, non-fatal myocardial infarction, and percutaneous coronary intervention/coronary artery bypass grafting 90 days after imaging).

RESULTS

A total of 2357 patients underwent PET MPI during the study period (47% female, mean age 66 ± 12 years, 87% hypertensive, 47% diabetic, 79% dyslipidemia). After a mean follow-up of 11.6 ± 6.6 months, 141 patients (6.0%, 5.1 per 1000 person-year) experienced MACE (86 D/24 MI/39 PCI/9 CABG). In nested multivariable Cox models, LVM was not independently associated with outcomes (HR 1.00, P = .157) and had no incremental prognostic value (C index: 0.75, P = .571) over MFR and clinical variables.

CONCLUSION

Our analysis shows that LVM provides no independent and incremental prognostic value over MFR and clinical variables.

Association between the reflection magnitude and blood pressure in a multiethnic cohort: the Healthy Life in an Urban Setting study

AIMS

Reflection magnitude (RM), the ratio of the amplitudes of the backward and forward central arterial pressure waves, has been shown to predict cardiovascular events. However, the association with blood pressure (BP) and hypertension is unclear.

METHODS

We assessed RM in 10 195 individuals of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish and Moroccan origin aged between 18 and 70 years (54.2% female) participating in the Healthy Life in an Urban Setting study. To determine RM, central arterial pressure and flow were reconstructed from finger BP. Hypertension was defined based on office-BP and medication. Associations with BP, hypertension, and hypertensive organ damage were assessed using linear regression models with correction for relevant covariates.

RESULTS

Mean RM was 62.5% (standard deviation [SD] 8.0) in men and 63.8% (SD 8.1) in women. RM was lowest in Dutch and highest in South-Asian and African participants. RM increased linearly with 1.35 (95% confidence interval [CI] 1.23-1.46) for every 10 mmHg increase in systolic BP from 120 mmHg onwards, while the relation with diastolic BP was nonlinear. RM was 2.40 (95% CI 2.04-2.76) higher in hypertensive men and 3.82 (95% CI 3.46-4.19) higher in hypertensive women compared to normotensive men and women. In hypertensive men and women with ECG-based left ventricular hypertrophy or albuminuria RM was 1.64 (95% CI 1.09-2.20) and 0.94 (95% CI 0.37-1.52) higher compared to hypertensive participants without hypertensive organ damage.

CONCLUSION

RM is associated with BP, hypertension and hypertensive organ damage, and may in part explain disparities in hypertension associated cardiovascular risk.

Association between the reflection magnitude and blood pressure in a multiethnic cohort: the Healthy Life in an Urban Setting study

Aims:

Reflection magnitude (RM), the ratio of the amplitudes of the backward and forward central arterial pressure waves, has been shown to predict cardiovascular events. However, the association with blood pressure (BP) and hypertension is unclear.

Methods:

We assessed RM in 10 195 individuals of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish and Moroccan origin aged between 18 and 70 years (54.2% female) participating in the Healthy Life in an Urban Setting study. To determine RM, central arterial pressure and flow were reconstructed from finger BP. Hypertension was defined based on office-BP and medication. Associations with BP, hypertension, and hypertensive organ damage were assessed using linear regression models with correction for relevant covariates.

Results:

Mean RM was 62.5% (standard deviation [SD] 8.0) in men and 63.8% (SD 8.1) in women. RM was lowest in Dutch and highest in South-Asian and African participants. RM increased linearly with 1.35 (95% confidence interval [CI] 1.23–1.46) for every 10 mmHg increase in systolic BP from 120 mmHg onwards, while the relation with diastolic BP was nonlinear. RM was 2.40 (95% CI 2.04–2.76) higher in hypertensive men and 3.82 (95% CI 3.46–4.19) higher in hypertensive women compared to normotensive men and women. In hypertensive men and women with ECG-based left ventricular hypertrophy or albuminuria RM was 1.64 (95% CI 1.09–2.20) and 0.94 (95% CI 0.37–1.52) higher compared to hypertensive participants without hypertensive organ damage.

Conclusion:

RM is associated with BP, hypertension and hypertensive organ damage, and may in part explain disparities in hypertension associated cardiovascular risk.

An electrocardiography score predicts heart failure hospitalization or death beyond that of cardiovascular magnetic resonance imaging

The electrocardiogram (ECG) and cardiovascular magnetic resonance imaging (CMR) provide powerful prognostic information. The aim was to determine their relative prognostic value. Patients (n = 783) undergoing CMR and 12-lead ECG with a QRS duration < 120 ms were included. Prognosis scores for one-year event-free survival from hospitalization for heart failure or death were derived using continuous ECG or CMR measures, and multivariable logistic regression, and compared. Patients (median [interquartile range] age 55 [43-64] years, 44% female) had 155 events during 5.7 [4.4-6.6] years. The ECG prognosis score included (1) frontal plane QRS-T angle, and (2) heart rate corrected QT duration (QTc) (log-rank 55). The CMR prognosis score included (1) global longitudinal strain, and (2) extracellular volume fraction (log-rank 85). The combination of positive scores for both ECG and CMR yielded the highest prognostic value (log-rank 105). Multivariable analysis showed an association with outcomes for both the ECG prognosis score (log-rank 8.4, hazard ratio [95% confidence interval] 1.29 [1.09-1.54]) and the CMR prognosis score (log-rank 47, hazard ratio 1.90 [1.58-2.28]). An ECG prognosis score predicted outcomes independently of CMR. Combining the results of ECG and CMR using both prognosis scores improved the overall prognostic performance.

ECG in left ventricular hypertrophy: A change in paradigm from assessing left ventricular mass to its electrophysiological properties

Left ventricular hypertrophy (LVH) detected electrocardiographically is documented as an independent cardiovascular risk factor. However, the reasoning for using electrocardiography (ECG) for LVH detection is frequently referring to its low cost and availability, which should compensate for the main problem of the ECG criteria for LVH detection (ECG-LVH) - the high number of ECG false negative results and the resulting low sensitivity. This opinion paper is focused on the scientific evidence for advocating the usefulness of ECG in LVH assessment. The classical paradigm assumes that the increased left ventricular mass generates a stronger electrical field that has to be reflected in the increased QRS amplitude. However, the solid angle theorem postulates that the recorded ECG voltage depends not only on the extent of the activation front that is increased in LVH, but also on the electrical characteristics of myocardium. There is an accumulated evidence from animal and clinical studies documenting significant alterations of structural and functional properties of hypertrophied myocardium, both of cardiomyocytes as well as of interstitium. These alterations are associated with significant changes of active and passive electrical properties of myocardium modifying the resultant QRS amplitudes. The new paradigm should consider the altered electrical properties of hypertrophied myocardium in interpreting the whole spectrum of QRS patterns seen in LVH patients: the increased QRS voltage, the QRS voltage within normal limits, occurrence of left axis deviation and left bundle branch block. Thus further research is necessary for utilizing the unique diagnostic information provided by ECG: to link the agreements as well as the disagreements between ECG and imaging methods findings to pathophysiological processes and patho-anatomical backgrounds, to the risk assessment and the clinical status of patients with LVH.

Cardiac functional imaging

During the last 20 years, cardiac imaging has drastically evolved. Positron emission tomography (PET), fast three-dimensional (3D) imaging with the latest generations of echocardiography & multi-detector computed tomography (CT), stress perfusion assessed by magnetic resonance imaging (MRI), blood flow analysis using four-dimensional (4D) flow MRI, all these techniques offer new trends for optimal noninvasive functional cardiac imaging. Dynamic functional imaging is obtained by acquiring images of the heart at different phases of the cardiac cycle, allowing assessment of cardiac motion, function, and perfusion. Between CT and Cardiac MRI (CMR), CMR has the best temporal resolution, which is suitable for functional imaging while cardiac CT provides higher spatial resolution with isotropic data that have an identical resolution in the three dimensions of the space. The latest generations of CT scanners enable whole heart assessment in one beat, offering also an acceptable temporal resolution with the possibility to display the images in a dynamic mode. Another rapidly growing technique using functional and molecular imaging for the assessment of biological and metabolic pathways is the PET using radio-labeled tracers. Meanwhile, the oldest cardiac imaging tool with doppler ultrasound technology has never stopped evolving. Echocardiography today performs 3D imaging, stress perfusion, and myocardial strain assessment, with high temporal resolution. It still is the first line and more accessible exam for the patient. These different modalities are complementary and may be even combined into PET-CT or PET-MRI. The ability to combine the functional/molecular data with anatomical images may implement a new dimension to our diagnostic tools.

Discrepancy between left ventricular hypertrophy by echocardiography and electrocardiographic hypertrophy: clinical characteristics and outcomes

Background

The clinical significance of the discrepancy between left ventricular hypertrophy (LVH) by echocardiography and ECG remains to be elucidated.

Methods

After excluding patients who presented with pacemaker placement, QRS duration ≥120 ms and cardiomyopathy and moderate to severe valvular disease, we retrospectively analysed 3212 patients who had undergone both scheduled transthoracic echocardiography (echo) and ECG in a hospital-based population. Cornell product >2440 mm · ms was defined as ECG-based LVH; left ventricular mass index >115 g/m² for men and >95 g/m² for women was defined as echo-based LVH. The study population was categorised into four groups: patients with both ECG-based and echo-based LVH (N=131, 4.1%), those with only echo-based LVH (N=156, 4.9%), those with only ECG-based LVH (N=409, 12.7%) and those with no LVH (N=2516, 78.3%).

Results

The cumulative 3-year incidences of a composite of all-cause death and major adverse cardiovascular events were 32.0%, 33.8%, 19.2% and 15.7%, respectively. After adjusting for confounders, the HRs relative to that in no LVH were 1.63 (95% CI 1.16 to 2.28), 1.68 (95% CI 1.23 to 2.30) and 1.09 (95% CI 0.85 to 1.41) in patients with both ECG-based and echo-based LVH, those with only echo-based LVH, and those with only ECG-based LVH, respectively.

Conclusions

Echo-based LVH without ECG-based LVH was associated with a significant risk of adverse clinical events, and the risk was comparable to that in patients with both echo-based and ECG-based LVH.

Diagnostic Ability of Peguero-Lo Presti Electrocardiographic Left Ventricular Hypertrophy Criterion in Severe Aortic Stenosis

Traditional electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH), introduced in the pre-echocardiographic era of diagnosis, have a relatively low sensitivity (usually not exceeding 25–40%) in detecting LVH. A novel Peguero-Lo Presti ECG-LVH criterion was recently shown to exhibit a higher sensitivity than the traditional ECG-LVH criteria in hypertension. Our aim was to test the diagnostic ability of the novel Peguero-Lo Presti ECG-LVH criterion in severe aortic stenosis. We retrospectively analyzed 12-lead ECG tracings and echocardiographic records from the index hospitalization of 50 patients with isolated severe aortic stenosis (mean age: 77 ± 10 years; 30 women and 20 men). Exclusion criteria included QRS > 120 ms, bundle branch blocks or left anterior fascicular block, a history of myocardial infarction, more than mild aortic or mitral regurgitation, and significant LV dysfunction by echocardiography. We compared the agreement of the novel Peguero-Lo Presti criterion and traditional ECG-LVH criteria with echocardiographic LVH (LV mass index > 95 g/m² in women and >115 g/m² in men). Echocardiographic LVH was found in 32 out of 50 study patients. The sensitivity of the Peguero-Lo Presti criterion in detecting LVH was improved (55% vs. 9–34%) at lower specificity (72% vs. 78–100%) in comparison to 8 single traditional ECG-LVH criteria. Additionally, the positive predictive value (77% vs. 72%), positive likelihood ratio (2.0 vs. 1.5), and odds ratio (3.2 vs. 2.4) were higher for the Peguero-Lo Presti criterion versus the presence of any of these 8 traditional ECG-LVH criteria. Cohen’s Kappa, a measure of concordance between ECG and echocardiography with regard to LVH, was 0.24 for the Peguero-Lo Presti criterion, −0.01–0.13 for single traditional criteria, and 0.20 for any traditional criterion. However, by the receiver operating characteristics (ROC) curve analysis, the overall ability to discriminate between patients with and without LVH was insignificantly lower for the Peguero-Lo Presti versus Cornell voltage as a continuous variable (area under the ROC curve: 0.65 (95% CI, 0.48–0.81) vs. 0.71 (0.55–0.86), p = 0.5). In conclusion, our preliminary results suggest a slightly better, albeit still low, agreement of the novel Peguero-Lo Presti ECG criterion compared to the traditional ECG-LVH criteria with echocardiographic LVH in severe aortic stenosis.

Electrocardiographic Versus Echocardiographic Left Ventricular Hypertrophy in Severe Aortic Stenosis

Although ECG used to be a traditional method to detect left ventricular hypertrophy (LVH), its importance has decreased over the years and echocardiography has emerged as a routine technique to diagnose LVH. Intriguingly, an independent negative prognostic effect of the "electrical" LVH (i.e., by ECG voltage criteria) beyond echocardiographic LVH was demonstrated both in hypertension and aortic stenosis (AS), the most prevalent heart valve disorder. Our aim was to estimate associations of the ECG-LVH voltage criteria with echocardiographic LVH and indices of AS severity. We retrospectively manually analyzed ECG tracings of 50 patients hospitalized in our center for severe isolated aortic stenosis, including 32 subjects with echocardiographic LVH. The sensitivity of single traditional ECG-LVH criteria in detecting echocardiographic LVH was 9-34% and their respective specificity averaged 78-100%. The ability to predict echocardiographic LVH was higher for S-waves than R-waves (mean area under the receiver operating curve (AUC): 0.62-0.70 vs. 0.58-0.65). Among combinations of R- and S-waves, the discriminating ability was highest for the Cornell voltage (AUC: 0.71) compared to the Sokolow-Lyon, Romhilt and Gubner-Ungerleider voltage (AUC: 0.62-0.68). By multiple regression, peak aortic pressure gradient was positively related to the Sokolow-Lyon (β = 1.7 ± 0.5, p = 0.002) and Romhilt voltage (β = 1.3 ± 0.5, p = 0.01), but not Cornell (0.5 ± 0.3, p = 0.2) or Gubner-Ungerleider voltage (β = 0.0 ± 0.5, p > 0.9), regardless of LV mass index. In conclusion, echocardiographic LVH and stenosis severity appear to have distinct associations with traditional ECG-LVH criteria in AS. A moderate diagnostic superiority of the Cornell voltage criterion with regard to anatomic LVH might result from its unique ability to include depolarization vectors in both the frontal and horizontal plane with consequent lesser sensitivity to the confounding effect of obesity.

Electrocardiographic Risk Markers of Cardiac Death: Gender Differences in the General Population

Background

Cardiac death is one of the leading causes of death and sudden cardiac death (SCD) is estimated to cause approximately 50% of cardiac deaths. Men have a higher cardiac mortality than women. Consequently, the mechanisms and risk markers of cardiac mortality are not as well defined in women as they are in men.

Aim

The aim of the study was to assess the prognostic value and possible gender differences of SCD risk markers of standard 12-lead electrocardiogram in three large general population samples.

Methods

The standard 12-lead electrocardiographic (ECG) markers were analyzed from three different Finnish general population samples including total of 20,310 subjects (49.9% women, mean age 44.8 ± 8.7 years). The primary endpoint was cardiac death, and SCD and all-cause mortality were secondary endpoints. The interaction effect between women and men was assessed for each ECG variable.

Results

During the follow-up (7.7 ± 1.2 years), a total of 883 deaths occurred (24.5% women, p < 0.001). There were 296 cardiac deaths (13.9% women, p < 0.001) and 149 SCDs (14.8% women, p < 0.001). Among those who had died due to cardiac cause, women had more often a normal electrocardiogram compared to men (39.0 vs. 27.5%, p = 0.132). After adjustments with common cardiovascular risk factors and the population sample, the following ECG variables predicted the primary endpoint in men: left ventricular hypertrophy (LVH) with strain pattern (p < 0.001), QRS duration > 110 ms (p < 0.001), inferior or lateral T-wave inversion (p < 0.001) and inferolateral early repolarization (p = 0.033). In women none of the variables remained significant predictors of cardiac death in multivariable analysis, but LVH, QTc ≥ 490 ms and T-wave inversions predicted SCD (p < 0.047 and 0.033, respectively). In the interaction analysis, LVH (HR: 2.4; 95% CI: 1.2–4.9; p = 0.014) was stronger predictor of primary endpoint in women than in men.

Conclusion

Several standard ECG variables provide independent information on the risk of cardiac mortality in men but not in women. LVH and T-wave inversions predict SCD also in women.

Electrocardiographic criteria which have the best prognostic significance in hypertensive patients with echocardiographic hypertrophy of left ventricle: 15-year prospective study

BACKGROUND

Electrocardiography is the first-choice technique for detecting left ventricular hypertrophy in patients with arterial hypertension. It is necessary to know the probable outcome for every patient during the treatment, with the aim of improving cardiovascular event prevention.

HYPOTHESIS

Certain electrocardiographic criteria for left ventricular hypertrophy may predict outcomes of patients with left ventricular hypertrophy during a 15-year follow-up.

METHODS

Fifteen-year prospective study of 83 consecutive patients (53 male and 30 female; mean age 55.3 ± 8.1) with echocardiographic left ventricular hypertrophy (left ventricular mass index 170.3 ± 31.6 g/m2 ). Electrocardiographic left ventricular hypertrophy was determined by means of Gubner-Ungerleider voltage, Lewis voltage, voltage of R wave in aVL lead, Lyon-Sokolow voltage, Cornell voltage and Cornell product, voltage RV6 and RV5 ratio, Romhilt-Estes score, Framingham criterion and Perugia criterion.

RESULTS

One or more composite events were registered in 32 (38.5%) patients during 15-year follow-up. Positive Lyon-Sokolow score (17.6% vs. 47.3%; P < 0.05), Lewis voltage (9.8% vs. 21.9%; P < 0.05), Cornell voltage (15.7% vs. 37.5%; P < 0.05), and Cornell product (9.8% vs. 34.4%; P < 0.01) were more frequent in a group of patients with composite events. Odd ratio for Cornell product was 4.819 (95% CI 1.486-15.627).

CONCLUSION

Patients with echocardiographic left ventricular hypertrophy who had positive Lewis voltage, Lyon-Sokolow voltage, Cornell voltage, and Cornell product showed worse 15-year outcome. The strongest predictor of cardiovascular events was positive result of Cornell product.

Electrocardiography for the detection of left ventricular hypertrophy in an elderly population with long-standing hypertension in primary care: a secondary analysis of the CHELLO cohort study

OBJECTIVES

To investigate: (1) the prevalence of left ventricular hypertrophy (LVH) in elderly primary care patients with long-standing asymptomatic hypertension, and (2) the diagnostic value of ECG as a screening tool in the detection of LVH compared with echocardiography in this specific patient population.

DESIGN AND SETTINGS

A cross-sectional study in five general practices in the south-east of the Netherlands.

PARTICIPANTS

Patients with primary care-managed hypertension, aged between 60 and 85 years, without known heart failure.

PRIMARY AND SECONDARY OUTCOME MEASURES

Between June 2010 and January 2013, the patients underwent structured interviews, blood pressure assessment, laboratory testing, ECGs and echocardiograms. The primary outcome was to investigate the ability of ECG to detect LVH, compared with echocardiography as a reference test (gold standard).

RESULTS

Four hundred and twenty-two patients (44% male; ages 70±7 years) who underwent ECG and echocardiographic assessment to determine LVH were included. The median duration of hypertension was 10 (4-15) years. The overall prevalence of LVH was 44%, which increased with age (p<0.001); up to 60% of patients were ≥75 years. ECG intimated LVH in 47 patients (11%) but in only 26 of those (55%) was LVH confirmed by echocardiography. The sensitivity of ECG for detecting LVH was poor (14%).

CONCLUSIONS

Asymptomatic primary care patients with long-standing hypertension have a high prevalence of previously undetected LVH, which increases with age. ECG is inadequate for detecting LVH in these patients. Early detection of LVH could potentially create more awareness for the optimal regulation of hypertension and compliance to therapy. Therefore, echocardiography should be considered a screening device for the detection of LVH in this population.

Accurate Prediction of Coronary Heart Disease for Patients With Hypertension From Electronic Health Records With Big Data and Machine-Learning Methods: Model Development and Performance Evaluation

BACKGROUND

Predictions of cardiovascular disease risks based on health records have long attracted broad research interests. Despite extensive efforts, the prediction accuracy has remained unsatisfactory. This raises the question as to whether the data insufficiency, statistical and machine-learning methods, or intrinsic noise have hindered the performance of previous approaches, and how these issues can be alleviated.

OBJECTIVE

Based on a large population of patients with hypertension in Shenzhen, China, we aimed to establish a high-precision coronary heart disease (CHD) prediction model through big data and machine-learning.

METHODS

Data from a large cohort of 42,676 patients with hypertension, including 20,156 patients with CHD onset, were investigated from electronic health records (EHRs) 1-3 years prior to CHD onset (for CHD-positive cases) or during a disease-free follow-up period of more than 3 years (for CHD-negative cases). The population was divided evenly into independent training and test datasets. Various machine-learning methods were adopted on the training set to achieve high-accuracy prediction models and the results were compared with traditional statistical methods and well-known risk scales. Comparison analyses were performed to investigate the effects of training sample size, factor sets, and modeling approaches on the prediction performance.

RESULTS

An ensemble method, XGBoost, achieved high accuracy in predicting 3-year CHD onset for the independent test dataset with an area under the receiver operating characteristic curve (AUC) value of 0.943. Comparison analysis showed that nonlinear models (K-nearest neighbor AUC 0.908, random forest AUC 0.938) outperform linear models (logistic regression AUC 0.865) on the same datasets, and machine-learning methods significantly surpassed traditional risk scales or fixed models (eg, Framingham cardiovascular disease risk models). Further analyses revealed that using time-dependent features obtained from multiple records, including both statistical variables and changing-trend variables, helped to improve the performance compared to using only static features. Subpopulation analysis showed that the impact of feature design had a more significant effect on model accuracy than the population size. Marginal effect analysis showed that both traditional and EHR factors exhibited highly nonlinear characteristics with respect to the risk scores.

CONCLUSIONS

We demonstrated that accurate risk prediction of CHD from EHRs is possible given a sufficiently large population of training data. Sophisticated machine-learning methods played an important role in tackling the heterogeneity and nonlinear nature of disease prediction. Moreover, accumulated EHR data over multiple time points provided additional features that were valuable for risk prediction. Our study highlights the importance of accumulating big data from EHRs for accurate disease predictions.

Prevalence of ECGs Exceeding Thresholds for ST-Segment-Elevation Myocardial Infarction in Apparently Healthy Individuals: The Role of Ethnicity

Background

Early prehospital recognition of critical conditions such as ST‐segment–elevation myocardial infarction (STEMI) has prognostic relevance. Current international electrocardiographic STEMI thresholds are predominantly based on individuals of Western European descent. However, because of ethnic electrocardiographic variability both in health and disease, there is a need to reevaluate diagnostic ST‐segment elevation thresholds for different populations. We hypothesized that fulfillment of ST‐segment elevation thresholds of STEMI criteria (STE‐ECGs) in apparently healthy individuals is ethnicity dependent.

Methods and Results

HELIUS (Healthy Life in an Urban Setting) is a multiethnic cohort study including 10 783 apparently healthy subjects of 6 different ethnicities (African Surinamese, Dutch, Ghanaian, Moroccan, South Asian Surinamese, and Turkish). Prevalence of STE‐ECGs across ethnicities, sexes, and age groups was assessed with respect to the 2 international STEMI thresholds: sex and age specific versus sex specific. Mean prevalence of STE‐ECGs was 2.8% to 3.4% (age/sex‐specific and sex‐specific thresholds, respectively), although with large ethnicity‐dependent variability. Prevalences in Western European Dutch were 2.3% to 3.0%, but excessively higher in young (<40 years) Ghanaian males (21.7%–27.5%) and lowest in older (≥40 years) Turkish females (0.0%). Ethnicity (sub‐Saharan African origin) and other variables (eg, younger age, male sex, high QRS voltages, or anterolateral early repolarization pattern) were positively associated with STE‐ECG occurrence, resulting in subgroups with >45% STE‐ECGs.

Conclusions

The accuracy of diagnostic tests partly relies on background prevalence in healthy individuals. In apparently healthy subjects, there is a highly variable ethnicity‐dependent prevalence of ECGs with ST‐segment elevations exceeding STEMI thresholds. This has potential consequences for STEMI evaluations in individuals who are not of Western European descent, putatively resulting in adverse outcomes with both over‐ and underdiagnosis of STEMI.

Is Electrocardiography-Left Ventricular Hypertrophy an Obsolete Marker for Determining Heart Failure Risk With Hypertension?

See Article Johnson et al.

Missing Link between Molecular Aspects of Ventricular Arrhythmias and QRS Complex Morphology in Left Ventricular Hypertrophy

The aim of this opinion paper is to point out the knowledge gap between evidence on the molecular level and clinical diagnostic possibilities in left ventricular hypertrophy (LVH) regarding the prediction of ventricular arrhythmias and monitoring the effect of therapy. LVH is defined as an increase in left ventricular size and is associated with increased occurrence of ventricular arrhythmia. Hypertrophic rebuilding of myocardium comprises interrelated processes on molecular, subcellular, cellular, tissue, and organ levels affecting electrogenesis, creating a substrate for triggering and maintaining arrhythmias. The knowledge of these processes serves as a basis for developing targeted therapy to prevent and treat arrhythmias. In the clinical practice, the method for recording electrical phenomena of the heart is electrocardiography. The recognized clinical electrocardiogram (ECG) predictors of ventricular arrhythmias are related to alterations in electrical impulse propagation, such as QRS complex duration, QT interval, early repolarization, late potentials, and fragmented QRS, and they are not specific for LVH. However, the simulation studies have shown that the QRS complex patterns documented in patients with LVH are also conditioned remarkably by the alterations in impulse propagation. These QRS complex patterns in LVH could be potentially recognized for predicting ventricular arrhythmia and for monitoring the effect of therapy.

Myocardial phenotypes and dysfunction in HFpEF and HFrEF assessed by echocardiography and cardiac magnetic resonance

Heart failure (HF) with either reduced or preserved ejection fraction is an increasingly prevalent condition. Cardiac imaging plays a central role in trying to identify the underlying cause of the underlying systolic and diastolic dysfunction, as the imaging findings have implications for patient's management and individualised treatment. The imaging modalities used more frequently in patients with heart failure in clinical routine are echocardiography and cardiac magnetic resonance. Both techniques keep some strengths and weakness due to their spatial and temporal resolution. Notably, several features in the diagnostic algorithm of heart failure with preserved systolic function (HFpEF) may be improved by an integrated approach. This review focuses on the role of each modality in characterising cardiac anatomy, systolic and diastolic function as well as myocardial tissue characterisation in the most common phenotypes of dilated and hypertrophied hearts.

Interrelation Between Electrocardiographic Left Atrial Abnormality, Left Ventricular Hypertrophy, and Mortality in Participants With Hypertension

Left ventricular hypertrophy (LVH) and left atrial abnormality (LAA) are common correlated complications of hypertension. It is unclear how common for electrocardiographic markers of LAA (ECG-LAA) to coexist with ECG-LVH and how their coexistence impacts their prognostic significance. This analysis included 4,077 participants (61.2 ± 13.0 years, 51.2% women, 48.6% whites) with hypertension from the Third National Health and Nutrition Examination Survey. ECG-LVH was defined by Cornell voltage criteria. ECG-LAA was defined as deep terminal negativity of P wave in V1 >100 µV. Cox proportional hazard analysis was used to examine the associations between various combinations of ECG-LAA and ECG-LVH with all-cause mortality over a median follow-up of 14 years. The baseline prevalence of ECG-LVH, ECG-LAA, and the concomitant presence of both was 3.6%, 2.7%, and 0.34%, respectively. In a multivariable-adjusted model, mortality risk was highest in the group with concomitant ECG-LAA and ECG-LVH (hazard ratio [HR; 95% confidence interval {CI}] 2.69 [1.51, 4.80]), followed by isolated ECG-LAA (HR [95% CI] 1.63 [1.26, 2.12]), and then isolated ECG-LVH (HR [95% CI] 1.40 [1.08, 1.81]), compared with the group without ECG-LAA or ECG-LVH. Effect modification of these results by age and diabetes but not by gender or race was observed. In models with similar adjustment where ECG-LVH and ECG-LAA were entered as 2 separate variables and subsequently additionally adjusted for each other, the mortality risk was essentially unchanged for both variables. In conclusion, in participants with hypertension, ECG-LAA and ECG-LVH are independent markers of poor outcomes, and their concomitant presence carries a higher risk than either marker alone.

Short-term repeatability of electrocardiographic criteria of left ventricular hypertrophy

BACKGROUND

Left ventricular hypertrophy (LVH) is a marker of cardiac end-organ damage and a risk factor for cardiovascular morbidity and mortality. Although clinical trials and cohort studies commonly use the electrocardiogram (ECG) for LVH assessment, the repeatability of ECG-LVH criteria has not been sufficiently examined. Therefore, we evaluated the repeatability of ECG-LVH criteria.

METHODS

Participants (n = 63) underwent two standard ECGs at each of two visits, two weeks apart. The ECGs were processed centrally to calculate Cornell voltage (CV) LVH, Cornell voltage product (CVP) LVH, Sokolow-Lyon (SL) LVH, and Sokolow-Lyon product (SLP) LVH. We also used the waveforms measurements contributing to these LVH criteria as continuous variables, referred to here as CV-index, CVP-index, and SL-index. We calculated the intraclass correlation coefficient (ICC), minimal detectable change (95% confidence), and the prevalence-adjusted bias-adjusted kappa (PABAK).

RESULTS

ICCs (95% confidence intervals (CI)) were 0.97 (0.96, 0.98) for CV-index, 0.97 (0.95, 0.98) for CVP-index, and 0.93 (0.90, 0.96) for log of SL-index. Minimal detectable change between repeat measures of CV-index, CVP-index, and log of SL-index were ≥236.7 mV, ≥26.7 mV, and ≥0.09 mV, respectively. The within-visit PABAK was 1 for all ECG-LVH criteria, except for the first visit SLP-LVH (PABAK = 0.93). Between-visit PABAK ranged from 0.83 to 0.97 across LVH criteria.

CONCLUSIONS

CV, CVP, and SL ECG-LVH as continuous variables have excellent repeatability, and as binary variables have excellent within-visit agreement and good between-visit agreement. These results alleviate concerns about the repeatability the ECG-LVH use in clinical trials and epidemiologic studies.

Effect of Intensive Blood Pressure Reduction on Left Ventricular Mass, Structure, Function, and Fibrosis in the SPRINT-HEART

In observational studies, left ventricular mass (LVM) and structure are strong predictors of mortality and cardiovascular events. However, the effect of hypertension treatment on LVM reduction and its relation to subsequent outcomes is unclear, particularly at lower blood pressure (BP) targets. In an ancillary study of SPRINT (Systolic Blood Pressure Intervention Trial), where participants were randomly assigned to intensive BP control (target systolic BP target <120 mm Hg) versus standard BP control (<140 mm Hg), cardiac magnetic resonance imaging was performed at baseline and 18-month follow-up to measure: LVM, volumes, ejection fraction, and native T1 mapping for myocardial fibrosis. At baseline, 337 participants were examined (age: 64±9 years, 45% women); 300 completed the 18-month exam (153 intensive control and 147 standard control). In the intensive versus standard BP control group at 18 months, there was no difference in change in LVM (mean±SE =-2.7±0.5 g versus -2.3±0.7 g; P=0.368), ejection fraction, or native T1 (P=0.79), but there was a larger decrease in LVM/end-diastolic volume ratio (-0.04±0.01 versus -0.01±0.01; P=0.002) a measure of concentric LV remodeling. There were fewer cardiovascular events in the intensive control group, but no significant association between the reduced events and change in LVM or any other cardiac magnetic resonance imaging measure. In SPRINT-HEART, contrary to our hypothesis, there were no significant between-group differences in LVM, function, or myocardial T1 at 18-month follow-up. These results suggests that mediators other than these LV measures contribute to the improved cardiovascular outcomes with intensive BP control.

Interrelations Between Hypertension and Electrocardiographic Left Ventricular Hypertrophy and Their Associations With Cardiovascular Mortality

Electrocardiogram (ECG) is the most common method for assessment of left ventricular hypertrophy (LVH) in contemporary clinical trials. However, our understanding of the relation between hypertension and LVH is based on studies used imaging to ascertain LVH. To fill this gap in knowledge, we examined the interrelationships between hypertension, ECG-LVH and cardiovascular disease (CVD) mortality in 6,105 patients free of CVD who were followed for 14.0 years (median). The was an exponentianl ECG-LVH prevalence rates (2.40%, 4.45%, 5.75%, 8.51%, 14.38%) were exponentially increases as systolic blood pressure increases (<120 mm Hg, 120 to 129 mm Hg, 130 to 139 mm Hg, 140 to 159 mm Hg, >160 mm Hg, respectively); trend p value <0.001. Hypertension was associated with more than double the risk of ECG-LVH (odds ratio (95% confidence interval [CI]) 2.45 [1.83, 3.30]), and each standard-deviation increase in systolic blood pressure (19 mm Hg) was associated with 49% increased odds of ECG-LVH (odds ratio [95% CI] 1.49 [1.38, 1.61]). During follow-up, 733 CVD-deaths occurred. In separate Cox models, both ECG-LVH and hypertension were associated with CVD mortality (hazard ratio [95% CI] 1.39 [1.07, 1.81] and 1.39 [1.18, 1.62], respectively). However, when ECG-LVH and hypertension were entered together in the same model, the risk of CVD mortality was essentially unchanged for hypertension after adjusting for ECG-LVH, but markedly attenuated for ECG-LVH after adjusting for hypertension. In conclusion, the relation between hypertension and ECG-LVH follows a similar pattern to that reported in literature for imaging-LVH which provides support for the current practice of using ECG for assessment of LVH in contemporary hypertension clinical trials. The inability of ECG-LVH to explain the association between hypertension and CVD mortality suggests that LVH is only one of many factors by which hypertension exerts its impact on CVD.

Peguero Electrocardiographic Left Ventricular Hypertrophy Criteria and Risk of Mortality

Background: Peguero electrocardiographic left ventricular hypertrophy (ECG-LVH) criteria are newly developed criteria that have shown better diagnostic performance than the traditional Cornell-voltage and Sokolow-Lyon criteria. However, prediction of poor outcomes rather than detection of increased left ventricular mass is becoming the primary use for ECG-LVH criteria which requires investigating any new ECG-LVH criteria in terms of prediction.

Aims: To examine the prognostic significance of the newly developed Peguero ECG-LVH criteria.

Methods: We compared the prognostic significance of Peguero ECG-LVH with Cornell-voltage and Sokolow-Lyon ECG-LVH criteria in 7,825 participants (age 59.8 ± 13.4 years; 52.7% women) from the third National Health and Nutrition Examination Survey who were free of major intraventricular conduction defects. ECG-LVH criteria were derived from digital ECG tracings processed at a central core laboratory.

Results: At baseline, ECG-LVH was detected in 11.8% by Peguero; in 4.3% by Cornell voltage and in 6.4% by Sokolow-Lyon. During a median follow up of 13.8 years, 2,796 all-cause mortality events occurred. In multivariable models adjusted for demographics and cardiovascular risk factors, presence of Peguero ECG-LVH was associated with increased risk of all-cause mortality [HR (95% CI): 1.29 (1.16, 1.44)]. This association was not significantly different from the associations of Cornell voltage-LVH or Sokolow-Lyon LVH with all-cause mortality [HR (95%CI): 1.32 (1.12, 1.55) and 1.24 (1.07, 1.43), respectively; p-values for comparisons of these HRs with the HR of Peguero ECG-LVH 0.817 and 0.667, respectively]. Similar patterns of associations were observed with cardiovascular, ischemic heart disease and heart failure mortalities.

Conclusion: Peguero ECG-LVH is predictive of increased risk of death similar to the traditional ECG-LVH criteria.

Global ECG Measures and Cardiac Structure and Function: The ARIC Study (Atherosclerosis Risk in Communities)

BACKGROUND

Electric excitation initiates myocardial mechanical contraction and coordinates myocardial pumping. We hypothesized that ECG global electric heterogeneity (GEH) and its longitudinal changes are associated with cardiac structure and function.

METHODS AND RESULTS

Participants from the ARIC study (Atherosclerosis Risk in Communities) (N=5114; 58% female; 22% blacks) with resting 12-lead ECGs (visits 1-5) and echocardiographic assessment of left ventricular (LV) ejection fraction, LV global longitudinal strain, LV mass index, LV end-diastolic volume index, and LV end-systolic volume index at visit 5 were included. Longitudinal analysis included ARIC participants (N=14 609) with measured GEH at visits 1 to 4. GEH was quantified by spatial ventricular gradient, QRS-T angle, and sum absolute QRS-T integral. Cross-sectional and longitudinal regressions were adjusted for manifest and subclinical cardiovascular disease. Having 4 abnormal GEH parameters was associated with a 6.4% (95% confidence interval, 5.5-7.3) LV ejection fraction decline, a 24.2 g/m2 (95% confidence interval, 21.5-26.9) increase in LV mass index, a 10.3 mL/m2 (95% confidence interval, 8.9-11.7) increase in LV end-diastolic volume index, and a 7.8 mL/m2 (95% confidence interval, 6.9-8.6) increase in LV end-systolic volume index. Altogether, clinical and ECG parameters accounted for approximately one third of LV volume and 20% of systolic function variability. The associations were significantly stronger in cardiovascular disease. Sum absolute QRS-T integral increased by 20 mV*ms for each 3-year period in participants who demonstrated LV dilatation at visit 5. Sudden cardiac death victims demonstrated rapid GEH worsening, whereas those with LV dysfunction demonstrated slow GEH worsening. Healthy aging was associated with a distinct pattern of spatial ventricular gradient azimuth decrement.

CONCLUSIONS

GEH is a marker of subclinical abnormalities in cardiac structure and function.

Combining ECG Criteria for Left Ventricular Hypertrophy Improves Risk Prediction in Patients With Hypertension

BACKGROUND

Patients with hypertension with ECG left ventricular hypertrophy (LVH) have higher cardiovascular morbidity and mortality, but single ECG criteria may underestimate risk. Whether continued presence or new development of ECG LVH by 2 criteria can further concentrate risk during blood pressure lowering is unclear.

METHODS AND RESULTS

Incident stroke, myocardial infarction, cardiovascular death, the composite of these outcomes, and all-cause mortality were examined in relation to the presence of on-treatment ECG LVH by Cornell product and/or Sokolow-Lyon voltage during a mean of 4.8±0.9 years follow-up in 9193 patients with hypertension randomized to losartan- or atenolol-based regimens. Patients were categorized into 4 groups according to the presence or absence of ECG LVH by each criterion at baseline and yearly during the study. At baseline, LVH by both criteria was present in 960 patients (10.4%). Compared with the absence of ECG LVH by both criteria, persistence or development of ECG LVH by both criteria entered as a time-varying covariate was associated with >3-fold increased risks of events in multivariable Cox analyses adjusting for randomized treatment, baseline risk factors, and on-treatment heart rate and systolic and diastolic blood pressures. Patients with ECG LVH by either Cornell product or Sokolow-Lyon voltage had 45% to 140% higher risks of all end points.

CONCLUSIONS

Persistence or development of ECG LVH by both Cornell product and Sokolow-Lyon voltage criteria during antihypertensive therapy is associated with markedly increased risks of cardiovascular end points and all-cause mortality. Further study is indicated to determine whether additional therapy in these patients can reduce their risk.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00338260.

Office and Home Blood Pressures as Determinants of Electrocardiographic Left Ventricular Hypertrophy Among Black Nigerians Compared With White Flemish

BACKGROUND

The association of electrocardiographic left ventricular hypertrophy (ECG-LVH) with blood pressure (BP) in Blacks living in sub-Saharan Africa remains poorly documented.

METHODS

In 225 Black Nigerians and 729 White Flemish, we analyzed QRS voltages and voltage-duration products and 12 criteria diagnostic of ECG-LVH in relation to office BP (mean of 5 consecutive readings) and home BP (duplicate morning and evening readings averaged over 1 week).

RESULTS

In multivariable analyses, QRS voltage and voltage-duration indexes were generally higher in Blacks than Whites. By using any of 12 criteria, ECG-LVH was more prevalent among Black than White men (54.4% vs. 36.0%) with no ethnic difference among women (17.1%). Precordial voltages and voltage-duration products increased with office and home systolic BP (SBP), and increases were up to 3-fold steeper in Blacks. In Blacks vs. Whites, increases in the Sokolow–Lyon voltage associated with a 10-mm Hg higher SBP were 0.18 mV (95% confidence interval [CI], 0.09–0.26) vs. 0.06 mV (0.02–0.09) and 0.17 mV (0.07–0.28) vs. 0.11 mV (CI, 0.07–0.15) for office and home BP, respectively, with a significant ethnic gradient (P < 0.05). The risk of ECG-LVH increased more with office and home BP in Blacks than Whites.

CONCLUSIONS

Associations of ECG voltages and voltage-duration products and risk of ECG-LVH with BP are steeper in Black Nigerians compared with a White reference population. In resource-poor settings of sub-Saharan Africa, the ECG in combination with office and home BP is an essential instrument in risk stratification across the entire BP range.

Left Ventricular Hypertrophy by the Surface ECG

Left ventricular hypertrophy (LVH) is defined as an increase in left ventricular mass (LVM) associated with structural changes of myocardium. The increase in LVM and associated changes are associated with changes in depolarization and repolarization, manifested as a variety of altered QRS and T patterns. Increased QRS voltage has been considered to be a specific ECG finding in LVH, and ECG criteria based on this increased QRS voltage are generally recommended. These ECG changes are also predictive of adverse cardiovascular outcomes. However, it must also be noted that the majority of patients with increased LVM do not have increased QRS voltage. While this is often considered a limitation of ECG in LVH diagnosis, the authors of this minireview consider it more likely that the electrical effects, represented in the altered ECG, and the increased LVM are independent effects, associated by virtue of their common relationship with an underlying pathologic state. This revised view challenges cardiologists and electrocardiologists to explore the interrelationships between electrical, biochemical, and mechanical alterations of myocardial remodeling seen with heart disease, to advance our understanding of this process and its effects, including the evolution of the ECG changes known as "LVH".

The emerging role of Cardiovascular Magnetic Resonance in the evaluation of hypertensive heart disease

BACKGROUND

Arterial hypertension is the commonest cause of cardiovascular death. It may lead to hypertensive heart disease (HHD), including heart failure (HF), ischemic heart disease (IHD) and left ventricular hypertrophy (LVH).

MAIN BODY

According to the 2007 ESH/ESC guidelines, the recommended imaging technique is echocardiography (echo), when a more sensitive detection of LVH than that provided by ECG, is needed. Cardiovascular Magnetic Resonance (CMR), a non-invasive, non-radiating technique, offers the following advantages, beyond echo: a) more reliable and reproducible measurements of cardiac parameters such as volumes, ejection fraction and cardiac mass b) more accurate differentiation of LVH etiology by providing information about tissue characterisation c) more accurate evaluation of myocardial ischemia, specifically if small vessels disease is present d) technique of choice for diagnosis of renovascular, aortic tree/branches lesions and quantification of aortic valve regurgitation e) technique of choice for treatment evaluation in clinical trials. The superiority of CMR against echocardiography in terms of reproducibility, operator independency, unrestricted field of view and capability of tissue characterization makes the technique ideal for evaluation of heart, quantification of aortic valve regurgitation, aorta and aortic branches.

CONCLUSIONS

CMR has a great potential in early diagnosis, risk stratification and treatment follow up of HHD. However, an international consensus about CMR in HHD, taking under consideration the cost-benefit ratio, expertise and availability, is still warranted.

Diffuse Myocardial Fibrosis Reduces Electrocardiographic Voltage Measures of Left Ventricular Hypertrophy Independent of Left Ventricular Mass

Background

Myocardial fibrosis quantified by myocardial extracellular volume fraction (ECV) and left ventricular mass (LVM) index (LVMI) measured by cardiovascular magnetic resonance might represent independent and opposing contributors to ECG voltage measures of left ventricular hypertrophy (LVH). Diffuse myocardial fibrosis can occur in LVH and interfere with ECG voltage measures. This phenomenon could explain the decreased sensitivity of LVH detectable by ECG, a fundamental diagnostic tool in cardiology.

Methods and Results

We identified 77 patients (median age, 53 [interquartile range, 26–60] years; 49% female) referred for contrast‐enhanced cardiovascular magnetic resonance with ECV measures and 12‐lead ECG. Exclusion criteria included clinical confounders that might influence ECG measures of LVH. We evaluated ECG voltage‐based LVH measures, including Sokolow‐Lyon index, Cornell voltage, 12‐lead voltage, and the vectorcardiogram spatial QRS voltage, with respect to LVMI and ECV. ECV and LVMI were not correlated (R²=0.02; P=0.25). For all voltage‐related parameters, higher LVMI resulted in greater voltage (r=0.33–0.49; P<0.05 for all), whereas increased ECV resulted in lower voltage (r=−0.32 to −0.57; P<0.05 for all). When accounting for body fat, LV end‐diastolic volume, and mass‐to‐volume ratio, both LVMI (β=0.58, P=0.03) and ECV (β=−0.46, P<0.001) were independent predictors of QRS voltage (multivariate adjusted R²=0.39; P<0.001).

Conclusions

Myocardial mass and diffuse myocardial fibrosis have independent and opposing effects upon ECG voltage measures of LVH. Diffuse myocardial fibrosis quantified by ECV can obscure the ECG manifestations of increased LVM. This provides mechanistic insight, which can explain the limited sensitivity of the ECG for detecting increased LVM.

The 4th Report of the Working Group on ECG diagnosis of Left Ventricular Hypertrophy

The 4th Report provides a brief review of publications focused on the electrocardiographic diagnosis of left ventricular hypertrophy published during the period of 2010 to 2016 by the members of the Working Group on ECG diagnosis of Left Ventricular Hypertrophy. The Working Group recommended that ECG research and clinical attention be redirected from the estimation of LVM to the identification of electrical remodeling, to better understanding the sequence of events connecting electrical remodeling to outcomes. The need for a re-definition of terms and for a new paradigm is also stressed.

Left ventricular hypertrophy by ECG versus cardiac MRI as a predictor for heart failure

OBJECTIVE

To determine if there is a significant difference in the predictive abilities of left ventricular hypertrophy (LVH) detected by ECG-LVH versus LVH ascertained by cardiac MRI-LVH in a model similar to the Framingham Heart Failure Risk Score (FHFRS).

METHODS

This study included 4745 (mean age 61±10 years, 53.5% women, 61.7% non-whites) participants in the Multi-Ethnic Study of Atherosclerosis. ECG-LVH was defined using Cornell voltage product while MRI-LVH was derived from left ventricular mass. Cox proportional hazard regression was used to examine the association between ECG-LVH and MRI-LVH with incident heart failure (HF). Harrell's concordance C-index was used to estimate the predictive ability of the model when either ECG-LVH or MRI-LVH was included as one of its components.

RESULTS

ECG-LVH was present in 291 (6.1%), while MRI-LVH was present in 499 (10.5%) of the participants. Both ECG-LVH (HR 2.25, 95% CI 1.38 to 3.69) and MRI-LVH (HR 3.80, 95% CI 1.56 to 5.63) were predictive of HF. The absolute risk of developing HF was 8.81% for MRI-LVH versus 2.26% for absence of MRI-LVH with a relative risk of 3.9. With ECG-LVH, the absolute risk of developing HF 6.87% compared with 2.69% for absence of ECG-LVH with a relative risk of 2.55. The ability of the model to predict HF was better with MRI-LVH (C-index 0.871, 95% CI 0.842 to 0.899) than with ECG-LVH (C-index 0.860, 95% CI 0.833 to 0.888) (p<0.0001).

CONCLUSIONS

ECG-LVH and MRI-LVH are predictive of HF. Substituting MRI-LVH for ECG-LVH improves the predictive ability of a model similar to the FHFRS.

Improvements in ECG accuracy for diagnosis of left ventricular hypertrophy in obesity

OBJECTIVES

The electrocardiogram (ECG) is the most commonly used tool to screen for left ventricular hypertrophy (LVH), and yet current diagnostic criteria are insensitive in modern increasingly overweight society. We propose a simple adjustment to improve diagnostic accuracy in different body weights and improve the sensitivity of this universally available technique.

METHODS

Overall, 1295 participants were included-821 with a wide range of body mass index (BMI 17.1-53.3 kg/m(2)) initially underwent cardiac magnetic resonance evaluation of anatomical left ventricular (LV) axis, LV mass and 12-lead surface ECG in order to generate an adjustment factor applied to the Sokolow-Lyon criteria. This factor was then validated in a second cohort (n=520, BMI 15.9-63.2 kg/m(2)).

RESULTS

When matched for LV mass, the combination of leftward anatomical axis deviation and increased BMI resulted in a reduction of the Sokolow-Lyon index, by 4 mm in overweight and 8 mm in obesity. After adjusting for this in the initial cohort, the sensitivity of the Sokolow-Lyon index increased (overweight: 12.8% to 30.8%, obese: 3.1% to 27.2%) approaching that seen in normal weight (37.8%). Similar results were achieved in the validation cohort (specificity increased in overweight: 8.3% to 39.1%, obese: 9.4% to 25.0%) again approaching normal weight (39.0%). Importantly, specificity remained excellent (>93.1%).

CONCLUSIONS

Adjusting the Sokolow-Lyon index for BMI (overweight +4 mm, obesity +8 mm) improves the diagnostic accuracy for detecting LVH. As the ECG, worldwide, remains the most widely used screening tool for LVH, implementing these findings should translate into significant clinical benefit.

Do Combined Electrocardiographic and Echocardiographic Markers of Left Ventricular Hypertrophy Improve Cardiovascular Risk Estimation?

The authors estimated the risk of cardiovascular mortality associated with echocardiographic (ECHO) left ventricular hypertrophy (LVH) and subtypes of this phenotype in patients with and without electrocardiographic (ECG) LVH. A total of 1691 representatives of the general population were included in the analysis. During a follow-up of 211 months, 89 cardiovascular deaths were recorded. Compared with individuals with neither ECHO LVH nor ECG LVH, fully adjusted risk of cardiovascular mortality increased (hazard ratio [HR], 3.36; 95% confidence interval [CI], 1.51-7.47; P=.003) in patients with both ECHO-LVH and ECG-LVH, whereas the risk entailed by ECHO-LVH alone was of borderline statistical significance (P=.04). Combined concentric nondilated LVH and ECG-LVH, but not concentric nondilated LVH alone, predicted cardiovascular death (HR, 3.79; 95% CI, 1.25-11.38; P=.01). Similar findings were observed for eccentric nondilated LVH (HR, 3.37; 95% CI, 1.05-10.78; P=.04.). The present analysis underlines the value of combining ECG and ECHO in the assessment of cardiovascular prognosis related to abnormal left ventricular geometric patterns.