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

Importance of T1-Mapping Sequence in Patients with Hypertrophic Cardiomyopathy without Foci of Non-Ischemic Myocardial Injury in Late Gadolinium Enhancement Sequence

BACKGROUND

The aim of this study was to assess the importance of T1-mapping sequences in the diagnosis of hypertrophic cardiomyopathy (HCM) in patients without foci of non-ischemic myocardial injury in classic cardiac magnetic resonance (CMR) sequences.

METHODS

Two groups were compared: 28 patients with HCM, without any foci of myocardial injury in the late gadolinium enhancement (LGE) sequence (HCM group), and 28 patients without cardiomyopathy (CON group). Classic CMR sequences and T1-mapping sequences were performed. The following parameters were assessed: T1 time of the whole left ventricular myocardium, T1 time of myocardium in the basal, middle and apical layers of the left ventricle, and T1 time in individual segments of the left ventricular myocardium. Myocardial extracellular volume (ECV) was assessed similarly.

RESULTS

ECV was significantly higher in the HCM group than in the CON group, for the whole left ventricular myocardium, for the basal and apical layers of the left ventricle, and for segments 1-3, 8, and 13-16 of the left ventricle. Regression analysis showed that a higher left-ventricular mass index (LVMI), a higher body mass index and older age are factors independently associated with a higher ECV of the whole myocardium but only in the group with LVMI ≥ 131.84 g/m2.

CONCLUSION

In patients with HCM without foci of non-ischemic myocardial injury, higher ECV values of the left ventricular myocardium are observed.

Accurate diagnosis of apical hypertrophic cardiomyopathy using explainable advanced electrocardiogram analysis

AIMS

Typical electrocardiogram (ECG) features of apical hypertrophic cardiomyopathy (ApHCM) include tall R waves and deep or giant T-wave inversion in the precordial leads, but these features are not always present. The ECG is used as the gatekeeper to cardiac imaging for diagnosis. We tested whether explainable advanced ECG (A-ECG) could accurately diagnose ApHCM.

METHODS AND RESULTS

Advanced ECG analysis was performed on standard resting 12-lead ECGs in patients with ApHCM [n = 75 overt, n = 32 relative (<15 mm hypertrophy); a subgroup of which underwent cardiovascular magnetic resonance (n = 92)], and comparator subjects (n = 2449), including healthy volunteers (n = 1672), patients with coronary artery disease (n = 372), left ventricular electrical remodelling (n = 108), ischaemic (n = 114) or non-ischaemic cardiomyopathy (n = 57), and asymmetrical septal hypertrophy HCM (n = 126). Multivariable logistic regression identified four A-ECG measures that together discriminated ApHCM from other diseases with high accuracy [area under the receiver operating characteristic (AUC) curve (bootstrapped 95% confidence interval) 0.982 (0.965-0.993)]. Linear discriminant analysis also diagnosed ApHCM with high accuracy [AUC 0.989 (0.986-0.991)].

CONCLUSION

Explainable A-ECG has excellent diagnostic accuracy for ApHCM, even when the hypertrophy is relative, with A-ECG analysis providing incremental diagnostic value over imaging alone. The electrical (ECG) and anatomical (wall thickness) disease features do not completely align, suggesting that future diagnostic and management strategies may incorporate both features.

Estimating Left Ventricular Mass from the Electrocardiogram across the Spectrum of LV Mass from Normal to Increased LV Mass in an Older Age Group

Objectives

To examine the relationship of QRS voltages and left ventricular (LV) mass across the spectrum of individuals with different LV mass.

Methods

Twenty QRS voltage measurements or combinations were determined in a consecutive series of 159 adults with an ECG and echocardiogram without previous myocardial infarction, left or right bundle branch block, pre-excitation, or electronic pacemaker.

Results

The four strongest and significant correlations between QRS and LV mass were S in V4, deepest S wave in any precordial lead plus S in V4, S in V3, and S in V3 plus R in AVL times QRS duration. For men, the strength of the relationships were S in V3 (F = 33.8), deepest S wave in any precordial lead plus S V4 (F = 33.7), S in V3 plus R aVL (F = 29.9), S in V4 (F = 29.79), and deepest S in precordial leads (F = 17.9). The R wave in AVL alone did not correlate with LV mass. Criteria using the R wave in lateral precordial leads did not correlate as strongly with LV mass. For women, only S in V4 significantly correlated with LV mass. Overall, the R wave voltage in limb leads (AVL I or II) did not correlate with precordial S wave amplitudes. Univariate and multivariate analysis showed that some but not all QRS voltages correlated with each other. In multivariate analysis, using only single variables and not combination of QRS variables, the only significant relationship between QRS voltage and left ventricular mass was for men the S in V3 (p = 0.04) and for women S in V4 (p = 0.016) and R in V6 (p = 0.04).

Conclusion

The S wave in V3 and V4 correlate most strongly with LV mass while the R wave in limb leads, including AVL, do not correlate.

[Clinical differences between transthyretin cardiac amyloidosis and hypertensive heart disease]

INTRODUCTION

A significant percentage of patients eventually diagnosed with cardiac transthyretin amyloidosis (TTRA) was previously diagnosed with hypertensive heart disease (HHD), since both conditions usually present with heart failure (HF) with preserved ejection fraction (HFpEF) and ventricular hypertrophy. Our objectives were to evaluate the clinical, electrocardiographic and echocardiographic differences, and to analyse whether there exists a differential prognosis between these two nosological entities.

MATERIALS AND METHODS

We retrospectively included all patients with HHD for whom a cardiac scintigraphy with 99mTc-diphosphonate (GDPD) and a free light chains test in blood and urine were ordered for ATTR screening in our centre, in the period between 2016 and 2021. Those diagnosed with other types of amyloidosis were excluded from the analysis.

RESULTS

A total of 72 patients were analyzed: 33 were finally diagnosed with TTRA and 39 with CHTA. Patients with TTRA had higher levels of ultrasensitive troponin I (TnI-US) and N-terminal brain natriuretic propeptide (NT-ProBNP); in electrocardiography (ECG) they presented a pseudo-infarction pattern more frequently as well as conduction disturbances; in echocardiography (TTE) they presented a higher degree of ventricular hypertrophy, left ventricular dysfunction and worse diastolic function parameters, with elevated filling pressures. In the 4-year follow-up, the ATTR group showed greater need for pacemaker (PCM), with no evidence regarding mortality, development of atrial fibrillation (AF), or more admissions for heart failure (HF).

CONCLUSIONS

In our series, patients with TTRA showed clinical, electrocardiographic and echocardiographic differences compared to patients with HHD, with increased risk of need for PCM.

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 Associations of Cardiac Biomarkers and Cardiac Magnetic Resonance Measures of Fibrosis in the Multiethnic Study of Atherosclerosis (MESA)

Abnormalities in myocardial substrate, including diffuse and replacement fibrosis, increase the risk of cardiovascular disease (CVD). Data are sparse on whether electrocardiogram (ECG) measures, coupled with circulating biomarkers, may aid in identifying cardiac fibrosis. This study aimed to determine whether 12-lead ECG and biomarkers together augment the prediction of cardiac fibrosis in participants who are free of known CVD. This is a cross-sectional analysis in the MESA (Multiethnic Study of Atherosclerosis) study at visit 5 (2010 to 2012), with measurements of biomarkers (cardiac troponin T and growth differentiation factor-15), gadolinium-enhanced cardiac magnetic resonance imaging, and ECG. Logistic regression associations of ECG measures with cardiac magnetic resonance surrogates of fibrosis (highest quartile extracellular volume [interstitial fibrosis] and late gadolinium enhancement [replacement fibrosis]) were adjusted for demographics and risk factors. Using the C-statistic, we evaluated whether adding ECG measures and biomarkers to clinical characteristics improved the prediction of either type of fibrosis. There were 1,170 eligible participants (aged 67.1 ± 8.6 years). Among the ECG measures, QRS duration (odds ratio [OR] 1.41 per 10 ms, 95% confidence interval [CI] 1.10 to 1.81), major ST-T abnormalities (OR 3.03, 95%CI 1.20, 7.65), and abnormal QRS-T angle (OR 6.32, 95%CI 3.00, 13.33) were associated with replacement fibrosis, whereas only abnormal QRS-T angle (OR 3.05, 95%CI,1.69, 5.48) was associated with interstitial fibrosis. ECG markers, in addition to clinical characteristics, improved the prediction of replacement fibrosis (p = 0.002) but not interstitial fibrosis. The addition of cardiac troponin T and growth differentiation factor-15 to the ECG findings did not significantly improve the model discrimination for either type of cardiac fibrosis. In CVD free participants, simple ECG measures are associated with replacement fibrosis and interstitial fibrosis. The addition of these measures improves identification of replacement but not interstitial fibrosis. These findings may help refine the identification of myocardial scar in the general population.

Electrocardiographic Markers of Adverse Left Ventricular Remodeling and Myocardial Fibrosis in Severe Aortic Stenosis

The optimal timing for aortic valve replacement (AVR) in aortic stenosis (AS) is still controversial and may be guided by markers of adverse left ventricular (LV) remodeling. We aim to assess electrocardiographic (ECG) strain in relation to LV remodeling and myocardial fibrosis. 83 severe AS patients underwent surgical AVR, with preoperative 12-lead ECG, cardiovascular magnetic resonance with T1 mapping and echocardiography with global longitudinal strain analysis. Collagen volume fraction (CVF) was measured in myocardial biopsies sampled during AVR. Patients with ECG strain had more severe AS, more advanced LV remodeling and evidence of heart failure. Patients with ECG strain had more diffuse fibrosis, as evident by higher mean native T1 values (974.8 ± 34 ms vs. 946.5 ± 28 ms, p < 0.001). ECG strain was the only predictor of increased LV mass index on multivariate regression analysis (OR = 7.10, 95% CI 1.46-34.48, p = 0.02). Patients with persistent ECG strain at 1 year following AVR had more advanced LV remodeling and more histological fibrosis (CVF 12.5% vs. 7.3%, p = 0.009) at baseline assessment. Therefore, ECG strain is a marker of adverse LV remodeling and interstitial myocardial fibrosis. Lack of improvement in ECG strain following AVR indicates more advanced baseline LV injury and higher levels of myocardial fibrosis.

Relating QRS voltages to left ventricular mass and body composition in elite endurance athletes

PURPOSE

Electrocardiogram (ECG) QRS voltages correlate poorly with left ventricular mass (LVM). Body composition explains some of the QRS voltage variability. The relation between QRS voltages, LVM and body composition in endurance athletes is unknown.

METHODS

Elite endurance athletes from the Pro@Heart trial were evaluated with 12-lead ECG for Cornell and Sokolow-Lyon voltage and product. Cardiac magnetic resonance imaging assessed LVM. Dual energy x-ray absorptiometry assessed fat mass (FM) and lean mass of the trunk and whole body (LBM). The determinants of QRS voltages and LVM were identified by multivariable linear regression. Models combining ECG, demographics, DEXA and exercise capacity to predict LVM were developed.

RESULTS

In 122 athletes (19 years, 71.3% male) LVM was a determinant of the Sokolow-Lyon voltage and product (β = 0.334 and 0.477, p < 0.001) but not of the Cornell criteria. FM of the trunk (β = - 0.186 and - 0.180, p < 0.05) negatively influenced the Cornell voltage and product but not the Sokolow-Lyon criteria. DEXA marginally improved the prediction of LVM by ECG (r = 0.773 vs 0.510, p < 0.001; RMSE = 18.9 ± 13.8 vs 25.5 ± 18.7 g, p > 0.05) with LBM as the strongest predictor (β = 0.664, p < 0.001). DEXA did not improve the prediction of LVM by ECG and demographics combined and LVM was best predicted by including VO₂max (r = 0.845, RMSE = 15.9 ± 11.6 g).

CONCLUSION

LVM correlates poorly with QRS voltages with adipose tissue as a minor determinant in elite endurance athletes. LBM is the strongest single predictor of LVM but only marginally improves LVM prediction beyond ECG variables. In endurance athletes, LVM is best predicted by combining ECG, demographics and VO₂max.

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.

Improved evaluation of left ventricular hypertrophy using the spatial QRS-T angle by electrocardiography

Electrocardiographic (ECG) signs of left ventricular hypertrophy (LVH) lack sensitivity. The aim was to identify LVH based on an abnormal spatial peaks QRS-T angle, evaluate its diagnostic performance compared to conventional ECG criteria for LVH, and its prognostic performance. This was an observational study with four cohorts with a QRS duration < 120 ms. Based on healthy volunteers (n = 921), an abnormal spatial peaks QRS-T angle was defined as ≥ 40° for females and ≥ 55° for males. In other healthy volunteers (n = 461), the specificity of the QRS-T angle to detect LVH was 96% (females) and 98% (males). In patients with at least moderate LVH by cardiac imaging (n = 225), the QRS-T angle had a higher sensitivity than conventional ECG criteria (93–97% vs 13–56%, p < 0.001 for all). In clinical consecutive patients (n = 783), of those who did not have any LVH, 238/556 (43%) had an abnormal QRS-T angle. There was an association with hospitalization for heart failure or all-cause death in univariable and multivariable analysis. An abnormal QRS-T angle rarely occurred in healthy volunteers, was a mainstay of moderate or greater LVH, was common in clinical patients without LVH but with cardiac co-morbidities, and associated with outcomes.

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.

Influenza virus replication in cardiomyocytes drives heart dysfunction and fibrosis

Cardiac dysfunction is a common complication of severe influenza virus infection, but whether this occurs due to direct infection of cardiac tissue or indirectly through systemic lung inflammation remains unclear. To test the etiology of this aspect of influenza disease, we generated a novel recombinant heart-attenuated influenza virus via genome incorporation of target sequences for miRNAs expressed in cardiomyocytes. Compared with control virus, mice infected with miR-targeted virus had significantly reduced heart viral titers, confirming cardiac attenuation of viral replication. However, this virus was fully replicative in the lungs and induced similar systemic inflammation and weight loss compared to control virus. The miR-targeted virus induced fewer cardiac conduction irregularities and significantly less fibrosis in mice lacking interferon-induced transmembrane protein 3 (IFITM3), which serve as a model for influenza-associated cardiac pathology. We conclude that robust virus replication in the heart is required for pathology, even when lung inflammation is severe.

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.

Arrhythmogenic right ventricular cardiomyopathy and sports activity: from molecular pathways in diseased hearts to new insights into the athletic heart mimicry

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease associated with a high risk of sudden cardiac death. Among other factors, physical exercise has been clearly identified as a strong determinant of phenotypic expression of the disease, arrhythmia risk, and disease progression. Because of this, current guidelines advise that individuals with ARVC should not participate in competitive or frequent high-intensity endurance exercise. Exercise-induced electrical and morphological para-physiological remodelling (the so-called 'athlete's heart') may mimic several of the classic features of ARVC. Therefore, the current International Task Force Criteria for disease diagnosis may not perform as well in athletes. Clear adjudication between the two conditions is often a real challenge, with false positives, that may lead to unnecessary treatments, and false negatives, which may leave patients unprotected, both of which are equally inacceptable. This review aims to summarize the molecular interactions caused by physical activity in inducing cardiac structural alterations, and the impact of sports on arrhythmia occurrence and other clinical consequences in patients with ARVC, and help the physicians in setting the two conditions apart.

Electrocardiographic parameters of left ventricular hypertrophy and prediction of mortality in hemodialysis patients

Background

In hemodialysis patients, left ventricular hypertrophy (LVH) contributes to high cardiovascular mortality. We examined cardiovascular mortality prediction by the recently proposed Peguero-Lo Presti voltage since it identifies more patients with electrocardiographic (ECG) LVH than Cornell or Sokolow-Lyon voltages.

Methods

A total of 308 patients on hemodialysis underwent 24 h ECG recordings. LVH parameters were measured before and after dialysis. The primary endpoint of cardiovascular mortality was recorded during a median 3-year follow up. Risk prediction was assessed by Cox regression, both unadjusted and adjusted for the Charlson Comorbidity Index and the Cardiovascular Mortality Risk Score.

Results

The Peguero-Lo Presti voltage identified with 21% the most patients with positive LVH criteria. All voltages significantly increased during dialysis. Factors such as ultrafiltration rate, Kt/V, body mass index, sex, and phosphate were the most relevant for these changes. During follow-up, 26 cardiovascular deaths occurred. Post-dialysis Peguero-Lo Presti cut-off as well as the Peguero-Lo Presti and Cornell voltages were independently associated with cardiovascular mortality in unadjusted and adjusted analysis. The Sokolow-Lyon voltage was not significantly associated with mortality. An optimal cut-off for the prediction of cardiovascular mortality was estimated at 1.38 mV for the Peguero-Lo Presti.

Conclusions

The post-dialysis Peguero-Lo Presti cut-off as well as the Peguero-Lo Presti and Cornell voltages allowed independent risk prediction of cardiovascular mortality in hemodialysis patients. Measuring the ECG LVH parameters after dialysis might allow a standardized interpretation as dialysis-specific factors influence the voltages.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01068-0.

The electrocardiogram: Still a useful marker for LV fibrosis in aortic stenosis

Left ventricular (LV) strain on the electrocardiogram (ECG) (down-sloping, convex ST-segment depression with asymmetric T-wave inversion in leads V5 and V6) reflects fibrosis as a result of subendocardial ischemia. It is associated with a significantly increased risk of cardiovascular events independent of the presence of LV hypertrophy on the echocardiogram or cardiac magnetic resonance (CMR) scan. Ongoing studies of early aortic valve replacement in asymptomatic patients with severe aortic stenosis are using ECG changes as a marker of possible fibrosis shown by midwall late gadolinium enhancement on CMR. However, until these studies report, it is still reasonable to respond to LV strain on the ECG by tightening control of systemic hypertension and consider intervention in cases where indications are otherwise in borderline.

Prediction of current and new development of atrial fibrillation on electrocardiogram with sinus rhythm in patients without structural heart disease

BACKGROUND

Diagnosis of atrial fibrillation (AF) based on electrocardiogram (ECG) with sinus rhythm remains a major challenge. Obtaining a panoramic view with hundreds of automatically measured ECG parameters at sinus rhythm on the predictive capability for AF would be informative.

METHODS

We used a single-center database of a specialist cardiovascular hospital (Shinken Database 2010-2017; n = 19,170). We analyzed 12,863 index ECGs with sinus rhythm after excluding those showing AF rhythm, other atrial tachyarrhythmia, pacing beat, or indeterminate axis, and those of patients with structural heart diseases. We used 438 automatically measured ECG parameters in the MUSE data management system. The predictive models were developed using random forest algorithm with the 10-fold cross-validation method.

RESULTS

In 12,863 index ECGs with sinus rhythm, a predictive capability for current paroxysmal AF (n = 1131) by c-statistics was 0.99981 ± 0.00037 for training dataset and 0.91337 ± 0.00087 for testing dataset, respectively. Excluding AF at baseline (n = 11,732), a predictive capability for newly developed AF (n = 98) by c-statistics was 0.99973 ± 0.00086 for training dataset and 0.99160 ± 0.00038 for testing dataset, respectively. The distribution of parameter importance was mostly similar among P, QRS, and ST-T segment for both current and newly developed AF.

CONCLUSIONS

This study intended to provide panoramic information in relation between ECG parameters and AF. The parameter importance of ECG parameters for predicting AF was mostly similar in P, QRS, and ST-T segment in models for both current and future AF.

Electrocardiographic voltage criteria in patients with hypertrophic cardiomyopathy

BACKGROUND

Several ECG voltage criteria have been proposed for the diagnosis of left ventricular hypertrophy (LVH). Notably, ECG criteria have been historically validated in concentric LVH but not in hypertrophic cardiomyopathy (HCM), wherein the hypertrophy pattern is typically asymmetric.

OBJECTIVES

The aim of our study was to evaluate the performance of ECG voltage criteria for LVH diagnosis in the HCM population.

MATERIAL AND METHODS

The electrocardiograms of 92 HCM patients and 41 sex- and age-matched controls were evaluated with the most frequently used ECG voltage criteria for LVH diagnosis. Cardiac magnetic resonance (MRI) was performed in HCM and controls in order to quantify LVH and its distribution.

RESULTS

In the HCM population, the maximal diagnostic accuracy was achieved by Amplitude total and Amplitude total product criteria (58% for both), while the Cornell Voltage best performed in septal HCM (62%), the Sokolov in aVL and Gubner criteria in apical HCM (79% for both) and the Cornell Voltage and Product in anterior HCM (86% for both). All the ECG voltage criteria showed a poor correlation with left ventricular mass and maximal thickness measured by cardiac MRI.

CONCLUSIONS

In our study, only a few ECG voltage criteria used for the detection of LVH in clinical practice showed an acceptable performance in the HCM population. Further studies are needed to clarify the role of ECG for LVH detection in HCM patients.

Patients with elevated blood pressure or stage 1 hypertension have structural heart disease

BACKGROUND

The 2017 American College of Cardiology (ACC) and the American Heart Association (AHA) recommendations lower the hypertension threshold to 130/80 mmHg and recommends treatment for high-risk patients. Our aim is to determine whether the new blood pressure categories are associated with left ventricular (LV) structural changes and whether echocardiograms can provide risk stratification and help treatment initiation.

METHODS

We conducted a cross-sectional study and performed screening echocardiograms to consecutive primary care patients. We calculated the Framingham score to identify patients with a low or intermediate score who had structural heart disease.We classified everyone as having normal, elevated blood pressure, stage 1 or stage 2 hypertension according to the 2017 ACC/AHA guidelines. We defined structural heart disease as having LV hypertrophy and an abnormal LV mass index.

RESULTS

We included 16 650 patients who underwent a screening echocardiogram and had recorded blood pressure. Out of the 16 650 patients, 1465 patients had a normal blood pressure, 1382 had elevated blood pressure, 1333 had stage 1 hypertension, and the remainder had stage 2 hypertension. The adjusted odds ratios of having structural heart disease for elevated blood pressure and stage 1 hypertension were 1.30; 95% CI, 1.112-1.64; P < 0.01 and 1.69; 95% CI, 1.25-2.30; P < 0.01, respectively. We identified 542 patients with stage 1 hypertension who had a low or intermediate Framingham score and 19% (95% CI, 16-23%) had structural heart disease.

CONCLUSION

A quarter of patients identified as having elevated blood pressure or stage 1 hypertension have structural heart disease. Screening echocardiograms may help to risk stratify those patients deemed ineligible for treatment.

Left Ventricular Extracellular Volume Expansion Is Not Associated with Atrial Fibrillation or Atrial Fibrillation-mediated Left Ventricular Systolic Dysfunction

PURPOSE

To determine whether left ventricular (LV) extracellular volume (ECV) expansion is associated with atrial fibrillation (AF) or AF-mediated LV systolic dysfunction (LVSD) while minimizing the influence of biologic and imaging methodologic confounders.

MATERIALS AND METHODS

This study examined the prevalence of LV ECV expansion in 137 patients with AF (mean age, 62 years ± 11 [standard deviation]; 92 male patients and 45 female patients; 83 paroxysmal and 54 persistent) who underwent preablation cardiovascular MRI. Biologic confounders were minimized by measuring the ECV fraction and excluding patients with severe LV hypertrophy, defined as wall thickness greater than 1.5 cm. Imaging confounders were minimized by using an arrhythmia-insensitive-rapid (AIR) cardiac T1 mapping pulse sequence. Other cardiac functional parameters, including LV ejection fraction (LVEF) and left atrial end-diastolic volume indexed to body surface area, were assessed using cine cardiovascular MRI. A substudy was conducted in 32 patients with no AF (mean age, 54 years ± 16) in sinus rhythm to establish control values and convert these values between the AIR sequence and literature-based modified Look-Locker inversion recovery (MOLLI) values.

RESULTS

The mean ECV was not significantly different (P > .05) between patients with AF with a normal LVEF (24.5% ± 2.8; n = 107), patients with AF with LVSD (24.5% ± 2.5; n = 30), and patients with no AF (24.4% ± 3.8; n = 32), but there was a significant interaction between ECV and CHA₂DS₂-VASc score (P = .045). Compared with the literature data obtained from healthy control patients scanned using MOLLI, 99.3% of patients with AF had ECV below the fibrosis cutoff point (32.8% when converted from MOLLI T1 mapping to AIR T1 mapping), including a subset of patients with AF (n = 28) with low CHA₂DS₂-VASc score (0/1 for men/women).

CONCLUSION

Study results suggest that an LV ECV expansion is not associated with AF or AF-mediated LVSD. Supplemental material is available for this article. © RSNA, 2020See also the commentary by Stillman in this issue.

The transition from hypertension to hypertensive heart disease and heart failure: the PREFERS Hypertension study

Aims

Despite evidence‐based therapeutic approaches, target blood pressure is obtained by less than half of patients with hypertension. Hypertension is associated with a significant risk for heart failure, in particular heart failure with preserved left ventricular (LV) ejection fraction (HFpEF). Although treatment is suggested to be given early after hypertension diagnosis, there is still no evidence‐based medical treatment for HFpEF. We aim to study the underlying mechanisms behind the transition from uncomplicated hypertension to hypertensive heart disease (HHD) and HFpEF. To this end, we will combine cardiac imaging techniques and measurements of circulating fibrosis markers to longitudinally monitor fibrosis development in patients with hypertension.

Methods and results

In a prospective cohort study, 250 patients with primary hypertension and 60 healthy controls will be characterized at inclusion and after 1 and 6 years. Doppler echocardiography, cardiac magnetic resonance imaging, and electrocardiogram will be used for measures of cardiac structure and function over time. Blood biomarkers reflecting myocardial fibrosis, inflammation, and endothelial dysfunction will be analysed. As a proxy for HFpEF development, the primary endpoint is to measure echocardiographic changes in LV function and structure (E/e′ and LAVI) and to relate these measures of LV filling to blood pressure, biomarkers, electrocardiogram, and cardiac magnetic resonance.

Conclusions

We aim to study the timeline and transition from uncomplicated hypertension to HHD and HFpEF. In order to identify subjects prone to develop HHD and HFpEF, we want to find biomarkers and cardiac imaging variables to explain disease progression. Ultimately, we aim at finding new pathways to prevent HFpEF.

Association of ECG parameters with late gadolinium enhancement and outcome in patients with clinical suspicion of acute or subacute myocarditis referred for CMR imaging

BACKGROUND

Risk stratification of myocarditis is challenging due to variable clinical presentations. Cardiovascular magnetic resonance (CMR) is the primary non-invasive imaging modality to investigate myocarditis while electrocardiograms (ECG) are routinely included in the clinical work-up. The association of ECG parameters with CMR tissue characterisation and their prognostic value were investigated in patients with clinically suspected myocarditis.

METHODS AND RESULTS

Consecutive patients with suspected myocarditis who underwent CMR and ECG were analysed. Major adverse cardiovascular event (MACE) included all-cause death, hospitalisation for heart failure, heart transplantation, documented sustained ventricular arrhythmia, or recurrent myocarditis. A total of 587 patients were followed for a median of 3.9 years. A wide QRS-T angle, low voltage and fragmented QRS were significantly associated with late gadolinium enhancement. Further, a wide QRS-T angle, low voltage and prolonged QTc duration were associated with MACE in the univariable analysis. In a multivariable model, late gadolinium enhancement (HR: 1.90, 95%CI: 1.17-3.10; p = 0.010) and the ECG parameters of a low QRS voltage (HR: 1.86, 95%CI: 1.01-3.42; p = 0.046) and QRS-T-angle (HR: 1.01, 95%CI: 1.00-1.01; p = 0.029) remained independently associated with outcome. The cumulative incidence of MACE was incrementally higher when findings of both CMR and ECG were abnormal (p<0.001).

CONCLUSION

In patients with clinically suspected myocarditis, abnormal ECG parameters are associated with abnormal tissue characteristics detected by CMR. Further, ECG and CMR findings have independent prognostic implications for morbidity and mortality. Integrating both exams into clinical decision-making may play a role in risk stratification in this heterogeneous patient population.

IFITM3 protects the heart during influenza virus infection

Influenza virus can disseminate from the lungs to the heart in severe infections and can induce cardiac pathology, but this has been difficult to study due to a lack of small animal models. In humans, polymorphisms in the gene encoding the antiviral restriction factor IFN-induced transmembrane protein 3 (IFITM3) are associated with susceptibility to severe influenza, but whether IFITM3 deficiencies contribute to cardiac dysfunction during infection is unclear. We show that IFITM3 deficiency in a new knockout (KO) mouse model increases weight loss and mortality following influenza virus infections. We investigated this enhanced pathogenesis with the A/PR/8/34 (H1N1) (PR8) influenza virus strain, which is lethal in KO mice even at low doses, and observed increased replication of virus in the lungs, spleens, and hearts of KO mice compared with wild-type (WT) mice. Infected IFITM3 KO mice developed aberrant cardiac electrical activity, including decreased heart rate and irregular, arrhythmic RR (interbeat) intervals, whereas WT mice exhibited a mild decrease in heart rate without irregular RR intervals. Cardiac electrical dysfunction in PR8-infected KO mice was accompanied by increased activation of fibrotic pathways and fibrotic lesions in the heart. Infection with a sublethal dose of a less virulent influenza virus strain (A/WSN/33 [H1N1]) resulted in a milder cardiac electrical dysfunction in KO mice that subsided as the mice recovered. Our findings reveal an essential role for IFITM3 in limiting influenza virus replication and pathogenesis in heart tissue and establish IFITM3 KO mice as a powerful model for studying mild and severe influenza virus-induced cardiac dysfunction.

The Evolving Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Systemic Amyloidosis

Systemic amyloidosis is a serious multiorgan disease with reduced life expectancy, irrespective of type. The impact of magnetic resonance imaging (MRI) in managing this condition has been immense. The last decade in particular has seen a surge of interest in the assessment and evaluation of the heart in patients with systemic amyloidosis by cardiovascular magnetic resonance imaging (CMR), with approximately 85% of all publications on this subject arising in the last 10 years. This has been largely driven by the creation of new sequences and their subsequent modernisation and technical development, thereby rendering previously prohibitive methods clinically more relevant and applicable. In turn, this has led to an increased awareness and recognition of the disease. This review demonstrates how MRI has become a pivotal diagnostic tool in the assessment of cardiac amyloidosis over the last 2 decades, with the ability to track disease and predict mortality. Several different pathognomonic patterns of late gadolinium enhancement (LGE) are now recognised and are able to prognosticate. T1 mapping and extracellular volume (ECV) techniques have resulted in even earlier disease detection before LGE is even visible and along with T2 mapping, provide new insights into biology. As newer therapies also evolve and become available, the need for accurate tracking of cardiac disease response to treatment carries increasing importance. All these are examined in this review, mainly focussing on light-chain (AL) and transthyretin (ATTR) amyloidosis.

Cornell product in an electrocardiogram is related to reduced LV regional wall motion

Electrocardiographic left ventricular hypertrophy (LVH) diagnosed by Cornell product and the Sokolow-Lyon voltage are associated with anatomical LVH; therefore, we investigated whether Cornell product and the Sokolow-Lyon voltage were associated with echocardiographic regional wall motion (measured by 2D-strain imaging). We reviewed data on 288 consecutive hypertensive patients who underwent both echocardiography and electrocardiography. Electrocardiographic LVH was calculated as follows: Cornell voltage, S in lead V3 + R in lead aVL; Cornell product, Cornell voltage (+0.6 mV for females) × QRS duration; and Sokolow-Lyon voltage, S in lead V1 + R in lead V5. The mean age of the subjects was 64.3 ± 13.2 years; 47.9% were men, and 65.2% were taking antihypertensive medications. Both Cornell product (r = 0.392, P < 0.001) and the Sokolow-Lyon voltage (r = 0.315, P < 0.001) were significantly related to left ventricular mass index (LVMI), and the relationship between Cornell product and LVMI (beta = 0.24, P = 0.001) was independent of the Sokolow-Lyon voltage (beta = 0.25, P < 0.001). In multivariate linear regression analysis in which the two ECG-LVH were included together, Cornell product was related to global longitudinal strain (beta = 0.24, P = 0.002), even after adjusting for the Sokolow-Lyon voltage (P = 0.835). Additionally, the Cornell voltage was related to the inner/outer ratio of circumferential strain (beta = 0.17, P = 0.033) after adjusting for the Sokolow-Lyon voltage (P = 0.318). By contrast, the Sokolow-Lyon voltage was related to the relative wall thickness and E/e' on tissue Doppler imaging, even after adjusting for Cornell product. In conclusion, Cornell product and voltage were associated with longitudinal regional wall motion and with the transmurality of regional wall motion in the short axis direction.

Association of isolated minor nonspecific ST-T abnormalities with left ventricular hypertrophy and diastolic dysfunction

The aim of this study was to examine the associations of isolated minor nonspecific ST-T abnormalities (NSSTTA) on 12-lead electrocardiogram (ECG) with left ventricular (LV) diastolic function and LV geometry on echocardiography. A cross-sectional study comprised of 74,976 Koreans who underwent ECG and echocardiography as part of a comprehensive health examination between March 2011 and December 2014. ECG was coded using Minnesota Code criteria. The frequencies of NSSTTA, impaired LV relaxation, and echocardiographic LVH were 1,139 (1.5%), 21,118 (28.2%), and 1,687 (2.3%) patients, respectively. The presence of NSSTTA was positively associated with the prevalence of impaired LV relaxation and LVH on echocardiography. In a multivariable-adjusted model, the odds ratio (95% CIs) comparing patients with NSSTTA to control patients was 1.55 (1.33-1.80) for impaired LV relaxation and 3.15 (2.51-3.96) for echocardiographic LVH. The association between NSSTTA and impaired LV relaxation was stronger in the intermediate to high cardiovascular disease-risk group than in the low-risk group according to Framingham Risk Score stratification (P for interaction = 0.02). NSSTTA were associated with increased prevalence of impaired LV relaxation and LVH, suggesting NSSTTA as an early indicator of subclinical cardiac dysfunction and geometric abnormalities.

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".