QRS Axis Research Articles

Abstract 13921: Automated Estimation of Computed-Tomography-Derived Left Ventricular Mass Using Sex-Specific, 12-lead-ECG-Based Temporal Convolutional Network

Introduction: Increased left ventricular myocardial mass (LVM) is associated with adverse cardiovascular outcomes. Various rule-based criteria using limited electrocardiogram (ECG) features lacks sensitivity for evaluating LVM. Recent studies using deep learning methods have made progress in LVM evaluation taking advantage of ECG amplitude data. Hypothesis: We hypothesized that LVM prediction with deep learning models are improved by adding inter-lead information and building sex-specific models. Methods: This study proposed a novel deep learning-based method, the eLVMass-Net, by using ECG-LVM (n=1,459) paired data. ECG signals, QRS duration and axis, demographic features were used as input data. ECG signals were encoded by a temporal convolutional network (TCN) encoder. We adopted a total of four models (non-lead-grouping v. lead-grouping, non-sex-specific v. sex-specific) for LVM estimation. For lead-grouping models, the encoders were constructed based on segregated limb and precordial leads. For sex-specific models, we constructed models on both genders separately. Encoded ECG features and demographic features were concatenated for LVM prediction. To evaluate the performance, we utilized a 5-fold cross-validation approach with the evaluation metrics, mean absolute error (MAE) and mean absolute percentage error (MAPE). Results: For non-sex-specific models, eLVMass-Net has achieved an MAE of 14.33±0.71 and an MAPE of 12.90%±1.12%, outperforming the best state-of-the-art method (MAE 19.51±0.82; MAPE 17.62%±0.78%; P < 0.01). Sex-specific models achieved even lower MAPE for both males and females respectively (male MAPE 12.55%±0.88%; female MAPE 12.52%±0.34%), which also surpassed state-of-the-art methods. Adding the information of QRS axis and duration did not significantly improve the model performance (P = 0.28). The saliency map showed that T wave in precordial leads and QRS complex in limb leads are important features with increasing LVM. Conclusions: This study proposed a novel LVM estimation method, outperforming previous methods by emphasizing relevant heartbeat waveforms, inter-lead information, and non-ECG demographic features. The sex-specific analysis is crucial in improving LVM prediction.

Electrocardiographic Characteristics in 438 Neonates with Atrial Septal Defects

Arrhythmias and electrocardiographic (ECG) abnormalities are common among patients with atrial septal defects (ASDs). We studied a large cohort of neonates with ASDs to investigate whether ECG abnormalities are present at this early stage or develop later, secondary to hemodynamic changes. We analyzed the echocardiograms and ECGs from the Copenhagen Baby Heart Study, a population-based cohort study. We compared ECG characteristics of 438 neonates with secundum ASDs to 1314 matched controls. In subgroup analyses, we investigated whether electrocardiographic characteristics were associated with age at examination. Neonates with ASDs (median age, 11 days; males, 51%) had longer P-wave durations (58 vs. 56 ms, p < 0.001), PR intervals (100 vs. 96 ms, p < 0.001), and a more rightward-shifted QRS axis (116 vs. 114 degrees, p = 0.032) compared to controls (median age, 10 days; males, 51%). There were no differences between cases and controls in the P-wave area, amplitude, or axis. Subgroup analyses showed that the differences in P-wave duration and PR interval were present in neonates examined in the first week after birth. The difference in the QRS axis was not found in neonates examined this early but was found in neonates examined at age two to four weeks. In conclusion, ASDs are associated with ECG changes from the neonatal phase. The P-wave duration and PR interval are longer in neonates with ASDs when compared to controls as early as the first week after birth, indicating that these changes are not purely secondary, but that neonates with an ASD have altered cardiac electrical activity.ClinicalTrials.gov Identifier NCT02753348 (April 27, 2016)

Anatomical cardiac and electrocardiographic axes correlate in both upright and supine positions: an upright/supine CT study

The correlation between the anatomical cardiac and electrocardiographic axes has been discussed for several years. Using upright computed tomography, this study aimed to reveal the relationship between the anatomical cardiac and electrocardiographic axes in both the supine and upright positions. Upright CT and standard supine CT were performed for healthy volunteers, following electrocardiography in both upright and supine position. On CT images, the coordinates of apex, the center of aortic valve (AV) and mitral valve (MV) were recorded, and the vectors and angles were calculated. Subcutaneous and visceral fat volume were semi-automatically calculated in a workstation. From a total 190 volunteers, 41 males were performed electrocardiography and included for this study. The QRS and anatomical axes (AV-apex and MV-apex axis) were significantly correlated in both supine and upright positions, while the angle of the AV-apex to Z axis was the most correlated (supine: r = − 0.54, p = 0.0002, upright: r = − 0.47, p = 0.0020). The anatomical axis moved in the dorsal and caudal directions from the supine to upright position. Multiple regression analysis revealed that the anatomical axis from the AV-apex to the Z-axis was determined according to age, body height, subcutaneous and visceral fat volumes.

The QRS frontal plane axis changes during left bundle branch block after transcatheter aortic valve replacement.

Left bundle branch block (LBBB) is common after transcatheter aortic valve replacement (TAVR) and associated with a left or normal QRS axis. We aim to assess the QRS frontal plane axis shift changes during LBBB after TAVR and determine if the risk of procedure-related high degree atrioventricular block (AVB) is affected by QRS axis shift changes. In a retrospective single-center study of 720 consecutive patients who underwent TAVR, 141 (19.6%) with normal baseline QRS duration developed a new LBBB after TAVR and constituted the study group. Most patients (59.6%) were females and the mean age of the cohort was 81.2±6 years. As compared with the baseline QRS axis before TAVR, the occurrence of LBBB was associated with a leftward QRS axis shift (by 40±28.3°) in 73% of the study patients and a rightward (by 18.6±19.4°) or no change in QRS axis in 25.6% and 1.4% of the study patients, respectively. A left QRS axis (-30°) was observed in 14.9% and 38.3% of the study patients before and after TAVR, respectively. The group of patients exhibiting a rightward or no QRS axis shift had a greater incidence of high degree AVB than the group of patients exhibiting a leftward QRS axis shift (18.4%vs. 6.8%, p=.056). Although post TAVR-LBBB is associated with a leftward QRS axis shift in most patients, a non-negligible proportion of patients (27%) exhibited a rightward or no QRS axis shift. The latter group tend to have a higher risk of developing high degree AVB.

Electrocardiographic characteristics of newborns with ventricular septal defects: a Copenhagen Baby Heart Study

Ventricular septal defects (VSD) represent the most common congenital heart defect in newborns. We assessed the electrocardiographic characteristics of newborns with VSDs in a general population sample. The Copenhagen Baby Heart Study is a prospective population–based cohort study offering cardiac evaluation of newborns. Echocardiograms and electrocardiograms were obtained within 30 days after birth and systematically analysed. A VSD was identified in 530 newborns (mean age 11 ± 7 days, 42% boys). Newborns with VSDs had a more left-shifted QRS axis (116 ± 34 vs. 120 ± 3°, p = 0.02), and a higher S-wave amplitude in V1 (721 ± 584 vs. 636 ± 549 µV, p = 0.001) than controls. The largest differences were found in newborns with large or perimembraneous VSDs with a higher frequency of left axis deviation, higher S-wave amplitudes in V1, and higher R- and S-wave amplitudes in V6 compared with controls. R-waves in V1 and V6 were significantly associated to left ventricular mass, whereas S-waves in V1 and V6 were dependent on left ventricular end-diastolic diameter on echocardiography. Conclusion: Newborns with VSDs showed significant differences in QRS axis, and R- and S-wave precordial amplitudes compared to matched controls. Perimembranous and large VSDs had the greatest effect on the neonatal ECG.What is Known:• Ventricular septal defects in newborns are prevalent and may affect cardiac function and structure.What is New:• The Copenhagen Baby Heart Study is the largest study including a cohort of unselected newborns undergoing postnatal cardiac examination.• We found that newborns with VSD showed significant electrocardiographic differences depending on size and type of VSD compared with healthy newborns.

Prognostic significance of quantitative electrocardiographic parameters in patients with non-high-risk pulmonary embolism

BackgroundElectrocardiogram (ECG) abnormalities indicating right ventricular strain have been reported to have prognostic value in severe cases of acute pulmonary embolism (PE). We aimed to analyze the prognostic significance of other quantitative ECG parameters in non-high-risk acute PE. MethodsConsecutive patients with non-high-risk acute PE were prospectively enrolled. The following baseline ECG parameters were collected: rhythm, heart rate, QRS axis, right bundle branch block (RBBB) pattern, S1Q3T3 pattern, T-wave inversion, ST-segment elevation, Qr in lead V1, PR Interval, QRS complex duration, QT interval, P-wave amplitude and duration, R- and S-wave amplitudes. The primary endpoint was early discharge within three days. Associations between ECG parameters and early discharge were analyzed. ResultsOverall, 383 patients were enrolled (median age: 67 years, 57% female): 277 (72.3%) with low-risk and 106 (27.7%) with intermediate-risk. The two groups of patients differed in several ECG signs of right ventricular strain and many other quantitative parameters like R- and S-wave amplitudes. In the multivariate logistic regression analysis, the S-wave depth in lead V5 (S-V5) was the only independent prognostic factor for early discharge (odds ratio = 0.137, 95% confidence interval = 0.031-0.613, p = 0.009). The optimum cutoff value of S-V5 for predicting early discharge derived from the receiver operative characteristic curve was 0.15 mv (c-statistic = 0.66, p =0.003). ConclusionsSeveral ECG signs of right ventricular strain and many other quantitative parameters were associated with disease severity in non-high-risk acute PE. An S-V5 lesser than 0.15 mv was predictive for early discharge in these patients.

Mayo Clinic VT calculator: A practical tool for accurate wide complex tachycardia differentiation.

The discrimination of ventricular tachycardia (VT) versus supraventricular wide complex tachycardia (SWCT) via 12-lead electrocardiogram (ECG) is crucial for achieving appropriate, high-quality, and cost-effective care in patients presenting with wide QRS complex tachycardia (WCT). Decades of rigorous research have brought forth an expanding arsenal of applicable manual algorithm methods for differentiating WCTs. However, these algorithms are limited by their heavy reliance on the ECG interpreter for their proper execution. Herein, we introduce the Mayo Clinic ventricular tachycardia calculator (MC-VTcalc) as a novel generalizable, accurate, and easy-to-use means to estimate VT probability independent of ECG interpreter competency. The MC-VTcalc, through the use of web-based and mobile device platforms, only requires the entry of computerized measurements (i.e., QRS duration, QRS axis, and T-wave axis) that are routinely displayed on standard 12-lead ECG recordings.

Relationship between left-axis deviation and onset of cardiac adverse events in right ventricular pacing.

The electrical axis shows alterations during right ventricular pacing (RVP), including a normal axis and left axis deviation; however, it remains unknown if differences in the electrical axis affect the occurrence of cardiac adverse events. The purpose of this study was to determine whether a left axis deviation increases the incidence of adverse cardiac events compared with a normal axis. This study analysed 156 patients with RVP. The patients were divided into two groups: those with left axis deviation after RVP (LAD group) and those with a normal axis (NA group). The primary composite outcome was the new-onset of atrial fibrillation (AF) and worsening heart failure (HF). The QRS axis of the LAD (n=77) and NA (n=79) groups were-64.5±14.3° and 29.8±36.5°, respectively (P<0.001). The median follow-up was 1100days and, regarding primary composite outcomes (hazard ratio, 1.03; 95% confidence interval, 0.64 to 1.65; P=0.89), 29/77 (37.6%) and 28/79 (35.4%) patients in the LAD and NA groups, respectively, developed AF (hazard ratio, 1.07; 95% confidence interval, 0.64 to 1.81; P=0.77). Furthermore, 8/77 (10.3%) and 12/79 (15.1%) patients in the LAD and NA groups, respectively, experienced worsening HF (hazard ratio, 0.65; 95% confidence interval, 0.26 to 1.60; P=0.35). The risk of cardiac adverse events in patients with RVP (new-onset AF or worsening HF, cardiovascular death, myocardial infarction, and stroke) and overall mortality with LAD is not higher than that with NA.

Differentiating primary sarcomeric hypertrophic cardiomyopathy from Noonan syndrome: can the electrocardiogram be of use?

Noonan syndrome is a multi-system genetic disorder and patients may suffer from hypertrophic cardiomyopathy. Previous studies have identified electrocardiographic features that may support a diagnosis of Noonan syndrome. In this two-centre retrospective study, we analysed typical Noonan syndrome-related electrocardiographic features in 30 patients with Noonan syndrome with hypertrophic cardiomyopathy and compared these with the electrocardiographic features in 15 children with sarcomeric hypertrophic cardiomyopathy. Typical Noonan syndrome-related electrocardiographic features are a negative aVF, small left precordial R-waves, large right precordial S-waves, and abnormal Q-wave. We also analysed electrocardiographic features of hypertrophic cardiomyopathy: ST-segment abnormalities and T-wave abnormalities. A negative aVF was seen in 83% of patients with Noonan syndrome-related hypertrophic cardiomyopathy in contrast to 27% of patients with primary sarcomeric hypertrophic cardiomyopathy (p < 0.001). An extreme QRS axis in the north-west was seen only in patients with Noonan syndrome-related hypertrophic cardiomyopathy. This QRS axis deviation is likely to be determined by the Noonan syndrome-related hypertrophic cardiomyopathy and not by the type of hypertrophic cardiomyopathy. There were no differences between the two groups in the frequency of large right precordial S-waves and small R-waves in the left precordial leads V5 and V6. However, an abnormal R/S ratio was more often seen in patients with Noonan syndrome-related hypertrophic cardiomyopathy (p < 0.001). Pathologic Q-waves were seen statistically more frequently in patients with sarcomeric hypertrophic cardiomyopathy (p = 0.009). The occurrence of ST-segment and T-wave pathology did not statistically differ between the two groups. Electrography can be of use in differentiating sarcomeric hypertrophic cardiomyopathy from Noonan syndrome-related hypertrophic cardiomyopathy.

Right and left ventricular mass development in early infancy: Correlation of electrocardiographic changes with echocardiographic measurements

BackgroundRight ventricular mass indexed to body surface area (RVMI) decreases and left ventricular mass index (LVMI) increases rapidly and substantially during early infancy. The relationship between these sizeable mass transformations and simultaneous electrocardiographic changes have not been previously delineated. MethodsNormal term infants (#45 initially enrolled) were prospectively evaluated at 2 days and at 2-week, 2-month, and 4-month clinic visits. Ventricular masses were estimated with 2D echocardiographic methods. QRS voltages were measured in leads V1, V6, I and aVF. ResultsMean QRS axis shifted from 135 (95%CI 124, 146) to 65 degrees (95%CI 49, 81) and correlated with both RVMI decrease and LVMI increase (R = 0.46⁎ vs. 0.25†, respectively. *p < 0.01, †p < 0.05). As RVMI decreased from mean 28.1 (95%CI 27.1, 29.1) to 23.3 g/m2 (95%CI 21.4, 25.2) so did V1R and V6S voltages. RVMI changes correlated with V1R, V6S, and V1R + V6S voltages (R = 0.29*, 0.23† and 0.35*, respectively. *p < 0.01, †p < 0.05) but not with V1R/S ratio. As LVMI increased from 44.6 (95%CI 42.9, 46.3) to 55.4 g/m2 (95%CI 52.3, 58.5) V6R and V6Q increased but V1S voltage did not. LVMI changes correlated with V6R, V6R-S, and V6(Q + R)-S voltages (R = 0.31*, 0.34*, and 0.38* respectively. *p < 0.01) but not with V1S or V6R/S (R = 0.01 and 0.18 respectively, p = NS). Conclusions: During early infancy the RVMI decrease correlates best with the QRS axis shift and V1R + V6S voltage, and the LVMI increase correlates best with V6R-S and V6(Q + R)-S voltages

Ventricular Electrocardiographic Signatures Associated with Dementia and Plasma Alzheimer's Disease Biomarkers in Older Adults: A Population-Based Study.

Evidence has emerged that altered ventricular electrocardiogram profiles are associated with dementia, but the neuropathological mechanisms underlying their associations are poorly understood. To investigate the interrelationships of ventricular electrocardiogram profiles with dementia and plasma Alzheimer's disease (AD) biomarkers among older adults. This population-based cross-sectional study included 5,153 participants (age ≥65 years; 57.3% women) living in rural communities in China; of these, 1,281 had data on plasma amyloid-β (Aβ)40, Aβ42, total-tau, and neurofilament light chain (NfL) protein. The QT, QTc, JT, JTc, QRS intervals, and QRS axis were derived from the 10-second electrocardiogram recording. The DSM-IV criteria were followed for clinical diagnosis of dementia, the NIA-AA criteria for AD, and the NINDS-AIREN criteria for vascular dementia (VaD). Data were analyzed using general linear models, multinomial logistic models, and restricted cubic splines. Of the 5,153 participants, 299 (5.8%) were diagnosed with dementia, including 194 with AD and 94 with VaD. Prolonged QT, QTc, JT, and JTc intervals were significantly associated with all-cause dementia, AD, and VaD (p < 0.05). Left QRS axis deviation was significantly associated with all-cause dementia and VaD (p < 0.01). In the subsample of plasma biomarkers (n = 1,281), prolonged QT, JT, and JTc intervals were significantly associated with a lower Aβ42/Aβ40 ratio and higher plasma NfL concentrations (p < 0.05). Alterations in ventricular repolarization and depolarization are independently associated with all-cause dementia, AD, VaD, and AD plasma biomarkers in older adults (age ≥65 years). Ventricular electrocardiogram parameters may be valuable clinical markers for dementia and the underlying AD pathologies and neurodegeneration.

Diverse QRS morphology reflecting variations in lead placement for left bundle branch area pacing.

Left bundle branch area pacing (LBBAP) is a potential alternative to His bundle pacing. This study aimed to investigate the impact of different septal locations of pacing leads on the diversity of QRS morphology during non-selective LBBAP. Non-selective LBBAP and left ventricular septal pacing (LVSP) were achieved in 50 and 21 patients with atrioventricular block, respectively. The electrophysiological properties of LBBAP and their relationship with the lead location were investigated. QRS morphology and axis showed broad variations during LBBAP. Echocardiography demonstrated a widespread distribution of LBBAP leads in the septum. During non-selective LBBAP, the qR-wave in lead V1 indicated that the primary location for pacing lead was the inferior septum (93%). The non-selective LBBAP lead was deployed deeper than the LVSP lead in the inferior septum. The Qr-wave in lead V1 with the inferior axis in aVF suggested pacing lead placement in the anterior septum. The penetration depth of the non-selective LBBAP lead in the anterior septum was significantly shallower than that in the inferior septum (72 ± 11 and 87 ± 8%, respectively). In lead V6, the deep S-wave indicated the time lag between the R-wave peak and the latest ventricular activation in the coronary sinus trunk, with pacemaker leads deployed closer to the left ventricular apex. Different QRS morphologies and axes were linked to the location of the non-selective LBBAP lead in the septum. Various lead deployments are feasible for LBBAP, allowing diversity in the conduction system capture in patients with atrioventricular block.

Electrocardiographic Predictors of Complete Heart Block During Right Ventricular Lead Implantation in Patients Who Underwent Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) device procedures have their own complications in addition to the complications associated with standard pacemaker implantations. This study aimed to analyze the predictors of the right bundle branch injury resulting in complete heart block (CHB) during right ventricular (RV) lead implantation in patients who underwent CRT with defibrillator. We conducted an observational study of consecutive 790 patients who underwent CRT with defibrillator device implantation at our institution from 2010 to 2022. Relevant clinical information and complete data regarding the echocardiographic data, implantation procedure, and clinical follow-up were collected into a computerized database. A total of 29 patients (3.7%) had CHB during RV lead implantation. In multivariate analysis, left axis deviation (odds ratio [OR] 2.408, 95% confidence interval [CI] 1.025 to 5.658, p=0.044), QRS width (OR 1.022, 95% CI 1.001 to 1.043, p=0.035) and QRS alternans (OR 4.214, 95% CI 1.788 to 9.930, p=0.001) were found independently related to right bundle branch injury resulting in CHB development during RV lead implantation. In conclusion, left axis deviation, QRS width, and QRS alternans were associated with a higher rate of CHB, and these findings provide insight into optimal and safe CRT device implantation strategies based on preprocedural characteristics.

An electrocardiographic score to predict pulmonary hypertension in children with atrial septal defect

BackgroundIn limited resource settings, identification of factors that predict the occurrence of pulmonary hypertension(PH) in children with atrial septal defect(ASD) is important to decide which patients should be prioritized for defect closure to prevent complication. Echocardiography and cardiac catheterization are not widely available in such settings. No scoring system has been proposed to predict PH among children with ASD. We aimed to develop a PH prediction score using electrocardiography parameters for children with ASD in Indonesia.MethodsA cross-sectional study reviewing medical record including ECG record was conducted among all children with newly diagnosed isolated ASD admitted to Dr Sardjito Hospital in Yogyakarta, Indonesia during 2016–2018. Diagnosis of ASD and PH was confirmed through echocardiography and/or cardiac catheterization. Spiegelhalter Knill-Jones approach was used to develop PH prediction score. Accuracy of prediction score was performed using a receiver operating characteristic (ROC) curve.ResultsOf 144 children, 50(34.7%) had PH. Predictors of pulmonary hypertension were QRS axis ≥120°, P wave ≥ 3 mm at lead II, R without S at V1, Q wave at V1, right bundle branch block (RBBB), R wave at V1, V2 or aVR > normal limit and S wave at V6 or lead I > normal limit. ROC curve from prediction scores yielded an area under the curve (AUC) 0.908(95% CI 0.85–0.96). Using the cut-off value 3.5, this PH prediction score had sensitivity of 76%(61.8–86.9), specificity 96.8%(91.0-99.3), positive predictive value 92.7%(80.5–97.5), negative predictive value 88.4%(82.2–92.6), and positive likelihood ratio 23.8(7.7–73.3).ConclusionsA presence of PH in children with ASD can be predicted by the simple electrocardiographic score including QRS axis ≥120°, P wave ≥3 mm at lead II, R without S at V1, Q wave at V1, RBBB, R wave at V1, V2 or aVR > normal limit and S wave at V6 or lead I > normal limit. A total score ≥ 3.5 shows a moderate sensitivity and high specificity to predict PH among children with ASD.

Ventricular electrocardiographic signatures associated with dementia and plasma Alzheimer’ s biomarkers in older adults: The MIND‐China study

AbstractBackgroundCardiovascular risk factors and cardiovascular diseases (CVDs) have been linked with dementia. In addition, amyloid‐β (Aβ) is detected in the heart of patients with Alzheimer’s disease (AD). However, no population‐based studies have yet investigated the interrelationships of ventricular electrocardiographic (ECG) profiles (e.g., QT, JT, QRS intervals, and QRS axis angle) with dementia and plasma Alzheimer’s biomarkers.MethodThis population‐based cross‐sectional study included 5110 participants (age ≥65 years; 57.2% women) from the baseline assessments of the multimodal interventions to delay dementia and disability in rural China (MIND‐China) in March‐September 2018; of these, 1273 had data on plasma Aβ42, Aβ40, total‐tau, and neurofilament light chain (NfL) that were measured using the single molecule array (SIMOA) technology. Ventricular ECG parameters included QT, QTc, JT, JTc, QRS intervals, and QRS axis angle. The DSM‐IV criteria were followed for the diagnosis of dementia, the NIA‐AA criteria for AD, and NINDS‐AIREN criteria for vascular dementia (VaD). Data were analyzed using the general linear models, multinomial logistic models, and restricted cubic splines.ResultOf the 5110 participants, 296 (5.79%) were diagnosed with dementia (192 with AD; 93 with VaD). The multivariable‐adjusted odds ratios (95% CI) of dementia associated with the quartiles of QT interval were 1.00 (reference), 1.66 (1.11‐2.50), 1.93 (1.25‐3.00), and 1.78 (1.10‐2.91), respectively. QTc, JT, and JTc intervals had analogous associations with dementia, and these ventricular ECG parameters were significantly associated with an increased likelihood of AD and VaD. The restricted cubic spline model suggested a significant association of QRS axis left deviation with VaD. In the plasma biomarker subsample, JT and JTc intervals were associated with multivariable‐adjusted β coefficients (95% CI) of ‐0.15 (‐0.27‐ ‐0.03) and ‐0.11 (‐0.20‐ ‐0.01), respectively, for Aβ42/Aβ40 ratio. The multivariable‐adjusted β coefficients (95% CI) of plasma NfL associated with QT, JT, and JTc intervals were 0.04 (0.01‐0.08), 0.06 (0.02‐0.09), and 0.04 (0.01‐0.07), respectively.ConclusionVentricular ECG signatures for dementia and plasma Alzheimer’s biomarkers in rural‐dwelling older adults are characterized by altered ventricular repolarization and depolarization. These results support the view that Aβ metabolism and neurodegeneration might be involved in the associations of ventricular ECG profiles with dementia.

Features of 12-lead electrocardiography in patients with critical aortic stenosis

Aim. To study the features of 12-lead electrocardiography (ECG) in patients with critical aortic stenosis referred for transcatheter aortic valve implantation.Material and methods. The study included 50 patients aged 76,6±6,5 years. The presence of intraventricular block, voltage criteria for left ventricular hypertrophy (LVH), fragmented QRS complex, and repolarization alternans were assessed on the ECG. The frontal QRS-T angle (fQRS-Ta) was estimated as the absolute value of the difference between the QRS axis and T wave axis.Results. Intraventricular blocks were present in 10 (20%) patients: 8 (36%) patients with pulmonary hypertension (PH), 2 (7%) patients without PH (p=0,028). Voltage criteria for LVH were present in 24 (60%) patients. In the presence of voltage criteria for LVH, the mean aortic valve gradient, the left ventricular mass index (LVMI) and the aortic valve area (AVA) were significantly greater. Fragmented QRS complex in the chest leads was more common in patients with past myocardial infarction, intraventricular block, with PH. Strain pattern was present in 9 (23%) patients, while nonspecific repolarization changes — in 27 (67%) patients. Patients with strain pattern had significantly higher mean pressure gradient and more often had PH. Correlations were found between fQRS-Ta and mean pressure gradient (r=0,39; p=0,005), AVA (r=-0,40; p=0,004), LVMI (r=0,30; p=0,03). The fQRS-Ta was significantly greater in the presence of PH — 128±48o, while without PH — 97±49o (p=0,03).Conclusion. In the studied group of patients with aortic stenosis, intraventricular block, fragmented QRS in the chest leads, strain pattern were more common in the presence of PH. In the presence of voltage criteria for LVH, LVMI, mean pressure gradient were significantly greater, while AVA — lower. The fQRS-Ta was significantly greater in the presence of intraventricular blocks, PH, as well as orrelated with mean pressure gradient and AVA.

Value of frontal QRS axis for risk stratification of individuals with prolonged PR interval.

There is ongoing controversy regarding the prognostic value of PR prolongation among individuals free of cardiovascular diseases. It is necessary to risk-stratify this population according to other electrocardiographic parameters. This study is based on the Third National Health and Nutrition Examination Survey. Cox proportional hazard models were constructed and Kaplan-Meier method was used. A total of 6188 participants (58.1 ± 13.1 years; 55% women) were included. The median frontal QRS axis of the entire study population was 37° (IQR: 11-60°). PR prolongation was present in 7.6% of the participants, of whom 61.2% had QRS axis ≤37°. In a multivariable-adjusted model, mortality risk was highest in the group with concomitant prolonged PR interval and QRS axis ≤37° (hazard ratio [HR]: 1.20; 95% confidence interval [CI]: 1.04-1.39). In models with similar adjustment where population were reclassified depending on PR prolongation and QRS axis, prolonged PR interval and QRS axis ≤37° was still associated with increased risk of mortality (HR: 1.18; 95% CI: 1.03-1.36) compared with normal PR interval. QRS axis is an important factor for risk stratification in population with PR prolongation. The extent to which this population with PR prolongation and QRS axis ≤37° is at higher risk of death compared with the population without PR prolongation.

Acute performance of stylet driven leads for left bundle branch area pacing: a comparison with lumenless leads

Abstract Funding Acknowledgements Type of funding sources: None. Background Lumen-less leads (LLL) and stylet driven leads (SDL) are currently used for left bundle branch area pacing (LBBAP). We sought to evaluate the acute performance of SDL during LBBAP in comparison with LLL. Methods This is an observational retrospective study including consecutive patients undergoing LBBAP at our institution.Acute lead performance was evaluated including implant success rate,electrical parameters,ECG characteristics and lead related complications (intraprocedure LBBAP lead dislodgment after having being penetrated into the septum in an stable position needing lead repositioning, septal perforation, coronary venous fistula, development of complete AV block not previously present and LBBAP lead damage during implant).Conduction system capture criteria were assessed before patient discharge during asynchronous ventricular pacing. Ventricular lead position within the septum was evaluated using paced QRS axis, fluoroscopic orthogonal views and post-procedure TTE, and classified as basal,mid or apical septum. Results 451 consecutive LBBAP implants were included, 333 using LLL and 118 using SDL. LBBAP acute success was significantly higher with LLL (91.6% for LLL vs 79.7% for SDL,p=0.001).Among patients with successful LBBAP,LBB capture criteria were achieved in 53.2% for LLL vs 36.4% for SDL,while left ventricular septal pacing (LVSP) was achieved in 39% vs 44.1%,respectively (p&amp;lt;0.0001). A basal lead position was more frequently obtained with LLL (19.8% for LLL vs 13.3% for SDL),while SDL were more frequently located at mid to apical septal positions (86.7% for SDL vs 80.1% for LLL, p=0.003).Paced ECG axis was inferior in 43.9% of LLL vs 28.9% of SDL and superior in 24.5% vs 42.1%, respectively,p=0.001.Intraprocedure lead dislodgment occurred in 9.3% of SDL vs 2.1% of LLL,p=0.001.In 5 cases of SDL (4.2%),lead damage occurred during lead implant needing lead replacement due to helix entrapment or malfunction with no such cases registered among LLL patients.Acute LBBAP lead-related complications were significantly higher for SDL vs LLL (29.1% vs 12.6%, respectively, p&amp;lt;0.0001,table 1),none of them needing additional interventions.Among patients with LBBAP criteria at the end of the procedure,34 (7.5%) experienced loss of r prime wave in V1 with paced QRS widening before hospital discharge,more frequently in patients with SDL (17.8% vs. 9.4%, respectively,p&amp;lt;0.0001) indicative of lead microdislodgment. Conclusions In our experience,acute lead performance is different between LLL and SDL.LBBAP implant success rate is significantly higher with LLL with higher percentage of patients with LBB capture criteria in comparison with SDL.SDL are associated with a more mid to apical and inferior lead position in the septum.A significantly higher rate of lead related complications during the implant procedure as well as higher rates of acute microdislodgment after implantation were also seen in SDL,none of them needing acute re-intervention.

Electrocardiographic abnormalities of adult patients with Marfan syndrome and their associations with body habitus and chest wall asymmetry

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Cardiac risk in the young charity, and Robert Luff Foundation. Background There are only limited reports of electrocardiographic (ECG) abnormalities in adults with Marfan syndrome (MFS) and their associations with skeletal features commonly found in this patient group. Purpose We aimed to characterize the ECG in adult Marfan patients fulfilling the Ghent criteria and assess the relationship between ECG abnormalities, body habitus, chest and back deformities. Methods We studied all MFS patients aged ≥18 years old seen in our Aortopathy clinic between October 2015 and December 2019, who had not undergone cardiothoracic surgery. We collected information on demographics, body habitus (height, weight and body mass index-BMI), medical treatment and echocardiographic measurements. Chest wall asymmetry were defined as presence of pectus excavatum (PE), or pectus carinatum (PC). The ECGs were systematically analysed based on established criteria. Data regarding T wave inversion (TWI) and its localisation were recorded. Early QRS transition was defined as transition zone in leads V1-V2 or V2-V3. Vertical axis as an axis between +60 degrees and +90 degrees. Left ventricular hypertrophy (LVH) was defined according to Sokolow-Lyon criteria. Results 146 consecutive MFS patients were included (mean age 39±14.8 years, females 53.4%, Caucasian 81.1%, BMI 24±6 Kg/m2). Chest wall asymmetry were present in 42.5% of the patients (PE 17.6%, PC 22.3%) and scoliosis in 48.4% of them. Echocardiography revealed a mean aortic root was 40.1±6.4 mm but no evidence of significant cardiomyopathy in any of the patients. Four individuals exhibited moderate mitral and aortic regurgitation. Positive LVH ECG criteria were observed in 22.6% of the cohort. Anterior TWI was found in 10.7%, inferior TWI in 4.4% and lateral in 2.5%. An early QRS transition zone was shown in 33.9% and a vertical axis in 44%. Body habitus was associated with ECG abnormalities; patients with a vertical axis were younger (33.7±12 years vs 45.5±15 years), taller (184.4±9.7cm vs 179.2±10.2cm, p=0.003) and had lower BMI (21.7±4.4Kg/m2 vs 26.3±5.8Kg/m2, p&amp;lt;0.001). Vertical axis was more common in females compared to males (61.4% versus 38.6%. P=0.09) while LVH was more common in males (69.4% vs 30.6%, p = 0.002). Patients with LVH criteria were younger (36.7±11.9 years vs 40.9±15.6 years), taller (184.9 cm vs 180.7 cm, p=0.05) and had lower BMI (22 ±2.9Kg/m2 vs 24.5±6.0Kg/m2, p&amp;lt;0.047. Anterior TWI were more common in patient with PE (p=0.05). Lateral and Inferior TWI were not associated with any specific chest wall asymmetry. Conclusion In the present cohort of adult MFS patients, a positive LVH criteria and vertical QRS axis were more common in those who were younger, taller and had a lower BMI. Pathological TWI were present in almost a fifth of MFS patients. Patients with pectus excavatum were more likely to have anterior TWI. These findings may provide insights for better interpretation of the ECG variation in patients with MFS.

Loss of the Tbx5 gene in the ventricular conduction system induces spontaneous ventricular arrhythmias

The ventricular conduction system (VCS) and the working myocardium (WM) derive from the same myogenic progenitors during the embryonic development. The VCS development is regulated by numerous genes including the T-box transcription factor 5 (Tbx5). In human, Tbx5 mutations cause Holt-Oram syndrome, an autosomal dominant disease associated with heart abnormalities such as arrhythmias. In adult mice, the deletion of the Tbx5 gene provoked a slowing of ventricular conduction due to a loss of the gap junction Connexin 40 and dysfunction of cardiac channels. However, it is still unknown how Tbx5 deletion affects the development and the function of the VCS. The aim is to study the consequences of the Tbx5 deletion in embryonic progenitors of the ventricular conduction system on cardiac function in adult mice. Conditional deletion of Tbx5 alleles in mice was induced by expressing the Cre recombinase under the control of the Connexin 40 (Cx40) gene. We studied two groups of mutants: Tbx5 deletion at embryonic days E13-14 targeting both the ventricular conduction system and the working myocardium (“VCS + WM” group; n = 40) and mice deleted at E18-P2 targeting only the ventricular conduction system (“VCS” group; n = 17). Surface ECGs were achieved monthly until 3 months of age, when immunostaining was performed on the left VCS. Immunostaining showed a reduced expression of the two major connexines in the ventricle (Cx40 and Cx43) and a reduced number of conductive cells in both mutants, suggesting a defective maturation of the VCS (Fig. 1). Furthermore, the loss of Cx43 was correlated with that of Tbx5, reflecting a direct transcriptional effect. Surface ECG revealed a significant increase of the ventricular activation duration in both mutants (P < 0.01). Moreover, premature ventricular contractions (PVCs) and a left QRS axis deviation were observed in both mutants. Finally, these PVCs disappeared with age in both mutants under resting conditions, and are unmasked when the heart is challenged with a β-1 adrenergic agonist. Our results provide new insights into Tbx5 targets in the VCS. Tbx5 deletion impacts the maturation and the anatomy of the VCS as proved by the deviation of the ventricular electrical axis, which even occurs when the VCS is already formed. Tbx5 appears to have a direct impact on the Gja1 gene, encoding the gap junction Cx43, which is reduced at the junction between the VCS and the WM in both mutants and may be responsible for PVCs.