Journal Of Electrocardiology[JOURNAL]
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200 papers
Early electrocardiographic repolarization changes are associated with subclinical cancer therapy-related cardiac dysfunction in lymphoma patients: A machine learning-assisted longitudinal study.
Sarıhan M, Şahin M, Kaya AN … +3 more , Türk R, Kutlu M, Sönmez M
J Electrocardiol · 2026 · PMID 41806788 · Publisher ↗
UNLABELLED: Anthracycline-induced cardiotoxicity remains a significant clinical challenge. We evaluated longitudinal electrocardiographic (ECG) repolarization changes in 36 lymphoma patients receiving doxorubicin-based c...
UNLABELLED: Anthracycline-induced cardiotoxicity remains a significant clinical challenge. We evaluated longitudinal electrocardiographic (ECG) repolarization changes in 36 lymphoma patients receiving doxorubicin-based chemotherapy and explored their association with subclinical cancer therapy-related cardiac dysfunction (CTRCD) using an exploratory machine learning-assisted approach. Standard 12‑lead ECGs, echocardiography including left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), and cardiac biomarkers were assessed across sequential chemotherapy cycles. Significant prolongation of corrected QT, corrected JT interval (JTc), and T-peak to T-end interval was detected as early as the second cycle (all p < 0.001), whereas QT dispersion and corrected QT dispersion increased significantly from the fourth cycle onward (p < 0.001). Upon treatment completion, GLS declined significantly (-19.66 ± 2.95% to -18.36 ± 2.51%, p < 0.001), while LVEF remained preserved (p = 0.286). Exploratory Random Forest feature importance analysis was used for feature prioritization rather than predictive modeling, and it prioritized changes in JTc and corrected QT dispersion as the ECG parameters most strongly associated with GLS reduction, with JTc accounting for approximately 28% of the model-derived importance. These findings suggest that doxorubicin-induced ventricular repolarization abnormalities precede overt systolic dysfunction and accompany GLS-defined subclinical CTRCD. Focused ECG monitoring of repolarization parameters may serve as a cost-effective adjunct to echocardiographic surveillance for early cardiotoxicity detection. STRUCTURED ABSTRACT: Background: Anthracycline-induced cardiotoxicity remains a major clinical challenge in cancer survivors. Although global longitudinal strain (GLS) is a sensitive marker of early myocardial dysfunction, the temporal behavior of electrocardiographic (ECG) repolarization parameters across sequential chemotherapy cycles remains incompletely characterized. PURPOSE: To investigate longitudinal ECG repolarization changes during doxorubicin therapy and to explore, using an exploratory machine learning-assisted approach, which ECG markers demonstrate the greatest relative importance in association with subclinical cancer therapy-related cardiac dysfunction (CTRCD). METHODS: This retrospective study included 36 patients with lymphoma treated with doxorubicin-based chemotherapy. Standard 12‑lead ECGs were analyzed at baseline and after the 2nd, 4th, and 6th chemotherapy cycles. Echocardiographic parameters, including left ventricular ejection fraction (LVEF) and GLS, and cardiac biomarkers were assessed at baseline and after treatment completion. An exploratory Random Forest regressor was used solely for feature prioritization to evaluate the relative importance of delta (Δ) ECG repolarization parameters in modeling absolute GLS change (ΔGLS). RESULTS: QTcB, corrected JT (JTc), and T-peak to T-end (Tp-e) intervals were significantly prolonged as early as the second cycle (p < 0.001), whereas QT dispersion (QTd) and corrected QT dispersion (QTcd) increased significantly from the fourth cycle onward (p < 0.001). At chemotherapy completion, GLS declined significantly (-19.66 ± 2.95% to -18.36 ± 2.51%, p < 0.001), while LVEF remained preserved (p = 0.286). Feature importance analysis prioritized ΔJTc and ΔQTcd as the ECG markers most strongly associated with GLS reduction, with JTc accounting for approximately 28% of the model-derived importance. CONCLUSIONS: Doxorubicin-induced ventricular repolarization abnormalities precede overt systolic dysfunction and emerge as early as the second chemotherapy cycle. Exploratory machine learning-assisted analysis highlights JTc and QTcd as prioritized ECG markers associated with subclinical CTRCD. Focused ECG monitoring may serve as a cost-effective and widely accessible adjunct to echocardiographic cardiotoxicity surveillance.
Not just a Wenckebach, not yet a complete heart block.
Rahman Zahin M, Chow CL
J Electrocardiol · 2026 · PMID 41797011 · Publisher ↗
BACKGROUND: ECG manifestations of aortic valve Infective endocarditis are rare and typically consist of evidence of AV dysfunction - from 1st degree AV block to complete heart block. We present an interesting ECG in a ge...
BACKGROUND: ECG manifestations of aortic valve Infective endocarditis are rare and typically consist of evidence of AV dysfunction - from 1st degree AV block to complete heart block. We present an interesting ECG in a gentleman with E faecalis bacteraemia, in the setting of aortic root abscess. CASE REPORT: An 80-year-old male with a past medical history of a bioprosthetic valve and ascending aorta replacement presented to the hospital with generalized malaise, poor oral intake, febrile to 39 °C and dyspnoea. He grew Enterococcus faecalis in his blood cultures and imaging of his chest, abdomen and pelvis was unremarkable. His ECG demonstrated new onset Wenckebach physiology and subsequent transesophageal echocardiography revealed an aortic root abscess. DISCUSSION/CONCLUSION: He was referred with an ECG of atrial bigeminy with 1st degree AV block, but upon closer review, there are several other key findings. Firstly, his ECG demonstrates Wenckebach physiology with a consistent PP interval of 560 ms. However, his ECG exhibits more than just Wenckebach in that the first QRS has a more aberrant appearance than the second one. We postulate this is due to Gap phenomenon where there are functional differences in conduction properties in proximal and distal components of the AV node and phase 4 conduction block where a period of nonconduction due to a blocked P wave results in a reduced responsiveness of Purkinje/bundle branch conducting tissues. Thus, the first QRS (130 ms) appears more aberrant than the second (100 ms). This case highlights the importance of identifying AV dysfunction in septic patients whilst demonstrating an interesting ECG and the importance of recognizing Wenckebach which may have a subtle appearance.
Neonatal narrow-complex SVT unmasking pre-excitation.
Veglia MG, Pesce S, Cortese F … +1 more , Stolfi L
J Electrocardiol · 2026 · PMID 41795536 · Publisher ↗
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A position-related ventricular tachycardia originating from the moderator band: A case report and review of the literature.
Wang X, Xia B, Shi Y … +5 more , Li X, Tang H, Chi R, Li B, Ma W
J Electrocardiol · 2026 · PMID 41774969 · Publisher ↗
We report a case of drug-refractory ventricular tachycardia (VT) triggered by left lateral and supine positions, with only one prior case reported. The patient's VT originated from the moderator band(MB) and occurred in...
We report a case of drug-refractory ventricular tachycardia (VT) triggered by left lateral and supine positions, with only one prior case reported. The patient's VT originated from the moderator band(MB) and occurred in the left lateral and supine positions, but stopped when in the right lateral position. Symptoms disappeared after the patient experienced catheter ablation targeting the head end of the MB. We found that the clinical characteristics of VT originating from the MB could be manifested on electrocardiogram. The mechanism of posture-induced VT may be related to the effect of ventricular pressure on calcium channels and may be related to the age of the patient.
Distinctive electrocardiographic pattern in acute myocardial infarction.
Tomcsányi J, Papp E, Bózsik B
J Electrocardiol · 2026 · PMID 41762865 · Publisher ↗
Diffuse antero-inferior ST-elevation with typical chest pain most often reflects proximal. RCA occlusion, wrap-around LAD occlusion, or multivessel disease. We present a STEMI case with unique QRS and ST-segment pattern....
Diffuse antero-inferior ST-elevation with typical chest pain most often reflects proximal. RCA occlusion, wrap-around LAD occlusion, or multivessel disease. We present a STEMI case with unique QRS and ST-segment pattern. The anterior chest leads V1, V2 and V3 mimic their augmented unipolar limb lead counterparts of aVR, aVL and aVF, respectively. This is best explained by the Littmann concept, which states that precordial leads V1-V3 reflect not only the horizontal electrocardiographic plane of the heart, but they also have strong frontal plane projection.
Novel electrocardiographic diagnosis of left ventricular hypertrophy with right bundle branch block in a Taiwanese clinical cohort.
Ou Yang MH, Wu CT
J Electrocardiol · 2026 · PMID 41740279 · Publisher ↗
BACKGROUND: The diagnostic accuracy of electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) in Taiwanese adults remains uncertain, particularly in the presence of complete right bundle branch block...
BACKGROUND: The diagnostic accuracy of electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) in Taiwanese adults remains uncertain, particularly in the presence of complete right bundle branch block (CRBBB). METHODS: We retrospectively enrolled 431 Taiwanese adults, including 205 with normal conduction and 226 with CRBBB. Echocardiographic left ventricular mass index (LVMI) served as the reference standard. We evaluated the sensitivity, specificity and area under the receiver operating characteristic curve (AUC) of six traditional ECG criteria: Sokolow-Lyon index, RaVL, modified Sokolow-Lyon, Cornell voltage, Gubner-Ungerleider and Peguero-Lo Presti. Linear regression examined associations between individual ECG parameters and LVMI, with a focus on the impact of CRBBB. Exploratory analyses were conducted to derive novel ECG indices. RESULTS: Traditional ECG criteria showed low sensitivity but high specificity overall. In patients with normal conduction, Cornell voltage performed best in females and Gubner-Ungerleider in males. However, diagnostic performance decreased substantially in the presence of CRBBB, particularly for criteria relying on anteroseptal leads. In CRBBB patients, QRS duration demonstrated stronger correlation with LVMI than voltage-based criteria. In our cohort, ECG criteria with superior performance is SD× QRS (AUC 0.754) in males with CRBBB, QRS duration (AUC 0.868) in CRBBB females and BMI<24, and SV4 amplitude (AUC 0.702) in CRBBB females with BMI≥ 24. CONCLUSION: Traditional ECG criteria for LVH originally developed in Western cohorts demonstrated limited diagnostic performance in Taiwanese adults, particularly in the setting of CRBBB. QRS duration and derived indices may provide more accurate alternatives for detecting LVH in this population.
A new and modified northern occlusion myocardial infarction pattern.
Ni H, Wan X, Shi T … +2 more , Gao Z, Pan H
J Electrocardiol · 2026 · PMID 41719915 · Publisher ↗
BACKGROUND: Currently, it is challenging to identify atypical occlusive myocardial infarction (OMI) in clinical practice. OBJECTIVE: To analyze and discuss the potential electrocardiogram (ECG) manifestations of the rece...
BACKGROUND: Currently, it is challenging to identify atypical occlusive myocardial infarction (OMI) in clinical practice. OBJECTIVE: To analyze and discuss the potential electrocardiogram (ECG) manifestations of the recently proposed Northern occlusive myocardial infarction (Northern OMI) in the context of acute coronary syndrome (ACS), as well as the associated vessel types. METHODS: We conducted a retrospective analysis of clinical data from patients who exhibited ST-segment elevation (STE) in leads aVR and aVL on electrocardiography over the past 18 months. Patients with typical ECG manifestations associated with ST-segment elevation occlusive myocardial infarction (STE-OMI) were excluded. All included patients underwent emergent coronary angiography to confirm the presence of coronary artery lesions. RESULTS: A total of 9 patients with STE in leads aVR and aVL were included in the study. Their ECG findings did not fully meet the current diagnostic criteria for Northern OMI. Among these patients, 8 were diagnosed with OMI, with culprit vessels involving both single-vessel and multivessel lesions, 7 received timely coronary intervention treatment and 1 declined coronary intervention owing to advanced age and comorbidities, opting instead for conservative treatment. The remaining case was attributed to acute brainstem hemorrhage, timely therapeutic intervention was administered. CONCLUSION: The current diagnostic model for Northern OMI may have limitations. This study proposes an modified diagnostic criterion characterized by ST-segment elevation in leads aVR and aVL, accompanied by reciprocal ST-segment depression (STD) in at least leads II, III, and aVF.
P-wave peak time: An emerging electrocardiographic marker of atrial stress and ischemic burden-review.
Zhang AJ, Chelu MG, Taing K … +1 more , Birnbaum Y
J Electrocardiol · 2026 · PMID 41719914 · Publisher ↗
The 12‑lead electrocardiogram (ECG) remains a cornerstone of cardiovascular assessment, providing a noninvasive window into cardiac electrical and structural function beyond other markers of ischemia and arrhythmias. P-w...
The 12‑lead electrocardiogram (ECG) remains a cornerstone of cardiovascular assessment, providing a noninvasive window into cardiac electrical and structural function beyond other markers of ischemia and arrhythmias. P-wave peak time (PWPT), defined as the interval from P-wave onset to its maximal amplitude, has emerged as a novel electrocardiographic marker of atrial conduction and hemodynamic stress. Increasing evidence suggests that PWPT prolongation accompanies elevated ventricular filling pressures, atrial stretch, and chronic atrial remodeling across a spectrum of ischemic conditions, including both obstructive coronary artery disease and ischemia with no obstructive coronary arteries (INOCA). In addition to serving as a marker of acute ischemia, PWPT also appears to capture long-term atrial structural and electrophysiologic changes, including fibrosis and conduction slowing. These same processes are central to the development of atrial fibrillation, providing a biologically plausible link between PWPT prolongation and arrhythmogenic risk. Moreover, given its simplicity and compatibility with computerized ECG analysis, PWPT represents a promising adjunctive marker for cardiovascular risk stratification. Further investigation in larger and more diverse populations is warranted to define its prognostic significance and clinical utility.
Validity of the single-limb electrocardiographic technology in the warfighter monitor™.
Vivas PH, Acosta RJ, Kantrowitz AB … +5 more , Ben-David K, Wittels HL, Wishon MJ, Wittels SH, Rosen G
J Electrocardiol · 2026 · PMID 41719913 · Publisher ↗
BACKGROUND: Devices equipped with electrocardiographic (ECG) technology possess design limitations reducing their feasibility across a range of users and environments. PURPOSE: This study evaluated the validity of a nove...
BACKGROUND: Devices equipped with electrocardiographic (ECG) technology possess design limitations reducing their feasibility across a range of users and environments. PURPOSE: This study evaluated the validity of a novel, single-limb biomedical device using single‑lead ECG technology located on the upper arm for monitoring cardiac activity in a large, diverse sample. METHODS: A cross-sectional study was conducted among 931 adults from May to September 2024 at an outpatient medical center in the United States. ECG recordings were captured on the Warfighter Monitor™ (WFM; Tiger Tech Solutions, Miami, FL). Each participant wore two ECGs simultaneously, a standard Lead-I ECG on the chest (ECG-Chest) and a WFM on the upper arm (ECG-Bicep), for 5 to 7 min. Agreement between ECG-Chest and ECG-Bicep measurements for HR and HRV were evaluated using Pearson correlations, Bland-Altman, and ANOVA. RESULTS: The study population was diverse in age (17-99 years), sex (53.4% male), and ethnicity (53.7% Hispanic or Latino), and comorbidities: cardiovascular (61.2%), respiratory (31.5%), cancer (20.3%), endocrine (43.4%), and neurological (32.5%) disorders. Near-perfect correlations (0.995-0.997, p < 0.0001) and negligible mean differences (-0.02 to 0.05 bpm or ms, p < 0.00001) were found between ECG-Chest and ECG-Bicep for HR and HRV metrics. CONCLUSION: The near-perfect agreement in HR and HRV between ECG recordings measured at the chest and bicep, confirms the strong validity of the WFM for precise, ECG-based monitoring across a broad set of demographics. These results demonstrate the high accuracy, versatility, and feasibility of the WFM to accurately monitor HR and HRV.
Postoperative junctional ectopic tachycardia with variable QRS morphology: A case report.
Lovrenčić L, Bakoš M
J Electrocardiol · 2026 · PMID 41702317 · Publisher ↗
Junctional ectopic tachycardia (JET) is a rare but clinically important arrhythmia most often encountered in infants and children, either congenitally or within 72 h after congenital heart surgery. We report a neonate wh...
Junctional ectopic tachycardia (JET) is a rare but clinically important arrhythmia most often encountered in infants and children, either congenitally or within 72 h after congenital heart surgery. We report a neonate who developed postoperative JET with variable QRS morphologies after an arterial switch operation, in whom QP interval and QRS duration correlated with the preceding RR interval. The arrhythmia caused hemodynamic instability requiring antiarrhythmic therapy and supportive measures. This case illustrates the diverse electrocardiographic manifestations of postoperative JET and highlights the importance of early rhythm characterization to guide timely, mechanism-based management in critically ill neonates.
The limits of the frontal QRS axis in modern electrocardiography.
de Alencar JN
J Electrocardiol · 2026 · PMID 41698299 · Publisher ↗
BACKGROUND: The frontal QRS axis is reported on every 12‑lead electrocardiogram (ECG) and is still taught as a precise geometric descriptor of ventricular depolarization. Contemporary biophysics and vectorcardiography, h...
BACKGROUND: The frontal QRS axis is reported on every 12‑lead electrocardiogram (ECG) and is still taught as a precise geometric descriptor of ventricular depolarization. Contemporary biophysics and vectorcardiography, however, raise fundamental questions about what this number actually represents and how it should be used. METHODS: This conceptual review examines how the frontal QRS axis is computed in clinical practice, identifies the physical assumptions made, and contrasts axis-based interpretation with three-dimensional, time-integrated metrics. RESULTS: Ventricular depolarization is a three-dimensional, time-varying process that generates a QRS loop, not a single stable vector. The clinically reported "mean" QRS axis is derived from net limb‑lead amplitudes (typically R-S), algebraically adding sequential deflections as if they were simultaneous. This construct is therefore neither a true resultant vector nor a rigorous time average of the depolarization field, but an algebraic summary of projected amplitudes. Its numerical value depends on method choice, lead selection, and geometric approximations. By contrast, three-dimensional measures such as spatial QRS-T angle and vectorcardiographic QRS area preserve temporal integration and spatial information. CONCLUSIONS: The frontal QRS axis should be regarded as a low-dimensional, categorical descriptor rather than a primary geometric truth. Hyper-precise angular reporting is not physically justified. Contemporary ECG practice and automated systems should prioritize spatial QRS-T angle, QRS area, and related vectorcardiographic indices, reserving the frontal axis for ordinal classification within a broader, three-dimensional framework.
Electrocardiographic atrial cardiomyopathy markers in sinus rhythm and the risk of incident atrial fibrillation and ischemic stroke a retrospective cohort study.
Ömür SE, Zorlu Ç, Genç Tapar G … +3 more , Karaman K, Karayakali M, Çelik A
J Electrocardiol · 2026 · PMID 41691880 · Publisher ↗
BACKGROUND: Electrocardiographic (ECG) markers of atrial cardiomyopathy obtained in sinus rhythm may help identify outpatients at increased risk of incident atrial fibrillation (AF) and related adverse outcomes. AIM: To...
BACKGROUND: Electrocardiographic (ECG) markers of atrial cardiomyopathy obtained in sinus rhythm may help identify outpatients at increased risk of incident atrial fibrillation (AF) and related adverse outcomes. AIM: To evaluate the associations of P-wave terminal force in lead V1 (PTFV1) and deep terminal negativity of the P wave in V1 (DTNPV1) with incident AF and clinical outcomes in a contemporary outpatient cohort. METHODS: We conducted a retrospective cohort study of consecutive adults undergoing clinically indicated outpatient 12‑lead ECG in sinus rhythm between September 2022 and September 2025. Abnormal PTFV1 was defined as ≥4000 μV·ms and DTNPV1 as a biphasic P wave in V1 with terminal negative amplitude >100 μV. The primary endpoint was incident AF, defined as the first new AF episode after the index ECG requiring objective rhythm documentation on a 12‑lead ECG/rhythm strip or ambulatory monitor report (≥30 s); diagnostic codes alone were not sufficient. Secondary endpoints were incident ischemic stroke/TIA, heart failure (HF) hospitalization, all-cause mortality, and a composite outcome. Associations were assessed using Cox proportional hazards models with prespecified multivariable adjustment. RESULTS: The final cohort included 1500 patients; 400 (26.7%) had abnormal PTFV1. Over a median follow-up of 3.2 years, incident AF occurred in 301 patients (20.1%). AF incidence was higher in the abnormal vs normal PTFV1 groups (31.0% vs 16.1%), and abnormal PTFV1 independently predicted incident AF (adjusted HR 1.35, 95% CI 1.03-1.77). Abnormal PTFV1 was also associated with incident stroke/TIA (7.8% vs 4.0%; adjusted HR 1.34, 95% CI 1.01-1.78), incident HF hospitalization (17.5% vs 10.0%; adjusted HR 1.22, 95% CI 1.01-1.48), and the composite endpoint (37.5% vs 30.0%; adjusted HR 1.28, 95% CI 1.10-1.48). All-cause mortality was numerically higher but not statistically significant after adjustment (6.3% vs 4.5%; adjusted HR 1.35, 95% CI 0.82-2.21). DTNPV1 was not independently associated with incident AF after adjustment. CONCLUSION: In outpatients with sinus-rhythm ECGs, abnormal PTFV1 is independently associated with higher risk of incident AF and other clinically relevant outcomes, supporting its potential role in targeted rhythm surveillance and risk stratification.
Diagnostic agreement of smartphone-based electrocardiogram with coronary angiography in identifying vessel involvement in patients with myocardial infarction.
Mohan C, Gururani K, Rawat A … +5 more , Singh Y, Chandola N, Agarwal D, Singh SYP, Prabhakar M
J Electrocardiol · 2026 · PMID 41691879 · Publisher ↗
BACKGROUND: Acute myocardial infarction (MI) remains one of the major causes of morbidity and mortality throughout the world. The objectives of this study were to determine the diagnostic agreement between the findings f...
BACKGROUND: Acute myocardial infarction (MI) remains one of the major causes of morbidity and mortality throughout the world. The objectives of this study were to determine the diagnostic agreement between the findings from Portable (Spandan Pro) and Conventional Electrocardiogram with coronary angiography (CAG) regarding vessel involvement in MI patients, and to assess related risk factors. METHODOLOGY: This study was an Observational, Single-arm, Cross-sectional study performed on 109 subjects at a local hospital in Dehradun. The study was approved by the Institutional Ethics Committee, and informed consent was obtained from all the participants. For diagnostic agreement, Statistical analyses such as Cohen's κ, weighted κ, prevalence- and bias-adjusted κ (PABAK), and Jaccard index were used. RESULTS: The mean age of the included patients was 58 ± 11.96 years, with a significant male predominance (88.07%). For overall vessel involvement of ECGs with CAG, portable ECG showed a higher sensitivity (84.76 vs. 78.10%), and for LAD artery, it also showed higher sensitivity (88.46% vs. 82.05%) compared to the conventional ECG. Diagnostic agreement showed substantial agreement with CAG (PABAK 0.68), and according to the Jaccard Index, there was a moderate agreement (approximately 50%) between the ECG-derived findings with CAG across all types of vessel diseases. The most prevalent confounding factor among the participants was smoking (41.9%), followed by Hypertension (39.0%) and diabetes (34.3%). CONCLUSION: This study indicates that Portable ECG performed comparably to conventional ECG and had a moderate level of diagnostic agreement with CAG in the detection of vessel involvement in patients with MI.
Mechanisms of atrial fibrillation in mitral regurgitation patients: Insights from noninvasive electrocardiographic imaging.
Vijayakumar R, Yates TA, McGilvray M … +7 more , Razo N, Sinn LA, Schuessler RB, Zemlin CW, Rudy Y, Damiano RJ, Schill MR
J Electrocardiol · 2026 · PMID 41691878 · Full text
OBJECTIVE: Noninvasive Electrocardiographic Imaging (ECGI) was used to define the mechanisms of atrial fibrillation (AF) in mitral regurgitation (MR), which remain poorly understood. METHODS: Seventeen patients with dege...
OBJECTIVE: Noninvasive Electrocardiographic Imaging (ECGI) was used to define the mechanisms of atrial fibrillation (AF) in mitral regurgitation (MR), which remain poorly understood. METHODS: Seventeen patients with degenerative MR and AF undergoing were studied. Thirteen age-matched patients with lone AF provided a control group. Epicardial electrograms were constructed noninvasively with ECGI using 256 body surface electrocardiograms and patient-specific heart-torso geometry from delayed-enhancement magnetic resonance imaging (DE-MRI) or computed tomography (CT) scans. Bi-atrial epicardial activation time maps and phase maps were generated. AF drivers were classified as focal (radial activation) or rotors (high curvature wavefront rotating about a center). Left atrial (LA) fibrosis was quantified from the DE-MRI scans in 5 MR patients. RESULTS: The LA and right atrium (RA) harbored 61% and 36% of drivers, respectively and the anterior inter-atrial groove had 3% of the sources. 51% of the drivers were mapped in the posterior LA. One third of drivers occurred repeatedly. The left PV and LA appendage regions had the most repetitive drivers. Activation patterns varied from single macro-reentry to simultaneous wavelets resulting in wave breaks and collisions. Driver distribution and activation patterns remained similar between MR and lone AF groups, except stable rotors were not observed in MR. DE-MRI maps showed bi-atrial fibrosis. Drivers and discontinuous wavefront propagation were often localized in fibrotic regions. CONCLUSIONS: AF activation patterns in MR were complex and exhibited spatio-temporal variability. Bi-atrial drivers were present. The posterior LA harbored the highest percentage of drivers. This region also exhibited fibrosis in a subset of patients, suggesting that it may play a role in creating the AF substrate.
Electrocardiogram-based false positive diagnosis of left ventricular hypertrophy during tachycardia: What more needs to be done.
Madias JE
J Electrocardiol · 2026 · PMID 41689969 · Publisher ↗
This short communication aims at raising an insight about an observation made 26 years ago, describing a transient false positive electrocardiogram (ECG)-based diagnosis of left ventricular hypertrophy (LVH) in patients...
This short communication aims at raising an insight about an observation made 26 years ago, describing a transient false positive electrocardiogram (ECG)-based diagnosis of left ventricular hypertrophy (LVH) in patients with various tachycardias (e.g, sinus, supraventricular, atrial fibrillation) with or without evidence of LVH as assessed by cardiac imaging. The mechanism is purported to be due to a tachycardia-mediated shortening of the diastolic left ventricular (LV) dimensions due to tachycardias, with the diastolic LV volume centroid displaced closer to the anterior chest wall (e.g. "Wilson's proximity effect"). This insight prevents an inappropriate diagnosis of LVH; also, it is possible that the absence of such a phenomenon during tachycardias may imply in some cases advanced acute or chronic heart failure, resulting in LV diastolic dilatation, counteracting this ECG phenomenon. The author advocates that automated ECG interpretation algorithms providing interpretation upon recording of an ECG should be modified to reflect on this insight, since many physicians rely inappropriately on the automated ECG interpretation.
Predictive value of standard electrocardiographic parameters for major adverse cardiovascular events in patients with coronary heart disease: A retrospective cohort study.
Yang M, Zhao H, Yin Y … +2 more , Li X, Zhan Y
J Electrocardiol · 2026 · PMID 41679256 · Publisher ↗
BACKGROUND: Accurate risk stratification is crucial for managing patients with coronary heart disease (CHD). This study aimed to investigate the value of baseline electrocardiogram (ECG) indicators in predicting one-year...
BACKGROUND: Accurate risk stratification is crucial for managing patients with coronary heart disease (CHD). This study aimed to investigate the value of baseline electrocardiogram (ECG) indicators in predicting one-year major adverse cardiovascular events (MACE) in patients with CHD. METHODS: This single-center, retrospective cohort study enrolled 200 hospitalized patients with a confirmed CHD diagnosis. Baseline demographic, clinical, echocardiographic, and 12-lead ECG data were collected. The primary endpoint was the occurrence of MACE (a composite of cardiac death, non-fatal acute MI, severe arrhythmia, severe heart failure, and stroke) within one year. Univariate and multivariable logistic regression analyses were performed to identify independent ECG predictors, with predictive performance evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: During a one-year follow-up, 29 of 200 patients (14.5%) experienced a MACE. Patients with MACE had significantly worse baseline cardiac function, including lower left ventricular ejection fraction (LVEF) and higher E/e' ratio. In multivariable analysis, higher resting heart rate (OR per 10 bpm: 1.54, 95% CI: 1.09-2.17, P=0.014), longer QRS duration (OR per 10 ms: 1.69, 95% CI: 1.16-2.47, P=0.006), and longer corrected QT (QTc) interval (OR per 10 ms: 1.63, 95% CI: 1.23-2.15, P<0.001) were independent predictors of MACE. A combined model integrating these three parameters demonstrated excellent predictive accuracy (AUC=0.85, 95% CI: 0.78-0.92), superior to any single parameter. The QTc interval was the best single predictor (AUC=0.79). CONCLUSION: Higher resting heart rate, longer QRS duration, and longer QTc interval are independent and powerful predictors of one-year MACE in patients with CHD. A combined model using these simple ECG markers provides robust risk stratification, offering significant incremental predictive value over baseline clinical factors.
Toward self-validating ECG Systems: A personalized, uncertainty-aware approach for detecting and estimating lead misplacement.
Rafiei A, Dwivedi T, Xue J … +4 more , Schlesinger DE, Katebi N, Albert DE, Clifford GD
J Electrocardiol · 2026 · PMID 41662810 · Publisher ↗
BACKGROUND: Electrode positioning directly influences the interpretation and diagnostic quality of ECG recordings. While current solutions mainly focus on detecting lead swaps in standard full-lead configurations, the gr...
BACKGROUND: Electrode positioning directly influences the interpretation and diagnostic quality of ECG recordings. While current solutions mainly focus on detecting lead swaps in standard full-lead configurations, the growing adoption of portable and reduced-lead devices underscores the need for effective methods to identify and quantify electrode misplacement in various settings. METHODS: We developed and evaluated an end-to-end, personalized, uncertainty-aware framework that took ECG waveforms as input and automatically detected and estimated potential electrode misplacement, using an annotated dataset of 4608 Mayo Clinic 12-lead ECGs. The pipeline combined a deep convolutional encoder to identify the lead source area with a regression head that leveraged the learned representation to estimate misplacement direction and magnitude. It also incorporated patient-specific ECG morphology for personalization and integrated an uncertainty quantification mechanism based on Monte Carlo dropout to enhance decision confidence. RESULTS: The proposed method achieved over 94% classification accuracy in detecting the lead source area and estimated lead misplacement with a mean absolute error (MAE) of 2.2 cm. Incorporating personalized information enhanced results, reaching 97.5% accuracy and an MAE of 2.0 cm, while also largely maintaining performance for ECG determinations such as myocardial infarction and atrial fibrillation. The uncertainty-aware layer further reduced false corrections by flagging unfamiliar or ambiguous cases, boosting accuracy to 98.6% and lowering the MAE to 1.8 cm. CONCLUSION: This study introduced a practical solution to improve ECG lead placement accuracy, enabling self-validating lead positioning that can enhance diagnostic reliability and support broader adoption of ECG technology in both clinical and decentralized care.
The Tp-e interval and Tp-e/QT ratio as markers of ventricular repolarization dispersion and atrial conduction heterogeneity following electrical injury: A retrospective case-control study.
Yanik A, Ozgen E, Boyacı F … +2 more , Akcay M, Sahin MK
J Electrocardiol · 2026 · PMID 41655556 · Publisher ↗
Electrical injuries are a significant cause of cardiovascular morbidity and life-threatening arrhythmias. This study aimed to evaluate markers of ventricular repolarization dispersion and atrial conduction heterogeneity,...
Electrical injuries are a significant cause of cardiovascular morbidity and life-threatening arrhythmias. This study aimed to evaluate markers of ventricular repolarization dispersion and atrial conduction heterogeneity, specifically, the Tp-e interval, Tp-e/QT ratio, and P-wave dispersion, in patients presenting with electrical injury METHODS: In this retrospective case-control study, 50 patients with electrical injury were compared with 59 age- and sex-matched healthy controls. Standard 12‑lead electrocardiograms were obtained for all participants. Key parameters, Tp-e interval, Tp-e/QT ratio, Tp-e/QTc ratio, and P-wave dispersion, were manually measured by two blinded cardiologists with excellent interobserver reliability. A subgroup analysis was also performed within the injury cohort based on troponin status RESULTS: The Tp-e interval was significantly prolonged in the electrical injury group compared to controls (median 85.0 ms vs. 80.0 ms, p < 0.001). The Tp-e/QT ratio (0.24 vs. 0.21, p < 0.001), Tp-e/QTc ratio (0.20 vs. 0.19, p = 0.005), and P-wave dispersion (45.0 ms vs. 25.0 ms, p < 0.001) were also elevated in patients with electrical injury. Notably, no significant differences in these electrocardiographic parameters were observed between troponin-positive and troponin-negative subgroups CONCLUSION: Electrical injury is associated with significant acute abnormalities in ventricular repolarization and atrial conduction heterogeneity, independent of troponin elevation. The Tp-e interval, Tp-e/QT ratio, and P-wave dispersion may serve as potential electrocardiographic markers of arrhythmic risk in this population, though their prognostic utility requires validation in prospective studies.
Correlation between Electrical Synchrony Index values measured by Synchromax® and left ventricular mechanical dispersion assessed by strain echocardiography.
Villarroel-Ábrego H, Garillo RN, Bumaguin DB … +2 more , Lignati BN, Ferrari ADL
J Electrocardiol · 2026 · PMID 41650800 · Publisher ↗
BACKGROUND: Left ventricular (LV) mechanical dyssynchrony results from nonuniform myocardial activation, leading to inefficient LV contraction and worse clinical outcomes. Synchromax® is a noninvasive system that perform...
BACKGROUND: Left ventricular (LV) mechanical dyssynchrony results from nonuniform myocardial activation, leading to inefficient LV contraction and worse clinical outcomes. Synchromax® is a noninvasive system that performs real-time spatial variance analysis of QRS complexes from a standard electrocardiogram, generating an electrical synchrony index (ESI) that may be a potential marker of LV mechanical dyssynchrony. This study evaluated the efficacy of the ESI in predicting LV mechanical dyssynchrony compared to the gold standard: LV mechanical dispersion (LVMD) > 60 ms as measured by speckle-tracking strain echocardiography. METHODS: A cross-sectional study was conducted with consecutive adult patients undergoing echocardiography in San Salvador, El Salvador. Clinical, electrocardiographic (rhythm, QRS duration, ESI), and echocardiographic (LVMD, LV ejection fraction, global longitudinal strain) data were collected. RESULTS: Eighty-four studies from 83 patients were analyzed. Mean ESI was 0.36 ± 0.31 and mean LVMD was 58.4 ± 27.1 ms. The ESI showed a sensitivity of 70.0% and a specificity of 88.9%, with negative and positive predictive values of 84.2% and 77.8%, respectively. Agreement with the gold standard was moderate (kappa = 0.60; p < 0.001). ROC curve analysis demonstrated good discriminative performance (area under the curve = 0.81), superior to QRS duration (area under the curve = 0.71) for identifying LV mechanical dyssynchrony. CONCLUSIONS: The optimal ESI cutoff was 0.42. ESI correlated consistently and significantly with LVMD, indicating that it may be a more sensitive functional marker than QRS duration, especially in cases without evident dyssynchrony. The ESI is a simple, accessible tool for complementary assessment of ventricular electromechanical synchrony.
Electrocardiographic repolarization changes following conduction system pacing in pacemaker-induced cardiomyopathy.
Sahin AT, Canpolat U, Dural M … +7 more , Dogan M, Yunus GO, Ozkaya I, Kesriklioglu S, Kan MU, Sertdemir AL, Gul EE
J Electrocardiol · 2026 · PMID 41616431 · Publisher ↗
BACKGROUND: Pacemaker-induced cardiomyopathy (PICM) occurs in a subset of patients exposed to chronic right ventricular pacing (RVP) and results in left ventricular dysfunction due to pacing-related dyssynchrony. Left bu...
BACKGROUND: Pacemaker-induced cardiomyopathy (PICM) occurs in a subset of patients exposed to chronic right ventricular pacing (RVP) and results in left ventricular dysfunction due to pacing-related dyssynchrony. Left bundle branch area pacing (LBBAP) has emerged as a physiologic pacing strategy capable of restoring conduction system activation and reversing PICM. However, the acute effects of LBBAP on ventricular repolarization in PICM remain unclear. This study evaluated immediate repolarization changes after LBBAP in PICM compared with a control cohort of non-ischemic dilated cardiomyopathy (DCM) patients undergoing LBBAP. METHODS: We retrospectively analyzed clinical, electrocardiographic, and pacing data from patients receiving successful LBBAP. Baseline and post-implant ECG intervals (QT, QTc, Tp-Te) were manually measured; T-wave memory (TWM) was qualitatively assessed. Procedure parameters (RWPT, V6-V1 interpeak interval, output-dependent QRS transition), procedural success, and complications were recorded. RESULTS: Sixty patients were included (28 PICM vs. 32 DCM). Baseline LVEF was higher in patients with PICM compared to DCM (35 ± 8% vs. 29 ± 7%; p = 0.003). LBBAP success was similar (93% vs. 96%). PICM patients had wider paced QRS (149 ms vs. 128 ms; p = 0.02) and longer V6-V1 interval (46 ± 12 vs. 38 ± 10 ms; p = 0.02), but repolarization metrics showed no adverse changes and remained comparable between groups. QT shortened similarly (PICM: 476 → 437 ms; DCM: 466 → 432 ms), QTc minimally increased without group interaction, Tp-Te decreased, and TWM was frequent in both cohorts (63% vs. 64%). Complications rate was also comparable. CONCLUSION: LBBAP does not induce unfavorable acute repolarization changes in PICM and yields repolarization responses comparable to DCM controls, supporting its safety and physiologic benefit in PICM upgrades.
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