Evaluation of the difference between automated and measured QTc intervals in children.

Abenezer Lemma; Klea Gjuzi; Brady Kwong; Lindsey Flanagan; Alexis Z Tomlinson; Chandra Srinivasan; Victoria L Vetter

doi:10.1016/j.jelectrocard.2026.154418

Home/Archive/PubMed

PubMed · 42556221

Evaluation of the difference between automated and measured QTc intervals in children.

Abenezer Lemma·Klea Gjuzi·Brady Kwong·Lindsey Flanagan·Alexis Z Tomlinson·Chandra Srinivasan·Victoria L Vetter

View original source ↗Export metadata ↓

Abstract

BACKGROUND: The corrected QT interval (QTc) is obtained through automated ECG computations or manual physician measurements. We hypothesized that differences exist in children between the measured and automated QTc intervals within and between Healthy and hypertrophic cardiomyopathy (HCM) subjects with greater differences for HCM due to structural abnormalities. METHODS: QT measurements - Bazett correction- automated (aQTc) and measured (mQTc), were extracted from the GE MUSE database for 385 Healthy pediatric (single ECG) and 208 HCM subjects (2 ECGs), stratified by age < 12 and ≥ 12 yrs., sex, race, and ethnicity. QTc means (SD), automated and measured differences, and the difference of the differences of aQTc and mQTc were analyzed overall and by subgroups. All ECGs were read by one pediatric cardiologist with a second cardiologist reading a random subset of HCM ECGs to evaluate intraclass correlations and agreement. RESULTS: The mQTc intervals were shorter than aQTc intervals within Healthy (p < 0.001) and within first HCM ECGs (p < 0.001) with both aQTc and mQTc shorter in Healthy than HCM (p < 0.001). The difference in these differences was significant overall using HCM ECG 1 but not HCM ECG 2. Healthy subject aQTc and mQTc intervals differed by age, sex, and race (p < 0.002). HCM ECG 1 aQTc- mQTc intervals differed for age < 12 yrs., as well as by sex and race. HCM ECG 2 intervals differed only for age < 12 yrs. CONCLUSIONS: Compared to measured values, automated QTc values were significantly longer in both Healthy and HCM subjects. Automated measurements may overestimate the QTc.

Explore related subjects

Humans Female Electrocardiography Child Male Reproducibility of Results Diagnosis, Computer-Assisted Sensitivity and Specificity Cardiomyopathy, Hypertrophic Child, Preschool Adolescent Algorithms Reference Values Infant Journal Article Comparative Study

Keep this discovery

BibTeX RIS

Abenezer Lemma, Klea Gjuzi, Brady Kwong, Lindsey Flanagan, Alexis Z Tomlinson, Chandra Srinivasan, Victoria L Vetter. 2026-08-01. Evaluation of the difference between automated and measured QTc intervals in children.. https://doi.org/10.1016/j.jelectrocard.2026.154418

Cite the original work for its findings. Save a collection to share your selection of sources.

Discover connections

Journal Article; Comparative Study resource Adolescent subject Algorithms subject Child subject Child, Preschool subject Comparative Study subject Diagnosis, Computer-Assisted subject Female subject Humans subject Infant subject Journal Article subject Male subject

Connections use source metadata and explicit phrase matches, not verified experimental comparisons.

KEEP EXPLORING

Related citations

PubMed2026

Comparison between measured and synthesized posterior lead electrocardiograms during percutaneous coronary intervention-induced myocardial ischemia.

BACKGROUND: Posterior/inferolateral myocardial ischemia is frequently underrecognized on standard 12‑lead electrocardiography (ECG). Synthesized posterior leads derived from the standard 12‑lead ECG have been proposed as an alternative to directly measured posterior leads; however, their accuracy under controlled ischemic conditions has not been fully validated. METHODS: We prospectively enrolled 26 consecutive patients undergoing percutaneous coronary intervention (PCI) in whom simultaneously recorded measured and synthesized posterior lead ECGs (V7-V9) were obtained during balloon-induced myocardial ischemia. ST-segment deviation was measured at the ST junction (STJ), 40 ms (ST1), and 80 ms (ST2) thereafter. Agreement between measured and synthesized posterior leads was assessed using Pearson correlation and Bland-Altman analyses. As an exploratory patient-level analysis, diagnostic performance was compared with reciprocal anterior ST-segment depression (V1-V4). RESULTS: Strong correlations were observed between measured and synthesized posterior lead ST-segment deviations (V7: r = 0.89; V8: r = 0.86; V9: r = 0.83; all P < 0.001). Bland-Altman analysis demonstrated minimal systematic bias (within ±0.004 mV) and narrow limits of agreement. Synthesized posterior leads showed higher diagnostic performance than reciprocal anterior ST-segment depression (AUC 0.917 vs. 0.708), although the difference was not statistically significant (DeLong test, P = 0.197). Using a 0.05 mV threshold, synthesized posterior leads demonstrated 83.3% sensitivity, 100% specificity, and 96.2% overall accuracy. CONCLUSIONS: Synthesized posterior leads closely reproduced measured posterior lead ST-segment deviations during percutaneous coronary intervention (PCI)-induced myocardial ischemia, supporting the technical validity of posterior lead reconstruction. Larger prospective studies are warranted to determine whether synthesized posterior leads provide incremental diagnostic value beyond careful interpretation of the standard 12‑lead ECG.

Humans↗

PubMed2026

Prognostic value of early changes in the frontal QRS-T angle in patients with heart failure and left bundle branch block undergoing cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected patients with heart failure (HF). The frontal QRS-T angle (FQTA), reflecting ventricular depolarization-repolarization heterogeneity, has been associated with major adverse cardiovascular events (MACE). We aimed to assess the prognostic value of changes in the FQTA after CRT in predicting long-term MACE. METHODS: A total of 223 consecutive HF patients with left bundle branch block who underwent CRT between 2018 and 2022 were retrospectively analyzed. The FQTA was measured before and after CRT, and the change (ΔFQTA) was calculated. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff value for predicting the primary outcome, MACE. Patients were subsequently stratified according to this cutoff value. Independent predictors were identified using multivariable Cox proportional hazards regression analysis. RESULTS: ROC analysis identified 22.5° as the optimal cutoff value for predicting MACE (AUC: 0.711; 95% CI: 0.642-0.781; p < 0.001). During a mean follow-up of 34.6 ± 17.6 months, patients with ΔFQTA <22.5° had a significantly higher incidence of MACE compared with those with greater angle reduction (44.7% vs. 11.9%; p < 0.001). In multivariable Cox regression analysis, chronic kidney disease (HR: 2.517; p = 0.002) and ΔFQTA <22.5° (HR: 4.56; p < 0.001) were independently associated with MACE. CONCLUSION: A greater reduction in FQTA after CRT is associated with improved long-term outcomes and may serve as a practical electrocardiographic marker for risk stratification.

Humans↗

PubMed2026

Feasibility and efficacy of left bundle branch area pacing guided by modified chest lead 1.

BACKGROUND: Left bundle branch area pacing (LBBAP) typically requires 12‑lead electrocardiogram (ECG) measurements using an electrophysiology (EP) recording system. However, a simplified approach using modified chest lead 1 (MCL1) is potentially feasible. This study aimed to compare the success rate and pacing outcomes of LBBAP guided by MCL1 with those guided by the 12‑lead ECG using an EP recording system. METHODS: This retrospective, single-center study included patients with preserved left ventricular ejection fraction who underwent LBBAP for bradyarrhythmia. LBBAP was either guided by 12‑lead ECG using an EP recording system or by MCL1. In the MCL1 group, a follow-up examination with a 12‑lead ECG using an EP recording system was conducted within one week postoperatively. RESULTS: A total of 65 patients underwent LBBAP (EP recording system group: n = 35; MCL1 group: n = 30). The overall success rate of LBBAP was 84.6%, with no significant difference between groups (88.5% vs. 80.0%, p = 0.49). No significant differences were observed in the paced QRS duration (140.4 ± 8.0 vs. 141.9 ± 13.1 ms, p = 0.54), V6-V1 interpeak interval (39.7 ± 16.5 vs. 38.3 ± 15.6 ms, p = 0.79), or V6 R-wave peak time (69.8 ± 12.3 vs. 71.5 ± 12.1 ms, p = 0.68). CONCLUSIONS: MCL1-guided LBBAP was feasible and achieved a high success rate, with outcomes comparable to those of conventional EP recording system-guided implantation. This simplified approach may reduce procedural complexity and may allow LBBAP implantation without the routine use of an EP recording system.

Humans↗