Diagnostic Value of the TpTe Interval in Children with Ventricular Arrhythmias

Prediction of breath-holding spells based on electrocardiographic parameters using machine-learning model

BACKGROUND

Breath-holding spells (BHS) are common in infancy and early childhood and may appear like seizures. Factors such as autonomic dysfunction and iron deficiency anemia are thought to contribute to the incidence of BHS. In this study, electrocardiographic (ECG) parameters of patients with BHS were compared to those of healthy, normal children. Logistic regression and machine-learning (ML) models were then created to predict these spells based on ECG characteristics.

METHODS

In this case-control study, 52 BHS children have included as the case and 150 healthy children as the control group. ECG was taken from all children along with clinical examinations. Multivariate logistic regression model was used to predict BHS occurrence based on ECG parameters. ML model was trained and validated using the Gradient-Boosting algorithm, in the R programming language.

RESULTS

In BHS and control groups, the average age was 11.90 ± 6.63 and 11.33 ± 6.17 months, respectively (p = .58). Mean heart rate, PR interval, and QRS interval on ECGs did not differ significantly between the two groups. BHS patients had significantly higher QTc, QTd, TpTe, and TpTe/QT (all p-values < .001). Evaluation of the ML model for prediction of BHS, fitting on the testing data showed AUC, specificity, and sensitivity of 0.94, 0.90, and 0.94 respectively.

CONCLUSION

There are repolarization changes in patients with BHS, as the QTc, QTd, TpTe, and TpTe/QT ratio were significantly higher in these patients, which might be noticeable for future arrhythmia occurrence. In this regard, we developed a successful ML model to predict the possibility of BHS in suspected subjects.

Prognostic Value of Tpeak-Tend Interval in Early Diagnosis of Duchenne Muscular Dystrophy Cardiomyopathy

The most common cause of death in patients with Duchenne muscular dystrophy (DMD) is cardiomyopathy. Our aim was to investigate the relationship between the Tpeak-Tend (Tp-e) interval and the premature ventricular contraction (PVC) burden and therefore early arrhythmic risk and cardiac involvement in DMD patients. Twenty-five patients with DMD followed by pediatric cardiology were included in the study. Those with a frequency of <1% PVC in the 24 h Holter were assigned to Group 1 (n = 15), and those with >1% were assigned to Group 2 (n = 10). Comparisons were made with healthy controls (n = 27). Left ventricular ejection fraction (LVEF) was lowest in Group 2 and highest in the control group (p < 0.001). LV end-diastolic diameter was greater in Group 2 than in Group 1 and the control group (p = 0.005). Pro-BNP and troponin levels were higher in Group 1 and Group 2 than in the control group (p = 0.001 and p < 0.001, respectively). Tp-e interval was longer in Group 2 compared to Group 1 and the control group (p < 0.001). The LVEF (OR 0.879, 95% CI 0.812-0.953; p = 0.002) and Tp-e interval (OR 1.181, 95% CI 1.047-1.332; p = 0.007) were independent predictors of PVC/24 h frequency of >1%. A Tp-e interval > 71.65 ms predicts PVC > 1%, with a sensitivity of 80% and a specificity of 90% (AUC = 0.842, 95% CI (0.663-1.000), p = 0.001). Determination of Tp-e prolongation from ECG data may help in the determination of cardiac involvement and early diagnosis of arrhythmic risk in DMD.

Patients with Achilles Tendon Rupture Are Prone to Develop Ventricular Arrhythmia

BACKGROUND AND OBJECTIVES

This study aimed to examine the ventricular repolarization (VR) disturbances of patients operated on for acute spontaneous Achilles tendon ruptures (ATRs), by comparing them with a healthy individual control group.

MATERIALS AND METHODS

Between June 2014 and July 2020, a total of 29 patients (28 males, 1 female; mean age: 40 ± 9.78 years; range, 21-66 years) who presented to the emergency department within the first three weeks of injury, and were diagnosed with acute spontaneous ATRs and treated with an open Krackow suture technique, were retrospectively analyzed. Fifty-two healthy individuals (47 males, 5 females; mean age: 39 ± 11.45 years; range, 21-66 years) were recruited as a control group from the cardiology outpatient clinic. Clinical data (demographic features and laboratory parameters (serum glucose, creatinine, hemoglobin, white blood cell count, and lipid profile)) and electrocardiograms (ECGs) were collected from medical records. ECGs were evaluated for heart rate and VR parameters of QRS width, QTc interval, cQTd interval, Tp-e interval, and Tp-e/QT ratio. The clinical data and these ECG parameters were compared between groups.

RESULTS

There was no statistically significant difference between groups, regarding clinical data (all p < 0.05). Among ECG parameters, heart rate, QRS width, QTc interval, and cQTd interval were similar between groups (all p < 0.05). There were two important statistically significant findings of this research: The mean Tp-e interval was longer (ATR group: 72.4 ± 24.7, control group: 58.8 ± 14.5, p: 0.01), and the Tp-e/QT ratio was higher (ATR group: 0.2 ± 0.1, control group: 0.16 ± 0.4, p: 0.027) in the ATR group.

CONCLUSIONS

According to the ventricular repolarization disturbances found in this study, patients with ATR may be at a higher risk of ventricular arrhythmia than healthy people. As a result, ATR patients should be assessed for ventricular arrhythmia risk by an expert cardiologist.

ECG as a risk stratification tool in patients with wearable cardioverter-defibrillator

BACKGROUND

The wearable cardioverter defibrillator (WCD) is increasingly used in patients at elevated risk for ventricular arrhythmias but not fulfilling the indications for an implantable cardioverter defibrillator (ICD). Currently, there is an insufficient risk prediction of fatal arrhythmias in patients at risk. In this study, we assessed the prognostic role of baseline electrocardiogram (ECG) in WCD patients.

METHODS

WCD patients from diverse clinical institutions in Germany (n = 227) were retrospectively enrolled and investigated for the incidences of death or ventricular arrhythmias during WCD wearing. In addition, the widely accepted ECG predictors of adverse outcome were analyzed in patients with arrhythmic events.

RESULTS

Life-threatening arrhythmias occurred in 22 (9.7 %) patients, mostly in subjects with ischemic heart disease (15 of 22). There was no difference in baseline left ventricular ejection fraction (LVEF) in subjects with and without arrhythmic events (31.3 ± 7.9 % vs. 32.6 ± 8.3 %; p = 0,24). Patients with arrhythmia exhibited significantly longer QRS duration (109.5 ± 23.1 ms vs. 100.6 ± 22.3 ms, p = 0,04), Tpeak-Tend (Tp-e) (103.1 ± 15.6 ms vs. 93.2 ± 19.2 ms, p = 0,01) and QTc (475.0 ± 60.0 ms vs. 429.6 ± 59.4 ms, p < 0,001) intervals. In contrast, no significant differences were found for incidences of fragmented QRS (27.3 % vs. 24 %, p = 0.79) and inverted/biphasic T-waves (16.6 % vs. 22.7 %, p = 0,55). In multivariate regression analysis both Tp-e (HR 1.03; 95 % CI 1.001-1.057; p = 0.02) and QTc (HR 1.02; 95 % CI 1.006-1.026; p < 0.001) were identified as independent predictors of ventricular arrhythmias. After WCD use, the prophylactic ICD was indicated in 76 patients (33 %) with uneventful clinical course but persistent LVEF ≤35 %. The ECG analysis in these subjects did not reveal any relevant changes in arrhythmogenesis markers.

CONCLUSIONS

ECG repolarization markers Tp-e and QTc are associated with malignant arrhythmias in WCD patients and may be used - in addition to other established risk markers - to identify appropriate patients for ICD implantation.