Search Results (15)

Background and Objectives: Obstructive sleep apnea syndrome (OSAS) and heart failure (HF) frequently coexist, amplifying cardiovascular risk through mechanisms involving chronic inflammation and autonomic dysfunction. This study investigates the impact of systemic inflammation, measured by the systemic immune-inflammation index (SII), and OSAS severity, assessed by the apnea–hypopnea index (AHI), on myocardial repolarization heterogeneity in patients with both conditions. Materials and Methods: In this retrospective study, 160 patients with HF and polysomnography-confirmed OSAS (AHI ≥ 5 events/h) were evaluated between January 2018 and November 2024. Patients were stratified by QT dispersion (QTd < 40 ms vs. ≥40 ms) to assess electrical heterogeneity. SII was calculated from neutrophil, platelet, and lymphocyte counts, and electrocardiographic markers (QTd, frontal QRS-T angle, T wave peak-to-end interval [TPEI]) were measured. Logistic regression and receiver operating characteristic (ROC) analyses were used to identify predictors of repolarization heterogeneity and ventricular arrhythmias. Results: Patients with QTd ≥ 40 ms (n = 78) exhibited higher SII (p < 0.001) and AHI (p < 0.001) compared to those with QTd < 40 ms (n = 82). SII and AHI independently predicted increased QTd in multivariate analysis (p = 0.01 and p < 0.001, respectively). ROC analysis identified SII ≥ 625.4 (sensitivity 73.1%, specificity 72%) and AHI ≥ 22.4 (sensitivity 79.5%, specificity 79.3%) as optimal cut-offs for predicting repolarization heterogeneity. SII, QTd, and TPEI were significantly associated with ventricular arrhythmias (p < 0.05). Patients with moderate-to-severe OSAS (AHI ≥ 15) had higher rates of ventricular tachyarrhythmias (17.8% vs. 5.7%, p = 0.03) and sudden cardiac death (9.3% vs. 1.9%, p = 0.05). Conclusions: Elevated SII and AHI are independent predictors of myocardial repolarization heterogeneity in patients with HF and OSAS, contributing to increased arrhythmic risk. These findings highlight the potential use of SII and AHI as accessible biomarkers for risk stratification, particularly in patients with a preserved ejection fraction, and underscore the need for targeted interventions to mitigate inflammation and OSAS severity. Full article

Background: Despite the survival benefit of ICDs in patients with HFrEF, most recipients do not receive appropriate therapy during follow-up. Existing risk models based on echocardiographic and clinical parameters show limited predictive accuracy for arrhythmic events. This study aimed to assess whether ECG-derived markers outperform conventional measures in predicting appropriate ICD shocks. Methods: This retrospective observational study included 375 patients with HFrEF who underwent ICD implantation for primary prevention at least six months before study enrollment. Twelve-lead surface ECGs were analyzed for a QTc interval, Tp-e/QT ratio, frontal QRS-T angle, and maximum deflection index (MDI). Clinical, echocardiographic, and arrhythmic event data obtained from device interrogations were evaluated. Receiver operating characteristic (ROC) curve analysis and multivariate logistic regression were performed to identify independent predictors of appropriate ICD shocks. Results: Patients who experienced appropriate ICD shocks had significantly higher rates of a complete bundle branch block, digoxin use, QRS duration, QTc, Tp-e/QT ratio, frontal QRS-T angle, MDI, and right-ventricular pacing ratio. Conversely, beta-blocker use was significantly lower in this group. In multivariate analysis, independent predictors of appropriate shocks included the patient’s digoxin use (OR = 2.931, p = 0.003), beta-blocker use (OR = 0.275, p = 0.002), frontal QRS-T angle (OR = 1.009, p < 0.001), QTc interval (OR = 1.020, p < 0.001), and Tp-e/QT ratio (OR = 4.882, p = 0.050). The frontal QRS-T angle had a cutoff value of 105.5° for predicting appropriate ICD shocks (sensitivity: 73.6%, specificity: 85.2%, AUC = 0.758, p < 0.001). Conclusions: Electrocardiographic markers, particularly the frontal QRS-T angle, QTc interval, and Tp-e/QT ratio, demonstrated superior predictive power for appropriate ICD shocks compared to conventional echocardiographic and clinical measures. These easily obtainable, non-invasive ECG parameters may improve current risk stratification models and support more individualized ICD implantation strategies. Full article

Background/Objectives: Obesity is a major cause of repolarisation defects of the heart. The frontal QRS-T angle is a new parameter used for cardiac evaluation. This study aimed to evaluate the effects of a laparoscopic cholecystectomy and anaesthetic agents on the frontal QRS-T angle in individuals with obesity. Methods: A total of 91 patients who underwent a laparoscopic cholecystectomy surgery were included in this study. The patients were divided into two groups according to body mass index (BMI) < 30 (n = 68) and ≥30 (n = 23). The frontal QRS-T angle (FQRST), QT interval (QT), corrected QT, and other electrocardiography (ECG) findings were recorded at different time points. Results: In the BMI ≥ 30 group, the frontal QRS-T angle and QT interval measured during the intraoperative period were statistically higher than those of the BMI < 30 group (p < 0.001, p < 0.001). Additionally, the frontal QRS-T angle value was statistically higher in all patients postoperatively compared with the preoperative and intraoperative periods (p < 0.001). Furthermore, there was a positive correlation between the BMI and the frontal QRS-T angle. Our study found that the QRS-T angle and the QT interval duration measured during surgery in the BMI ≥ 30 group who underwent a laparoscopic cholecystectomy were significantly higher than in the BMI < 30 group. Conclusions: We recommend close haemodynamic monitoring during and after surgery for patients with obesity undergoing a laparoscopic cholecystectomy. Full article

Aim: The frontal QRS-T (fQRS-T) angle serves as an electrocardiography indicator that visually represents the disparity between the frontal QRS axis and the T axis. The heterogeneity between cardiac depolarization and repolarization rises with an increase in the fQRS-T angle. Prior research has demonstrated a relationship between the fQRS-T angle and the extent of atherosclerosis, along with the risk of cardiovascular mortality. The non-alcoholic fatty liver disease fibrosis score (NFS) is a non-invasive scoring tool used to quantify the degree of liver fibrosis in individuals with non-alcoholic fatty liver disease (NAFLD). Non-alcoholic fatty liver disease increases the risk of atherosclerotic cardiovascular disease, which can be predicted using the NFS. The objective of this study is to examine the potential correlation between the fQRS-T angle and NFS in patients with stable angina pectoris. Materials and Methods: This cross-sectional study included 177 (48 women) non-alcoholic patients who underwent coronary angiography due to stable angina pectoris. Individual NFS values were calculated using clinical and laboratory data. Patients were categorized into two groups based on a NFS threshold value of 0.67. Following a minimum fasting period of 12 h, biochemical laboratory parameters were acquired using a peripheral venous sample, and electrocardiographic data were recorded. Results: The univariate logistic regression analysis revealed significant associations between hypertension (p = 0.018), coronary artery disease (p = 0.014), neutrophil (p = 0.024), hemoglobin (p = 0.038), and low-density lipoprotein (LDL, p = 0.007) with the NFS. The electrocardiographic variables related to the score included the QRS duration (p = 0.015), Pmax (p = 0.026), QTC interval (p = 0.02), and fQRS-T angle (p < 0.001). In the multivariate logistic regression analysis, NFS was independently associated with LDL (OR: 0.984, 95% CI: 0.970–0.998, p = 0.024) and fQRS-T angle (OR: 3.472, 95% CI: 1.886–6.395, p < 0.001). Conclusions: The FQRS-T angle may exhibit a distinct correlation with NAFLD. Extensive investigations should validate this link, since the fibrosis score can serve as an effective tool for monitoring patients prior to the onset of clinical symptoms associated with liver fibrosis. Full article

This study explores the potential of unsupervised machine learning algorithms to identify latent cardiac risk profiles by analyzing ECG-derived parameters from two general groups: clinically healthy individuals (Norm dataset, n = 14,863) and patients hospitalized with heart failure (patients’ dataset, n = 8220). Each dataset includes 153 ECG and heart rate variability (HRV) features, including both conventional and novel diagnostic parameters obtained using a Universal Scoring System. The study aims to apply unsupervised clustering algorithms to ECG data to detect latent risk profiles related to heart failure, based on distinctive ECG features. The focus is on identifying patterns that correlate with cardiac health risks, potentially aiding in early detection and personalized care. We applied a combination of Uniform Manifold Approximation and Projection (UMAP) for dimensionality reduction and Hierarchical Density-Based Spatial Clustering (HDBSCAN) for unsupervised clustering. Models trained on one dataset were applied to the other to explore structural differences and detect latent predispositions to cardiac disorders. Both Euclidean and Manhattan distance metrics were evaluated. Features such as the QRS angle in the frontal plane, Detrended Fluctuation Analysis (DFA), High-Frequency power (HF), and others were analyzed for their ability to distinguish different patient clusters. In the Norm dataset, Euclidean distance clustering identified two main clusters, with Cluster 0 indicating a lower risk of heart failure. Key discriminative features included the “ALPHA QRS ANGLE IN THE FRONTAL PLANE” and DFA. In the patients’ dataset, three clusters emerged, with Cluster 1 identified as potentially high-risk. Manhattan distance clustering provided additional insights, highlighting features like “ST DISLOCATION” and “T AMP NORMALIZED” as significant for distinguishing between clusters. The analysis revealed distinct clusters that correspond to varying levels of heart failure risk. In the Norm dataset, two main clusters were identified, with one associated with a lower risk profile. In the patients’ dataset, a three-cluster structure emerged, with one subgroup displaying markedly elevated risk indicators such as high-frequency power (HF) and altered QRS angle values. Cross-dataset clustering confirmed consistent feature shifts between groups. These findings demonstrate the feasibility of ECG-based unsupervised clustering for early risk stratification. The results offer a non-invasive tool for personalized cardiac monitoring and merit further clinical validation. These findings emphasize the potential for clustering techniques to contribute to early heart failure detection and personalized monitoring. Future research should aim to validate these results in other populations and integrate these methods into clinical decision-making frameworks. Full article

Background and Objectives: Major depressive disorder (MDD) is a prevalent psychiatric illness increasingly recognized as a systemic condition with implications for cardiovascular diseases. Growing evidence indicates that individuals with MDD have an elevated risk of cardiovascular mortality, underscoring the need for reliable, non-invasive biomarkers to assess cardiac risk. While underlying mechanisms remain unclear, electrocardiogram (ECG)-based markers offer a promising, non-invasive means of evaluation. Among these, the electrical risk score (ERS), a composite derived from specific ECG parameters, has emerged as a predictor of adverse cardiac outcomes. This study aimed to investigate the association between ERS and MDD, and whether ERS correlates with depression severity and illness duration. Materials and Methods: In this retrospective cross-sectional study, 12-lead ECGs were evaluated to calculate the ERS based on six ECG parameters: heart rate, corrected QT interval, Tp-e interval, frontal QRS-T angle, QRS transition zone, and presence of left ventricular hypertrophy according to Sokolow–Lyon criteria. The Hamilton Depression Rating Scale (HAM-D) was utilized. Results: The study included 102 patients with MDD and 62 healthy controls. No significant differences were observed in baseline or laboratory parameters between the groups. However, heart rate, Tp-e interval, frontal QRS-T angle, and ERS were significantly higher in the depression group. ROC analysis identified ERS as the strongest predictor of depression. ERS was significantly higher in patients with severe depression compared to those with mild symptoms and showed a positive correlation with both disease duration and HAM-D score. Conclusions: Here, we show that the ECG-derived ERS is significantly elevated in patients with MDD and is associated with increased cardiac risk. ERS outperformed conventional ECG parameters in identifying individuals with depression and demonstrated positive associations with both illness duration and symptom severity. These findings suggest that ERS may serve as a practical, non-invasive biomarker for assessing cardiovascular vulnerability in this population. Full article

Background and Objectives: Post-term pregnancies are associated with increased risks of perinatal complications. This study aimed to evaluate potential cardiac electrophysiological changes in pregnant women by comparing the QRS duration, interval of corrected QT (QTc), and frontal QRS-T angle [f(QRS-T)] between term and post-term pregnancies. Materials and Methods: In this observational prospective study, 120 pregnant women were enrolled—60 term (37–41 weeks) and 60 post-term (≥42 weeks). All participants underwent standard 12-lead electrocardiography (ECG) and caesarean section with spinal anaesthesia. The QTc interval, QRS duration, and frontal QRS-T angle were measured. Demographic parameters such as age, gestational week, height, and weight were recorded. The SPSS software was used to analyse the data with p < 0.05 as the threshold for significance. Results: Post-operative QTc interval (417.3 ± 20.5 vs. 410.2 ± 14.5, p = 0.032) and f(QRS-T) (28 [16–55] vs. 22 [14–34], p = 0.042) were significantly higher in the post-term group than in the term group. When the change in the f(QRS-T) angle was analysed, there was a significant widening of this angle in the post-term group (from 21 [11–37] to 28 [16–55], p = 0.002). The increased f(QRS-T) angle reflects greater heterogeneity in ventricular depolarisation and repolarisation, which may indicate sub-clinical myocardial stress or altered autonomic regulation in the post-term period. Although no overt arrhythmias were observed, subtle changes in P-wave morphology and QT dispersion were more prevalent in the post-term group. Conclusions: Prolonged QRS duration and an increased f(QRS-T) angle in post-term pregnancies can reflect the underlying changes in cardiac electrophysiology related to prolonged gestation. These ECG parameters may serve as non-invasive indicators of sub-clinical cardiac stress, which could be relevant for anaesthetic risk assessment and perinatal management. Full article

Background: The impact of Celiac Disease (CD) is not only limited to the intestinal system, but extraintestinal manifestations may also be seen. In this context, cardiac manifestations have recently been the focus of attention. This study aimed to evaluate myocardial repolarization properties in CD patients by assessing the frontal QRS-T Angle (fQRS-T) on electrocardiography (ECG). Methods: A total of 302 patients, including 150 CD patients and 152 control group patients, were included in the study. ECG parameters, including fQRS-T, QRS interval, and QTc interval, were calculated for each patient and compared between the groups. In addition, the relationship of these ECG parameters with disease duration was also analyzed. Results: The median disease duration was 38.5 (16 to 96) months in the CD group. Significantly wider QRS interval (92 (86 to 96) vs. 83 (76.3 to 93), p < 0.001) and fQRS-T (23 (13 to 37) vs. 18 (6.3 to 27), p < 0.001) values were observed in the CD group. Among CD patients, those with longer disease duration (>38.5 months) exhibited significantly wider QRS intervals (94 (88 to 98) vs. 88 (84 to 94), p < 0.001) and frontal QRS-T angles (29 (14 to 47) vs. 16 (10 to 25), p < 0.001) compared to those with shorter disease duration. A positive correlation between the disease duration and fQRS-T was also demonstrated (r = 0.478, p < 0.001). Multivariable logistic regression identified QRS interval (OR: 1.060, 95% CI: 1.032–1.088, p < 0.001) and frontal QRS-T angle (OR: 1.028, 95% CI: 1.013–1.043, p < 0.001) as independent predictors of CD. Additionally, the QRS interval (OR: 1.066, 95% CI: 1.012–1.124, p = 0.016) and frontal QRS-T angle (OR: 1.021, 95% CI: 1.003–1.038, p = 0.021) were significant predictors of longer disease duration. A linear regression analysis confirmed that disease duration was a stronger predictor of frontal QRS-T angle widening (B: 0.389, 95% CI: 0.102–0.677, p < 0.001) compared to age (B: 0.184, 95% CI: 0.123–0.245, p = 0.008). Conclusions: In this study, we demonstrated that chronic inflammation secondary to CD may have negative effects on cardiac repolarization and that this effect is closely related to disease duration. Full article

Background and Objectives: Preeclampsia, a pregnancy-induced hypertensive disorder, shares cardiovascular characteristics in etiology, prognosis, and fetomaternal risks. Electrocardiography plays a pivotal role in assessing cardiovascular risks. Beyond conventional predictors, identifying easily obtainable and reproducible electrocardiographic markers may significantly contribute to the early identification of individuals at risk of preeclampsia. In this study, we aimed to investigate the value of the Frontal QRS-T angle and other electrocardiographic parameters in predicting the development of preeclampsia. Materials and Methods: A total of 62 pregnant patients diagnosed with preeclampsia and 50 healthy pregnant patients as the control group were included in this study. The first- and third-trimester electrocardiographic parameters were compared within groups and between groups. Results: The Frontal QRS-T angle was significantly elevated in patients with preeclampsia compared to the controls (55.0 ± 40.8 vs. 19.5 ± 15.1; p = 0.002). The first-trimester Frontal QRS-T angles in the patients with preeclampsia were higher than those of the controls (29.5 ± 25.0 vs. 15.3 ± 11.5; p = 0.015). A high Frontal QRS-T angle independently marked preeclampsia development in antenatal and late pregnancy (p = 0.003 and p = 0.042, respectively). The diagnostic accuracy of the Frontal QRS-T angle in predicting preeclampsia surpassed other electrocardiographic parameters. Conclusions: This study shows that the Frontal QRS-T angle may be a candidate to be an independent predictor for the development of preeclampsia. In this context, the Frontal QRS-T angle, which is an electrocardiographic parameter, seems promising. Full article

Background and objectives: The frontal QRS-T angle is a novel parameter of myocardial repolarization. Weight gain during pregnancy and physiological changes during a cesarian section may affect the frontal QRS-T angle. We aimed to assess the effect of body mass index (BMI) on the frontal QRS-T angle in pregnant women undergoing cesarean section with spinal anesthesia. Method and materials: This study included 90 pregnant women. BMI was calculated for all pregnant women. The study population was divided into two groups: BMI < 30 (n = 66) and BMI ≥ 30 (n = 24). QT interval measurements and the frontal QRS-T angle were obtained from the report of an electrocardiography machine. Results: It was found that the pre-operative and post-operative frontal QRS-T angle (p = 0.045 and p = 0.007) and QTc interval (p = 0.037 and p < 0.001) were higher in pregnant women with a BMI ≥ 30 than in pregnant women with a BMI < 30. In addition, when compared to pre-operative values, the post-operative frontal QRS-T angle (from 24.0 [20.0–41.5] to 34.5 [19.5–50.0], p = 0.031) and QTc interval (from 420.6 ± 13.3 to 431.7 ± 18.3, p = 0.010) were increased in the BMI ≥ 30 group, whereas no significant post-operative increase was observed in the BMI < 30 group. In correlation analysis, BMI was positively correlated with the frontal QRS-T angle and QTc interval. Conclusions: The frontal QRS-T angle and QTc interval were importantly increased in pregnant women with a BMI ≥ 30 than in pregnant women with a BMI < 30. Also, after cesarean section operation with spinal anesthesia, the frontal QRS-T angle and QTc were increased significantly in the BMI ≥ 30 group, whereas no significant change was observed in the BMI < 30 group. Therefore, it is suggested to perform close post-operative monitoring in pregnant women with a BMI ≥ 30 undergoing cesarean section with spinal anesthesia. Full article

Background and Objectives: A deficiency in serum 25-hydroxyvitamin D levels is associated with a number of cardiovascular situations, such as high blood pressure, heart failure, atherosclerotic heart disease, and peripheral artery disease. The frontal QRS-T angle has recently been proposed as a marker of ventricular repolarization. A wider frontal QRS-T angle has been positively correlated with adverse cardiac events. The objective of our study was to examine the association between serum 25-hydroxyvitamin D level and the frontal QRS-T angle. Materials and Methods: A total of 173 consecutive patients aged 18–60 years undergoing routine cardiology check-up evaluation, and not receiving concurrent vitamin D treatment were included in the study. Patients were classified in three groups, depending on their vitamin D levels, and categorized as follows: Group 1—deficient (<20 ng/mL), Group 2—insufficient (20–29 ng/mL), or Group 3—optimal (≥30 ng/mL). The frontal QRS-T angle was determined using the automated reports generated by the electrocardiography machine. Results: The average age of participants was 45.8 (±12.2) years, and 55.5% of participants were female (p < 0.001). Individuals with low vitamin D concentrations exhibited a wider frontal QRS-T angle. It was determined that vitamin D level is an independent predictive factor for the frontal QRS-T angle. Conclusions: As the levels of 25-hydroxyvitamin D decrease, repolarization time assessed by frontal QRS-T angle is widened. Our findings indicate that lower concentrations of vitamin D may increase the susceptibility to ventricular arrhythmia. Full article

Background: The heart’s electrical activity has been the subject of numerous research concerning various physiological parameters. The frontal QRS-T angle (FQRST) is an advanced ECG variable with clinical epidemiological utility. This study aimed to determine the relationship between FQRST and physical activity exposure among young adults. Methods: We recorded the ECG with 12 leads of 124 participants (mean age 20.28 ± 2.23 years, age range 18–27 years). Next, we measured their physical activity level (PAL) with the International Physical Activity Questionnaire—Short Form (IPAQ), which categorizes activity into three classes: low, moderate, or high. Results: An inferential analysis, based on the Kruskal-Wallis H test and Mann–Whitney U test, revealed a statistically significant difference in FQRST between the three groups of subjects, classified by their PAL (p < 0.001). We also identified a significant regression model between the body mass index (BMI) and the FQRST (p < 0.001). Conclusions: The physical activity regime of young adults significantly influences the concordance between ventricular depolarization and repolarization, reflected in the FQRST’s width. Also, we found a regression model between FQRST and BMI with statistical significance. Full article

Background: Fabry disease (FD) is an X-linked, lysosomal storage disorder leading to severe cardiomyopathy in a significant proportion of patients. To identify ECG markers that reflect early cardiac involvement and disease progression, we conducted a long term retrospective study in a large cohort of FD patients. Methods: A total of 1995 ECGs from 133 patients with classical FD (64% females, 80% treated with enzyme replacement therapy), spanning 20 years of follow-up, were compared to ECGs from 3893 apparently healthy individuals. Generalized linear mixed models were used to evaluate the effect of age, FD and sex on: P-wave duration, PR-interval, QRS-duration, QTc, Cornell index, spatial QRS-T angle and frontal QRS-axis. Regression slopes and absolute values for each parameter were compared between FD patients and control subjects. Results: At a younger age (<40 years), the Cornell index was higher and frontal QRS-axis more negative in FD patients compared to controls (p < 0.05). For the other ECG parameters, the rate of change, more than the absolute value, was greater in FD patients compared to controls (p < 0.05). From the fifth decade (men) or sixth (women) onwards, absolute values for P-wave duration, QRS-duration, QTc and spatial QRS-T angle were longer and higher in FD patients compared to control subjects. Conclusions: ECG abnormalities indicative of FD are age and sex dependent. Tracking the rate of change in ECG parameters could be a good way to detect disease progression, guiding treatment initiation. Moreover, monitoring ECG changes in FD can be used to evaluate the effectiveness of treatment. Full article

Background: Previous studies have evaluated average electrocardiographic (ECG) values in healthy subjects or specific subpopulations. However, none have evaluated ECG average values in not selected populations, so we examined ECG changes with respect to age and sex in a large primary population. Methods: From digitized ECG stored from 2008 to 2021 in the Modena province, 130,471 patients were enrolled. Heart rate, P, QRS and T wave axis, P, QRS and T wave duration, PR interval, QTc, and frontal QRS-T angle were evaluated. Results: All ECG parameters showed a dependence on age, but only some of them with a straight-line correlation: QRS axis (p < 0.001, R² = 0.991, r = 0.996), PR interval (p < 0.001, R² = 0.978, r = 0.989), QTc (p < 0.001, R² = 0.935, r = 0.967), and, in over 51.5 years old, QRS-T angle (p < 0.001, R² = 0.979, r = 0.956). Differences between females and males and in different clinical settings were observed. Conclusions: ECG changes with ageing are explainable by intrinsic modifications of the heart and thorax and with the appearance of cardiovascular diseases and comorbidities. Age-related reference values were computed and applicable in clinical practice. Significant deviations from mean values and from Z-scores should be investigated. Full article

Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (n = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (n = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, p < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, p < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, p < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined. Full article