T-wave Peak Research Articles

Electrocardiographic ventricular arrhythmia parameters during diagnosis and after the treatment of acromegaly: A case-control study

BackgroundThe risk of death is increased in acromegaly patients compared to the general population, and cardiovascular system-related complications are among the risk factors decreasing life expectancy. The Tp-e interval, which is the distance between the point where the T-wave peaks and ends on electrocardiography (ECG), shows ventricular rapolarization and, together with the Tp-e/QT and Tp-e/QTc ratios, these are relatively new tools that predict ventricular arrhythmia. We aimed to evaluate the ECG of acromegaly patients at the time of diagnosis and compare the results with current ECG findings. Material and methodsThe study included 103 acromegaly patients and 81 control subjects. Of the 103 patients, 41 patients had only baseline ECG, 23 patients had only current ECG and 39 patients had both baseline and current ECGs. Heart rate, QT interval and corrected QT (QTc) interval, Tp-e, Tp-e/QT, Tp-e/QTc values on the ECGs were measured by a cardiologist. ResultsIn the acromegaly patients with both baseline and current ECGs, heart rate, QRS duration, Tp-e, and Tp-e/QTc ratio were decreased. The decrease in these arrhythmia parameters was similar in active and remission patients. Compared to the control group, in acromegaly patients with only baseline ECG, heart rate, QTc interval, Tp-e, Tp-e/QT, and Tp-e/QTc were decreased. ConclusionVentricular arrhythmia parameters improve with treatment in patients with acromegaly. The decrease in ventricular arrhythmia parameters was similar in active and remission patients, which can be explained by the significant decrease in IGF-1 levels compared to the time of diagnosis, even in patients with active disease.

Cerebral Ischemia and Reperfusion-Induced Changes in Left Ventricular Function and Electrocardiogram in Mice

Background: Stroke may produce functional and electrical heart disturbances. The underlying characteristics and mechanisms have not been fully elucidated. Objectives: To evaluate whether acute cerebral ischemia (I) and reperfusion (R) may cause cardiac dysfunction and electrocardiographic alterations in an experimental mice model. Methods: Male mice that underwent cerebral ischemia and reperfusion (I/R) were evaluated by electrocardiography (ECG) and echocardiography. Heart rate, corrected QT (QTc) interval, T-wave peak to T-wave end (Tp-Te) interval, left ventricular ejection fraction (LVEF), shortening fraction (SF) and isovolumetric relaxation time (IVRT) were analyzed. Cerebral infarct size was calculated, and neurological deficit was assessed with the Longa scale. Results: Twenty-four hours after R, a statistically significant decrease in LVEF (I/R: 66.5±1.5% vs. sham: 74.3±0.9%; p=0.002) and in SF (I/R: 42.9±1.7% vs sham: 52.3±1.7%; p=0.004) was observed. QTc interval prolongation was observed during I/R (baseline: 125.1±4.3 ms; 60 min after I: 143.8±5.2 ms; 24 h after R: 170.3±5.8 ms; p=0.002). Tp-Te interval was not prolonged during I (baseline: 25.9±1.3 ms vs. 60 min after I: 23.8±1.4 ms; p=0.999) but it was prolonged during R (24 h after R: 32.0±2.3 ms; p=0.049). Cerebral infarct size was 34.9±2.5% and survival in the I/R group was 43.3%. Conclusion: Acute cerebral ischemia induces mild left ventricular dysfunction and disturbances in ventricular repolarization which intensify within the first 24 hours after reperfusion.

Comparison between mathematical methods to estimate blood glucose levels from ECG signals

Diabetes mellitus, known as diabetes, is a chronic disease that affects the control of blood glucose concentration levels, it is a disease that mostly affects adults (type 2 diabetes), but it can also occur in children (type 1 or childhood diabetes), as well as in pregnant women (gestational diabetes). Diabetes is one of the diseases with the highest prevalence and high mortality worldwide. Diabetes has no cure, but continuous monitoring to maintain blood glucose levels in normal ranges reduces the possibility of suffering from gastrointestinal problems, vision loss, limb amputations (such as diabetic foot) and damage to vital organs such as the heart and kidneys, among other associated complications. This article compares the results in glucose estimation by using a linear, quadratic and cubic regression considering the electrical characteristics generated in the cardiac conduction (HR, HRV, T-wave peak, and QT interval) recorded on a single-lead electrocardiogram (VII), used as a non-invasive blood glucose estimation model. The best estimate was obtained using a cubic regression. The validation was performed using the Clarke grid having 77.78 % of data in the A zone and 22.22 % in the B zone and a Pearson correlation value of 0.94103 in the cubic regression.

Are the Exacerbations of Chronic Obstructive Pulmonary Disease a Risk Factor for Cardiac Arrhythmia?

Aim: Hypoxemia, hypercapnia, and automaticity—which are dependent on exacerbation—increase the risk of arrhythmia by causing abnormal atrial and ventricular repolarization in chronic obstructive pulmonary disease (COPD). This study aimed to foresee the possibility of arrhythmia by evaluating the electrocardiograms (ECG) of patients having COPD attacks. Material and Method: In total, 120 patients (66 in the COPD group and 54 in the control group) were included. The differences between the two groups were statistically examined by determining (in milliseconds) QT and QTc interval maximum (max), minimum (min), and dispersion (disp); T-wave peak to end (Tp-e) max, min, and disp; Tp-e max/QT max, Tp-e max/QTc max proportions; and P wave max, min, and disp duration in the ECG parameters of the patients. Results: Forty-eight (64%) of the males included in the study were in the COPD group and 27 (36%) in the control group, whereas 18 (40%) of the females were in the COPD group and 27 (60%) in the control group. There was no significant difference between the ages of the patients and the levels of sodium and potassium (p = 0.189, 0.353, and 0.071). There was a significant difference between QT max and min in the groups, whereas there was no difference in terms of QT disp (p < 0.001, p < 0.001, and p = 0.490). There was a significant difference between the Tp-e max, min, and disp values in the COPD and control groups (p = 0.041, p < 0.001, and p = 0.001, respectively). There was no significant difference between the groups in terms of the P max duration (p = 0.442), but significant differences between the two groups in P min and disp durations were determined (p = 0.003 and p < 0.001, respectively). In receiver operating characteristic analysis made for P disp and Tp-e disp values in which a firm difference was made, 30 ms was determined as the cutoff for both parameters. Conclusion: To our knowledge, this is the first study that the rise of the dispersions of P wave and Tp-e intervals (without rise of QTc disp.) is detected on the evaluation of atrial and ventricular arrhythmia risks on COPD acute attacks.

Improved T-wave detection in electrocardiogram signals based non-stationary wavelet transform and QRS complex cancellation with kurtosis analysis

Objective. The T-wave in electrocardiogram (ECG) signal has the potential to enumerate various cardiac dysfunctions in the cardiovascular system. The primary objective of this research is to develop an efficient method for detecting T-waves in ECG signals, with potential applications in clinical diagnosis and continuous patient monitoring. Approach. In this work, we propose a novel algorithm for T-wave peak detection, which relies on a non-decimated stationary wavelet transform method (NSWT) and involves the cancellation of the QRS complex by utilizing its local extrema. The proposed scheme contains three stages: firstly, the technique is pre-processed using a two-stage median filter and Savitzky–Golay (SG) filter to remove the various artifacts from the ECG signal. Secondly, the NSWT technique is implemented using the bior 4.4 mother wavelet without downsampling, employing 24 scale analysis, and involves the cancellation of QRS-complex using its local positions. After that, Sauvola technique is used to estimate the baseline and remove the P-wave peaks to enhance T-peaks for accurate detection in the ECG signal. Additionally, the moving average window and adaptive thresholding are employed to enhance and identify the location of the T-wave peaks. Thirdly, false positive T-peaks are corrected using the kurtosis coefficients method. Main results. The robustness and efficiency of the proposed technique have been corroborated by the QT database (QTDB). The results are also validated on a self-recorded database. In QTDB database, the sensitivity of 98.20%, positive predictivity of 99.82%, accuracy of 98.04%, and detection error rate of 1.95% have been achieved. The self-recorded dataset attains a sensitivity, positive predictivity, accuracy, and detection error rate of 99.94%, 99.96%, 99.90%, and 0.09% respectively. Significance. A T-wave peak detection based on NSWT and QRS complex cancellation, along with kurtosis analysis technique, demonstrates superior performance and enhanced detection accuracy compared to state-of-the-art techniques.

Abstract 11749: Identifying Infants With Long QT Syndrome Type 1: Looking Beyond the QTc

Background: Abnormal repolarization in long QT syndrome type 1 (LQT1) is characterized by QT prolongation and abnormal T-waves. In the absence of familial disease, LQT1 is easily missed in infants as the QTc is often normal, exposing children to life-threatening arrhythmia. Hypothesis: T-wave morphology metrics are superior to QTc for diagnosis of LQT1. Aim: Compare quantifiable aspects of T-wave morphology and QTc to differentiate infants with and without LQT1. Methods: Infants aged 0.5-6 months with a pathogenic/likely pathogenic KCNQ1 variant were compared to age/sex-matched controls in a 1:2 ratio. Measurements were made in leads II/V5. T-wave morphology was assessed by J-point to T-wave peak (J-Tp) and Tp to T-wave end (Tp-Te). Bazett’s formula was used to correct for heart rate and Te defined using the tangent method. Results: We identified 34 LQT1 infants and 68 controls. The median (IQR) QTc was 457 (430-476) ms for LQT1 cases and 402 (392-420) ms for controls (p<0.001). The 98%tile QTc for controls was 448 ms and 13/34 (38%) LQT1 cases were below this value. In lead II, LQT1 cases had a significantly longer rate corrected J-Tp compared to controls, 294 (272-312) ms v. 222 (211-234) ms (p <0.001) and shorter Tp-Te, 71 (60-80) ms v. 85 (75-95) ms (p<0.001). The J-Tp/Tp-Te ratio was 0.25 in LQT1 cases and 0.39 in controls (p<0.001). Findings were similar in V5. V5 rate corrected J-Tp best discriminated between LQT1 cases and controls (ROC AUC 0.99, optimal cut point ≥256ms) and outperformed QTc (AUC 0.92). This remained true in those with QTc <98%tile (AUC 0.98). Measurements in a subset of 30 infants made by 3 ECG readers showed superior reliability for J-Tp in leads II and V5 (ICC coefficient 0.92) compared to QTc (0.88). Conclusions: Nearly 40% of infants with LQT1 have a normal a QTc, yet a significantly abnormal and quantifiable T-wave morphology. J-Tp and Tp-Te are reliable and reproducible measurements and should be included in the assessment of potential infantile LQT1.

Evaluation of cardiac biomarkers, electrocardiogram changes and echocardiography findings before and after exercise in paediatric athletes

Purpose: The aim of this study was to investigate the structural and electrical changes in the heart associated with exercise in young athletes under 18 years of age and to examine the relationship between these changes and biochemical markers.
 Materials and Methods: In this study, 32 male paediatric athletes (five rowers, five kayakers and 22 footballers) were prospectively evaluated. Dynamic exercise training for 75 minutes was applied to all athletes. An echocardiographic evaluation was performed on the athletes at rest. An electrocardiogram (ECG) was taken before and after the exercise. Blood samples were taken from all athletes before the exercise, during the first hour of exercise and after the fourth hour of the training session to analyse the serum levels of creatine kinase myocardial band, troponin T(cTnT) and pro-brain natriuretic peptide.
 Results: The mean age of all athletes was 15.3±0.9 years. In the echocardiography examination, end-diastolic thickness, left ventricular end-diastolic diameter, posterior wall end-diastolic diameter, left ventricular end-systolic diameter, left ventricular mass measurements (LVM) and left ventricular mass indices (LVMI) were higher among the rowers than in the remaining groups. In the post-exercise ECG, T-wave peaks were observed in 16 individuals, including all rowers, all kayakers, and six footballers. The cTnT values in the first hour and after the fourth were 0.31–0.71 ng/ml in football players, 0.10–0.27 ng/ml in rowers, and 0.04–0.15 ng/ml kayakers. An increase in cTnT levels was detected after the fourth hour of exercise in all groups. There was a correlation between T-wave peaks in the ECG taken after exercise and age, cTnT serum level and increased LVM. 
 Conclusion: In this study, we found T-wave peaks in half of the athletes after exercise. The serum cTnT levels of young athletes may be elevated by exercise and that LVM and LVMI may be higher in athletes. Echocardiography and ECG evaluations should be performed in paediatric athletes.

Extraction and Digitization of ECG Signals from Standard Clinical Portable Document Format Files for the Principal Component Analysis of T-wave Morphology.

T-wave analysis from standard electrocardiogram (ECG) remains one of the most available clinical and research methods for evaluating myocardial repolarization. T-wave morphology was recently evaluated to aid with diagnosis and characterization of diastolic dysfunction. Unfortunately, PDF stored ECG datasets limit additional numerical post-processing of ECG waveforms. In this study, we apply a simple custom process pipeline to extract and re-digitize T-wave signals and subject them to principal component analysis (PCA) to define primary T-wave shape variations. We propose simple pre-processing and digitization algorithms programmable as a MATLAB tool using standard thresholding functions without the need for advanced signal analysis. To validate digitized datasets, we compared clinically standard measurements in 20 different ECGs with the original ECG machine interpreted values as a gold standard. Afterwards, we analyzed 212 individual ECGs for T-wave shape analysis using PCA. The re-digitized signal was shown to preserve the original information as evidenced by excellent agreement between original - machine interpreted and re-digitized clinical variables including heart rate: bias ~ 1bpm (95% CI: -1.0 to 3.5), QT interval: bias ~ 0.000 ms (95% CI: -0.012 to 0.012), PR interval: bias = -0.015 ms (95% CI: -0.015 to 0.003), and QRS duration: bias = -0.001 ms (95% CI: -0.007 to 0.006). PCA revealed that the first principal component universally modulates the T-wave height or amount of repolarization voltage regardless of the investigated ECG lead. The second and third principal components described variation in the T-wave peak onset and the T-wave peak morphology, respectively. This study presents a straightforward method for re-digitizing ECGs stored in the PDF format utilized in many academic electronic medical record systems. This process can yield re-digitized lead specific signals which can be retrospectively analyzed using advanced custom post-processing numerical analysis independent of commercially available platforms.

Dual assessment of abnormal cardiac electrical dispersion and diastolic dysfunction for early detection of the epileptic heart condition

BackgroundPeople with epilepsy (PWE) are at increased risk for premature death due to many factors. Sudden unexpected death in epilepsy (SUDEP) is among the most important causes of death in these individuals and possibly, sudden cardiac death (SCD) in epilepsy is also as important. The possibility of concurrent derangement in electrical and mechanical cardiac function, which could be a marker of early cardiac involvement in PWE, has not been investigated in that population. MethodsElectrical dispersion indices (T-wave peak to T-wave end, TpTe; QT dispersion, QTd; QT interval corrected for heart rate, QTc) were analyzed in patients with pharmacoresistant temporal lobe epilepsy and compared to a control group. The electromechanical relationship between those indices and echocardiographic parameters were further assessed in PWE. ResultsIn 19 PWE and 21 controls, we found greater TpTe and QTd in PWE (TpTe: 91.6 ± 16.4 ms vs. 65.2 ± 12.1 ms, p < 0.0001; and QTd: 45.3 ± 13.1 ms vs. 19 ± 6.2 ms, p < 0.0001, respectively). QTc was similar between PWE and controls (419.2 ± 31.4 ms vs. 435.1 ± 31.4 ms, p = 0.12). In multivariate linear regression, TpTe, QTc, and epilepsy duration were related to left ventricular mass; QTc was associated with left atrial volume; QTc, the number of seizures per month, epilepsy duration and antiseizure medication explained 81% of E/A mitral wave Doppler ratio. ConclusionsThis is the first report to demonstrate concurrent electrical dispersion and diastolic dysfunction in PWE. These noninvasive biomarkers could prove useful in early detection of the “Epileptic Heart” condition.

Abstract 10266: T-Wave Features Predict Functional Worsening in Children With Pulmonary Arterial Hypertension: Machine Learning Insights From Standard ECG

Introduction: Various T-wave characteristics have been shown to be predictive of ventricular diastolic dysfunction and sudden cardiac death in adults. However, specific T-wave morphologies and their predictive potential in pediatric patients is unknown. Hypothesis: Machine learning derived T-wave characteristics will be different between children with pulmonary arterial hypertension (PAH) and healthy controls. Furthermore, T-wave characteristics will be predictive of clinical functional worsening in PAH patients. Methods: Principal component analysis (PCA) was applied to ECGs collected for children with PAH (n=155) at the time of diagnostic catheterization and matched healthy controls (n=47) to describe basic T-wave characteristics. Patients (&lt;18 y/o) with PAH were defined as a mean pulmonary pressure &gt;25 mmHg in the absence of obstructive left heart disease. Interpreted T-wave features were then compared between PAH and control groups. Identified T-wave measurements underwent survival analysis using standardized PAH functional class worsening as a clinical endpoint. Results: Identified T-wave principal components were 1) T-wave height and 2) early or late incidence of T-wave peak (FIGURE- 1A). The second principal component was associated with PAH diagnostic specificity (94%). Time from T-wave peak to T-wave end (TpTe) as measured in leads V4 to V6 was significantly higher in children with PAH (all P &lt; 0.001) (FIGURE - 1B). V4 derived TpTe value &gt; 132 ms and V5 derived TpTe value &gt; 135 ms were associated with the higher probability of clinical functional worsening (P = 0.018 and P = 0.002, respectively) (FIGURE - 1C). Conclusions: T-wave features derived from standard ECG are 1) different between children with PAH and their healthy peers and 2) predictive of clinical functional worsening.

Effects of β-blockers on ventricular repolarization documented by 24-hour electrocardiography in long QT syndrome type 2

Long QT syndrome (LQTS) is an inherited arrhythmia disorder characterized by ventricular repolarization abnormalities and a risk of sudden cardiac death. The electrophysiological components generating the high risk of arrhythmias in LQTS are prolonged repolarization, increased dispersion of repolarization, and early afterdepolarizations, which are clinically estimated as QT interval, T-wave peak to T-wave end (TPE) interval, and T2/T1-wave amplitude ratio, respectively. In experimental LQTS type 2 (LQT2) models, β-blockers decrease dispersion of repolarization and prevent early afterdepolarizations. In clinical studies in patients with LQT2 , β-blockers are more effective against exercise-induced than arousal-induced cardiac events. The aim of the study was to investigate the effects of β-blocker therapy on repolarization properties in LQT2. QT and TPE intervals and maximal T2/T1-wave amplitude ratios recorded by 24-hour electrocardiograms before and during β-blocker therapy were evaluated in 25 patients with LQT2. β-Blocker therapy decreased the maximal T2/T1-wave amplitude ratio from 2.9 ± 1.1 to 1.8 ± 0.7 (P < .001), but did not change the pause-induced T2/T1-wave amplitude ratio. Under medication, abrupt maximal TPE intervals were shorter at heart rates of ≥75 beats/min and maximal QT intervals were shorter at a heart rate of 100 beats/min. β-Blockers stabilize ventricular repolarization in LQT2 by reducing electrocardiographic early afterdepolarizations and by reducing abrupt prolongation of electrocardiographic dispersion of repolarization and ventricular repolarization duration at elevated heart rates. The effect of β-blockers on pause-induced electrocardiographic early afterdepolarizations is weak. The findings provide electrocardiographic explanation for the protective effects of β-blockers against exercise-induced cardiac events in LQT2.

The association between QTc, QTd, TPE, and fragmented QRS before and after PPCI with hospital mortality in STEMI patients.

ST-elevation myocardial infarction (STEMI) is known to be associated with significant arrhythmia and consequent mortality. QT prolongation is a risk factor for arrhythmia in STEMI patients who underwent primary percutaneous coronary intervention (PPCI). The aim of this investigation was to evaluate the association of corrected QT interval (QTc), QT dispersion (QTd), T-wave peak to end (TPE), and fragmented QRS with mortality in these patients. Eligible patients with the characteristic symptoms of STEMI who underwent PPCI were included. QTc, QTd, TPE, and fragmented QRS were measured before and after the PPCI. These predictors were compared between patients who died during hospitalization and discharged patients. After coronary angiography, 10 patients (4%) died during the hospitalization after PPCI. Comparing the non-survivers and discharged patients in terms of arrhythmia predictors showed that the mean QT dispersion and TPE before intervention were significantly higher in the non-survivors. Also, the number of patients who experienced fragmented QRS both before and after the intervention was significantly higher in the non-survivors. These data suggested that evaluating such arrhythmia predictors, especially before PPCI, could be used as a predictor of mortality in STEMI patients who underwent PPCI.

Combined molybdenum target X-ray and magnetic resonance imaging examinations improve breast cancer diagnostic efficacy.

BACKGROUNDEarly-stage breast cancer patients often lack specific clinical manifestations, making diagnosis difficult. Molybdenum target X-ray and magnetic resonance imaging (MRI) examinations both have their own advantages. Thus, a combined examination methodology may improve early breast cancer diagnoses.AIMTo explore the combined diagnostic efficacy of molybdenum target X-ray and MRI examinations in breast cancer.METHODSPatients diagnosed with breast cancer at our hospital from March 2019 to April 2021 were recruited, as were the same number of patients during the same period with benign breast tumors. Both groups underwent molybdenum target X-ray and MRI examinations, and diagnoses were given based on each exam. The single (i.e., X-ray or MRI) and combined (i.e., using both methods) diagnoses were counted, and the MRI-related examination parameters (e.g., T-wave peak, peak and early enhancement rates, and apparent diffusion coefficient) were compared between the groups.RESULTSIn total, 63 breast cancer patients and 63 benign breast tumor patients were recruited. MRI detected 53 breast cancer cases and 61 benign breast tumor cases. Molybdenum target X-ray detected 50 breast cancer cases and 60 benign breast tumor cases. The combined methodology detected 61 breast cancer cases and 61 benign breast tumor cases. The sensitivity (96.83%) and accuracy (96.83%) of the combined methodology were higher than single-method MRI (84.13% and 90.48%, respectively) and molybdenum target X-ray (79.37% and 87.30%, respectively) (P < 0.05). The combined methodology specificity (96.83%) did not differ from single-method MRI (96.83%) or molybdenum target X-ray (95.24%) (P > 0.05). The T-wave peak (169.43 ± 32.05) and apparent diffusion coefficient (1.01 ± 0.23) were lower in the breast cancer group than in the benign tumor group (228.86 ± 46.51 and 1.41 ± 0.35, respectively). However, the peak enhancement rate (1.08 ± 0.24) and early enhancement rate (1.07 ± 0.26) were significantly higher in the breast cancer group than in the benign tumor group (0.83 ± 0.19 and 0.75 ± 0.19, respectively) (P < 0.05).CONCLUSIONCombined molybdenum target X-ray and MRI examinations for diagnosing breast cancer improved the diagnostic sensitivity and accuracy, minimizing the missed- and misdiagnoses risks and promoting timely treatment intervention.

Pengelolaan Anestesi pada Pasien yang dilakukan Eksisi Tumor Medula Spinalis Servikal 2-3 dengan Ventrikel Ekstra Sistole

Compression of the spinal cord can cause irritation to the autonomic nervous system. Hyperinervation of sympathetic nerves at high risk for arrhythmias characterized by electrocardiographic results in changes in P-wave duration, QRS duration, ST-segment depression, T-wave peak interval, and ventricular extrasystole. A 52-year-old male with an intra-extramedullar tumor in cervical 2-3, tetraparesis, dysrhythmias, and ventricular extrasystole bigemini. Wide excision of tumor and posterior stabilization would be performed. The pulse was 90x/minute palpable irregularly. Electrocardiography examination revealed irregular rhythm 82 x/minute and ventricular extrasystole 10 x/minute. Echocardiography showed grade 3 diastolic dysfunction with preserved LV function. Before the procedure, the patient was given management for the dysrhythmia and ventricular extrasystole with analgetics and amiodaron 150mg (10ml) in the first 10 minutes followed by 360mg (200mg) for the next 6 hours, 540mg for the next 18 hours and analgetics. General anesthesia carried out with midazolam 3mg, fentanyl 200mcg, lidocaine 60mg, propofol 100mg, and atricurium 30mg, with manual intubation in-line. After arterial line and central venous catheter insertion, the patient was placed in the prone position. Surgery lasted for approximately 6 hours. The patient was treated in the ICU for 2 days before moving to the usual ward. Amiodarone can be considered in ventricular extrasystole requiring immediate treatment with stable hemodynamic.

Effect of noise on the electrocardiographic parameters.

Noise, defined as any sound that is unpleasant, is one of the most important environmental problems. Prolonged exposure to noise has been shown to be associated with the development of cardiovascular diseases. No study investigated the effect of noise on surface electrocardiography (ECG). The aim of our study is to investigate the effect of noise on surface ECG parameters including P-wave dispersion (PWD), QT intervals, corrected QT interval (QTc), T-wave peak to end (Tp-e) interval, and Tp-e/QT and Tp-e/QTc ratios. A total of 51 people working in the textile factory affected by the noise and 43 volunteers without any disease and who were not exposed to noise were included in this study. The average noise level in the textile factory was 112dB. A 12-lead ECG was obtained from all individuals. PR interval, PWD, QRS duration, QT interval, QTc interval, Tp-e interval, and Tp-e/QT and Tp-e/QTc ratios were calculated for all individuals. The noise group had significantly increased PWD [35 (28-40) vs. 28 (22-36) p = 0.029], QT interval ( 373.5 ± 27.3 vs. 359.3 ± 2.74, p = 0.001), QTc interval [(409 ± 21 vs. 403 ± 13 p = 0.045)], Tp-e interval [(90.6 ± 6.0 vs. 83.5 ± 7.3 p < 0.001)], Tp-e/QT [(0.24 ± 0.03 vs. 0.23 ± 0.02, p = 0.015)] and Tp-e/QTc [(0.22 ± 0.02 vs. 0.21 ± 0.02 p < 0.001)] compared to control group. Also, duration of working was positively correlated with PWD (r = 0.468, p = 0.001) and Tp-e/QTc ratio (r = 0.328, p = 0.019). In multiple linear regression linear regression analysis, noise was the independent predictor of both PWD (β = 0.244, p = 0.032) and Tp-e/QTc (β = 0.319, p = 0.003) CONCLUSION: We showed that noise significantly increased PWD, QT and Tp-e interval measurements. Also, noise was the independent predictor for both PWD and Tp-e/QTc.

Electrocardiographic Evaluation of the Ventricular Arrhythmia Risk in Patients Diagnosed With Schizophrenia.

The purpose of this study was to examine electrocardiographic ventricular arrhythmia predictors in patients with schizophrenia by comparing with healthy controls. The study included 100 patients with schizophrenia and 100 healthy controls. Electrocardiography (ECG) was performed on all participants in resting position. T-wave peak to end (Tp-e), QT ranges, P-wave dispersion (Pd), and R-R range were measured. Then, the Schizophrenia Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS) were applied to the schizophrenia group. The PANSS positive symptom subscale was calculated as 10.41 (SD = 2.27), the negative symptom subscale was calculated as 14.44 (SD = 5.42), and the overall functionality level was calculated as 27.04 (SD = 5.43). The mean CDSS score was determined to be 3.74 (SD = 2.15). No differences were detected in the heart rate measurements of the patient and control groups in ECG results (P = .427). The minimum QT interval and minimum Tp-e wave times were found to be low in the patient group (P < .001 for both intervals). Corrected QTc dispersion, Pd, Tp-e dispersion, and QT dispersion were found to be higher in the patient group than in healthy controls (P < .001 for all intervals). Based on our results, it is possible to speculate that patients with schizophrenia are at a risk of developing cardiac arrhythmia and cardiac dysfunction if they do not receive treatment. For this reason, clinicians should pay attention to cardiac transmission problems when organizing the treatment of patients. Further studies should be conducted to determine cardiac problems in patients with schizophrenia.

Ventricular transmural decremental conduction explains short t-peak-t-end interval in “in silico” ECG reconstruction model

Abstract Introduction In chronic hepatic cirrhosis (CHC), T-wave peak to T-wave end interval (TPTE) has shown prognostic value for survival and liver transplantation. Altered cellular ionic regulatory systems may produce decremental conduction in ventricular endocardial to epicardial activation wavefront propagation and ECG waveforms, particularly the T-wave. It was investigated whether ventricular transmural activation wavefront conduction may affect T-wave shape and impact TPTE duration, using “in silico” ECG reconstruction. Methods Mammalian-derived ventricular endocardial to epicardial AP waveforms (APW) were simulated and deployed in 10 discrete layers in homogeneous impedance ventricular wedge-like model. A uniform conduction model was employed to mimic normal heart, in which the speed of propagation of the activation wavefront was nonzero and constant in all layers. In CHC heart, a decremental conduction model was employed, in which the speed of propagation of the activation wavefront was maximal at the endocardial layer and exponentially decayed to greater than zero speed at the epicardial layer. ECG was computed as the sum of dipoles weighted by the inverse of the squared distance to an observation electrode arbitrarily located outside the wedge. One dipole was one layer thick, and its charge was assumed as the time-integral of the current generated by the difference of potential between adjacent APW, from endocardial to epicardial layers. ECG was reconstructed in one axis. Results Two-dimensional transmural APW distribution and respective reconstructed ECGs are presented in Figures 1 and 2. In uniform endocardial to epicardial transmural conduction model, QRS complex was taller and shorter as well as TPTE was larger (Fig. 1) than respective counterparts in decremental conduction model (Fig. 2). Additionally, peak-amplitude of the T-wave as well as the maximal slope of the TPTE were lower in decremental as compared to uniform conduction model. Conclusion Using “in silico” ECG reconstruction, decrementally conducted model of epicardial to endocardial ventricular transmural activation wavefront propagation yields wider and lower amplitude QRS complex as well as shorter TPTE, as compared to respective counterparts in uniformly conducted activation wavefront model. Ventricular transmural decremental conduction model offers an insight into electrophysiological background of ECG findings in CHC. (NCT01433848) Transmural APW distribution vs ECG Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Universidade do Estado do Rio de Janeiro; Rio de Janeiro, RJ - Brazil

Prolonged Tp-e interval and Tp-e/QT ratio in patients with mitral annulus disjunction

Abstract Background Mitral annulus disjunction (MAD) is an abnormal atrial displacement of the mitral valve leaflet hinge point. MAD has been associated with mitral valve prolapse (MVP) and arrhythmic events. T-wave peak to T-wave end interval (Tp-e) and Tp-e/QTc are electrocardiographic (ECG) indices to predict ventricular tachyarrhythmia and cardiovascular mortality. Purpose We aimed to evaluate ventricular repolarization dispersion by using the Tp-e interval and Tp-e/QT ratio in patients with MAD and healthy controls. Methods A total of 35 patients with MAD (age 40.4±8.2 years; 66% female) and 37 healthy controls (age 37.6±9.5 years; 68% female) were enrolled. All subjects were evaluated by 12 lead standard ECG, 24-hour ambulatory ECG, and transthoracic echocardiography. The MAD distance was measured from the left atrial wall-mitral valve leaflet junction to the top of the left ventricular wall during end-systole in the parasternal long-axis view. The standard 12-lead electrocardiograms were analyzed; QTc, Tp-e and Tp-e/QTc were calculated. The Tp-e interval was defined as the interval from the peak of the T wave to the end of the T wave from precordial leads. Finally, the Tp-e/QT ratio was calculated from these measurements. The normality assumption was checked with the Shapiro-Wilk test and the Mann–Whitney U test was used for inter-group comparisons. Results Tp-e interval (61.9±6.0 ms vs. 77.1±5.9 ms, p&amp;lt;0.001) and Tp-e/QT ratio (0.14±0.01 vs. 0.17±0.02, p&amp;lt;0.001) were significantly prolonged in patients with MAD than in the control group. MVP was present in 24 (69%) patients with MAD. The prevalence of 30 premature ventricular contractions / hour were higher in MAD subgroup without MVP than those MAD with MVP (54.5% vs 16.7%, p=0.041). Mean MAD distance measured by echocardiography was 5.7±1.5 mm. The Spearman's rank-order correlation analyses revealed positive correlations of MAD distance with Tp-e interval (r=0.620, p=0.001) and Tp-e/QT ratio (r=0.372, p=0.028). Conclusions The patients with MAD had a prolonged Tp-e interval and Tp-e/QT ratio compared with normal subjects. Furthermore, this prolongation was well correlated with MAD distance. Patients with MAD, particularly with higher MAD distance, should be followed closely for arrhythmic outcomes. MAD distance and Tp-e interval Funding Acknowledgement Type of funding source: None

Relationship With Calcium, Nutrition Risk, QTc Interval, Tp-e Interval, and Tp-e/QTc Ratio of Critical Care Patients.

To our knowledge, there are studies related to QTc interval in critical care patients whose nutrition scores are evaluated but no studies evaluating T-wave peak and end interval (Tp-e interval), Tp-e/QT ratio, and Tp-e/QTc ratio, used to evaluate cardiac arrhythmia risk and ventricular repolarization change rates. Therefore, we aimed to investigate whether there is a change in Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio in patients whose nutrition scores are evaluated. This study was planned as a retrospective cross-sectional study. Forty-four patients with a risk score of ≤3 were defined as low-risk group, and 45 patients with a score of ≥4 were defined as high-risk group. Forty-five healthy patients of similar age and gender were included in the control group. All patients underwent 12-lead electrocardiography (ECG). The Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were measured on ECG. The study data were grouped as patients with high Nutritional Risk Screening 2002 (NRS-2002) risk score, low NRS-2002 risk score, and healthy control. QTc interval, Tp-e interval, and Tp-e/QTc ratios were significantly higher in patients with high nutrition risk. In a correlation analysis, Tp-e interval and Tp-e/QTc ratio were found to be independently associated with calcium, corrected calcium, and serum albumin level. QTc interval, Tp-e interval, and Tp-e/QTc ratios are significantly increased in patients with high nutrition risk score compared with healthy people and are independently associated with calcium and serum albumin levels; thus, they can be used more effectively in the follow-up of cardiac fatal arrhythmias.

The myocardial phenotype of Fabry disease pre-hypertrophy and pre-detectable storage.

AimsCardiac involvement in Fabry disease (FD) occurs prior to left ventricular hypertrophy (LVH) and is characterized by low myocardial native T1 with sphingolipid storage reflected by cardiovascular magnetic resonance (CMR) and electrocardiogram (ECG) changes. We hypothesize that a pre-storage myocardial phenotype might occur even earlier, prior to T1 lowering.Methods and resultsFD patients and age-, sex-, and heart rate-matched healthy controls underwent same-day ECG with advanced analysis and multiparametric CMR [cines, global longitudinal strain (GLS), T1 and T2 mapping, stress perfusion (myocardial blood flow, MBF), and late gadolinium enhancement (LGE)]. One hundred and fourteen Fabry patients (46 ± 13 years, 61% female) and 76 controls (49 ± 15 years, 50% female) were included. In pre-LVH FD (n = 72, 63%), a low T1 (n = 32/72, 44%) was associated with a constellation of ECG and functional abnormalities compared to normal T1 FD patients and controls. However, pre-LVH FD with normal T1 (n = 40/72, 56%) also had abnormalities compared to controls: reduced GLS (−18 ± 2 vs. −20 ± 2%, P < 0.001), microvascular changes (lower MBF 2.5 ± 0.7 vs. 3.0 ± 0.8 mL/g/min, P = 0.028), subtle T2 elevation (50 ± 4 vs. 48 ± 2 ms, P = 0.027), and limited LGE (%LGE 0.3 ± 1.1 vs. 0%, P = 0.004). ECG abnormalities included shorter P-wave duration (88 ± 12 vs. 94 ± 15 ms, P = 0.010) and T-wave peak time (Tonset – Tpeak; 104 ± 28 vs. 115 ± 20 ms, P = 0.015), resulting in a more symmetric T wave with lower T-wave time ratio (Tonset – Tpeak)/(Tpeak – Tend) (1.5 ± 0.4 vs. 1.8 ± 0.4, P < 0.001) compared to controls.ConclusionFD has a measurable myocardial phenotype pre-LVH and pre-detectable myocyte storage with microvascular dysfunction, subtly impaired GLS and altered atrial depolarization and ventricular repolarization intervals.