Tp-e Interval Research Articles

Evaluation of cardiac arrhythmias by electrocardiographic markers in pediatric patients who have tuberous sclerosis without cardiac rhabdomyoma

BackgroundTuberous sclerosis (TS) is an autosomal dominant and hereditary disorder. Cardiac rhabdomyoma and arrhythmias are the most deleterious risk factors linked to TS. Although arrhythmias in pediatric patients with TS who have cardiac rhabdomyoma have been frequently reported, arrhythmia in patients who have TS without rhabdomyoma is rarely reported in the literature. The study aimed to assess the susceptibility of pediatric patients who have TS without cardiac rhabdomyoma to cardiac arrhythmia using electrocardiographic (ECG) markers. MethodsThis prospective study included 10 patients who had TS without cardiac rhabdomyoma. The control group was made up of 30 healthy children of the same age and sex as the patient group. P wave, P wave dispersion, QT dispersion, QTc dispersion, TP-e interval, and TP-e interval dispersion were calculated on 12-lead surface ECGs for each patient in both groups and compared. ResultsP wave, P wave dispersion, QT dispersion, and QTc dispersion were found to be significantly higher in the patient group (P<0.001). Furthermore, patients had a greater Tp-e interval and Tp-e interval dispersion than healthy children (P<0.001). ConclusionPediatric patients with TS without cardiac rhabdomyoma might be prone to atrial and ventricular arrhythmias according to their prolonged ECG markers. Our findings suggest that patients with TS without cardiac rhabdomyoma need close monitoring for atrial and ventricular arrhythmias.

Stabil Koroner Arter Hastalığı Olan Hastalarda Bazal T-Dalgası Pik-Son İntervali ile Kalp Atış Hızı Düzelme İndeksi Arasındaki İlişki

OBJECTIVES: Autonomic dysfunction is detected in patients with coronary artery disease and is indicative of poor prognosis. The aim of this study was to compare baseline T peak-end interval (Tp-e) and heart rate recovery index [HRR-I] values in patients with stable coronary artery disease who had a left ventricular ejection fraction [EF] > 50 % and 50 %, had 3-vessel diseases on coronary angiography. Baseline Tp-e and heart rate values of both groups were measured and transthoracic echocardiograms were performed at the beginning. Both Group 1 and 2 were then subjected to exercise testing according to the Bruce protocol and heart rates were measured at the peak and 1st, 2nd, and 3rd minutes of exercise. RESULTS: There was a statistically significant difference between group 1 [95.8 ± 6.8 msec] and group 2 [71.4 ± 5.1 msec] with regard to basal Tp-e [P<0.0001]. There was a significant difference between group 1 [108.1±7.9] and group 2 [79.3±7.7] in terms of corrected Tp-e(cTp-e) values [P<0.0001]. Looking at HRR-I at the 1st-minute recovery phase [14.4 ± 2.1 vs 20.1 ± 3.5], when looking at HRR-I at the 2nd-minute recovery phase [26.3 ± 2.2 vs 45.1 ± 2.4], when looking at HRR-I at the 3rd-minute recovery phase [42.6 ± 2.9 vs 64.1 ± 2.6], there was a statistically significant difference between the groups [P<0.00001]. CONCLUSION: Autonomic delaying is more prominent, the Tp-e interval value was higher and HRR-I values were lower in patients with stable angina with EF < 50%.

Arrhythmia Risk Profile and Ventricular Repolarization Indices in COVID-19 Patients: A Systematic Review and Meta-Analysis.

Coronavirus disease 2019 (COVID-19) has been associated with cardiac arrhythmias. Several electrocardiographic markers have been used to predict the risk of arrhythmia in patients with COVID-19. We aim to investigate the electrocardiographic (ECG) ventricular repolarization indices in patients with COVID-19. We performed a comprehensive systematic literature search from PubMed, EuropePMC, SCOPUS, Cochrane Central Database, and Google Scholar Preprint Servers. The primary endpoints of this search were: Tp-e (T-peak-to-T-end) interval, QTd (QT dispersion), and Tp-e/QTc ratio in patients with newly diagnosed COVID-19 from inception up until August 2020. There were a total of 241 patients from 2 studies. Meta-analysis showed that Tp-e/QTc ratio was higher in COVID-19 group (mean difference 0.02 [0.01, 0.02], p < 0.001; I2: 18%,). Tp-e interval was more prolonged in COVID-19 group (mean difference 7.76 [3.11, 12.41], p < 0.001; I2: 80%) compared to control group. QT dispersion (QTd) also was increased in COVID-19 group (mean difference 1.22 [0.61, 1.83], p < 0.001 ; I2:30%). Several electrocardiographic markers including Tp-e/QTc, Tp-e interval, and QTd are significantly increased in patients with COVID-19.

Evaluation of Tp-e interval and Tp-e: QT and Tp-e: QTc ratios in patients infected with HIV and using antiretroviral therapy

Sudden cardiac death (SCD) is one of the causes of death among patients infected with human immunodeficiency virus (HIV). The T peak to T end interval (Tp-e interval) is a parameter that is used in the prediction of SCD. The aim of this study was to investigate the difference in Tp-e interval and Tp: QT and Tp: corrected QT interval (QTc) ratios between patients infected with HIV and healthy individuals as well as in other factors affecting patients infected with HIV.A total of 83 patients infected with HIV with negative HIV ribonucleic acid (RNA) levels who were receiving antiretroviral therapy (ART) and 83 healthy individuals were included in this study. All the participants underwent electrocardiography, their Tp-e and QT intervals were measured, and QTc intervals and Tp-e: QT and Tp-e: QTc ratios were calculated. In addition, in the patients infected with HIV, CD4 and CD8 T-cell count and HIV RNA levels were measured.The Tp-e interval was found to be longer and the Tp-e: QT and Tp-e: QTc ratios were found to be higher in patients infected with HIV. Nadir CD4 was observed to be an independent predictor of Tp-e interval (p=0.014, β=‒0.28). Furthermore, correlation analysis revealed a negative correlation of the nadir CD4 level and CD4: CD8 ratio with Tp-e interval and Tp-e: QT ratio.Low nadir CD4 and a reversed CD4: CD8 ratio in patients infected with HIV receiving ART were found to be associated with a prolonged Tp-e interval and increased Tp-e: QT and Tp-e: QTc ratios. Thus, more attention should be taken in terms of SCD in patients infected with HIV, especially in those with low nadir CD4 and reversed CD4: CD8 ratio.

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.

The Assessment of Ventricular Arrhythmia Indicators Based on Electrocardiography in Patients With Differentiated Thyroid Cancer Followed Up With Levothyroxine Suppression.

Levothyroxine suppression therapy (LST) can cause some unfavorable effects on the cardiovascular system in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate ventricular arrhythmia predictors based on electrocardiography (ECG) in patients with DTC with LST. The ECG parameters including QT, corrected QT (QTc), Tp-e intervals, Tp-e/QT, and Tp-e/QTC ratios of 265 patients with DTC who met the inclusion criteria were compared with 100 controls. No difference was observed in the number of patients with DTC and controls with prolonged and borderline QTc interval (P = .273). Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in patients (P = .002, P = .02, P = .003; respectively). Linear regression analysis suggested that male gender was a predictor of higher Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios (β = 4.322, R2 = 0.024, P = .042; β = 0.016, R2 = 0.048, P = .005; β = 0.015, R2 = 0.044, P = .006, respectively). A higher serum fT4 level was found to be associated with a higher Tp-e/QT ratio (β = 0.018, R2 = 0.089, P = .007). Ventricular arrhythmia indicators were found to be higher in patients with DTC with LST. Defining ventricular arrhythmia predictors through ECG, an easily accessible cardiac diagnostic tool, can be potentially useful in raising awareness of the possible cardiac harm of LST.

Sarkoidozlu Hastalarda Kardiyak-Elektrofizyolojik Denge İndeksinin ve Elektrokardiyografik Değişimlerin Değerlendirilmesi

Objective: Cardiac sarcoidosis (CS) can manifest with different clinical signs and has a poor prognosis, but the heart is rarely affected alone. We aim to evaluate the arrhythmogenic effects of sarcoidosis by using electrocardiography (ECG) in patients with or without cardiac involvement. Materials and Methods: A total of 61 patients under follow-up for pulmonary sarcoidosis were retrospectively reviewed and 50 healthy volunteers were enrolled in the study. Sarcoidosis patients were also grouped as with or without cardiac involvement (n=11/ n=35). QRS, QT, Tp-e, P wave morphology were measured manually. Then, Tp-e/QT, Tp-e/QTc, QT/QRS (index of cardiac electrophysiological balance), and QTc/QRS ratios were calculated and compared between groups. Results: Heart rate on ECG, QT/QTc interval, Tp-e intervals and Tp-e/QT ratio and PWD were significantly higher (p values < 0.018) and iCEB or iCEBc values, obtained with the QT/QRS ratio, were lower in the sarcoidosis group (p = 0.001). And we could not find a relationship between non-cardiac and CS and ECG parameters including QTc, Tp-e/QT ratio and iCEB (p= 0.501, p= 0.753 and p=0.490, respectively). Conclusion: The present study demonstrated a lower iCEB value and higher repolarization findings in sarcoidosis patient. However, there are no differences between with or without cardiac involvement.

Effect of dialysis and transplantation on myocardial repolarization parameters and P-wave dispersion in chronic kidney disease.

BackgroundChronic kidney disease (CKD) patients are at higher risk for cardiac arrhythmias. The risk of arrhythmia may change with different treatment modalities. We proposed to compare the effects of varied therapy methods on myocardial repolarization parameters (Tp‐e, QT, QTc intervals, Tp‐e/QT, Tp‐e/QTc ratios) and P‐wave dispersion (PWD) in patients with CKD.MethodsThree groups were formed from the patients aged between 18 and 65 years, as Group 1 consisting of CKD patients receiving hemodialysis (HD) three times a week, Group 2 consisting of predialysis CKD patients and Group 3 consisting of CKD patients who underwent successful transplantation. All patients’ basic demographic data, risk factors, and echocardiographic parameters were recorded, and electrocardiographic repolarization parameters and PWD were analyzed.ResultsThe PR, QT, and QTc intervals were significantly shorter in the transplantation group compared to the other groups (P = .020, P < .001, P = .035; respectively). Tp‐e interval, Tp‐e/QT, and Tp‐e/QTc ratios were significantly higher in the predialysis group compared to the other groups (P < .001, P < .001, P = .001; respectively), while there was no significant variation between the HD and transplantation groups (P > .05). PWD was significantly increased in the predialysis group compared to other two groups (P < .001), while no significant variation between the HD and transplantation groups was observed.ConclusionWe found that the Tp‐e interval, Tp‐e/QT, Tp‐e/QTc, and PWD were significantly higher in the predialysis CKD group, but the PR, QT, and QTc intervals were significantly shorter in the transplantation group compared to the other groups. The prognostic significance and prediction of these parameters in arrhythmic events in CKD patients requires further evaluation with long‐time follow‐up.

ECG markers of malignant arrhythmias and in-hospital outcome of COVID-19 pneumonia.

BackgroundECG abnormalities associated with COVID‐19 pneumonia and adverse outcome are undefined and poorly described in prior studies.ObjectivesTo assess the predictive role of baseline ECG markers of increased risk of malignant arrhythmias and cardiac death for adverse in‐hospital outcomes.Patients and methodsA retrospective study included 93 patients of newly diagnosed COVID‐19 with features consistent with pneumonia who were admitted to the hospital from August 20 to September 20, 2020. The main outcomes were defined as receiving mechanical ventilation, in‐hospital cardiac arrest, length of ICU stay, and degree of lung damage according to computed tomography (CT) score.ResultsIncreased QTc (QT corrected) interval, Tp‐e (T from peak to end) interval, and transmural dispersion of repolarization (TDR) were independent predictors of prolonged ICU stay (P < .0001) after adjustment for baseline clinical characteristics. Increasing age (P < .0001) followed by increased QTc interval (P = .02) and history of chronic lung disease (P = .04) were independent predictors of extensive lung damage. The independent predictors for in‐hospital cardiac arrest were increased QTc (P = .02) followed by increasing age (P = .04) and increased Tp‐e interval (P = .04).ConclusionRepolarization abnormalities on baseline ECG may be useful prognostic markers in patients with COVID‐19 pneumonia.

The Association between Tp-e interval, Tp-e/QT , and Tp-e/QTc Ratios and Coronary Artery Disease Spectrum and Syntax Score

Background Coronary artery disease (CAD) causes electrical heterogeneity on ventricular myocardium and ventricular arrhythmia due to myocardial ischemia linked to ventricular repolarization abnormalities. Objective Our aim is to investigate the impact of increased level of CAD spectrum and severity on ventricular repolarization via Tp-e interval, Tp-e/QT and Tp-e/QTc ratios. Methods 127 patients with normal coronary artery (group 1), 129 patients with stable CAD (group 2) and 121 patients with acute coronary syndrome (group 3) were enrolled. Tp-e interval, Tp-e/QT [...]

Investigating Novel Electrocardiographic Ventricular Repolarization Markers in Scleroderma Patients

Aim: Ventricular repolarization involves the J-wave, ST-segment, T-wave, and U-wave on the surface electrocardiography (ECG). QT dispersion, Tp-e interval, Tp-e/QT, Tp-e/QTc, Tp-e/JT, and Tp-e/JTc ratios are some indices that predict ventricular tachyarrythmias. Although studies, evaluating repolarization abnormalities in scleroderma have frequently focused on Tp-e interval, QT, and Tp-e/QT, in our study, we aimed to investigate the risk of ventricular arrhythmia by using Tp-e/JT and Tp-e/JTc ratios, which are relatively new parameters.Methods: The study comprised 42 patients with scleroderma (mean age: 50.8 ± 7.3 years; 38 women and 4 men) and 40 healthy controls (mean age: 47.9 ± 5.5 years; 37 women and 3 men). We leveraged a standard 12-lead ECG recording to measure Tp-e interval, Tp-e/JT, Tp-e/JTc, Tpe/QTc, and Tp-e/QT parameters for each patient.Results: Compared to the scleroderma patients electrocardiographic repolarization parameters including Tp-e (90.8 ± 10.9 vs 77.0 ± 10.2, p

Effects of surgical atrial septal defect closure operation on the frontal QRS-T angle

Aim: A new marker has been found for ventricular repolarization and depolarization heterogeneity, which is the frontal plane QRS-T [f(QRS-T)] angle between the directions of ventricular depolarization (QRS axis) and repolarization (T axis). Adverse cardiac outcomes can be detected based on observation of the f(QRS-T) angle.In atrial septal defect (ASD) patients, surgical closure of ASD is safer and more effective than its percutaneous closure with higher popularity in the last two decades. Nevertheless, we have scarce information about the impact of ASD closure on cardiac autonomic function and heart repolarization.The aim of the study is to investigate the potential effect of ASD operation on the f(QRS-T) angle and cardiac repolarization parameters.Materials and Methods: In our retrospective study design we sampled a total of 24 patients who underwent ASD closure surgery operation between December 2011 and January 2019. Preoperative and postoperative 6 week ECG parameters including the f(QRS-T) of the patients were compared.Results: When pre- and postoperative ECG parameters were compared, no statistically significant difference was found in QT interval (p=0.079), adjusted QT interval (p=0.079), Tpe interval (p=0.150) and Tpe/QTc ratio (p=0.696). An improvement was found in QRS duration (p=0.035), p wave duration (p0.001) and f(QRS)-T angle (p0.001).Conclusion: In our study, it was observed that surgical ASD closure operation was associated with heart repolarization parameters and improvement in f(QRS-T).

Tp-e Interval, Tp-e/QT and Tp-e/QTc Ratio in Patients with Primary Hyperparathyroidism and Relationship with Cardiac Arrhythmic Events

Tp-e Interval, Tp-e/QT and Tp-e/QTc Ratio in Patients with Primary Hyperparathyroidism and Relationship with Cardiac Arrhythmic Events

What is the Normal Value of Tpe Interval and Corrected Tpe Interval?

Objective: Increased T wave peak and end distance (Tpe interval) shows abnormal spread in ventricular repolarization, it is associated with increased risk of ventricular arrhythmia and poor prognosis. However, Tpe interval, corrected Tpe (Tpe-c) upper limit value, and normal reference interval have not been reported in healthy population. In our study, it was aimed to determine the normal reference range of Tpe and Tpe-c interval in healthy population.&#x0D; Materials and Methods: 414 healthcare professionals who had no complaints were included in the study. Tpe and Tpe-c measurements of all patients were performed on 12-lead electrocardiography taken at rest. Average and standard deviation, median, minimum, maximum, 95% confidence intervals (95% CI) values of these parameters were obtained.&#x0D; Results: According to the data obtained in our study; Tpe mean and standard deviation, median, minimum, and maximum values were found to be 70.3 ± 12.3 ms, 70 ms, 50 ms and 100 ms, respectively. The 95% CI value of the Tpe interval was detected as 50-90 ms. Tpe-c mean and standard deviation, median, minimum, and maximum values were found to be 76.1 ± 14.6 ms, 75 ms, 48 ms and 128 ms, respectively. The 95% CI of the Tpe-c interval was detected as 53-100 ms. It was determined that Tpe and Tpe-c intervals were not affected by demographic and clinical parameters.&#x0D; Conclusion: As a result of our study, it was determined that the upper limit of Tpe and Tpe-c interval values in adult, not-elderly and healthy normal population were 90 ms and 100 ms, respectively. It was thought that this information could be used for prolonged Tpe interval, which shows an increased risk of arrhythmia in daily practice. However, it was concluded that studies should be done in other communities and races on this subject as well.

Heart Rate Dependency and Inter-Lead Variability of the T Peak – T End Intervals

The electrocardiographic (ECG) assessment of the T peak–T end (Tpe) intervals has been used in many clinical studies, but several related physiological aspects have not been reported. Specifically, the sources of the Tpe differences between different ECG leads have not been systematically researched, the relationship of Tpe duration to underlying heart rate has not been firmly established, and little is known about the mutual correspondence of Tpe intervals measured in different ECG leads. This study evaluated 796,620 10-s 12-lead ECGs obtained from long-term Holters recorded in 639 healthy subjects (311 female) aged 33.8 ± 9.4 years. For each ECG, transformation to orthogonal XYZ lead was used to measure Tpe in the orthogonal vector magnitude (used as a reference for lead-to-lead comparisons) and to construct a three-dimensional T wave loop. The loop roundness was expressed by a ratio between its circumference and length. These ratios were significantly related to the standard deviation of Tpe durations in different ECG leads. At the underlying heart rate of 60 beats per minute, Tpe intervals were shorter in female than in male individuals (82.5 ± 5.6 vs 90.0 ± 6.5 ms, p < 0.0001). When studying linear slopes between Tpe intervals measured in different leads and the underlying heart rate, we found only minimal heart rate dependency, which was not systematic across the ECG leads and/or across the population. For any ECG lead, positive Tpe/RR slope was found in some subjects (e.g., 79 and 25% of subjects for V2 and V4 measurements, respectively) and a negative Tpe/RR slope in other subjects (e.g., 40 and 65% for V6 and V5, respectively). The steepest positive and negative Tpe/RR slopes were found for measurements in lead V2 and V4, respectively. In all leads, the Tpe/RR slope values were close to zero, indicating, on average, Tpe changes well below 2 ms for RR interval changes of 100 ms. On average, longest Tpe intervals were measured in lead V2, the shortest in lead III. The study concludes that the Tpe intervals measured in different leads cannot be combined. Irrespective of the measured ECG lead, the Tpe interval is not systematically heart rate dependent, and no heart rate correction should be used in clinical Tpe investigations.

Evaluation of Index of Cardio-Electrophysiological Balance in Patients With Atrial Fibrillation on Antiarrhythmic-Drug Therapy.

BackgroundIndex of cardio-electrophysiological balance (iCEB) has been described as a novel risk marker for predicting malignant ventricular arrhythmia. There remains limited evidence on the effects of amiodarone and propafenone used for sinus rhythm maintenance on iCEB in patients with atrial fibrillation (AF). The aim of this study was to evaluate iCEB in patients with AF on antiarrhythmic-drug therapy.MethodsA total of 108 patients with AF (68 patients using amiodarone and 40 patients using propafenone) and 50 healthy subjects were included in the study. All groups underwent a standard 12-lead surface electrocardiogram. QRS duration, QT, T wave peak-to-end (Tp-e) intervals, iCEB (QT/QRS) and iCEBc (heart rate-corrected QT (QTc)/QRS) rates were calculated from the electrocardiogram and compared between groups.ResultsQT, Tp-e intervals and Tp-e/QT ratio were significantly longer in the amiodarone group than the propafenone and control groups (P < 0.001, for all). iCEB was similar in the amiodarone and control groups (4.4 ± 0.6 and 4.2 ± 0.4; P > 0.05), while iCEB values in the propafenone group were significantly lower than the amiodarone group and control groups (3.9 ± 0.5; P < 0.001). There was a significantly difference in iCEBc values among the amiodarone, control and propafenone groups (4.8 ± 0.6, 4.6 ± 0.4 and 4.3 ± 0.6; P < 0.001, respectively).ConclusionsIn this study, higher iCEBc parameters were observed in patients using amiodarone, while iCEBc values were lowest among patients with AF using propafenone. Further studies are needed to determine whether these electrophysiological changes are associated with ventricular arrhythmias for patients with AF on antiarrhythmic-drug therapy.

The impact of fever on myocardial repolarization parameters

Background:It has been reported in the literature that the increase in body temperature shortens QT interval on electrocardiogram through heart rate modulation. However, the effects of fever on ventricular repolarization are not clearly known. This study elaborates on QT interval of isolated fever, corrected QT (cQT), Tp-e interval, the ratio of corrected Tp-e (cTp-e) and Tp-e/QT, and their impacts on arrhythmia potential.Methods:This prospective study was performed on 74 patients without any active and chronic diseases other than fever and upper respiratory tract infection. The study included patients at the age of 18–50 years suffering from fever above 38.2 °C. QT and Tp-e intervals of the patients were measured from their ECGs taken in febrile and afebrile periods. cQT and cTp-e values were calculated according to Bazett, Fridericia, and Framingham formulations.Results:QT and Tp-e intervals were observed to be shorter in the febrile period (p < 0.001 and p = 0.006 respectively). cTp-e was found to be longer in the febrile period according to Bazett, Fridericia, and Framingham formulations (p < 0.001, p = 0.002, p < 0.001, respectively). Tp-e/QT ratio was found to be higher in the febrile period than in the afebrile period (p < 0.001).Conclusion:Although QT, cQT, and Tpe intervals were shorter, cTpe interval and Tpe/QT ratio were longer and higher in the febrile period, respectively. These findings may indicate that fever may create a proarrhythmic effect by causing variability in the transmural distribution of myocardial repolarization.

&lt;p&gt;Assessment of Ventricular Repolarization in Sickle Cell Anemia Patients: The Role of QTc Interval, Tp-e Interval and Tp-e/QTc Ratio and Its Gender Implication&lt;/p&gt;

BackgroundMany specific and non-specific electrocardiographic abnormalities including ventricular arrhythmias have been reported in subjects with sickle cell anemia (SCA). In SCA patients, cardiac electrical abnormalities may be the leading cause of increased risk of arrhythmias. The corrected QT (QTc) interval, peak to the end of the T wave (Tp-e) interval and associated Tp-e/QTc ratio are promising measures of altered ventricular repolarization and increased arrhythmogenesis risk.AimThis study assessed ventricular repolarization abnormalities in subjects with SCA using the QTc interval, Tp-e interval and Tp-e/QTc ratio, and also evaluated the gender differences in these parameters, as well as their determinants.MethodsSixty subjects with SCA and 60 healthy control subjects, matched for age and gender, were studied. All participants underwent physical examination, hematological and biochemical evaluation, and 12-lead electrocardiography (ECG) recording. QT and Tp-e intervals were measured from the ECG, and the QTc interval was calculated using Bazett’s formula. Tp-e/QT and Tp-e/QTc ratios were also derived.ResultsQT and QTc intervals were prolonged in subjects with SCA. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in male SCA subjects, with a paradoxical shortening in female SCA subjects. Plasminogen activator inhibitor-1 (PAI-1) was an independent determinant of QTc, while body mass index (BMI) was an independent determinant of both Tp-e interval and Tp-e/QTc ratio.ConclusionOur results suggest an elevated risk for ventricular arrhythmogenesis in male SCA subjects. Furthermore, increased BMI and PAI-1 level are possible markers of ventricular repolarization abnormalities in SCA subjects.

Index of cardiac-electrophysiological balance and the effects of thrombolytic therapy on the electrocardiogram of patients with pulmonary embolism.

Different parameters on electrocardiograms (ECG) have been investigated to predict arrhythmia and mortality in patients with acute pulmonary embolism (APE). The acute effect of thrombolytic therapy (TT) on these parameters has not been investigated yet. We examined the data of 83 patients who were evaluated as high-risk APE and discharged from the hospital after TT. First, the high-risk APE patients' ECGs were compared with healthy control subjects (n = 55). After their admission and 24 hours later, the ECGs of patients with APE were compared. Heart rate, P-wave morphology, QRS duration, QT distance, Tp-e, and the index of cardiac electrophysiological balance (iCEB) were analyzed. Although P maximum was not different between the groups' ECGs, heart rate, QT, QTc (corrected QT) interval, Tp-e intervals, Tp-e/QT ratio, and P wave dispersion were significantly higher in the APE group ( P values < 0.031). iCEB or iCEBc (corrected iCEB) values were lower in APE group ( P < 0.001). After TT, we determined a decrease in heart rate, Tp-e interval, and Tp-e/QT ratio ( P < 0.001). Although we detected a decrease in the QT and QTc interval and QT dispersion (QTd), QTd had no statistical significance (respectively P -value 0.013, 0.029, and 0.096). The iCEB and iCEBc levels were lower after TT ( P -value was 0.035 and 0.044 respectively). The QT, QTc, Tp-e interval, Tp-e/QTc ratio, iCEB, and iCEBc values significantly decreased after TT. It may be thought that effective TT causes partial improvement in ventricular repolarization in an early period.

Acute effects of electronic cigarette smoking on ventricular repolarization in adults.

Electronic cigarette (e-cigarette) use is constantly increasing. However, the association between e-cigarette use and ventricular arrhythmia is unknown. Thus, in this study, we aimed to evaluate the markers of ventricular repolarization such as QT interval, corrected QT (QTc), QT dispersion (QTd), peak-to-end interval of the T wave (Tp-e), corrected Tp-e and Tp-e/QT ratios in e-cigarette users. The study population consisted 36 e-cigarette users and 40 healthy subjects. Ventricular repolarization parameters were obtained from 12-lead resting electrocardiogram. Ventricular repolarization parameters of the groups were compared. Basal demographic and laboratory data were similar in both groups. According to the electrocardiographic parameters, the Tp-e interval, corrected Tp-e, and Tp-e/QT ratio were significantly higher in individuals using e-cigarettes than in control subjects [74.9±6.4 milliseconds (ms) vs. 80.1±4.1ms, <0.001; 82.9±7.5 ms vs. 87.8±6.3 ms, p=0.003; 0.20±0.01 vs. 0.21±0.01, p=0.002; respectively]. This is the first study to show the disruption of ventricular repolarization properties in e-cigarette users. E-cigarette use in terms of public health leads to augmentation of transmural dispersion of repolarization, which may be potential indicator of ventricular arrhythmogenesis.