Indices Of Ventricular Repolarization Research Articles

Investigation of Heart Rate Variability and Ventricular Repolarization Indexes in Brucella Patients with Palpitations

Investigation of Heart Rate Variability and Ventricular Repolarization Indexes in Brucella Patients with Palpitations

Effect of long-term use of antipsychotics on the ventricular repolarization index

BackgroundThe risk of arrhythmia is usually assessed by the length of the corrected QT interval (QTc) when patients use antipsychotics. Prolonged QTc intervals are thought to increase the probability of malignant ventricular arrhythmias, and if we focus only on the QTc interval, we may be influenced by a single factor and make decisions that are not conducive to effective treatment. The index of cardiac electrophysiological balance (iCEB) is considered more valuable than the QTc for predicting drug-induced arrhythmias. It has been used in clinical practice, but no studies have observed changes in this index after the use of antipsychotics.ObjectiveTo investigate the changes in ventricular repolarization indices and the occurrence of arrhythmias in patients who have been using antipsychotic drugs for a long time, to compare the changes in iCEBc and QTc and to predict abnormal iCEBc values.MethodsPatients with schizophrenia who had been hospitalized for more than 4 years and who were receiving atypical antipsychotics underwent a 12-lead synchronized electrocardiogram (ECG) every 2–4 weeks. The baseline data were measured at admission, defined as the baseline (time0), and the most obvious abnormal changes in ventricular depolarization and repolarization measured every 12 months were one-year follow-up (time1), two-year follow-up (time2), three-year follow-up (time3), and four-year follow-up (time4). Repeated measures analysis of variance was used for comparisons. The types and doses of drugs taken at 5 time points were recorded and converted into chlorpromazine equivalents for comparison. The incidence of arrhythmia during the observation cycle was recorded.ResultsThe patients had been treated with antipsychotic medication for 4 years, and the duration of the QRS wave was longer in males than in females. TpTe, TpTe/QRS, TpTe/QT, TpTe/QTc, iCEB, and iCEBc increased significantly with hospital stay, while TpTe, TpTe/QRS, TpTe/QT, and TpTe/QTc exhibited more obvious changes in these indicators in female patients (P < 0.01). The changes in iCEB and iCEBc were more significant in males (P < 0.01). The incidences of arrhythmia (arrhythmic events included premature ventricular beats and premature atrial beats) within 5 time points were 2.5%, 6.25%, 6.25%, 6.25% and 5%, respectively. More than 90% of patients treated with antipsychotics did not have any arrhythmias. No TdP syncope or other cardiovascular symptoms were found in any of the patients.ConclusionAfter long-term use of antipsychotics, the ventricular repolarization index gradually increased with time. The new ventricular repolarization indices iCEB and iCEBc were more sensitive than the QTc at predicting arrhythmia. According to the abnormal QTc values in men and women, we predict that the abnormal value of the iCEBc in males is 4.528 and that in females is 5.315.

Study of electrocardiographic indices of myocardial repolarization in patients with obstructive sleep apnea

Abstract Background Obstructive sleep apnea (OSA) is a sleep disorder manifested by airflow severe reduction or stoppage during breathing exertion. OSA cases had a higher incidence of ventricular arrhythmias, according to reports. Aim This research aimed to determine ventricular repolarization in OSA cases using the electrocardiographic indices of ventricular repolarization. Patients and methods This observational research involved 60 patients who underwent overnight polysomnography (PSG). 20 cases with normal PSG were employed as controls. Moderate or severe OSA cases were employed as study group. Tp-e, QTc intervals &amp; Tp-e/QTc ratios measurement was performed in all patients. Results Patients had significantly prolonged QTc intervals, Tp-e intervals &amp; Tp-e/QTc ratio compared to controls (446.4 ± 36.99 ms vs. 408.6 ± 25.23 ms, 86.12 ± 17.63 ms vs. 66.65 ± 15.49 ms &amp; 0.19 ± 0.04 vs. 0.16 ± 0.04 respectively, P&lt;0.001). There was a significant positive correlation between OSA degree and Tp-e/QTc ratio (r=0.374, P=0.017), Tp-e/QT ratio (r=0.448, P=0.004) &amp; Tp-e interval (r=0.377, P=0.016). There is also significant correlation between such repolarization indices and both lowest SpO2 and arousal index (P&lt;0.05). Conclusions We concluded a significant positive correlation between OSA degree and Tp-e/QTc, Tp-e/QT ratios &amp; Tp-e interval. OSA is associated with prolonged Tp-e/QTc &amp; Tp-e/QT ratios and a prolonged Tp-e interval.

Effect of sacubutril/valsartan on Tp-e, QT, QTc, Tp-e/QTc parameters in heart failure with reduced ejection fraction

Purpose: The purpose of this study is to evaluate ventricular repolarization before, at the first month, and sixth month after Sacubutril/Valsartan, an angiotensin receptor neprilysin inhibitor (ARNI) treatment in heart failure patients with reduced ejection fraction (HFrEF).&#x0D; Materials and Methods: We included 49 patients with HFrEF who switched to ARNI therapy. The 12-lead electrocardiography (ECG) was evaluated before ARNI therapy and also during the first and sixth months of the therapy. We evaluated demographic, clinical, and laboratory parameters, as well as medications and ECG data, including heart rate. Additionally, we examined QT, QTc, Tp-e, Tp-e calculated (Tp-ec), Tp-ec/QTc, Tp-e/QT, and Tp-e/QTc.&#x0D; Results: After receiving ARNI treatment, ventricular repolarization indices were significantly reduced in the first and sixth months compared to before treatment. Specifically, the QTc values decreased from 457.6 ms to 443.8 ms, and the Tp-e/QT ratio decreased from 0.21±0.03 to 0.19±0.03. Additionally, the QTc values decreased from 457.6 ms to 444.9 ms, and the Tp-e/QT ratio decreased from 0.21±0.03 to 0.18±0.03. However, when the first and sixth months under ARNI treatment were compared, no significant difference was found (QTc: 443.8 ms vs. 444.9 ms, Tp-e/QT: 0.19±0.03 vs. 0.18±0.003).&#x0D; Conclusion: ARNI treatment in HFrEF positively affected QTc, Tp-e, and Tp-ec intervals and Tp-e/QT, Tp-e/QTc, and Tp-ec/QTc ratios, which are indicators of ventricular repolarization. Moreover, this effect started in the first month and continued in the sixth month.

Does vitamin D deficiency affect ventricular repolarization in the elderly?

Introduction: The aim of the current study is to establish whether vitamin D deficiency interacts with the electrocardiographic indices of abnormal ventricular repolarization in elderly patients. Material and Methods: 138 patients were divided into three groups: patients with vitamin D deficiency, patients with vitamin D insufficiency, and patients with adequate vitamin D levels. 12-lead electrocardiography and laboratory data were collected. Results: The resting heart rate, PR interval, QRS duration, QTd, and Tp-e dispersion were similar among the groups. However, the QTc interval was significantly prolonged in patients with vitamin D deficiency, when compared to patients with sufficient vitamin D levels. Vitamin D level was found as the only independent predictor of the QTc interval. The cut-off value of Vitamin D level determining the significant prolongation of QTc interval was found to be 20 ng/ml on ROC analysis (Area Under Curve: 0,629±0.051 (95% CI: 0,530-0.728, p=0.013). Conclusion: Low vitamin D levels are associated with QTc prolongation in the elderly. Vitamin D-deficient elderly patients may benefit from routine ECG screening. Timely diagnosis and treatment of vitamin D deficiency may aid in reducing the rate of arrhythmias in this patient population.

A comparison of electrocardiographic parameters in e-cigarette users, conventional cigarette smokers, and non-smokers

BackgroundSmoking is a major preventable risk factor for cardiovascular morbidity and mortality. Tobacco smoking induces atherosclerosis, ischemic heart diseases, and arrhythmias. The impact of electronic cigarettes on cardiovascular health is still controversial. This study aimed to evaluate the electrocardiographic parameters in chronic electronic cigarette users compared to chronic conventional cigarette smokers and a non-smoker control group of matched age and gender.ResultsThe study involved 105 volunteers with no history of chronic or cardiovascular diseases or cardioactive drug use. Participants were assigned into three study groups, chronic e-cigarette users, conventional cigarette smokers, and non-smokers, each consisting of 35 participants. Demographic data, smoking history, vital signs, and 12-lead electrocardiogram (ECG) were evaluated. Demographic data were insignificantly different among all study groups. The mean heart rate was significantly higher in chronic electronic cigarette users and conventional cigarette smokers compared to non-smokers (p < 0.001).QRS complex duration was significantly shorter in e-cigarette users and conventional smokers compared to non-smokers (p < 0.001). Prolonged QT and QTc intervals duration were recorded in e-cigarette users and conventional smokers compared to non-smokers (p < 0.001). All the ventricular repolarization indices (T wave—peak to T-end (Tpe) interval, TPe/QT ratio, and TPe/QTc ratio were significantly prolonged in chronic e-cigarette users, and conventional smokers compared to non-smokers (p < 0.001). Mean systolic, diastolic blood pressure, P wave amplitude and duration, and PR interval were insignificantly different between all groups (P > 0.05).ConclusionsChronic e-cigarette use is associated with higher heart rates, shorter QRS complex, prolonged QT, QTc duration, and prolonged ventricular repolarization indices compared to non-smokers of matched age and gender. Conclusively, e-cigarette use is associated with negative cardiovascular effects like conventional cigarette smoking.

Ranolazine improved left ventricular diastolic functions and ventricular repolarization indexes in patients with coronary slow flow.

Coronary slow flow (CSF) is a condition commonly encountered during angiography. Recent studies have shown the adverse effects of CSF on left ventricular diastolic functions. CSF reportedly increases the novel ventricular repolarization parameters. Ranolazine is a preparation with a prominent anti-anginal activity that has positive effects on anti-arrhythmic and diastolic parameters. In this context, this study was carried out to investigate the effects of ranolazine on left ventricular diastolic functions and repolarization in patients with CSF. Forty-six patients with CSF and 29 control subjects were included in the patient and control groups, respectively. Both groups received ranolazine for one month and were evaluated using 12-lead electrocardiography, conventional echocardiography, and tissue Doppler imaging at the baseline and after one month of ranolazine treatment. Corrected P, QT dispersion, and Tp-e interval values were significantly higher in the patient group than in the control group. There was a significant decrease in isovolumic relaxation time (IVRT) and deceleration time (DT) values after the ranolazine treatment compared to the baseline values in the patient group but not the control group. A significant increase was observed in the mean E and A velocities and the mean E/A ratio after the ranolazine treatment compared to the baseline values in the patient group. Additionally, there was a significant difference between the Tp-e interval and corrected P dispersion values measured after the ranolazine treatment compared to the baseline values in the patient group but not in the control group. This study's findings demonstrated that ranolazine positively affected impaired diastolic functions and repolarization parameters, particularly in patients with CSF.

Impact of coronary artery bypass grafting on ventricular repolarization indexes

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ventricular repolarization indexes (VRI) tend to be altered in patients with chronic coronary artery disease, which are associated with a higher risk of malignant arrhythmias and higher mortality. Coronary artery bypass grafting (CABG) is capable of reducing mortality, as well as improving arrhythmic burden in this population. However, we do not know whether these benefits can be explained by improvement in VRI. Purpose To determine whether there is improvement in VRI after CABG, as well as to analyse possible effects of clinical and surgical variables on these indexes. Methodology A total of 150 patients who underwent CABG were included. Through the evaluation of preoperative and hospital discharge electrocardiograms, the QT interval, the interval from the peak to the end of T wave (Tp-Te) and the Tp-Te/ QT ratio were analysed. The values obtained before and after CABG were compared, as well as their association with clinical and surgical variables. Results The population was predominantly male (77.3 %), mean age of 61.6±8.3 years-old and mean LVEF of 58.8±10.6 %. A reduction in the QT interval (398.93±34.68 vs 365.47±50.38 ms, p &amp;lt; 0.001), in the Tp-Te interval (72.2±17.2 vs 61.6±19.5 ms, p &amp;lt; 0.001) and in the Tp-Te/ QT ratio (0.18±0.17 vs 0.04±0.05, p = 0.004) after CABG. There was no correlation between VRI and clinical and surgical variables. Conclusion CABG had a important impact in the reduction of QT and Tp-Te intervals, as well as the Tp-Te/ QT ratio, suggesting that the acute improvement in the coronary perfusion is directly associated with the improvement in these VRI.

Blood pressure parameters affecting ventricular repolarization in obese children.

Ventricular repolarization (VR) increases the risk of sudden cardiac death due to ventricular arrhythmia. We aimed to evaluate the blood pressure (BP) parameters affecting VR in obese children. Obese (BMI ≥ 95p) and healthy children ≥ 120cm between January 2017 and June 2019 were included. Demographic and laboratory data, peripheral and central BPs evaluated by a device capable of ambulatory blood pressure monitoring (ABPM), and pulse wave analysis were assessed. Electrocardiographic ventricular repolarization indices, left ventricular mass index (LVMI), and relative wall thickness (RWT) were calculated. A total of 52 obese and 41 control patients were included. Uric acid, triglyceride, total cholesterol, LDL, and ALT values, systolic and diastolic office BPs, 24-h, daytime and nighttime systolic and mean arterial BPs, daytime diastolic BP SDS levels, daytime and nighttime systolic loads, daytime diastolic load, 24-h, daytime and nighttime central systolic and diastolic BPs, and pulse wave velocity values were significantly higher, whereas 24-h, daytime and nighttime AIx@75 were similar between the groups. fT4 levels of obese cases were significantly lower. QTcd and Tp-ed were higher in obese patients. Although RWT was higher in obese cases, LVMI values and cardiac geometry classifications were similar. The independent factors affecting VR in obese cases were younger age and higher diastolic load at night (B = - 2.83, p = 0.010; B = 0.257, p = 0.007, respectively). Obese patients have higher peripheral and central BP, arterial stiffness, and higher VR indices that develop before an increase in LVMI. It would be useful to prevent obesity from an early age and follow up nighttime diastolic load to control VR associated sudden cardiac death in obese children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Examination of New Electrocardiographic Repolarization Markers in Diabetic Patients with Noncritical Coronary Artery Disease.

Background Diabetes mellitus (DM) is a multisystemic, chronic disease that affects many organs. Coronary artery disease (CAD) is the leading cause of death in patients with DM. The electrocardiogram's new ventricular repolarization parameters can predict mortality and morbidity. The ventricular repolarization indices were examined in diabetic patients with a CAD diagnosis in this study. Methods The study group consisted of 84 DM patients (51 males; mean age 58.8 ± 6.6) with noncritical CAD. The control group consisted of 84 DM patients (47 males; mean age 58.7 ± 8.8) with a normal coronary artery. The intervals of QT, QRS, JT, and Tp-e were all measured. Tp-e/QT, Tp-e/QTc, Tp-e/JT, and Tp-e/JTc ratios were determined with QTc, QTd, QTdc, and JTc intervals. Results Heart rate (74.4 ± 13.1 vs. 70.0 ± 13.6 bpm, p: 0.036), QT (381.0 ± 30.3 vs. 368.6 ± 29.1 ms, p: 0.008), QTc (407.5 (359–450) vs. 389 (339–430) ms, p < 0.001), QTd (25.1 ± 6.2 vs. 21.9 ± 9.9 ms, p: 0.013), QTdc (26.7 ± 6.1 vs. 23.1 ± 10.8 ms, p: 0.010), Tp-e (95.7 ± 12.2 vs. 73.6 ± 9.8 ms, p < 0.001), JT (293.8 ± 22.0 vs. 283.5 ± 30.9 ms, p: 0.014), and JTc (313.6 ± 12.3 vs. 302.4 ± 33.7 ms, p=0.005) intervals, and Tp-e/QT (0.25 ± 0.03 vs. 0.20 ± 0.03 ms, p < 0.001), Tp-e/QTc [0.23 (0.19–2.33) vs. 0.19 (0.14–0.25) ms, p=0.007], Tp-e/JT (0.33 ± 0.04 vs. 0.26 ± 0.04 ms, p < 0.001), and Tp-e/JTc (0.30 ± 0.03 vs. 0.24 ± 0.03 ms, p < 0.001) ratios were all found to be significantly higher in diabetic patients with noncritical CAD. Conclusion In this study, ventricular repolarization markers on the surface ECG were found to be elevated in diabetic CAD patients. These variables may be related to fatal arrhythmic events. To be sure, large-scale, randomized controlled trials are required.

Temporal change of ventricular repolarization indices and index of cardioelectrophysiological balance (iCEB) during COVID-19 treatment including hydroxychloroquine at a tertiary referral hospital

Aim: Hydroxychloroquine (HCQ) is widely administered to patients with confirmed or suspected COVID-19. It may increase the risk of cardiac arrhythmias associated with QT and QTc prolongation. This study aimed to assess the change in iCEB, a new marker of drug-induced arrhythmia, and other repolarization parameters in suspected COVID-19 patients treated with short-course HCQ.&#x0D; Material and Method: This was a retrospective cross-sectional study including 40 patients hospitalized with suspected COVID-19 according to the CT findings and treated with HCQ. Serial assessments of the QT and QTc intervals and the calculation of the index of cardio-electrophysiological balance (iCEB) were performed using standard 12 lead electrocardiogram before hydroxychloroquine treatment, on the second day of HCQ treatment, and after the day of the last administered dose. &#x0D; Results: QT, QTcB, QTcF, iCEB, iCEBcB significantly increased on the second day of HCQ treatment compared to baseline (p=0.009, p=0.001, p=0.002, p=0.047, p=0.05, respectively). Similarly, QT, QTcB, QTcF, iCEBcB and iCEBcF were significantly higher on the fifth day compared to baseline (p=0.011, p=0.005, p=0.005, p=0.013, p=0.028, p=0.024 respectively). However, there were no differences between the second and the fifth days of treatment for any of the studied parameters.&#x0D; Conclusions: QT, QTc, and iCEB significantly increased compared to baseline on the second day, and remained increased on the fifth day of treatment. The differences were attributed to the amount of loading dose and the duration of HCQ treatment. Our study suggests that, along with other ECG markers, iCEB can be used in COVID-19 patients treated with HCQ.

Hadrontherapy for intra- or para-cardiac tumors: evaluation of cardiac radiation dose distribution and acute cardiac effects

Abstract Background There is growing interest in the possibility of using X-rays and hadrons (protons and carbon ions) for antiarrhythmic purposes both at the ventricular and the atrial level, but knowledge about the effects on cardiac tissue outside the target is still limited. Hadron therapy has the dosimetric advantage over photons of a greater ability to concentrate high doses on the target while minimizing the off-target dose. Oncological studies have shown a linear relationship between the mean total heart dose (Dm-heart) of X-rays and the long-term risk of heart damage, particularly when the Dm-heart is&amp;gt;5 Gray (Gy). Objectives We designed a prospective study aimed at investigating the effect of heavy particles on cardiac structure and function and on cardiac rhythm in patients undergoing hadrontherapy for intra or para-cardiac tumors. Methods Patients candidates to hadrontherapy with a mean predicted cardiac dose grather than zero underwent close cardiological monitoring including blood pressure detection, 12-lead ECG, 12-lead Holter ECG (including time-domain indices of heart rate variability in all cases and Brugada leads in selected cases), cardiac US and cardiac (troponin and natriuretic peptides) and inflammatory biomarkers. These assessments were obtained at baseline, during (ECG and biomarkers only) and at the end of the hadrontherapy cycle, and then every 3–6 months as appropriate. Physicists and radiotherapists collaborated to implement a robust optimization of the treatment plan aimed at minimizing cardiac dose. We present the results of the monitoring up to the end of the hadrontherapy. Results 17 consecutive patients (56±18 years, range 20–77 years, 59% male) have been enrolled to date, including 3 cases (18%) of intra-cardiac tumors (2 primary and 1 metastatic), who have undergone to 16±6 sessions of radiotherapy each, in 71% of cases with respiratory gating during delivery. Most patients (76%) were treated with carbon ions, the remaining with protons (mean total dose on the neoplastic target 51.8±10.7 Gy, from 2 to 4.2 Gy per fraction). Sixty-one percent of patients had ≥1 cardiovascular risk factor, 6% had a known heart disease (valvular cardiomyopathy despite aortic valve replacement with biological prosthesis and post-surgical pericarditis). The mean dose on the whole heart was 3.58±2.05 Gy, the maximum dose was 33.78±23.99 Gy, with a very variable dose distribution on cardiac substructures depending on the tumor site (table). At the end of the scheduled radiotherapy sessions (24±9 days), no significant changes were observed in cardiac function, cardiac rhythm, ventricular repolarization, biomarkers and autonomic indices. Conclusions Hadrontherapy with protons and carbon ions aimed at the treatment of para-cardiac or intra-cardiac tumors allowed to maintain a low heart Dm and showed no signs of acute cardiac toxicity. The collection of potential cardiac effects in the medium and long term is ongoing. Funding Acknowledgement Type of funding sources: None.

Impact of preeclampsia on ventricular repolarization indices

BackgroundBecause of cardiac hypertrophy and electrophysiological alterations associated with preeclampsia, worsening of preexisting arrhythmias or occurrence of de novo arrhythmias are common in patients with preeclampsia. Tp-e/QT and Tpe/QTc ratios are accepted as reliable indexes for predicting ventricular arrhythmias. In this study, we examined the impact of preeclampsia on ventricular repolarization indices in patients with preeclampsia by using the QT, QTc and Tp-e interval, Tp-e/QTratio, and Tp-e/QTc ratio. MethodsWe analyzed electrocardiographic recordings of sixty pregnant women with preeclampsia and thirty age-matched healthy pregnant women. Women presenting with preeclampsia were divided into 2 groups and classified as early (gestational age < 34 weeks at clinical onset) or late (≥34 weeks) onset preeclampsia. Ventricular repolarization indices were evaluated. ResultsThe QT and Tp-e intervals were found to be longer in patients with earlyonset preeclampsia compared to patients with late-onset preeclampsia and helthy pregnants (377.6 ± 23 ms vs 374.3 ± 15 ms, 362 ± 15 ms & 82.6 ± 9.4 ms vs 74.0 ± 10.6 ms, 68.6 ± 10 ms). In adition, Tp-e/QT and Tp-e/QTc ratio were significantly higher in this patient population compared to others (0.21 ± 0.02 vs 0.19 ± 0.02, 0.18 ± 0.02 & 0.19 ± 0.02 vs 0.16 ± 0.02, 0.15 ± 0,02, p < 0.05 respectively). ConclusionOur data showed that preeclampsia has unfavorable effects on electrocardiographic indices of ventricular repolarization compared to healthy pregnant women. This effect is more prominent in patients with early-onset preeclampsia.

His-bundle pacing versus cardiac resynchronisation therapy: Effect on ECG parameters of repolarization

IntroductionCardiac resynchronization therapy (CRT) by biventricular pacing (BiV) may worsen indices of ventricular repolarization. The impact of His bundle pacing (HBP) on repolarization is not well studied in patients with left ventricular systolic dysfunction. The aim of the study is to compare the repolarization parameters in ECG between these two pacing modalities. MethodsBaseline and post implant parameters of 20 patients who had undergone HBP were compared with 18 patients who underwent CRT (BiV) implantation. Repolarization parameters were monitored before implantation, within 24 hours and after 6 weeks of implantation. Patients were followed up till 6 months with clinical and echocardiographic parameters. ResultBaseline clinical, electrocardiographic and echocardiographic parameters were similar in both groups. Significant differences were noted in QTc, Tp-e and Tp-e/QTc between HBP and CRT groups both on immediate post implant and after 6 weeks of implantation. Compared to pre-implantation,significant shortening of Tp-e and Tp-e/QTc was observed immediately (90.54 ± 24.35 vs 69.62 ± 12.92, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.03, p < 0.05) and after 6 weeks (90.54 ± 24.35 vs 66.08 ± 14.95, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.02, p < 0.05) in HBP implant (group A). However, these changes were not present in CRT cohort (group B). During a follow up of 6 months, NYHA class and LV function between two groups remain comparable. ConclusionHBP is associated with significant reduction of Tp-e and Tp-e/QTc compared to CRT. Further evaluation is needed to determine whether this improvement in indices of repolarization is associated with reduction in clinical arrhythmic events or not.

Ventricular repolarization homogeneity in transthyretin cardiac amyloidosis

Abstract Funding Acknowledgements Type of funding sources: None. Background Non-sustained ventricular tachycardia is frequently observed in patients with transthyretin cardiac amyloidosis (TTR-CA); however, the incidence of sudden tachyarrhythmic death is low. Homogeneity of amyloid fibril deposition within the myocardium and conduction system may mitigate against sustained ventricular tachyarrhythmias. In contrast, myocardial scar heterogeneity is an established predictor of sudden cardiac death in conditions such as hypertrophic cardiomyopathy (HCM), as evidenced by increased myocardial dispersion of repolarization. Whether such indices of arrhythmogenesis are evident in TTR-CA has not been established. Purpose To compare ventricular repolarization indices in TTR-CA to HCM and controls without known cardiovascular disease. Methods We identified TTR-CA and HCM patients from our single center respective registries, and control patients from our clinical ECG database. Only patients in normal sinus rhythm without bundle branch block, cardiac pacing or artifact were included for analysis. Demographic and clinical data were abstracted. ECGs were analyzed at 25 mm/s paper speed and 10 mm/mV amplitude. ECG parameters included QT interval, QT dispersion, and T peak to T end (TpTe) using the tangent method. All measurements were performed by two blinded independent cardiologists. Results A total of 112 patients (45 TTR-CA, 32 HCM, and 35 controls) were studied. Despite a longer QTc in TTR-CA (468.4 ms in TTR-CA vs. 424.6 in controls; p &amp;lt; 0.001), patients with TTR-CA demonstrated similar repolarization indices as controls, including TpTE (93.0 ± 13.5 ms in TTR-CA vs 86.4 ± 12.2 ms in controls, p = 0.24), and TpTe/QTc (0.20 ± 0.03 in TTR-CA vs 0.2 ± 0.03 in controls, p = 0.99). In contrast, HCM patients demonstrated greater TpTe and TpTe/QTc compared with controls (Figure). and a trend toward increased QT dispersion in HCM vs. TTR-CA (p = 0.06). Conclusion Unlike HCM, patients with TTR-CA demonstrate a relative lack of myocardial repolarization heterogeneity compared with controls. This finding correlates with homogeneous distribution of myocardial amyloid fibrils and may explain the low observed incidence of sudden cardiac death in this population. Abstract Figure

Effects of SGLT2 Inhibitors as an Add-on Therapy to Metformin on Electrocardiographic Indices of Ventricular Repolarization.

Background According to EMPA-REG OUTCOME, trial use of empagliflozin in patients with a history of cardiovascular disease improves hospitalization for heart failure and decreases cardiovascular morbidity and mortality. Recent studies have shown that a prolonged T-peak to T-end interval on the resting electrocardiography is associated with an increased risk of cardiovascular mortality. Tp-e/corrected QT interval (QTc) ratio is a reliable index of prolonged ventricular repolarization. Objectives In this study, we examined the effects of sodium glucose co-transporters 2 (SGLT2) inhibitors as an add-on therapy to metformin on electrocardiographic indices of ventricular repolarization. Methods Electrocardiographic recordings before combination therapy along with three months and six months follow-up of 141 consecutive patients who were switched from monotherapy to combination therapy with two oral agents due to inadequate glycemic control were derived. QT interval (QT), QTc, Tp-e intervals and Tp-e/QT, Tp-e/QTc ratios were calculated and analyzed. Results After the six month follow-up, there was a significant decrease in the QT interval in patients who were using SGLT2 inhibitors as an add-on therapy to metformin compared to other glucose-lowering agents (373.4 ± 9.9 ms vs. 385.4 ± 12.5 ms, 382.9 ± 11.2 ms; p < 0.001 respectively). Furthermore, Tp-e/QT and Tp-e/QTc ratios were significantly lower in this patient population compared to control groups (0.186 ± 0.023 vs. 0.196 ± 0.021, 0.191 ± 0.017; p < 0.001 and 0.174 ± 0.021 vs. 0.199 ± 0.022, 0.195 ± 0.016; p < 0.001 respectively). Conclusions Our data showed that using SGLT2 inhibitors as an add-on therapy to metformin favorably alters ventricular repolarization indices in patients with type 2 diabetes mellitus.

Impact of cardiac rehabilitation on ventricular repolarization indices following coronary artery bypass grafting.

Background The aim of this study was to evaluate the effect of cardiac rehabilitation on electrocardiographic changes in patients undergoing isolated coronary artery bypass grafting. Methods Between January 2016 and July 2019, a total of 625 patients (485 males, 140 females; mean age: 59.6 years; range, 50.6 to 68.6 years) who underwent isolated coronary artery bypass grafting and survived were retrospectively analyzed. The patients were divided into two groups according to the participation in the cardiac rehabilitation program as follows: the Rehab(+) group (n=363) and the Rehab(-) group (n=262). Electrocardiographic parameters of both groups were compared. Results There was a significant decrease in the electrocardiographic findings of heart rate (p<0.001), QTc (p<0.001), Tpe duration (p<0.001), Tpe/QT ratio (p<0.001), and Tpe/QTc ratio (p<0.001) in the Rehab(+) group before and after surgery. There was a significant decrease in the Rehab(+) group, compared to the Rehab(-) group, in terms of parameters of QT interval (p=0.001), QTc (p=0.017), Tpe duration (p<0.001), Tpe/QT ratio (p<0.001), and Tpe/QTc ratio (p<0.001). Conclusion Cardiac rehabilitation program after coronary artery bypass grafting decreases ventricular repolarization indices of electrocardiography. Based on these changes, postoperative cardiac rehabilitation program may reduce the risk of ventricular arrhythmia and sudden cardiac death during follow-up.

Evaluation of electrocardiographic ventricular repolarization parameters in stable coronary artery disease

Aim: To examine the relationship between the SYNTAX score (SS) and cardiac repolarization parameters such as cQTd and Tp-e values, and Tp-e/QT, Tp-e/JT, Tp-e/QTc, and Tp-e/JTc ratios in patients who have stable angina pectoris. Methods: 12-lead resting electrocardiograms (ECGs) and SS of 160 patients (51 female and 109 male) undergoing coronary angiography with the pre-diagnosis of stable angina pectoris were evaluated. Patients with a SS below 22 were classified as Group 1 (low-SYNTAX), and those above 22 (high-SYNTAX) as Group 2. Forty-four patients with normal coronary angiography were included in Group 3. Results: Mean age of the patients was 62.4±9.1 years. The heart rate, QRS, QT, cQT and JT durations between the groups were similar. In addition, relatively recent ventricular repolarization indices such as Tp-e interval and Tp-e/QT, Tp-e/JT, Tp-e/QTc, and Tp-e/JTc ratios were also not substantially different between groups. Conclusion: Several surface ECG predictors of ventricular arrhythmias, including QTd, JT and Tp-e intervals and their ratios to QT and JT, are not significantly correlated with SYNTAX score-assessed CAD severity in patients with stable angina pectoris.

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.

T-wave peak-end interval and ratio of T-wave peak-end and QT intervals: novel arrhythmogenic and survival markers for dogs with myxomatous mitral valve disease

Introduction/objectivesIn the past few years, novel markers such as the interval between the peak and the end of T-wave (Tpte) and Tpte/QT ratio have been shown to have high sensitivity for ventricular arrhythmias and mortality. We analyzed these and other parameters of ventricular repolarization, such as QT interval, QT interval corrected for heart rate (QTc), and QT dispersion (QTd) in dogs with myxomatous mitral valve disease (MMVD). Additionally, we investigated their relationship with the progression of the disease, echocardiographic parameters, and ventricular arrhythmias and assessed their prognostic value with development of clinical signs or mortality as the final outcome. Animals, materials and methodsEpidemiological, clinical, echocardiographic, and electrocardiographic data were obtained from 236 dogs with MMVD and 15 healthy dogs. Prognostic and survival information was also recorded for the MMVD group. All ventricular repolarization indices were measured in 10 lead electrocardiographic recordings. ResultsWith the exception of the QT interval, most repolarization markers increased along with the frequency of arrhythmias and with the progression of MMVD. The parameters that best identified ventricular arrhythmias (AUC > 0.7) were Tpte (aVR, rV2, average rV2–V10, average rV2–V4) and Tpte/QT (II, aVR, rV2). In survival analysis, statistically significant markers with the highest differences in median survival were Tpte (maximum of any lead, maximum rV2–V10), QTc aVR, and Tpte rV2. ConclusionTpte and Tpte/QT are good non-invasive markers for clinical risk stratification in dogs with MMVD.