The effect of type 2 diabetes on electrocardiographic markers of significant cardiac events

Tpeak-Tend ECG Marker in Obesity and Cardiovascular Diseases: A Comprehensive Review

Globally, cardiovascular diseases are still the leading cause of death. Numerous methods are used to diagnose cardiovascular pathologies; there is still a place for straightforward and noninvasive techniques, such as electrocardiogram (ECG). Depolarization and repolarization parameters, including QT interval and its derivatives, are well studied. However, the Tpeak-Tend interval is a novel and promising ECG marker with growing evidence for its potential role in predicting malignant arrhythmias. In this review, we discuss the association between the Tpeak-Tend interval and several cardiovascular diseases, including long QT syndrome, cardiomyopathies, heart failure, myocardial infarction, and obesity, which constitutes one of the risk factors for cardiovascular diseases.

Cardiometabolic risk factors and electrocardiogram results in type 2 diabetes patients with or without non-infected foot ulcers: A comparative study

BACKGROUND: Numerous investigations have demonstrated that type-2 diabetes (T2D) causes electrocardiographic alterations, whether or not there are microvascular or macrovascular problems.

AIM: With respect to glycemic control and the accompanying cardio-metabolic risk factors, the goal of this study was to demonstrate the variations in electrocardiogram records between T2D patients with non-infected diabetic foot ulcers (DFUs) and those without ulcers.

METHODS: This study was performed in the Shar Teaching Hospital in the Sulaimani Governorate-Iraq from July 2018 to June 2019. 167 participants were grouped into Group I (T2D, n=72); Group II (T2D with non-infected diabetic foot ulcers, n=65) and Group III (healthy subjects, n= 30). Blood pressure, electrocardiography, and anthropometric measurements were taken. Fasting serum glucose and lipid profiles were assessed as part of laboratory tests.

RESULTS: Group II patients significantly differed from Group I by having lower diastolic blood pressure, a higher pulse pressure index, and a higher fasting serum glucose. The Group I patients had a significantly higher heart rate, a shortening of TQ-interval and widening of QRS dispersion. Group II patients had a significantly shorter TQ-interval compared with the corresponding value of Group I patients (523.6±136.4ms versus 579.2±110.0ms, respectively). These changes in the electrocardiograms are not related to the cardiometabolic risk factors.

CONCLUSION: In the non-infected diabetic foot, the TQ-interval, a measure of ventricular repolarization impairment, is much shorter and is linked to a broad pulse pressure. According to this finding, the electrocardiographic abnormalities are a result of cardiovascular autonomic dysfunction.

Tpeak-Tend Interval during Pregnancy and Postpartum

BACKGROUND

Pregnancy is a condition in which new cardiac arrhythmias can occur or prior undiagnosed arrhythmias may provide symptoms. The occurrence of severe ventricular arrhythmias and polymorphic ventricular tachycardia that may lead to fainting or sudden cardiac death is promoted by the prolongation of the QTc interval. The post-partum adaptation period is the most arrhythmogenic. TpTe (Tpeak-Tend interval) is a novel marker of arrhythmogenesis by many considered a more sensitive marker than QTc.

OBJECTIVE

The aim of our work was to determine the TpTe interval (Tpeak-Tend) in women in the first, second and third trimester of pregnancy and the post-partum period.

MATERIALS AND METHODS

The study group consisted of 128 women in pregnancy or postpartum and a control group of 32 non-pregnant women. A standard 12-lead ECG (electrocardiograph) recording with evaluation of the duration of TpTe and QTc was performed in all patients.

RESULTS

In comparison to the non-pregnant women, higher values of QTc and TpTe were observed starting in the first trimester with highest values observed in the postpartum period. Mean duration of TpTe interval during pregnancy (81.59 ± 5.92 ms) and in the whole study group (pregnancy + postpartum) (85.46 ± 6.45 ms) was significantly longer (p < 0.001) compared to the TpTe interval in the control group (74.06 ± 6.14 ms). During pregnancy and postpartum, the increase in the TpTe interval in comparison to the increase in the QTc parameter (31.10% vs. 4.18%) was significantly higher (p < 0.001).

CONCLUSIONS

The study showed an increase in the duration of the TpTe interval and QTc parameter during pregnancy and postpartum with the highest values in the postpartum period. TpTe interval increase was significantly higher compared to QTc increase during pregnancy and postpartum. Changes of TpTe interval were not associated with any clinical outcome or measure of arrythmia burden. Further studies are needed in order to see the clinical significance of these ECG findings, in particular for larger groups of patients with automatic measurement in correlation with echocardiography.

Ventricular repolarization heterogeneity in patients with COVID-19: Original data, systematic review, and meta-analysis

BACKGROUND

Coronavirus disease-2019 (COVID-19) has been associated with an increased risk of acute cardiac events. However, the effect of COVID-19 on repolarization heterogeneity is not yet established. In this study, we evaluated electrocardiogram (ECG) markers of repolarization heterogeneity in patients hospitalized with COVID-19. In addition, we performed a systematic review and meta-analysis of the published studies.

METHODS

QT dispersion (QTd), the interval between T wave peak to T wave end (TpTe), TpTe/QT (with and without correction), QRS width, and the index of cardio-electrophysiological balance (iCEB) were calculated in 101 hospitalized COVID-19 patients and it was compared with 101 non-COVID-19 matched controls. A systematic review was performed in four databases and meta-analysis was conducted using Stata software.

RESULTS

Tp-Te, TpTe/QT, QRS width, and iCEB were significantly increased in COVID-19 patients compared with controls (TpTe = 82.89 vs. 75.33 ms (ms), p-value = .005; TpTe/QT = 0.217 vs. 0.203 ms, p-value = .026). After a meta-analysis of 679 COVID-19 cases and 526 controls from 9 studies, TpTe interval, TpTe/QT, and TpTe/QTc ratios were significantly increased in COVID-19 patients. Meta-regression analysis moderated by age, gender, diabetes mellitus, hypertension, and smoking reduced the heterogeneity. QTd showed no significant correlation with COVID-19.

CONCLUSION

COVID-19 adversely influences the ECG markers of transmural heterogeneity of repolarization. Studies evaluating the predictive value of these ECG markers are warranted to determine their clinical utility.

The relationship between QT interval indices with cardiac autonomic neuropathy in diabetic patients: a case control study

BACKGROUND

Long QT interval (QT) and abnormal QT dispersion (QTd) are associated with sudden death. The relationship between cardiac autonomic neuropathy (CAN) and QT indices in type 2 diabetic patients were investigated.

METHODS

Totally 130 diabetic subjects (mean age 50.87 ± 13.9 years) were included (70 individuals with and 60 individuals without CAN). All participants had sinus cardiac rhythm. The patients who had diseases or take drugs that cause orthostatic hypotension (OH), cardiac arrhythmia and QT prolongation were excluded. After interview and examination, standard and continuous ECG was taken in supine position with deep breathing and standing up position. CAN diagnosis was based on Ewing's tests. QT, QT corrected (QTc), minimum QT (QT min), maximum QT (QT max) and mean ± SD of QT (QT mean) and QTd were assessed from standard ECG. QTc was calculated by Bazett's formula from V2 lead. QTc > 440 ms in men and QTc > 460 ms in women and QTd > 80 ms were considered abnormal.

RESULTS

In patients with CAN, 21.5% were symptomatic. The prevalence of abnormal QTc and QTd was 11.3% and 28.7%, respectively. There was no significant difference between the patients with or without CAN in terms of long QTc and abnormal QTd. However, the mean ± SD of QT max, QT mean and QTd was higher in the patients with CAN (P value < 0.03). The used cut points for QTc and QTd have high specificity (79% for both) and low sensitivity (30% and 37%, respectively). To use QTc and QTd as screening test for CAN in T2DM patients, the cutoff points 380 and 550 ms are suggested, respectively.

CONCLUSION

The prevalence of asymptomatic CAN was 3.7 times that of symptomatic CAN. In patients with CAN the QT max, QT mean and QTd were higher than those without CAN. There was no association between CAN and long QTc and abnormal QTd.

Correlation Between QTc Prolongation and Obstructive Sleep Apnea in Patients with Type 2 Diabetes Mellitus

BACKGROUND Obstructive sleep apnea (OSA) plays an important role in the progression of cardiovascular disease (CVD), and is a common symptom in patients with type 2 diabetes mellitus (T2DM). Prolongation of corrected QT interval (QTc) reflects ventricular arrhythmias and CVD. The aim of this study was to explore the relationship between OSA and QTc in T2DM patients and to evaluate the potential application of QTc in clinical practice. MATERIAL AND METHODS A total of 358 T2DM patients were involved in this study. OSA was diagnosed with apnea-hypopnea index ≥5 by full-night polysomnography and QTc was measured by a 12-lead electrocardiogram (ECG). Patients were grouped into 2 groups based on median QTc, and clinical data were studied. Logistic regression analysis was used to investigate the association between OSA and QTc with adjusted age, sex, body mass index (BMI), hypertension, total bilirubin (TBL), and smoking history. RESULTS Among 358 T2DM patients, 59.2% had OSA. Compared to those in the QTc <418 ms group, older patients, females, patients with higher BMI, and OSA patients in the QTc ≥418 ms group were more likely to have OSA (p<0.05). Correlation analysis suggested that OSA was associated with longer QTc (OR: 2.355, 95% CI: 1.529-3.626, p<0.001). For T2DM patients with QTc ≥418 ms, older patients (OR: 1.042, 95% CI: 1.042-1.064, p<0.001), females (OR: 2.36, 95% CI: 1.371-4.063, p<0.01), and patients with higher BMI (OR: 1.113, 95% CI: 1.037-1.195, p<0.01) were significantly more likely to have OSA. CONCLUSIONS In this cross-sectional study, we found that the presence and severity of OSA was associated with QTc prolongation in 358 patients with T2DM, and age, female sex, and BMI appear to be independent risk factors for OSA and CVD.

The Association of Metabolic Syndrome and Its Components with Electrocardiogram Parameters and Abnormalities Among an Iranian Rural Population: The Fasa PERSIAN Cohort Study

BACKGROUND

Metabolic syndrome (MetS) as a set of cardiac risk factors and its growing prevalence is one of the major concerns in different societies. In this study, we aimed to investigate the relationship between Mets and electrocardiogram (ECG) parameters and abnormalities as indicators for subclinical cardiovascular diseases (CVD).

METHODS

In this sub-analysis study, we used the data from Fasa PERSIAN Cohort Study which includes subjects age 35-70 years. Subjects with available ECG data included in the study (n=7002) and subjects with missing data on MetS components and non-sinus rhythm ECG were excluded (n=44). The MetS definition based on the Adult Treatment Panel (ATP) III guidelines and also a 12-lead ECG was obtained from all participants.

RESULTS

Our study population (n=6958) showed a mean age of 48.60±9.34 years and also 1656 (24.2%) subjects had MetS. Except for P duration, PR interval and S amplitude in men and P amplitude, S amplitude, Sokolow-Lyon Index, and QT interval in women, other ECG parameters differ significantly between subjects with and without Mets (P<0.05). Also among ECG abnormalities, prolonged P duration (≥120ms), QRS duration (≥100ms), and QTc interval (>450ms in male, >470ms in female) had a significant association with MetS in the total population. Waist circumferences (WC) showed the most count of significant relationship with ECG parameters in both genders. In males, WC more than ATP cut-points had significant associations with prolonged P and QRS duration, and also blood pressure (BP) had significant associations with prolonged P and QRS durations and QTc interval. In females, the MetS component except triglyceride had at least a significant relationship with prolonged P and/or QRS duration.

CONCLUSION

MetS and its component especially WC and BP were associated with ECG parameters and abnormalities. These associations with ECG as a marker of subclinical CVD showed the importance of MetS and each component in our population to monitor in the further longitudinal studies.

Association between ventricular repolarization variables and cardiac diastolic function: A cross-sectional study of a healthy Chinese population

BACKGROUND

Diastolic electromechanical couple, a well-described phenomenon in symptomatic heart failure, has not been well studied in healthy people. We hypothesized that ventricular repolarization variables, such as the QT interval, Tpeak-to-Tend (Tpe) interval and Tpe/QT ratio, are associated with cardiac diastolic function in the healthy Chinese population.

AIM

To assess the relationship between ventricular repolarization variables and cardiac diastolic function in apparently healthy Chinese individuals.

METHODS

This was a community-based cross-sectional study conducted in Shenyang, China. A total of 414 healthy subjects aged 35-91 years were enrolled. All subjects underwent standard 12-lead electrocardiography (ECG) and comprehensive echocardiography. ECG enabled the measurement of QT and Tpe intervals and Tpe/QT ratio. echocardiographic parameters, such as the ratio of mitral early diastolic inflow velocity (E) and late diastolic inflow velocity (A), E-wave deceleration time, left atrial volume (LAV) and LAV index, were measured to assess diastolic function. E/A < 0.75 was considered to indicate reduced diastolic function. ECG and echocardiography results were analyzed separately and in a blinded fashion. Correlation and regression analyses were applied to determine associations.

RESULTS

Ventricular repolarization variables, such as the QTc interval (393.59 ± 26.74 vs 403.86 ± 33.56; P < 0.001), Tpe interval (72.68 ± 12.41 vs 77.26 ± 17.86; P < 0.01), Tpe_c interval (76.36 ± 13.53 vs 83.32 ± 21.25; P < 0.001) and Tpe/QT ratio (0.19 ± 0.03 vs 0.20 ± 0.04; P < 0.01), were significantly different between the normal diastolic function group and the reduced diastolic function group. Significant associations were found between repolarization variables and diastolic function. After adjusting for all other possible confounders, the QTc and Tpe_c intervals were significantly associated with the E/A ratio (P = 0.008; P = 0.010). In men, the QTc interval was associated with abnormal diastolic function, and compared to the third QTc tertile, in the second QTc tertile, the odds ratio was 0.257 (95%CI: 0.102–0.649; P = 0.004).

CONCLUSION

Repolarization variables are associated with cardiac diastolic function even in healthy people. Moderate levels of the QTc interval exert a protective effect on diastolic dysfunction in men.