Relationship between QT interval and cardiovascular risk factors in healthy young subjects

QTc Interval of Healthcare Workers from India: Baseline and Effect of Hydroxychloroquine Prophylaxis during the COVID-19 Pandemic

Background

The aim of this study was to access the incidence of prolonged QTc interval and changes, if any, among Indian healthcare workers (HCWs) taking hydroxychloroquine (HCQ) prophylaxis while managing coronavirus disease 2019 (COVID-19) cases.

Methods

At the beginning of the COVID-19 pandemic, as per the Indian Council of Medical Research (ICMR) policy, HCWs were advised to take HCQ as prophylaxis after getting an electrocardiogram (ECG) while being posted to look after COVID-19 patients. A follow-up ECG was repeated for those who took HCQ. The normal upper limit for QTc interval of 460 milliseconds (ms) for females and 450 ms for males was considered.

Results

A baseline ECG was analyzed for 250 HCWs with a median age of 35 (30-43) years. The median QTc was 410 (395-421) ms with the prevalence of prolonged QTc of 1.8% in females and 0% in males. A follow-up ECG after HCQ intake for 43 HCWs was further analyzed. They had a median age of 35 (31-39) years and took an average dose of HCQ of 2372 ± 839 mg. Pre- and post-HCQ chemoprophylaxis QTc interval (ms) was as follows: 408 (386-419) and 405 (387-417), with P = 0.434, respectively.

Conclusion

Among Indian HCWs, the prevalence of prolonged QTc is 1.8% and 0% in females and males, respectively. HCQ intake as chemoprophylaxis for COVID-19 did not affect their QTc interval.

Prolongation of QTc interval at the beginning and during dialysis is associated with hypervolemia and calcium and magnesium change in the first 2 h

BACKGROUND AND AIMS

High rates of sudden cardiac death are mostly attributed to ventricular arrhythmias including QTc prolongation in hemodialysis patients. We aimed to investigate the correlation of electrolyte and volume changes with QTc interval prolongation in hemodialysis patients.

STUDY DESIGN

The present study is designed as a cross-sectional study.

METHODS

The study was conducted at the hemodialysis unit of a training and research hospital and its' satellite dialysis unit. Patients were divided into three groups. Group-1: with normal QTc interval both at the beginning and during dialysis session; group-2: with prolonged QTc interval at the beginning and remained prolonged during dialysis session; group-3: with normal QTc interval at the beginning but prolonged during the dialysis session. In addition, patients were evaluated in terms of QTc change between the beginning and 2nd hour (delta-QTc-1) and between 2nd hour and 4th hour (delta-QTc-2), respectively, and defined as 'patients with increased QTc interval' and 'patients without increased QTc interval'.

RESULTS

A total of 45 prevalent hemodialysis patients were enrolled in the study. 14 patients (31.1%) had normal QTc interval (group-1), 13 patients (28.9%) had prolonged QTc interval at the beginning and remained prolonged during dialysis session (group-2) and 18 patients (40%) had normal QTc interval at the beginning but prolonged during dialysis session (group-3). There was no statistically significant difference between groups in terms of baseline electrolyte levels. Calcium change in the first 2 h was lower in patients with QTc prolongation from the start or during the dialysis session (group-2 and group-3). In addition, systolic blood pressure (SBP) levels at the beginning of the session (118 ± 15 mmHg vs 124 ± 28 mmHg vs138 ± 24 mmHg; p = 0.04) and intradialytic ultrafiltration (UF) rate were higher (1.96 ± 0.6 L/4 h vs 2.6 ± 1.0 L/4 h vs 2.8 ± 0.9 L/4 h; p = 0.03) in group-2 and group-3 compared to patients in group-1. Increase in QTc interval was found higher in patients with less calcium increase (Rho: - 0.36; p = 0.01) and with greater magnesium decrease in the first 2 h (Rho: 0.31; p = 0.04).

CONCLUSION

QTc interval prolongation is common among hemodialysis patients. High intradialytic UF rates, change in serum magnesium and calcium levels in the first 2 h were found associated with QTc prolongation. However, QTc prolongation was found independently associated only with UF volume and calcium change in the first 2 h.

Corrected QT Interval Prolongation, Elevated Troponin, and Mortality in Hospitalized COVID-19 Patients

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has risen to the level of a global pandemic. Growing evidence has proven the cardiac involvement in SARS-CoV-2 infection. This study aims to evaluate the ability of cardiovascular complications determined by elevated troponin and electrocardiogram findings (e.g., corrected QT interval (QTc)) in predicting the severity of SARS-CoV-2 infection among hospitalized patients.

Methods

This is a retrospective review of medical records of 800 patients, admitted to Richmond University Medical Center in Staten Island, NY, and tested positive for SARS-CoV-2 between March 1, 2020 and July 31, 2020. A total of 339 patients met the study inclusion and exclusion criteria and were included in statistical analysis.

Results

Elevated serum troponin levels on admission statistically correlated with mortality in SARS-CoV-2 patients. Prolonged QTc was shown to have an independent statistically significant association with mortality among patients hospitalized with SARS-CoV-2.

Conclusions

Growing concern for cardiovascular sequelae of coronavirus disease 2019 (COVID-19) has prompted many researchers to investigate the role of cardiovascular complications in mortality due to SARS-CoV-2. Obtaining a simple electrocardiogram for hospitalized patients with COVID-19 could provide an independent prognostic tool and prompt more coordinated treatment strategies to prevent mortality among patients hospitalized with COVID-19.

Post-traumatic stress disorder and its association with stroke and stroke risk factors: A literature review

Stroke is a major cause of mortality and disability globally that has multiple risk factors. A risk factor that has recently gained more attention is post-traumatic stress disorder (PTSD). Literature searches were carried out for updated PTSD information and for the relationship between PTSD and stroke. The review was divided into two sections, one exploring PTSD as an independent risk factor for stroke, with a second concentrating on PTSD's influence on stroke risk factors. The study presents accumulating evidence that shows traumatic stress predicts stroke and is also linked to many major stroke risk factors. The review contributes knowledge to stroke aetiology and acts as a reference for understanding the relationship between PTSD and stroke. The information presented indicates that screening and identification of traumatic experience would be beneficial for directing stroke patients to appropriate psychological and lifestyle interventions. In doing so, the burden of stroke may be reduced worldwide.

In-Hospital Prognostic Value of Electrocardiographic Parameters Other Than ST-Segment Changes in Acute Myocardial Infarction: Literature Review and Future Perspectives

Electrocardiography (ECG) remains an irreplaceable tool in the management of the patients with myocardial infarction, with evaluation of the QRS and ST segment being the present major focus. Several ECG parameters have already been proposed to have prognostic value with regard to both in-hospital and long-term follow-up of patients. In this review, we discuss various ECG parameters other than ST segment changes, particularly with regard to their in-hospital prognostic importance. Our review not only evaluates the prognostic segments and parts of ECG, but also highlights the need for an integrative approach in big data to re-assess the parameters reported to predict in-hospital prognosis. The evolving importance of artificial intelligence in evaluation of ECG, particularly with regard to predicting prognosis, and the potential integration with other patient characteristics to predict prognosis, are discussed.

Early Screening of Hypertension and Cardiac Dysautonomia in Each Hypertensive is Needed-inference from a Study of QTc Interval in Gujarat, India

Background

Hypertension (HTN) is linked to cardiac dysautonomia that can end up as life-threatening arrhythmias. The same can be screened by simple electrocardiogram (ECG)-based QTc (QT corrected for heart rate) interval which indicates repolarization abnormality. We quantified QTc interval among treated hypertensives in comparison to controls, testing effect of age, gender, and blood pressure.

Methods

We conducted a cross-sectional study was done at a tertiary care teaching hospital of Gujarat, India, on 142 hypertensives on monotherapy (60 males, 82 females) and 72 age-, sex-, and time-matched normotensives. ECG was recorded with minimum 10 complexes of Lead II. QTc was derived from average of 10 values, using Bazett's formula. QTc > 0.43 s in male and > 0.45 s in female was considered abnormal.

Results

Hypertensives (mean age 40 and duration 5 years) had significantly higher QTc value than normotensives among males (0.42 vs. 0.40, P < 0.001), females (0.44 vs. 0.41, P < 0.001), and in total (0.43 vs. 0.41, P < 0.001) with 24% prevalence of ECG-based left ventricular hypertrophy. Hypertensives had odds ratio 1.63 in males (P = 0.15), 23.71 in females (P = 0.003), and 3.83 in total (P < 0.001) for prolonged QTc. QTc values were significantly affected by increasing age amongst hypertensives but not by duration of HTN or current blood pressure.

Conclusions

Our study showed a high prevalence of prolonged QTc, both qualitatively and quantitatively, in hypertensives on monotherapy with poor pressure control, associated with female gender and age but not duration or blood pressure. This underscores high risk of repolarization abnormality induced future event, suggesting QTc screening as primary prevention.

Addictive drugs, arrhythmias, and cardiac inward rectifiers

In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.

Correlation of Adiposity Indices with Electrocardiographic Ventricular Variables and Vascular Stiffness in Young Adults

INTRODUCTION

Excess adiposity constitute an important public health problem because of the associated increased risk of hypertension, coronary heart disease, type 2 diabetes and other disorders. Not only the contribution of general measures of adiposity but also central measures of adiposity have been observed.

AIM

To compare and correlate the central and general adiposity indices with ventricular electrocardiographic variables and vascular stiffness indices in normal, overweight and obese young adults.

MATERIALS AND METHODS

This was a cross-sectional study. Nearly ninety subjects were enrolled and were divided into 30 normal weight, 30 overweight and 30 obese group based on the BMI classification of WHO for Asian population with their age ranging from 18-25 years. Waist and hip circumferences were measured using stretchable tape. Two novel indices-conicity index and abdominal volume index were calculated using standard formula. ECG and pulse wave were recorded using the Physiopac - Medicaid systems. Statistical analysis was done using SPSS version 19.0 software. ANOVA test was done to compare the variables among three groups. Pearson's correlation coefficients were applied to establish the correlations between variables.

RESULTS

In our study Body Mass Index (BMI) and Conicity Index (CI) was significantly and strongly correlated with the ventricular electrocardiographic variables especially with QRS duration, QTc interval and with vascular stiffness indices. These indices can be used to assess the electrocardiographic abnormalities and vascular stiffness status.

CONCLUSION

Excess adipose tissue in young adults was closely linked to ventricular depolarization and repolarization abnormalities and also to increased vascular stiffness. Adiposity indices in particular (BMI, CI) provide a simple and non invasive approach to assess these abnormalities at the earliest in order to prevent future complications.

The association of prolonged QT interval on electrocardiography and chronic lead exposure

OBJECTIVES

The aim of this study was to examine the association of lead exposure with cardiac conduction disturbance among lead-exposed and nonexposed workers in Taiwan.

METHODS

The participants comprised 312 lead workers and 329 referents who had no known occupational lead exposure. During their annual health examination, they were invited to take part in the survey. Standard resting 12-lead electrocardiograms were obtained and the electrocardiographic features studied were related to blood lead levels (BLLs).

RESULTS

The mean BLLs were 26.05 (SD = 13.98) and 2.62 (SD = 1.42) μg/dL in lead-exposed and reference groups, respectively. Compared with the referents, lead workers had significantly shorter PR interval and longer QTc interval. Especially, workers with BLL > 30 μg/dL had the highest risk after adjusting for age, sex, body mass index, and other potential confounders.

CONCLUSION

The data suggest that lead exposure is positively associated with prolonged QTc interval.

Association between obesity and ECG variables in children and adolescents: A cross-sectional study

Obesity exhibits a wide variety of electrocardiogram (ECG) abnormalities in adults, which often lead to cardiovascular events. However, there is currently no evidence of an association between obesity and ECG variables in children and adolescents. The present study aimed to explore the associations between obesity and ECG intervals and axes in children and adolescents. A cross-sectional observational study of 5,556 students aged 5–18 years was performed. Anthropometric data, blood pressure and standard 12-lead ECGs were collected for each participant. ECG variables were measured manually based on the temporal alignment of simultaneous 12 leads using a CV200 ECG Work Station. Overweight and obese groups demonstrated significantly longer PR intervals, wider QRS durations and leftward shifts of frontal P-wave, QRS and T-wave axes, while the obese group also demonstrated significantly higher heart rates, compared with normal weight groups within normotensive or hypertensive subjects (P<0.05). Abdominal obesity was also associated with longer PR intervals, wider QRS duration and a leftward shift of frontal ECG axes compared with normal waist circumference (WC) within normotensive or hypertensive subjects (P<0.05). Gender was a possible factor affecting the ECG variables. Furthermore, the ECG variables, including PR interval, QRS duration and frontal P-wave, QRS and T-wave axes, were significantly linearly correlated with body mass index, WC and waist-to-height ratio adjusted for age, gender, ethnicity and blood pressure. However, there was no significant association between obesity and the corrected QT interval (P>0.05). The results of the current study indicate that in children and adolescents, general and abdominal obesity is associated with longer PR intervals, wider QRS duration and a leftward shift of frontal P-wave, QRS and T-wave axes, independent of age, gender, ethnicity and blood pressure.

QTc interval in a sample of long-term schizophrenia inpatients

This naturalistic study attempted to determine the prevalence of prolonged QTc interval in a relatively large population of inpatients hospitalized with chronic schizophrenia, and to explore QTc relationship with demographic variables, metabolic parameters and prescribed treatments. All inpatients from a Spanish long-term psychiatric hospital were cross-sectionally investigated to determine the prevalence of QTc prolongation and metabolic syndrome. The sample with a DSM-IV diagnosis of schizophrenia included 171 Caucasian inpatients, all of Spanish origin. A prolonged QTc interval was defined as >450 ms in men and >470 ms in women. The relationships between QTc and other continuous variables were assessed using a linear regression model with QTc as the dependent variable. Only 10 patients (6%) had a prolonged QTc interval; one case was possibly explained by hypokalemia. Three patients (2%) had a QTc > 500 ms. Gender, old age (> or = 50 years old), current smoking, systolic blood pressure, HDL cholesterol and history of arrhythmia were found to have significant effects on QTc interval in a linear regression analysis. After controlling for significant variables, the mean QTc interval was not significantly influenced by antipsychotic dose, type of antipsychotic treatment, the use of depot antipsychotics, or the number of different antipsychotics prescribed. Our study focused on long-term schizophrenia inpatients with frequent antipsychotic polypharmacy and high antipsychotic doses, and suggested that after excluding the case with hypokalemia length of QTc was associated with history of arrhythmias and with metabolic factors, while the effects of antipsychotic compound or class were not so evident.

Prognostic value of QTc interval dispersion changes during exercise testing in hypertensive men

INTRODUCTION The prognostic significance of QTc dispersion changes during exercise testing (ET) in patients with left ventricular hypertrophy is not clear. OBJECTIVE The aim was to study the dynamics of QTc interval dispersion (QTcd) in patients (pts) with left ventricular hypertrophy (LVH) during the exercise testing and its prognostic significance. METHOD In the study we included 55 men (aged 53 years) with hypertensive left ventricular hypertrophy and a negative ET (LVH group), 20 men (aged 58 years) with a positive ET and 20 healthy men (aged 55 years). There was no statistically significant difference in the left ventricular mass index (LVMI) between LVH group and ILVH group (160.9?14.9 g/m2 and 152.8?22.7 g/m2). The first ECG was done before the ET and the second one was done during the first minute of recovery, with calculation of QTc dispersion. The patients were followed during five years for new cardiovascular events. RESULTS During the ET, the QTcd significantly increased in LVH group (56.8?18.0 - 76.7?22.6 ms; p<0.001). A statistically significant correlation was found between the amount of ST segment depression at the end of ET and QTc dispersion at the beginning and at the end of ET (r=0.673 and r=0.698; p<0.01). The QTc dispersion was increased in 35 (63.6%) patients and decreased in 20 (36.4%) patients during the ET. Three patients (5.4%) in the first group had adverse cardiovascular events during the five-year follow-up. A multiple stepwise regression model was formed by including age, LVMI, QTc interval, QTc dispersion and change of QTc dispersion during the ET. There was no prognostic significance of QTc interval and QTc dispersion during five-year follow-up in regard to adverse cardiovascular events, but prognostic value was found for LVMI (coefficient ?=0.480; p<0.001). CONCLUSION The increase of QTc interval dispersion is common in men with positive ET for myocardial ischemia and there is a correlation between QTc dispersion and amount of ST segment depression. The increase of QTc interval dispersion during negative ET in patients with left ventricular hypertrophy has no significant predictive value for adverse cardiovascular events, as shown in our five-year follow-up study, but it requires confirmation by investigation of larger groups of patients.

Potential of metabolic agents as adjunct therapies in heart failure

Heart failure continues to have a significant morbidity and mortality rate despite several recent advances in treatment such as additional neurohumoral blockades and cardiac resynchronisation therapy. There is emerging evidence that, irrespective of etiology, heart failure is associated with an energetic disorder and that this may contribute to the pathogenesis of the syndrome. Recently, a number of studies have suggested that some metabolic agents may have potential as adjunctive therapy in patients with heart failure. These agents cause a shift of myocardial-substrate utilization away from free fatty acids toward glucose. Free fatty acid utilization consumes more oxygen to generate an equivalent amount of energy compared with glucose. Some of these agents are also effective antianginals, presumably by reducing the myocardial oxygen requirement. In this review we will discuss some of the current issues and progresses relating to metabolic manipulation in heart failure.

Modification of myocardial substrate use as a therapy for heart failure

Despite advances in treatment, chronic heart failure is still associated with significant morbidity and a poor prognosis. The scope for further advances based on additional neurohumoral blockade is small. Effective adjunctive therapies acting via a different cellular mechanism would, therefore, be attractive. Energetic impairment seems to contribute to the pathogenesis of heart failure. The findings from several studies have shown that the so-called metabolic agents could have potential as adjunctive therapies in heart failure. These agents cause a shift in the substrate used by the heart away from free fatty acids, the oxidation of which normally provides around 70% of the energy needed, towards glucose. The oxygen cost of energy generation is lessened when glucose is used as the substrate. In this review we aim to draw attention to the metabolic alteration in heart failure and we present evidence supporting the use of metabolic therapy in heart failure.