Race and Sex Differences in QRS Interval and Associated Outcome Among Patients with Left Ventricular Systolic Dysfunction

Identification of novel genes associated with atherosclerosis in Bama miniature pig

BACKGROUND

Atherosclerosis is a chronic cardiovascular disease of great concern. However, it is difficult to establish a direct connection between conventional small animal models and clinical practice. The pig's genome, physiology, and anatomy reflect human biology better than other laboratory animals, which is crucial for studying the pathogenesis of atherosclerosis.

METHODS

We used whole-genome sequencing data from nine Bama minipigs to perform a genome-wide linkage analysis, and further used bioinformatic tools to filter and identify underlying candidate genes. Candidate gene function prediction was performed using the online prediction tool STRING 12.0. Immunohistochemistry and immunofluorescence were used to detect the expression of proteins encoded by candidate genes.

RESULTS

We mapped differential single nucleotide polymorphisms (SNPs) to genes and obtained a total of 102 differential genes, then we used GO and KEGG pathway enrichment analysis to identify four candidate genes, including SLA-1, SLA-2, SLA-3, and TAP2. nsSNPs cause changes in the primary and tertiary structures of SLA-I and TAP2 proteins, the primary structures of these two proteins have undergone amino acid changes, and the tertiary structures also show slight changes. In addition, immunohistochemistry and immunofluorescence results showed that the expression changes of TAP2 protein in coronary arteries showed a trend of increasing from the middle layer to the inner layer.

CONCLUSIONS

We have identified SLA-I and TAP2 as potential susceptibility genes of atherosclerosis, highlighting the importance of antigen processing and immune response in atherogenesis.

The Association of QRS Duration with Risk of Adverse Outcomes in Sex- and Race- Based Subgroups: The Dallas Heart Study

Introduction

We explored sex and race differences in the prognostic implications of QRS prolongation among healthy adults.

Methods

Participants from the Dallas Heart Study (DHS) free of cardiovascular (CV) disease who underwent ECG testing and cMRI evaluation were included. Multivariable linear regression was used to examine the cross-sectional association of QRS duration with left ventricular (LV) mass, LV ejection fraction (LVEF), and LV end diastolic volume (LVEDV). Association of QRS duration with risk of MACE was evaluated using Cox models. Interaction testing was performed between QRS duration and sex/race respectively for each outcome of interest. QRS duration was log transformed.

Results

The study included 2,785 participants. Longer QRS duration was associated with higher LV mass, lower LVEF, and higher LVEDV, independent of CV risk factors ([β: 0.21, P<0.001], [β: - 0.13, P<0.001], [β: 0.22, P<0.001] respectively). Men with longer QRS duration were more likely to have higher LV mass and higher LVEDV compared to women (P-int=0.012, P-int=0.01, respectively). Black participants with longer QRS duration were more likely to have higher LV mass as compared to White participants (P-int<0.001). In Cox analysis, QRS prolongation was associated with higher risk of MACE in women (HR = 6.66 [95% CI: 2.32, 19.1]) but not men. This association was attenuated after adjustment for CV risk factors, with a trend toward significance (HR = 2.45 [95% CI: 0.94, 6.39]). Longer QRS duration was not associated with risk of MACE in Black or White participants in the adjusted models. No interaction between sex/race and QRS duration for risk of MACE was observed.

Discussion

In healthy adults, QRS duration is differentially associated with abnormalities in LV structure and function. These findings inform the use of QRS duration in identifying subgroups at risk for CV disease, and caution against using QRS duration cut offs uniformly for clinical decision making.

What is known?

QRS prolongation in healthy adults is associated with higher risk of death, cardiovascular disease, and left ventricular hypertrophy.

What the study adds?

QRS prolongation may reflect a higher degree of underlying LV hypertrophy in Blacks compared to Whites. Longer QRS interval may reflect higher risk of adverse cardiac events, driven by prevalent cardiovascular risk factors.

Graphic Abstract

Risk of underlying left ventricular hypertrophy in demographic groups based on QRS prolongation.

Pre-diagnostic predictors of mortality in patients with heart failure: The multi-ethnic study of atherosclerosis

Background

There are multiple predictive factors for cardiovascular (CV) mortality measured at, or after heart failure (HF) diagnosis. However, the predictive role of long-term exposure to these predictors prior to HF diagnosis is unknown.

Objectives

We aim to identify predictive factors of CV mortality in participants with HF, using cumulative exposure to risk factors before HF development.

Methods

Participants of Multi-Ethnic Study of Atherosclerosis (MESA) with incident HF were included. We used stepwise Akaike Information Criterion to select CV mortality predictors among clinical, biochemical, and imaging markers collected prior to HF. Using the AUC of B-spline-corrected curves, we estimated cumulative exposure to predictive factors from baseline to the last exam before HF. The prognostic performance for CV mortality after HF was evaluated using competing risk regression with non-CV mortality as the competing risk.

Results

Overall, 375 participants had new HF events (42.9% female, mean age: 74). Over an average follow-up of 4.7 years, there was no difference in the hazard of CV death for HF with reduced versus preserved ejection fraction (HR = 1.27, p = 0.23). The selected predictors of CV mortality in models with the least prediction error were age, cardiac arrest, myocardial infarction, and diabetes, QRS duration, HDL, cumulative exposure to total cholesterol and glucose, NT-proBNP, left ventricular mass, and statin use. The AUC of the models were 0.72 when including the latest exposure to predictive factors and 0.79 when including cumulative prior exposure to predictive factors (p = 0.20).

Conclusion

In HF patients, besides age and diagnosed diabetes or CVD, prior lipid profile, NT-proBNP, LV mass, and QRS duration available at the diagnosis time strongly predict CV mortality. Implementing cumulative exposure to cholesterol and glucose, instead of latest measures, improves predictive accuracy for HF mortality, though not reaching statistical significance.

Women are underrepresented in cardiac resynchronization therapy trials

INTRODUCTION

Current guidelines for cardiac resynchronization therapy (CRT) device implant are the same across both sexes however women have been traditionally underrepresented in randomized controlled trials (RCTs). We aimed to identify if the number of women included in CRT trials is representative of the real-world burden of heart failure (HF) in women.

METHODS

RCTs evaluating the benefit of CRT in HF patients referenced in the 2012 EHRA/HRS expert consensus statement on CRT in HF were included. Studies were evaluated for gender representation, baseline variables, and gender-based analysis of outcomes.

RESULTS

A total of 10 CRT trials including 8107 patients were studied. Of the total patient population in these RCTs, only 23% were women. Analysis of outcomes based on sex was reported only in 5 out of 10 trials. Of these five trials reporting sex-based outcomes, multicenter automatic defibrillator implantation trial with cardiac resynchronization therapy (MADIT-CRT) and resynchronization-defibrillation for ambulatory heart failure trial (RAFT) showed a greater benefit in women compared to men. Both MADIT and RAFT trials had a lower ejection fraction (EF) cut-off in the inclusion criteria (EF ≤ 30%) compared to the studies that did not find gender-based differences in the outcome (inclusion criteria: EF ≤ 35% or 40%). Additionally, women had less ischemic cardiomyopathy and more left bundle branch block (LBBB) compared to men in these two trials.

CONCLUSION

Women are underrepresented in CRT trials; however, they have been shown to derive a greater benefit from CRT compared to men. Appropriate measures should be taken in future studies to enhance the participation of women in clinical trials for more generalizable evidence.

Electrocardiographic QRS duration is influenced by body mass index and sex

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In a large group of subjects without overt conduction system disease, there was a positive association between increasing BMI and electrocardiographic QRS duration that was independent of other covariates such as sex and age.

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Females had narrower QRS complex than the males at similar age and in the similar BMI category.

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Findings of this research should prompt further studies to explore the underlying mechanisms for these observations and potential reversibility of the conduction abnormality with weight loss

Background

Electrocardiogram (ECG) measured QRS duration has been shown to influence cardiovascular outcomes. However, there is paucity of data on whether ECG QRS duration is influenced by obesity and sex in large populations.

Methods

All ECGs performed by a pathology provider over a 2-year period were included. ECGs with confounding factors and those not in sinus rhythm were excluded from the primary analysis.

Results

Of the 76,220 who met the inclusion criteria, 41,685 (55%) were females. The median age of the study cohort was 61 years (interquartile [IQR] range 48–71 years). The median QRS duration was 86 ms (IQR 80–94 ms). The median BMI was 27.6 kg/m² (IQR 24.2–31.8 kg/m²). When stratified according to the World Health Organization classification of BMI < 18.50 kg/m², 18.50–24.99 kg/m², 25.00–29.99 kg/m², and ≥ 30.00 kg/m², the median QRS durations were 82 ms (IQR 76–88 ms), 86 ms (IQR 80–92 ms), 88 ms (IQR 80–94 ms) and 88 ms (IQR 82–94 ms), respectively (p < 0.001 for linear trend). Median QRS duration for females was 84 ms (IQR 78–88 ms); for males, it was 92 ms (IQR 86–98 ms), p < 0.001. Compared to males, females had narrower QRS complexes at similar age and similar BMI. In multiple linear regression analysis, BMI correlated positively with QRS duration (standardized beta 0.095, p < 0.001) independent of age, sex, and heart rate.

Conclusions

In this large cohort there was a positive association between increasing BMI and QRS duration. Females had narrower QRS duration than males at similar age and similar BMI.

Electroanatomic Ratios and Mortality in Patients With Heart Failure: Insights from the ASIAN-HF Registry

Background

QRS duration (QRSd) is a marker of electrical remodeling in heart failure. Anthropometrics and left ventricular size may influence QRSd and, in turn, may influence the association between QRSd and heart failure outcomes.

Methods and Results

Using the prospective, multicenter, multinational ASIAN‐HF (Asian Sudden Cardiac Death in Heart Failure) registry, this study evaluated whether electroanatomic ratios (QRSd indexed for height or left ventricular end‐diastole volume) are associated with 1‐year mortality in individuals with heart failure with reduced ejection fraction. The study included 4899 individuals (aged 60±19 years, 78% male, mean left ventricular ejection fraction: 27.3±7.1%). In the overall cohort, QRSd was not associated with all‐cause mortality (hazard ratio [HR], 1.003; 95% CI, 0.999–1.006, P=0.142) or sudden cardiac death (HR, 1.006; 95% CI, 1.000–1.013, P=0.059). QRS/height was associated with all‐cause mortality (HR, 1.165; 95% CI, 1.046–1.296, P=0.005 with interaction by sex p_interaction=0.020) and sudden cardiac death (HR, 1.270; 95% CI, 1.021–1.580, P=0.032). QRS/left ventricular end‐diastole volume was associated with all‐cause mortality (HR, 1.22; 95% CI, 1.05–1.43, P=0.011) and sudden cardiac death (HR, 1.461; 95% CI, 1.090–1.957, P=0.011) in patients with nonischemic cardiomyopathy but not in patients with ischemic cardiomyopathy (all‐cause mortality: HR, 0.94; 95% CI, 0.79–1.11, P=0.467; sudden cardiac death: HR, 0.734; 95% CI, 0.477–1.132, P=0.162).

Conclusions

Electroanatomic ratios of QRSd indexed for body size or left ventricular size are associated with mortality in individuals with heart failure with reduced ejection fraction. In particular, increased QRS/height may be a marker of high risk in individuals with heart failure with reduced ejection fraction, and QRS/left ventricular end‐diastole volume may further risk stratify individuals with nonischemic heart failure with reduced ejection fraction.

Registration

URL: https://Clinicaltrials.gov. Unique identifier: NCT01633398.

Device therapy in heart failure with reduced ejection fraction-cardiac resynchronization therapy and more

In patients with heart failure with reduced ejection fraction (HFrEF), optimal medical treatment includes beta-blockers, ACE inhibitors/angiotensinreceptor-neprilysin inhibitors (ARNI), mineralocorticoid receptor antagonists, and ivabradine when indicated. In device therapy of HFrEF, implantable cardioverter-defibrillators and cardiac resynchronization therapy (CRT) have been established for many years. CRT is the therapy of choice (class I indication) in symptomatic patients with HFrEF and a broad QRS complex with a left bundle branch block (LBBB) morphology. However, the vast majority of heart failure patients show a narrow QRS complex or a non-LBBB morphology. These patients are not candidates for CRT and alternative electrical therapies such as baroreflex activation therapy (BAT) and cardiac contractility modulation (CCM) may be considered. BAT modulates vegetative dysregulation in heart failure. CCM improves contractility, functional capacity, and symptoms. Although a broad data set is available for BAT and CCM, mortality data are still lacking for both methods. This article provides an overview of the device-based therapeutic options for patients with HFrEF.

Electrophysiological properties of the South Asian heart

OBJECTIVE

The South Asian population has a lower burden of arrhythmia compared with Caucasians despite a higher prevalence of traditional cardiovascular risk factors. We aimed to determine whether this was due to differences in the electrophysiological properties of the South Asian heart.

METHODS

We performed a retrospective cohort study of South Asian and Caucasian patients who underwent an electrophysiology study for supraventricular tachycardia between 2005 and 2017. Surface ECG, intracardiac ECG and intracardiac conduction intervals were measured and a comparison between the two ethnic cohorts was performed.

RESULTS

A total of 5908 patients underwent an electrophysiology study at the Yorkshire Heart Centre, UK, during the study period. Of these 262 were South Asian and 113 met the eligibility criteria. South Asians had a significantly higher resting heart rate (p=0.024), shorter QRS duration (p=0.012) and a shorter atrioventricular (AV; p=0.001)) and ventriculoatrial (VA; p=0.013) effective refractory period (ERP). There was no difference in atrial or ventricular ERP. On linear regression analysis, South Asian ethnicity was independently predictive of a higher resting heart rate, narrower QRS and shorter AV-ERP and VA-ERP.

CONCLUSIONS

South Asians have significant differences in their resting heart rate, QRS duration and AV nodal function compared with Caucasians. These differences may reflect variations in autonomic function and may also be influenced by genetic factors. Electrophysiological differences such as these may help to explain why South Asians have a lower burden of arrhythmia.