Differences in Repolarization Heterogeneity Among Heart Failure With Preserved Ejection Fraction Phenotypic Subgroups

Outcomes with T-wave discordance of left bundle branch block and preserved or mildly reduced ejection fraction

AIMS

Left bundle branch block (LBBB) is associated with an increased risk of adverse outcomes for patients with heart failure. The prognosis of LBBB in patients with a preserved ejection fraction (EF) remains controversial. This study investigated the predictive value of T-wave discordance for the prognosis of patients with LBBB and preserved or mildly reduced EF.

METHODS AND RESULTS

We enrolled 707 patients with complete LBBB and left ventricular (LV) EF ≥ 40% observed using electrocardiograms (ECGs) and echocardiograms between January 2010 and December 2018. Their serial ECGs were reviewed during the follow-up period. The T-wave pattern was classified as discordant LBBB (dLBBB) or concordant LBBB (cLBBB) according to the 12-lead ECG T-wave morphology. The primary outcome was the composite of cardiovascular death or hospitalization for heart failure during a median follow-up period of 3.1 years. A multivariable Cox regression analysis was used to evaluate the independent predictors of the primary outcome. Patients with dLBBB had more comorbidities, a higher heart rate, a longer QRS and QTc duration, a larger LV end-systolic volume and left atrial dimension, a lower LVEF, and a higher mitral E/A ratio and E/e', compared with those with cLBBB. Older age [hazard ratio (HR) = 1.023, 95% confidence interval (CI) = 1.001-1.046, P = 0.023], history of heart failure (HR = 2.440, 95% CI = 1.524-3.905, P = 0.001), chronic kidney disease (HR = 1.917, 95% CI = 1.182-3.110, P = 0.008), larger LV end-systolic volume (HR = 1.046, 95% CI = 1.017-1.075, P = 0.002), lower LVEF (HR = 0.916, 95% CI = 0.885-0.948, P = 0.001), and presence of dLBBB (HR = 1.63, 95% CI = 1.011-2.628, P = 0.032) were independent predictors of the primary outcome in patients with LBBB and LVEF ≥ 40%. The discordant or concordant T-wave morphology of LBBB could transform from one subtype to the other in up to 23% of the study population during the follow-up period, and individuals with persistent or transformed dLBBB faced an increased risk of cardiovascular death or non-fatal heart failure hospitalization.

CONCLUSIONS

In patients with LBBB and EF ≥ 40%, dLBBB serves as an independent predictor of a higher risk of cardiovascular death or non-fatal heart failure hospitalization.

Selvester QRS Score is a Predictor of Mortality in Heart Failure with Preserved Ejection Fraction

BACKGROUND

The Selvester QRS (S-QRS) score on a 12-lead electrocardiogram (ECG) is associated with both the amount of myocardial scar and poor prognosis in myocardial infarction patients. However, its prognostic value in heart failure (HF) with preserved ejection fraction (HFpEF) is unknown.

OBJECTIVE

This study aims to investigate the predictive value of the S-QRS score for mortality in HFpEF.

METHODS

359 patients were retrospectively enrolled in this study. Electrocardiographic, echocardiographic, and laboratory features of the patients were recorded. The simplified S-QRS score was measured and recorded. The mean follow-up time of the patients was 38.1±9.5 months. Statistical significance was set at p < 0.05.

RESULTS

Of 359 patients, 270 were in the survivor group, and 89 were in the deceased group. Age, Hs-CRP, troponin, pro-BNP, left atrial (LA) diameter, LA volume index, QRS duration, Tpe, and S-QRS score were statistically high in the deceased group. In multivariate logistic regression analysis, age, Hs-CRP, NT-proBNP, LA diameter, LA volume index, Tpe, and S-QRS score were shown to be independent risk factors for mortality. In the receiver-operating characteristic (ROC) analysis, the cut-off value of the S-QRS score was 5.5, the sensitivity was 80.8%, and the specificity was 77.2% (AUC:0.880, p:0.00). In Kaplan-Meier analysis, it was found that mortality was higher in the group with S-QRS score ≥ 5.5 than in the group with S-QRS score < 5.5. (Long-rank, p:0.00).

CONCLUSIONS

We think that the S-QRS score can be used as a prognostic indicator of long-term mortality in patients with HFpEF.

Machine learning to define phenotypes and outcomes of patients hospitalized for heart failure with preserved ejection fraction: Findings from ASCEND-HF

BACKGROUND

Heart Failure with Preserved Ejection Fraction (HFpEF) is a heterogenous disease with few therapies proven to provide clinical benefit. Machine learning can characterize distinct phenotypes and compare outcomes among patients with HFpEF who are hospitalized for acute HF.

METHODS

We applied hierarchical clustering using demographics, comorbidities, and clinical data on admission to identify distinct clusters in hospitalized HFpEF (ejection fraction >40%) in the ASCEND-HF trial. We separately applied a previously developed latent class analysis (LCA) clustering method and compared in-hospital and long-term outcomes across cluster groups.

RESULTS

Of 7141 patients enrolled in the ASCEND-HF trial, 812 (11.4%) were hospitalized for HFpEF and met the criteria for complete case analysis. Hierarchical Cluster 1 included older women with atrial fibrillation (AF). Cluster 2 had elevated resting blood pressure. Cluster 3 had young men with obesity and diabetes. Cluster 4 had low resting blood pressure. Mortality at 180 days was lowest among Cluster 3 (KM event-rate 6.2 [95% CI: 3.5, 10.9]) and highest among Cluster 4 (18.8 [14.6, 24.0], P < .001). Twenty four-hour urine output was higher in Cluster 3 (2700 mL [1800, 3975]) than Cluster 4 (2100 mL [1400, 3055], P < .001). LCA also identified four clusters: A) older White or Asian women, B) younger men with few comorbidities, C) older individuals with AF and renal impairment, and D) patients with obesity and diabetes. Mortality at 180 days was lowest among LCA Cluster B (KM event-rate 5.5 [2.0, 10.3]) and highest among LCA Cluster C (26.3 [19.2, 35.4], P < .001).

CONCLUSIONS

In patients hospitalized for HFpEF, cluster analysis demonstrated distinct phenotypes with differing clinical profiles and outcomes.

Global status and trends in heart failure with preserved ejection fraction over the period 2009-2020: A bibliometric analysis

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) comprises about 50% of the cases of heart failure (HF), but so far there is no effective treatment strategy. This study used bibliometric methods to analyze the scientific literature on HFpEF in 2009 to 2020, and evaluate the global scientific output of HFpEF research, in order to explore the research status and trends in this field.

METHODS

Documents about the HFpEF research published in 2009 to 2020 were retrieved from Science Citation Index Expanded (SCIE) in Web of Science. This study used bibliometrix R-package, VOSviewer, and CiteSpace to conduct the bibliometric analysis.

RESULTS

A total of 1971 documents (1508 articles and 283 reviews) were retrieved to construct the local HFpEF literature collection for analysis. The number of annual documents had increased year by year in general, from 24 to 353. Relevant documents were mainly written in English, and mostly focused on the field of "Cardiovascular System Cardiology." USA ranked first in the relevant countries/regions with most documents, and the leading affiliation was Mayo Clin. Shah SJ was the most productive author, while Borlaug BA ranked highest among the local cited authors and G-index. Circulation was the most local cited source, while Eur J Heart Fail published the most documents and was rated as the top source in terms of G-index. "Paulus WJ, 2013, J Am Coll Cardiol" was the top local cited document within the local HFpEF literature collection, while "Owan TE, 2006, New Engl J Med" outside the local HFpEF literature collection was the most local cited reference. The keywords such as "mortality," "dysfunction," "diagnosis," "outcomes," and "diastolic dysfunction" were most frequent, while "hemodynamics," "comorbidity," "myocardial infarction," "inflammation," and "phenotype" indicated research frontiers or emerging trends. Furthermore, this study also found some deeper bibliometric relationships through bibliographic networks.

CONCLUSIONS

Due to the multi-dimensional bibliometric analysis, this study shows a wide view of scientific productivity related to HFpEF, and provides valuable guidance for researchers interested in HFpEF, assisting them in understanding the research status, identifying potential collaborators, discovering research hotspots and frontiers, and conducting more in-depth research.

The anti-aging factor Klotho protects against acquired long QT syndrome induced by uremia and promoted by fibroblast growth factor 23

BACKGROUND

Chronic kidney disease (CKD) is associated with increased propensity for arrhythmias. In this context, ventricular repolarization alterations have been shown to predispose to fatal arrhythmias and sudden cardiac death. Between mineral bone disturbances in CKD patients, increased fibroblast growth factor (FGF) 23 and decreased Klotho are emerging as important effectors of cardiovascular disease. However, the relationship between imbalanced FGF23-Klotho axis and the development of cardiac arrhythmias in CKD remains unknown.

METHODS

We carried out a translational approach to study the relationship between the FGF23-Klotho signaling axis and acquired long QT syndrome in CKD-associated uremia. FGF23 levels and cardiac repolarization dynamics were analyzed in patients with dialysis-dependent CKD and in uremic mouse models of 5/6 nephrectomy (Nfx) and Klotho deficiency (hypomorphism), which show very high systemic FGF23 levels.

RESULTS

Patients in the top quartile of FGF23 levels had a higher occurrence of very long QT intervals (> 490 ms) than peers in the lowest quartile. Experimentally, FGF23 induced QT prolongation in healthy mice. Similarly, alterations in cardiac repolarization and QT prolongation were observed in Nfx mice and in Klotho hypomorphic mice. QT prolongation in Nfx mice was explained by a significant decrease in the fast transient outward potassium (K⁺) current (I_tof), caused by the downregulation of K⁺ channel 4.2 subunit (Kv4.2) expression. Kv4.2 expression was also significantly reduced in ventricular cardiomyocytes exposed to FGF23. Enhancing Klotho availability prevented both long QT prolongation and reduced I_tof current. Likewise, administration of recombinant Klotho blocked the downregulation of Kv4.2 expression in Nfx mice and in FGF23-exposed cardiomyocytes.

CONCLUSION

The FGF23-Klotho axis emerges as a new therapeutic target to prevent acquired long QT syndrome in uremia by minimizing the predisposition to potentially fatal ventricular arrhythmias and sudden cardiac death in patients with CKD.

Increases in repolarization heterogeneity predict left ventricular systolic dysfunction and response to cardiac resynchronization therapy in patients with left bundle branch block

INTRODUCTION

This study aimed to investigate the association between T-wave morphology and impaired left ventricular ejection fraction (LVEF) in patients with complete left bundle branch block (cLBBB), and the predictive value of T-wave morphology for response to cardiac resynchronization therapy (CRT).

METHODS AND RESULTS

We enrolled 189 patients with cLBBB on electrocardiogram performed between January 2007 and December 2011 who underwent standard echocardiography. Repolarization parameters, including the QRS-to-T angle (TCRT), T-wave morphology dispersion (TMD), T-wave loop area (PL), and T-wave residuum (TWR), were reconstructed from digital standard 12-lead electrocardiograms by T-wave morphology analysis. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume at 12 months after CRT implantation. The clinical outcome endpoint was a composite of heart failure hospitalization, heart transplantation, or death during follow up (mean, 5.8 years). On logistic regression, a higher heart rate, longer QRS duration, increased TMD, and larger TWR were all independently associated with LVEF < 40%. Among 40 patients who underwent CRT, those with a larger TMD (P = .007), larger PL (P = .025), and more negative TCRT (P = .015) had better response to CRT. A large TMD (P = .018) and large PL (P = .003) were also independent predictors of the clinical outcome endpoint.

CONCLUSIONS

Increases in repolarization heterogeneity in patients with cLBBB are associated with impaired LVEF. A large TMD and large PL may be useful as additional predictors of response to CRT, improving patient selection for CRT.

The influence of sex on left ventricular strain in hypertensive population

OBJECTIVE

The aim of this study was to evaluate the influence of sex on left ventricular mechanics in hypertensive individuals.

METHODS

This cross-sectional study included 171 untreated hypertensive patients and 112 normotensive controls who underwent a 24-h ambulatory blood pressure monitoring and comprehensive echocardiographic examination including strain assessment.

RESULTS

Hypertensive women and men had significantly lower left ventricular global longitudinal and circumferential strains than their normotensive counterparts. Left ventricular global longitudinal strain was lower in hypertensive men than in women (-19.8 ± 2.2 vs. -17.9 ± 2.1%; P < 0.01). Left ventricular global circumferential strain was also reduced in hypertensive men in comparison with women (-21.0 ± 2.5 vs. -18.7 ± 2.3%; P < 0.01). The difference in left ventricular radial strain was not discovered between hypertensive women and men. Furthermore, left ventricular twist was significantly higher in hypertensive women than in hypertensive men (21.9 ± 4.1° vs. 20.6 ± 3.8°; P = 0.034). Female sex and arterial hypertension, and also their interaction, were associated with lower left ventricular mass index, increased left ventricular global longitudinal, and circumferential strains and increased left ventricular twist compared with hypertensive men.

CONCLUSION

Left ventricular longitudinal and circumferential strains were significantly reduced in hypertensive patients. However, the changes are more pronounced in hypertensive men than in women. Sex has a significant effect on the association between hypertension, and longitudinal and circumferential strain.

Electrocardiographic characteristics in patients with heart failure and normal ejection fraction: A systematic review and meta-analysis

BACKGROUND

Little is known about ECG abnormalities in patients with heart failure and normal ejection fraction (HeFNEF) and how they relate to different etiologies or outcomes.

METHODS AND RESULTS

We searched the literature for peer-reviewed studies describing ECG abnormalities in HeFNEF other than heart rhythm alone. Thirty five studies were identified and 32,006 participants. ECG abnormalities reported in patients with HeFNEF include atrial fibrillation (prevalence 12%-46%), long PR interval (11%-20%), left ventricular hypertrophy (LVH, 10%-30%), pathological Q waves (11%-18%), RBBB (6%-16%), LBBB (0%-8%), and long JTc (3%-4%). Atrial fibrillation is more common in patients with HeFNEF compared to those with heart failure and reduced ejection fraction (HeFREF). In contrast, long PR interval, LVH, Q waves, LBBB, and long JTc are more common in patients with HeFREF. A pooled effect estimate analysis showed that QRS duration ≥120 ms, although uncommon (13%-19%), is associated with worse outcomes in patients with HeFNEF.

CONCLUSIONS

There is high variability in the prevalence of ECG abnormalities in patients with HeFNEF. Atrial fibrillation is more common in patients with HeFNEF compared to those with HeFREF. QRS duration ≥120 ms is associated with worse outcomes in patients with HeFNEF. Further studies are needed to address whether ECG abnormalities correlate with different phenotypes in HeFNEF.

Complex Association of Sex Hormones on Left Ventricular Systolic Function: Insight into Sexual Dimorphism

BACKGROUND

Normal values of left ventricular ejection fraction (LVEF) and absolute values of global longitudinal strain (GLS) are lower in men than in women. Data concerning the association of sex hormone levels on these left ventricular systolic function surrogates are scarce. The aim of this study was to determine the association of sex hormones with systolic left ventricular function in healthy subjects and patients with congenital adrenal hyperplasia (CAH) as a model of testosterone dysregulation.

METHODS

Eighty-four adult patients with CAH (58 women; median age, 27 years; interquartile range, 23-36 years) and 84 healthy subjects matched for sex and age were prospectively included. Circulating concentrations of sex hormones were measured within 48 hours of echocardiography with assessment of LVEF and left ventricular longitudinal, radial, and circumferential strain.

RESULTS

LVEF and GLS were higher in healthy women than in healthy men (63.9 ± 4.2% vs 60.9 ± 5.1% [P < .05] and 20.0 ± 1.9% vs 17.9 ± 2.4% [P < .001], respectively), while there was no difference in LVEF or GLS between women and men with CAH (63.9 ± 4.5% vs 63.0 ± 4.6% [P = NS] and 19.4 ± 2.2% vs 18.3 ± 1.8% [P = NS], respectively). Bioavailable testosterone levels were higher in women with CAH than in female control subjects (0.08 ng/mL [interquartile range, 0.04-0.14 ng/mL] vs 0.16 ng/mL [interquartile range, 0.04-0.3 ng/mL], P < .001) and lower in men with CAH than in male control subjects (2.3 ng/mL [interquartile range, 1.3-3 ng/mL] vs 2.9 ng/mL [interquartile range, 2.5-3.4 ng/mL], P < .05). In men, LVEF and GLS were negatively correlated with bioavailable testosterone levels (r = -0.3, P ≤ .05, and r = -0.45, P < .01, respectively), while midventricular radial strain was positively correlated with bioavailable testosterone level (r = 0.38, P < .05). The absolute value of circumferential strain was positively correlated with follicle-stimulating hormone (r = 0.65, P < .0001).

CONCLUSIONS

These data support that the existence of sex dimorphism concerning left ventricular systolic cardiac function is significantly associated with testosterone levels.

Artificial intelligence in cardiology

Decision-making is complex in modern medicine and should ideally be based on available data, structured knowledge and proper interpretation in the context of an individual patient. Automated algorithms, also termed artificial intelligence that are able to extract meaningful patterns from data collections and build decisions upon identified patterns may be useful assistants in clinical decision-making processes. In this article, artificial intelligence-based studies in clinical cardiology are reviewed. The text also touches on the ethical issues and speculates on the future roles of automated algorithms versus clinicians in cardiology and medicine in general.