Increased Chamber Resting Tone Is a Key Determinant of Left Ventricular Diastolic Dysfunction

Age-Based Classification and Outcomes in Pediatric Heart Failure: Findings From a Retrospective Multicenter Cohort Study

BACKGROUND

Although heart failure is a well-known major global public health concern, the general understanding of the clinical status of pediatric heart failure (PHF) is inadequate. Therefore, this study aims to enhance the general understanding of clinical characteristics across different PHF age groups and provide references for improving PHF treatment strategies.

METHODS

This multicenter retrospective cohort study involved patients from 20 Chinese provinces, primarily including hospitalized patients (aged ≤18 years) diagnosed with heart failure between January 2013 and December 2022. The study subjects were categorized into 4 groups: neonatal, infant and toddler, young children, and adolescent.

RESULTS

Herein, 2903 hospitalized patients with PHF were included. Significant differences were observed across age groups in clinical characteristics, auxiliary examination results, comorbid diagnoses, and hospitalization outcomes. After adjusting for covariates, the odds of in-hospital death were significantly lower in the infant and toddler (odds ratio [OR], 0.46 [95% CI, 0.25-0.85]), young children (OR, 0.39 [95% CI, 0.18-0.85]), and adolescent (OR, 0.34 [95% CI, 0.13-0.87]) groups compared with the neonatal group. Furthermore, the odds of cardiovascular adverse events were significantly higher in the young children (OR, 1.91 [95% CI, 1.62-2.88]) and adolescent (OR, 2.16 [95% CI, 1.15-4.06]) groups compared with the neonatal group. Additionally, regarding the odds of a bad Ross class, the adolescent group had 1.85 times higher odds (95% CI, 1.11-3.09) compared with the neonatal group, 2.36 times (95% CI, 1.67-3.35) higher odds compared with the infant and toddler group, and 1.45 times (95% CI, 1.05-2.02) higher odds compared with the young children group (P<0.05).

CONCLUSIONS

This study emphasizes the importance of age-specific stratification in PHF management, revealing distinct clinical and prognostic differences across various developmental stages.

REGISTRATION

URL: https://www.chictr.org.cn. Unique identifier: ChiCTR2300078262.

Pathogenesis of cardiovascular diseases: effects of mitochondrial CF6 on endothelial cell function

Cardiovascular disease (CVD) stands as a predominant global cause of morbidity and mortality, necessitating effective and cost-efficient therapies for cardiovascular risk reduction. Mitochondrial coupling factor 6 (CF6), identified as a novel proatherogenic peptide, emerges as a significant risk factor in endothelial dysfunction development, correlating with CVD severity. CF6 expression can be heightened by CVD risk factors like mechanical force, hypoxia, or high glucose stimuli through the NF-κB pathway. Many studies have explored the CF6-CVD relationship, revealing elevated plasma CF6 levels in essential hypertension, atherosclerotic cardiovascular disease (ASCVD), stroke, and preeclampsia patients. CF6 acts as a vasoactive and proatherogenic peptide in CVD, inducing intracellular acidosis in vascular endothelial cells, inhibiting nitric oxide (NO) and prostacyclin generation, increasing blood pressure, and producing proatherogenic molecules, significantly contributing to CVD development. CF6 induces an imbalance in endothelium-dependent factors, including NO, prostacyclin, and asymmetric dimethylarginine (ADMA), promoting vasoconstriction, vascular remodeling, thrombosis, and insulin resistance, possibly via C-src Ca2+ and PRMT-1/DDAH-2-ADMA-NO pathways. This review offers a comprehensive exploration of CF6 in the context of CVD, providing mechanistic insights into its role in processes impacting CVD, with a focus on CF6 functions, intracellular signaling, and regulatory mechanisms in vascular endothelial cells.

Mechanism-based myofilament manipulation to treat diastolic dysfunction in HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a major public health challenge, affecting millions worldwide and placing a significant burden on healthcare systems due to high hospitalization rates and limited treatment options. HFpEF is characterized by impaired cardiac relaxation, or diastolic dysfunction. However, there are no therapies that directly treat the primary feature of the disease. This is due in part to the complexity of normal diastolic function, and the challenge of isolating the mechanisms responsible for dysfunction in HFpEF. Without a clear understanding of the mechanisms driving diastolic dysfunction, progress in treatment development has been slow. In this review, we highlight three key areas of molecular dysregulation directly underlying impaired cardiac relaxation in HFpEF: altered calcium sensitivity in the troponin complex, impaired phosphorylation of myosin-binding protein C (cMyBP-C), and reduced titin compliance. We explore how targeting these pathways can restore normal relaxation, improve diastolic function, and potentially provide new therapeutic strategies for HFpEF treatment. Developing effective HFpEF therapies requires precision targeting to balance systolic and diastolic function, avoiding both upstream non-specificity and downstream rigidity. This review highlights three rational molecular targets with a strong mechanistic basis and potential for therapeutic success.

Left ventricular volume and maximal functional capacity in heart failure with preserved ejection fraction: Size matters

AIMS

Emerging evidence suggests that smaller left ventricular volumes may identify subjects with lower cardiorespiratory fitness. Whether left ventricular size predicts functional capacity in patients with heart failure with preserved ejection fraction (HFpEF) is unclear. This study aimed to explore the association between indexed left ventricular end-diastolic volume (iLVEDV) and maximal functional capacity, assessed by peak oxygen consumption (peakVO2), in stable outpatients with HFpEF.

METHODS AND RESULTS

We prospectively analysed data from 133 consecutive stable outpatients who underwent cardiopulmonary exercise testing and echocardiography on the same day. Data were validated in a cohort of HFpEF patients from San Paolo Hospital, Milan, Italy. A multivariable linear regression assessed the association between iLVEDV and peakVO2. The mean age was 73.2 ± 10.5 years, and 75 (56.4%) were women. The median iLVEDV, indexed left ventricular end-systolic volume, and left ventricular ejection fraction were 46 ml/m2 (30-56), 15 ml/m2 (11-19), and 66% (60-74%), respectively. The median peakVO2 and percentage of predicted peakVO2 were 11 ml/kg/min (9-13) and 64.1% (53-74.4), respectively. Adjusted linear regression analysis showed that smaller iLVEDV was associated with lower peakVO2 (p = 0.0001). In the validation cohort, adjusted linear regression analysis showed a consistent pattern: a smaller iLVEDV was associated with a higher likelihood of reduced peakVO2 (p = 0.004).

CONCLUSIONS

In stable outpatients with HFpEF, a smaller iLVEDV was associated with a lower maximal functional capacity. These findings suggest a need for further studies to understand the pathophysiological mechanisms underlying these observations and to explore targeted treatment strategies for this patient subgroup.

Left ventricular diastolic dysfunction in non-myocardial disorders

This article reviews and discusses non-myocardial disorders that represent diagnostic challenges when evaluating patients for suspected heart failure with preserved left ventricular ejection fraction. This includes pre-capillary pulmonary hypertension, which is important to differentiate from post-capillary hypertension caused by left-sided heart disease. The impact of electrical disorders on LV diastolic function is also reviewed, and includes a discussion of left bundle branch, which has both a direct effect on LV diastolic function, as well as a long-term effect due to remodelling. Furthermore, evaluation of diastolic function in patients with atrial fibrillation is discussed. Pericardial diseases are reviewed as well as effects of a normal pericardium on diastolic function in failing hearts. Finally, the article reviews how valvular diseases impact LV diastolic function.