Effects of blood pressure and heart rate circadian rhythms on left atrial function

Role of circadian transcription factor REV-ERB in cardiovascular diseases: a review

Circadian rhythm, or the biological clock, is an intrinsic timing system present in organisms that operates on a cycle of approximately 24 h. Nearly every cell in the human body adheres to a specific circadian rhythm, governing various biological processes essential for overall health. REV-ERB, a key circadian clock-regulating gene, plays a crucial role in maintaining the precision of these rhythms. This gene influences many downstream targets associated with diverse pathophysiological processes, including metabolism, autophagy, immunity, inflammation, and aging across multiple organs. REV-ERB specifically impacts cardiac systolic function by regulating myocardial energy metabolism. In contemporary society, health and well-being are increasingly challenged by disruptions to the biological clock, such as night shifts, late-night activities, and jet lag. These disruptions often lead to circadian rhythm disorders, which are now being increasingly linked to heart diseases. This review explored the potential role of REV-ERB in the cardiovascular system. Beyond its role in circadian rhythm regulation, REV-ERB could significantly influence physiological and pathological processes related to cardiovascular health, including atherosclerosis, myocardial ischemia/reperfusion injury, and heart failure. Mechanistically, REV-ERB could regulate glucose and lipid metabolism, inflammation, autophagy, ferroptosis, and mitochondrial function. The review highlighted the protective roles and underlying mechanisms of REV-ERB in cardiovascular diseases, suggesting that multidisciplinary research may provide a basis for breakthroughs in REV-ERB-targeted therapies for cardiovascular disorders.

The heart rate non-dipping pattern was associated with target organ damage in patients with chronic kidney disease

PURPOSE

We performed the study to investigate the association between heart rate (HR) non-dipping pattern and target organ damage in patients with chronic kidney disease (CKD) and hypertension.

METHODS

In this cross-sectional study, 447 patients with CKD and hypertension were enrolled. 24 h ambulatory blood pressure monitoring was conducted. Linear regression and logistic regression analysis were conducted to investigate the association between HR non-dipping pattern and target organ damage, including estimated glomerular filtration rate (eGFR), left ventricular mass index (LVMI), and left ventricular hypertrophy (LVH).

RESULTS

Overall, 261 patients (58.4%) followed non-dipping patterns of HR. HR non-dipping pattern remained to be significantly associated with reduced eGFR (β: -0.384; 95% CI: -0.719 to -0.050; p = 0.025) and the higher prevalence of CKD stages 4-5 (OR: 2.141; 95% CI: 1.153 to 3.977; p = 0.016). Meanwhile, HR non-dipping pattern was independently associated with LVMI (β: 0.021; 95% CI: 0.000 to 0.041; p = 0.049) and LVH (OR: 1.78; 95% CI: 1.07 to 2.96; p = 0.027) after adjusting for confounding factors.

CONCLUSIONS

HR non-dipping pattern was independently associated with impaired renal function and cardiac damage. Non-dipping HR deserves further attention and needs to be detected and treated during the management of CKD patients.

Left atrial mechanics evaluated by two-dimensional strain analysis: alterations in essential hypertension

BACKGROUND

Hypertension is a cardiovascular risk factor that predisposes to cardiac structural alterations namely increased left ventricular (LV) wall thickness, reduced LV compliance and diastolic dysfunction, with consequent left atrial (LA) dilation and functional impairment. In this article, we evaluated differences in left atrial structure and function using two-dimensional speckle tracking echocardiography in patients with hypertension compared with controls.

METHODS

This was a retrospective cross-sectional study of 208 hypertensive patients and 157 controls who underwent a comprehensive transthoracic echocardiogram. Patients with hypertension were stratified by the presence of left ventricular hypertrophy (LVH).

RESULTS

Non-LVH hypertension patients had lower left atrial reservoir strain (LAS RES ) (34.78 ± 29.78 vs. 29.78 ± 6.08; P  = 0.022) and conduit strain (LAS CD ) (19.66 ± 7.29 vs. 14.23 ± 4.59; P  = 0.014) vs. controls despite similar left atrial volumes (LAV) . Left atrial contractile strain (LAS CT ) was not significantly different between non-LVH hypertension patients and controls (15.12 ± 3.77 vs. 15.56 ± 3.79; P  = 0.601). Left atrial mechanical dispersion was significantly higher in the LVH group compared with the non-LVH hypertension group (42.26 ± 13.01 vs. 50.06 ± 14.95; P  = 0.009). In multivariate regression analysis, LVH correlated with left atrial mechanical dispersion ( P  = 0.016). An age-hypertension interaction independently correlated with LAS CT ( P  < 0.001).

CONCLUSION

Hypertension results in functional left atrial changes even before development of LV hypertrophy and structural left atrial changes with increased left atrial volume. We demonstrate both a likely hypertension-associated left atrial myopathy that prevents age-related compensatory increase in left atrial contractile function, and impact of LVH in hypertension on left atrial dyssynchrony.

Targeting mitochondrial circadian rhythms: The potential intervention strategies of Traditional Chinese medicine for myocardial ischaemia‒reperfusion injury

Coronary artery disease has one of the highest mortality rates in the country, and methods such as thrombolysis and percutaneous coronary intervention (PCI) can effectively improve symptoms and reduce mortality, but most patients still experience symptoms such as chest pain after PCI, which seriously affects their quality of life and increases the incidence of adverse cardiovascular events (myocardial ischaemiareperfusion injury, MIRI). MIRI has been shown to be closely associated with circadian rhythm disorders and mitochondrial dysfunction. Mitochondria are a key component in the maintenance of normal cardiac function, and new research shows that mitochondria have circadian properties. Traditional Chinese medicine (TCM), as a traditional therapeutic approach characterised by a holistic concept and evidence-based treatment, has significant advantages in the treatment of MIRI, and there is an interaction between the yin-yang theory of TCM and the circadian rhythm of Western medicine at various levels. This paper reviews the clinical evidence for the treatment of MIRI in TCM, basic experimental studies on the alleviation of MIRI by TCM through the regulation of mitochondria, the important role of circadian rhythms in the pathophysiology of MIRI, and the potential mechanisms by which TCM regulates mitochondrial circadian rhythms to alleviate MIRI through the regulation of the biological clock transcription factor. It is hoped that this review will provide new insights into the clinical management, basic research and development of drugs to treat MIRI.

Global cognitive function correlates with P-wave dispersion in frail hypertensive older adults

P‐Wave Dispersion (PWD) is an ECG parameter defined as the difference between the longest and the shortest P‐Wave duration. PWD has been associated with hypertension, a leading cause of age‐related cognitive decline. Moreover, hypertension is associated with vascular dementia and Alzheimer's Disease. Based on these considerations, we evaluated PWD and global cognitive function in frail hypertensive older adults with a previous diagnosis of cognitive decline. We evaluated consecutive frail hypertensive patients ≥65‐year‐old with a Mini‐Mental State Examination (MMSE) score <26. Patients with evidence of secondary hypertension, history of stroke, myocardial infarction, or therapy with beta‐blockers or acetylcholinesterase inhibitors were excluded. Beta‐blocker therapy causes a significant decrease in PWD; patients treated with acetylcholinesterase inhibitors were not included to avoid confounding effects on cognitive function. By examining 180 patients, we found that PWD significantly correlated with MMSE score. Strikingly, these effects were confirmed in a linear multivariate analysis with a regression model. To our knowledge, this is the first study showing that PWD correlates with global cognitive function in frail hypertensive older adults.

Assessing the causal role of hypertension on left atrial and left ventricular structure and function: A two-sample Mendelian randomization study

Aim

The aim of this study was to investigate whether hypertension may be causally linked to left atrial (LA) and left ventricular (LV) structure and function.

Methods and results

We performed a two-Mendelian randomization (MR) analysis implementing the results from the FinnGen large-scale, genome-wide association study for hypertension (N = 218,754), and LV (N = 16,923) and LA studies (N = 35,648) by the UK Biobank to identify genetic instruments. The MR analysis was implemented using an inverse-variance weighted (IVW) approach. We identified a positive potential causal relationship between hypertension and indices for the LA maximum (LAmax with causal estimates of 0.126 [95% CI, (0.093 to 0.160)]); LA minimum (LAmin with causal estimates of 0.122 [95% CI, (0.089 to 0.156)]); LV function (causal estimates are LV end-diastolic volume (LVEDV), 0.078 [95% CI, (0.003 to 0.153)]; LV end-systolic volume (LVESV), 0.102 [95% CI, (0.030 to 0.173)]; LV mass (LVM), 0.171 [95% CI, (0.108 to 0.233)]; and LV mass to end-diastolic volume ratio (LVMVR at 0.098 [95% CI, (0.048 to 0.149)], respectively), which was directionally concordant with other robust MR methods. Other than this, we observed a significantly negative causal relationship between hypertension and the LA active emptying fraction (LAAEF), the LA passive emptying fraction (LAPEF), and the LA total emptying fraction (LATEF).

Conclusion

Our genetic analyses demonstrated a potential causal relationship between hypertension and the left atrium and left ventricle's structures and functions.