The Interventricular Septum: Structure, Function, Dysfunction, and Diseases

From apoplexy in antiquities to cerebrovascular stroke in modernity: a narrative timeline and tale

Background

Stroke is one of the commonest encountered brain and neurological disorders worldwide. Stroke management has had a major shift in the last 50 years and precisely since the discovery and approval of thrombolysis as an acute management followed by multiple trials on mechanical thrombectomy and its approval. Yet, Stroke is as old as the history of mankind. Historically stroke symptoms’ description is older than the descriptions of the Greco-Roman civilization (500 BC – 800 AD). Before Stroke, the term apoplexy was described in ancient civilizations and evidence of suffering and managing it is preserved within the mummies, inscriptions, and papyri of the Egyptian civilization, clay tablets of the Mesopotamian civilization, medical books of the Chinese civilization, and although physicians and scientists consider the Greco-Roman civilization the base for modern medicine, yet the golden age of Islam (800 – 1200 AD) might have shared more in identifying bases of stroke. The European Renaissance beginning from 1400 AD with its famous anatomists and physicians greatly contributed too to stroke localization and vascular supply.

Conclusions

As medicine and science are in a continuous chain from the past to the future through the present, the current comprehensive review highlights the major important and documented shifts in the history of stroke over more than 4500 years starting from ancient civilizations BC up to 2024 AD.

Proprioceptors of the human pericardium

In the human organism, all functions are regulated and, therefore, require a feedback mechanism. This control involves a perception of the spatial tensile state of cardiac tissues. The presence and distribution of respective proprioceptive corpuscles have not been considered so far. Therefore, a comprehensive study of the entire human fibrous pericardium was conducted to describe the presence of proprioceptors, their density, and distribution patterns. Eight human pericardial specimens gained from our body donation program were used to create a three-dimensional map of proprioceptors in the pericardium based on their histological and immunohistochemical identification. The 3D map was generated as a volume-rendered 3D model based on magnetic resonance imaging of the pericardium, to which all identified receptors were mapped. To discover a systematic pattern in receptor distribution, statistical cluster analysis was conducted using the Scikit-learn library in Python. Ruffini-like corpuscles (RLCs) were found in all pericardia and assigned to three histological receptor localizations depending on the fibrous pericardium's layering, with no other corpuscular proprioceptors identified. Cluster analysis revealed that RLCs exhibit a specific topographical arrangement. The highest receptor concentrations occur at the ventricular bulges, where their size reaches its maximum in terms of diameter, and at the perivascular pericardial turn-up. The findings suggest that the pericardium is subject to proprioceptive control. RLCs record lateral shearing between the pericardial sublayers, and their distribution pattern enables the detection of distinct dilatation of the heart. Therefore, the pericardium might have an undiscovered function as a sensor with the RLCs as its anatomical correlate.

Smoking and Health Profiles of Hypertensive Patients with COVID-19: An Exploratory Study of Key Physiological Markers

Background/Objectives: Smoking and hypertension are major contributors to cardiovascular diseases, with smoker hypertensives typically presenting with exacerbated health risks. These factors are associated with COVID-19 aggravation, but their cumulative impact in the context of this disease remains understudied. Our hypothesis was that hypertensive smokers display a more vulnerable health profile (versus non-smokers) upon hospital admission for COVID-19. Methods: This exploratory observational study compared the clinical profiles of hypertensive COVID-19 patients depending on their smoking status. Focusing on key cardiometabolic, blood, renal, hepatic, and inflammatory markers, this investigation included 100 hypertensive COVID-19 patients (50 smokers and 50 non-smokers) aged 50 and above. Logistic regression and Spearman's correlations were used to identify significant predictors and relationships among variables. Results: Hypertensive smokers with COVID-19 were significantly more likely to exhibit higher heart rate (p = 0.047), left atrial size (p = 0.013) and diameter (p = 0.040), left ventricular end-systolic volume (p = 0.036), and interventricular septal thickness (p ≤ 0.001). These patients were also much more prone to display elevated CRP (p = 0.035) and hemoglobin (p = 0.011). The renal profiles of the smokers and non-smokers differed, with the smokers showing a significantly greater likelihood to have high serum urea (p = 0.036), but normal-to-low serum potassium (p = 0.011) and sodium (p ≤ 0.001). Their lipid profile was less favorable, with higher triglycerides (p ≤ 0.001), but lower HDL (p = 0.008). The strongest predictors of smoking status were interventricular septal thickness, triglycerides, and serum sodium. Conclusions: Hypertensive smokers admitted to the hospital with COVID-19 tend to exhibit a more adverse clinical profile, particularly in terms of cardiovascular remodeling, lipid imbalances, renal profile, and inflammation. These findings suggest that smoking exacerbates the effects of hypertension in the context of COVID-19, highlighting the need for more aggressive monitoring and management in this patient group.

Left atrial strain in neonates with congenital diaphragmatic hernia and length of stay in pediatric intensive care unit

Introduction

The role of cardiac left ventricle (LV) dysfunction in children with congenital diaphragmatic hernia (CDH) has gained increasing attention. The hernia allows abdominal mass to enter thorax and subsequently both dislocating and compressing the heart. The pressure on vessels and myocardium alters blood flow and may interfere with normal development of the LV. A dysfunctional LV is concerning and impacts the complex pathophysiology of CDH. Hence, assessing both the systolic and diastolic LV function in the newborn with CDH is important, and it may add value for medical treatment and prognostic factors as length of stay (LOS) in pediatric intensive care unit (PICU). LV strain is considered an early marker of systolic dysfunction used in the pediatric population. Left atrial (LA) strain is an echocardiographic marker of LV diastolic dysfunction used in the adult population. When filling pressure of the LV increases, the strain of the atrial wall is decreased. We hypothesized that reduced LA strain and LV strain are correlated with the LOS in the PICU of newborns with CDH.

Methods

This retrospective observational cohort study included data of 55 children born with CDH between 2018 and 2020 and treated at Karolinska University Hospital, Sweden. Overall, 46 parents provided consent. Echocardiograms were performed in 35 children <72 h after birth. The LA reservoir strain (LASr), LV global longitudinal strain, LV dimensions, and direction of blood flow through the patent foramen ovale (PFO) were retrospectively assessed using the echocardiograms.

Results

Children with LASr <33% (n = 27) had longer stays in the PICU than children with LA strain ≥33% (n = 8) (mean: 20.8 vs. 8.6 days; p < 0.002). The LASr was correlated with the LOS in the PICU (correlation coefficient: -0.378; p = 0.025). The LV dimension was correlated with the LOS (correlation coefficient: -0.546; p = 0.01). However, LV strain was not correlated to LOS.

Conclusion

Newborns with CDH and a lower LASr (<33%) had longer stays in the PICU than children with LASr ≥33%. LASr is a feasible echocardiographic marker of diastolic LV dysfunction in newborns with CDH and may indicate the severity of the condition.

Prognostic Implications of Septal Hypertrophy in Patients with Heart Failure with Mildly Reduced Ejection Fraction

Cardiac remodeling is frequently observed in patients with heart failure (HF) and serves as an indicator of disease progression and severity. Septal hypertrophy represents an aspect of remodeling that can be easily assessed via an echocardiographic measurement of the interventricular septal end diastole (IVSd), but it has not been evaluated for its prognostic value, particularly in patients with heart failure with mildly reduced ejection fraction (HFmrEF). We retrospectively included 1881 consecutive patients hospitalized with HFmrEF (i.e., a left ventricular ejection fraction of 41-49% and signs and/or symptoms of HF) at one institution during a study period from 2016 to 2022. Septal hypertrophy, defined as an IVSd > 12 mm, was prevalent in 34% of the HFmrEF patients. Although septal hypertrophy was not associated with all-cause mortality at 30 months (median follow-up) (HR = 1.067; 95% CI: 0.898-1.267; p = 0.460), it was associated with an increased risk of hospitalization due to worsening HF at 30 months (HR = 1.303; 95% CI: 1.008-1.685; p = 0.044), which was confirmed even after multivariable adjustment (HR = 1.340; 95% CI: 1.002-1.792; p = 0.049) and propensity score matching (HR = 1.399; 95% CI: 1.002-1.951; p = 0.048). Although septal hypertrophy was not associated with the risk of all-cause mortality in patients with HFmrEF, it was identified as an independent predictor of long-term HF-related rehospitalization.

The right ventricular dysfunction and ventricular interdependence in patients with DM: assessment using cardiac MR feature tracking

BACKGROUND

To investigate the difference of right ventricular (RV) structural and functional alteration in patients with diabetes mellitus (DM) with preserved left ventricular ejection fraction (LVEF), and the ventricular interdependence in these patients, using cardiac MR (CMR) feature tracking.

METHODS

From December 2016 to February 2022, 148 clinically diagnosed patients with DM who underwent cardiac MR (CMR) in our hospital were consecutively recruited. Fifty-four healthy individuals were included as normal controls. Biventricular strains, including left/right ventricular global longitudinal strain (LV-/RVGLS), left/right ventricular global circumferential strain (LV-/RVGCS), left/right ventricular global radial strain (LV-/RVGRS) were evaluated, and compared between patients with DM and healthy controls. Multiple linear regression and mediation analyses were used to evaluate DM's direct and indirect effects on RV strains.

RESULTS

No differences were found in age (56.98 ± 10.98 vs. 57.37 ± 8.41, p = 0.985), sex (53.4% vs. 48.1%, p = 0.715), and body surface area (BSA) (1.70 ± 0.21 vs. 1.69 ± 0.17, p = 0.472) between DM and normal controls. Patients with DM had decreased RVGLS (- 21.86 ± 4.14 vs. - 24.49 ± 4.47, p = 0.001), RVGCS (- 13.16 ± 3.86 vs. - 14.92 ± 3.08, p = 0.011), and no decrease was found in RVGRS (22.62 ± 8.11 vs. 23.15 ± 9.05, p = 0.743) in patients with DM compared with normal controls. The difference in RVGLS between normal controls and patients with DM was totally mediated by LVGLS (indirect effecting: 0.655, bootstrapped 95%CI 0.138-0.265). The difference in RVGCS between normal controls and DM was partly mediated by the LVGLS (indirect effecting: 0.336, bootstrapped 95%CI 0.002-0.820) and LVGCS (indirect effecting: 0.368, bootstrapped 95%CI 0.028-0.855).

CONCLUSIONS

In the patients with DM and preserved LVEF, the difference in RVGLS between DM and normal controls was totally mediated by LVGLS. Although there were partly mediating effects of LVGLS and LVGCS, the decrease in RVGCS might be directly affected by the DM.