The MAASWERP Study: An International, Comparative Case Study on Measuring Biomechanics of the Aged Murine Aorta.

Introduction: Arterial stiffening is a hallmark of vascular ageing, and unravelling its underlying mechanisms has become a central theme in the field of cardiovascular disease. While various techniques and experimental setups are accessible for investigating biomechanics of blood vessels both in vivo and ex vivo, comparing findings across diverse methodologies is challenging.

Methods: Arterial stiffness in the aorta of adult (5 months) and aged (24 months) wild-type C57Bl/6J mice was measured in vivo, after which ex vivo biomechanical evaluation was performed using the Rodent Oscillatory Tension Setup to study Arterial Compliance (ROTSAC; University of Antwerp, Belgium) and the DynamX setup (Maastricht University, The Netherlands).

Interpretation of intra-operative strain differences in ascending thoracic aortic repair patients.

Local biaxial deformation plays a pivotal role in evaluating the tissue state of the ascending aorta and in driving intramural cell-mediated tissue remodeling. Unfortunately, the absence of anatomical markers on the ascending aorta presents challenges in capturing deformation. Utilizing our established intra-operative biaxial strain measurement method, we delineated local biaxial deformation characteristics in patients undergoing aortic valve replacement and coronary artery bypass graft surgery recipients (n = 20), and Aortic Repair surgery patients (n = 47).

Beat-to-beat variability of aortic pulse wave velocity: implications for aortic stiffness measurements.

Objectives: Aortic pulse wave velocity (aPWV) predicts cardiovascular risk. Being the reference method for aortic stiffness evaluation, invasive aPWV is also recommended for validation of noninvasive devices. Because of intrinsic haemodynamic variability and processing issues, aPWV shows beat-to-beat variability.

Accelerated atrial pacing reduces left-heart filling pressure: a combined clinical-computational study.

Background And Aims: Accelerated atrial pacing offers potential benefits for patients with heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF), compared with standard lower-rate pacing. The study investigates the relationship between atrial pacing rate and left-heart filling pressure.

Methods: Seventy-five consecutive patients undergoing catheter ablation for AF underwent assessment of mean left atrial pressure (mLAP) and atrioventricular (AV) conduction delay (PR interval) in sinus rhythm and accelerated atrial pacing with 10 bpm increments up to Wenckebach block.

The mechanistic interaction between mechanical dyssynchrony and filling pressure in cardiac resynchronization therapy candidates.

Background: Both left ventricular (LV) mechanical dyssynchrony and filling pressure have been shown to be associated with outcome in heart failure patient treated with cardiac resynchronization therapy (CRT).

Objectives: To investigate the mechanistic link between mechanical dyssynchrony and filling pressure and to assess their combined prognostic value in CRT candidates.

Methods: Left atrial pressure (LAP) estimation and quantification of mechanical dyssynchrony were retrospectively performed in 219 CRT patients using echocardiography.

Einthoven's triangle adapted for horses: Proposal for the Delta configuration.

Background: Reliable ECGs are crucial for diagnosing arrhythmias, yet a lack of standardization impedes arrhythmia diagnosis and treatment in horses.

Objectives: To objectively determine an optimal position of Einthoven's triangle for ECG recordings in horses at rest, which can form the basis for standardized ECG recording and improve diagnosis and treatment of arrhythmias.

Animals: The study involved 72 healthy, warmblood horses aged between 3 and 20 years.

Diagnostic value of reversed differential cyanosis in (supra)cardiac total anomalous pulmonary venous return.

Background: To investigate the occurrence of reversed differential cyanosis (RDC) in case of (supra)cardiac total anomalous pulmonary venous return (TAPVR), we explored the hemodynamic changes and oxygen saturation levels during the fetal-to-neonatal transition in (supra)cardiac TAPVR, thereby revealing determinant factors of RDC.

Methods: A computational model was used to simulate the cardiovascular fetal-to-neonatal transition up to 24 h after birth. Abnormalities associated with TAPVR, like patent ductus arteriosus (PDA) and persistent pulmonary hypertension of the neonate (PPHN), were imposed on the model.

Effect of rapid cooling, frozen storage, and thawing on the passive viscoelastic properties and structure of the rat aorta.

Biological tissues decay over time after harvesting, which alters their biomechanical properties. This poses logistical challenges for studies investigating passive arterial biomechanics as tissues need to be characterized shortly after excision. Freezing and cryopreservation methods can help alleviate the need for biomechanical testing of fresh tissue in human ex vivo studies.

Significance of Dynamic Axial Stretching on Estimating Biomechanical Behavior and Properties of the Human Ascending Aorta.

Contrary to most vessels, the ascending thoracic aorta (ATA) not only distends but also elongates in the axial direction. The purpose of this study is to investigate the biomechanical behavior of the ascending thoracic aorta (ATA) in response to dynamic axial stretching during the cardiac cycle. In addition, the implications of neglecting this dynamic axial stretching when estimating the constitutive model parameters of the ATA are investigated.

Parameter subset reduction for imaging-based digital twin generation of patients with left ventricular mechanical discoordination.

Background: Integration of a patient's non-invasive imaging data in a digital twin (DT) of the heart can provide valuable insight into the myocardial disease substrates underlying left ventricular (LV) mechanical discoordination. However, when generating a DT, model parameters should be identifiable to obtain robust parameter estimations. In this study, we used the CircAdapt model of the human heart and circulation to find a subset of parameters which were identifiable from LV cavity volume and regional strain measurements of patients with different substrates of left bundle branch block (LBBB) and myocardial infarction (MI).

Multipotent adult progenitor cells prevent functional impairment and improve development in inflammation driven detriment of preterm ovine lungs.

Background: Perinatal inflammation increases the risk for bronchopulmonary dysplasia in preterm neonates, but the underlying pathophysiological mechanisms remain largely unknown. Given their anti-inflammatory and regenerative capacity, multipotent adult progenitor cells (MAPC) are a promising cell-based therapy to prevent and/or treat the negative pulmonary consequences of perinatal inflammation in the preterm neonate. Therefore, the pathophysiology underlying adverse preterm lung outcomes following perinatal inflammation and pulmonary benefits of MAPC treatment at the interface of prenatal inflammatory and postnatal ventilation exposures were elucidated.

Translating myosin-binding protein C and titin abnormalities to whole-heart function using a novel calcium-contraction coupling model.

Mutations in cardiac myosin-binding protein C (cMyBP-C) or titin may respectively lead to hypertrophic (HCM) or dilated (DCM) cardiomyopathies. The mechanisms leading to these phenotypes remain unclear because of the challenge of translating cellular abnormalities to whole-heart and system function. We developed and validated a novel computer model of calcium-contraction coupling incorporating the role of cMyBP-C and titin based on the key assumptions: 1) tension in the thick filament promotes cross-bridge attachment mechanochemically, 2) with increasing titin tension, more myosin heads are unlocked for attachment, and 3) cMyBP-C suppresses cross-bridge attachment.

Virtual pacing of a patient's digital twin to predict left ventricular reverse remodelling after cardiac resynchronization therapy.

Aims: Identifying heart failure (HF) patients who will benefit from cardiac resynchronization therapy (CRT) remains challenging. We evaluated whether virtual pacing in a digital twin (DT) of the patient's heart could be used to predict the degree of left ventricular (LV) reverse remodelling post-CRT.

Methods And Results: Forty-five HF patients with wide QRS complex (≥130 ms) and reduced LV ejection fraction (≤35%) receiving CRT were retrospectively enrolled.

How to assess and treat right ventricular electromechanical dyssynchrony in post-repair tetralogy of Fallot: insights from imaging, invasive studies, and computational modelling.

Background And Aims: Right bundle branch block (RBBB) and resulting right ventricular (RV) electromechanical discoordination are thought to play a role in the disease process of subpulmonary RV dysfunction that frequently occur post-repair tetralogy of Fallot (ToF). We sought to describe this disease entity, the role of pulmonary re-valvulation, and the potential added value of RV cardiac resynchronization therapy (RV-CRT).

Methods: Two patients with repaired ToF, complete RBBB, pulmonary regurgitation, and significantly decreased RV function underwent echocardiography, cardiac magnetic resonance, and an invasive study to evaluate the potential for RV-CRT as part of the management strategy.

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

Background: Twitch-independent tension has been demonstrated in cardiomyocytes, but its role in heart failure (HF) is unclear. We aimed to address twitch-independent tension as a source of diastolic dysfunction by isolating the effects of chamber resting tone (RT) from impaired relaxation and stiffness.

Methods: We invasively monitored pressure-volume data during cardiopulmonary exercise in 20 patients with hypertrophic cardiomyopathy, 17 control subjects, and 35 patients with HF with preserved ejection fraction.

Electrophysiological effects of stretch-activated ion channels: a systematic computational characterization.

Cardiac electrophysiology and mechanics are strongly interconnected. Their interaction is, among others, mediated by mechano-electric feedback through stretch-activated ion channels (SACs). The electrophysiological changes induced by SACs may contribute to arrhythmogenesis, but the precise SAC-induced electrophysiological changes remain incompletely understood.

Evidence in Clinical Studies for the Role of Wall Thickness in Ascending Thoracic Aortic Aneurysms: A Scoping Review.

Background: Ascending thoracic aortic aneurysm is a chronic degenerative pathology characterized by dilatation of this segment of the aorta. Clinical guidelines use aortic diameter and growth rate as predictors of rupture and dissection. However, these guidelines neglect the effects of tissue remodeling, which may affect wall thickness.

The Maastricht Acquisition Platform for Studying Mechanisms of Cell-Matrix Crosstalk (MAPEX): An Interdisciplinary and Systems Approach towards Understanding Thoracic Aortic Disease.

Current management guidelines for ascending thoracic aortic aneurysms (aTAA) recommend intervention once ascending or sinus diameter reaches 5-5.5 cm or shows a growth rate of >0.5 cm/year estimated from echo/CT/MRI.

Impact of Estimated Left Atrial Pressure on Cardiac Resynchronization Therapy Outcome.

Background: We investigated the impact of baseline left atrial (LA) strain data and estimated left atrial pressure (LAP) by applying the 2016 American Society of Echocardiography and the European Association of Cardiovascular Imaging (ASE/EACVI) guidelines on cardiac resynchronization therapy (CRT) outcomes.

Methods: Datasets of 219 CRT patients were retrospectively analysed. All patients had full echocardiographic diastolic function assessment before CRT and were classified based on the guideline algorithm into normal LAP (nLAP = 40%), elevated LAP (eLAP = 49%) and indeterminate LAP (iLAP = 11%).