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Coupling of the Left Ventricle with the Systemic Circulation
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
External heart work comprises just a small fraction of ventricular work (for the systemic circulation normally some 10–20 percent of the total). In describing ventricular work, energy requirements and function as to this point, we have been dealing with total ventricular work. This is of overwhelming importance when describing cardiac function.
Immune Responses Regulated by Exosomal Mechanisms in Cardiovascular Disease
Published in Shyam S. Bansal, Immune Cells, Inflammation, and Cardiovascular Diseases, 2022
Brooke Lee, Ioannis D. Kyriazis, Ruturaj Patil, Syed Baseeruddin Alvi, Amit Kumar Rai, Mahmood Khan, Venkata Naga Srikanth Garikipati
Exosomes were derived from mesenchymal stem cells (MSCs) and encapsulated in a peptide-based hydrogel, and the self-assembled peptides were able to retain the exosomes for 22 days while exhibiting enzyme-triggered localized release of EVs (Han, Zhou et al. 2019). EVs derived from induced pluripotent stem cells (iPSCs) have also been encapsulated in a light-responsive hyaluronic acid–based hydrogel. These hydrogels reveal UV-based cross-linking and display localized retention for 14 days upon pericardial administration. Furthermore, the in vivo studies demonstrated significant cardiac function enhancement post-treatment (Zhu, Li et al. 2021). A shear-thinning hydrogel, made of gelatin and silicate nanoparticles, has been explored for the localized delivery of stem cell secretomes (including exosomes) for cardiac repair. The in vivo study demonstrated a significant improvement in cardiac function and suppressed inflammation (Waters, Alam et al. 2018). In another instance, a ureidopyrimidinone-based hydrogel was fabricated by incorporating cardiac progenitor cell-derived EVs. The hydrogel retained exosomes within the matrix for 4 days, and the released EVs were functionally viable (Mol, Lei et al. 2019). However, further research is warranted to develop hydrogels for exosome delivery that can accommodate large doses and exhibit sustained release with superior ability to be injected.
Perioperative Myocardial Infarction
Published in Stephen M. Cohn, Alan Lisbon, Stephen Heard, 50 Landmark Papers, 2021
Again, decisions in the perioperative setting are more challenging where determination of whether the patient is having refractory chest symptoms can be difficult in the setting of pain from the surgical wounds, administration of narcotics, or intubated status. The patient may have hemodynamic derangement from other cardiac or cardiac causes or some element of volume overload simply related to resuscitative measures. In such settings, it may be useful to assess cardiac function with echocardiography. If infarction is occurring, but there is very little contractile dysfunction, the care team will feel more confident in a conservative strategy. Cardiac tamponade, unrecognized profound right or left ventricular dysfunction, or valvular heart disease can aid in the management of unexplained hypotension. Again, relatively preserved myocardial functions may support a conservative approach with the myocardial infarction and/or direct further workup and management to other disorders.
Increased thoracic fluid content is associated with higher risk for pneumonia in patients undergoing maintenance hemodialysis
Published in Renal Failure, 2023
Lijuan Yan, Yumei Qiu, Jin Liu, Jining Wu, Junwei Yang, Weichun He
In addition to the factors mentioned above, another important factor associated with the development of pneumonia is heart failure. Previous studies have shown that approximately 40% of MHD patients had varying degrees of cardiac insufficiency [19,20], while cardiac insufficiency and associated fluid volume overload were correlated with the occurrence of pneumonia and all-cause mortality in MHD patients [21–23]. Cardiac function and fluid volume load are closely related and influence each other. Excessive fluid volume load is one of the contributors to heart failure, while cardiac insufficiency can also aggravate fluid overload. In this study, the analysis of the cardiac function and fluid volume load indicators showed that NT-proBNP and TFC were positively correlated with the occurrence of pneumonia, and TFC, but not NT-proBNP, was an independent risk factor for the development of pneumonia in MHD patients. Hence, not entirely consistent with previous studies, our findings suggested that TFC appeared to be more valuable for predicting pneumonia than NT-proBNP in MHD patients.
Shenlian extract attenuates myocardial ischaemia-reperfusion injury via inhibiting M1 macrophage polarization by silencing miR-155
Published in Pharmaceutical Biology, 2022
Min Song, Xihe Cui, Jing Zhang, Yujie Li, Jingjing Li, Yuanlong Zang, Qi Li, Qing Yang, Ying Chen, Weiyan Cai, Xiaogang Weng, Yajie Wang, Xiaoxin Zhu
Myocardial ischaemia-reperfusion injury refers to myocardial tissue injury induced by reperfusion therapy after myocardial infarction. Myocardial ischaemia reperfusion usually leads to failure of cardiac function, increased infarct size and disordered biochemical metabolism. The infarcted area is the most direct evaluation of cardiac function. CK level is viewed as a symbol of the effects and prognosis of MI/RI, lower activity of CK stands for an obvious protective effect after cardiac muscle injury (Apple 1989). LDH is also a biochemical index to diagnose ischaemic heart disease and was closely associated with heart disease development. During MI/R, timely blood perfusion results in reactive oxygen species (ROS) overproduction, SOD is the primary mediator of oxygen free radicals and can reduce the contents of ROS and alleviate oxidative stress in MI/R (Grill et al. 1992). In our experiment, the results proved that SL shrinks infarcted size, decreased CK, LDH levels and increases SOD activity, which illustrated SL attenuated MI/RI.
Novel 4DCT Method to Measure Regional Left Ventricular Endocardial Shortening Before and After Transcatheter Mitral Valve Implantation
Published in Structural Heart, 2021
Gabrielle M. Colvert, Ashish Manohar, Francisco J. Contijoch, James Yang, Jeremy Glynn, Philipp Blanke, Jonathon A. Leipsic, Elliot R. McVeigh
Typically, left ventricular (LV) ejection fraction (EF) is a parameter used to quantify cardiac function as well as eligibility and fitness for certain procedures. According to the AHA/ACC guidelines for valvular heart disease, surgery is a Class I indication for patients with severe primary MR and LVEF >30%; in contrast there is only a Class IIb indication for surgery in those with LVEF <30%.7 However, when mitral regurgitation (MR) is present, EF may not adequately represent LV systolic function because a significant proportion of the stroke volume flows retrograde into the left atrium,8 and it has been shown that EF is a late indicator of LV dysfunction.9,10 As an alternative, recent studies have demonstrated that myocardial deformation parameters, such as global longitudinal and circumferential strain, are more sensitive measures and can be utilized to detect disease earlier than significant changes in EF.11,12 Yet, many patients with secondary MR tend to also have dyssynchronous function and highly regional abnormalities; hence, these global metrics cannot accurately capture the full picture of LV function.12 High resolution regional measurements of myocardial function could provide a better characterization of the extent of LV dysfunction in patients with MR.