Isolated Papillary Muscle Preparation
John H. McNeill in Measurement of Cardiac Function, 2020
A very useful preparation of heart muscle for these types of in vitro studies is the papillary muscle, which attaches the wall of the ventricle to either the tricuspid or the mitral valve and is part of the endocardial layer of the ventricular wall. The muscle has its fibers arranged in a longitudinal, parallel fashion, and in small animals such as the mouse, hamster, rat, ferret, cat, and rabbit it is suitably thin so that diffusion of oxygen in vitro is adequate to allow stable function and to avoid hypoxic damage to the core of the tissue.16–19 As has been mentioned, during the cardiac cycle the papillary muscle contracts and shortens and functions to prevent regurgitant flow by holding the valve closed during the ejection phase of the cardiac cycle.
Death from natural causes
Jason Payne-James, Richard Jones in Simpson's Forensic Medicine, 2019
The area of muscle damaged by a myocardial infarction is further weakened by the process of cellular death and the generalised inflammatory response to these necrotic cells. The area of the myocardial infarct is most at risk between 3 days and 1 week after the clinical onset of the infarction and it is at this time that the compromised area of myocardium may rupture, leading to sudden death from a haemopericardium and cardiac tamponade (Figure 6.3a). The rupture occasionally occurs through the interventricular septum, resulting in a left–right shunt. If a papillary muscle is infarcted, it may rupture, which may cause mitral valve prolapse, which itself may be associated with sudden death or may present as a sudden onset of valve insufficiency with heart failure (Figure 6.3b).
Coronary Artery Disease
Jahangir Moini, Matthew Adams, Anthony LoGalbo in Complications of Diabetes Mellitus, 2022
The pathophysiology of acute coronary syndromes ranges from transient ischemia to infarction. Cell necrosis likely occurs even with milder forms. When tissue is only ischemic, there is impairments of contractility as well as relaxation. Hypokinetic or akinetic segments develop, which can bulge or expand during systole. This is known as paradoxical motion. The affected area’s size determines effects ranging from partial heart failure to cardiogenic shock. Usually, large portions of the myocardium must be ischemic in order to cause severe myocardial dysfunction. In about 66% of hospitalized patients with acute MI, there is some degree of heart failure. When there is low cardiac output and heart failure, the condition is called ischemic cardiomyopathy. If ischemia affects the papillary muscle, mitral valve regurgitation may follow. Mural thrombus formation may occur from dysfunctional wall motion.
Abdominal Ischemia-Reperfusion Induced Cardiac Dysfunction Can Be Prevented by MitoTEMPO
Published in Journal of Investigative Surgery, 2022
Ahmet Akkoca, Murat Cenk Celen, Seckin Tuncer, Nizamettin Dalkilic
In this study, papillary muscles were isolated from the left ventricle of the rat heart for isometric contraction recordings and histological examinations. Under anesthesia, the animals’ rib cages were opened by sternotomy, and hearts were rapidly removed and moved into fresh Krebs solution; having 135 mM NaCl, 5 mM KCl, 2.5 mM CaCl2, 1 mM MgSO4.7H2O, 1 mM NaH2PO4.2H2O, 15 mM NaHCO3, 11 mM glucose, pH adjusted to 7.40, gassed with 95% O2 + 5% CO2 mixture (All chemicals were purchased from Sigma-Aldrich, Germany). In this solution, the hearts were fixed from the right ventricle by a small steel pin in the position visible from the dorsal region, and both atria are separated from the hearts by microsurgical scissors. An incision was made from the level of the atrioventricular valve to the apex on the ventricular wall, and the ventricle was opened to make the papillary muscles visible. Finally, the papillary muscles were isolated by cutting off the connection with the ventricular tissue.
Use of a parametric finite element model of the mitral valve to assess healthy and pathological valve behaviors
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
T. Alleau, L. Lanquetin, A.-V. Salsac
The mitral valve is the cardiac valve separating the left atrium from the left ventricle. It is composed of four elements: the anterior and posterior leaflets; the annulus which serves as insertion site in the heart muscle for the leaflets; the chordae tendineae which are attached to pillars in the ventricular wall and ensure that the very flexible leaflets remain within the ventricle; the papillary muscles which are located at the tip of the chordae tendineae and actively modify the tension acting on the leaflets. In the physiological case, the valve is open during diastole letting blood flow into the ventricle, and close during systole: the leaflets then create a hermetic seal between the two chambers preventing blood from regurgitating into the left atrium when ejected into the aorta. Mitral insufficiency is a valvular heart disease caused by a leaky mitral valve. It is the most frequent valvular pathology in Western countries after aortic narrowing upon calcification (Singh et al. 1999).
Association of left bundle branch block with new onset abnormal wall motion in treated hypertensive patients with left ventricle hypertrophy: the LIFE Echo Sub-study
Published in Blood Pressure, 2019
Ildri M. Stokke, Zhi Bin Li, Silvana Cicala, Peter M. Okin, Sverre E. Kjeldsen, Richard B. Devereux, Kristian Wachtell
A visual, semi-quantitative method in parasternal long-axis, short-axis, and apical views was used to assess wall motion [9]. The left ventricle was divided into 5 segments at the base and at papillary muscles (anterior and inferior septum; anterior, lateral and inferior walls) and four apical segments (septum, anterior, lateral and inferior walls), according to the Mayo Clinic criteria [10]. Each segment with normal thickening (11]. Normal wall motion was assigned if the wall thickening was preserved in patients with LBBB [11]. If segmental wall motion abnormalities were present in two contiguous segments in a vascular territory, they were considered significant, while global wall motion abnormalities were identified when all segments were hypokinetic [10]. The presence of segmental and global wall motion abnormalities was examined regularly at 1, 2, 3, 4 and 5 years after study enrollment, and the results were reported as dichotomous variables.
Related Knowledge Centers
- Muscle Contraction
- Right Coronary Artery
- Tricuspid Valve
- Systole
- Chordae Tendineae
- Mitral Valve
- Heart Valve
- Left Anterior Descending Artery
- Circumflex Branch of Left Coronary Artery
- Left Marginal Artery