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The history of circulation
Published in Dinker B. Rai, Mechanical Function of the Atrial Diastole, 2022
Vital spirits flowing to the end arteries are continuously dissipated into the tissues. We can generalize the theory of the circulation during the pre-Galenic era as explained in the diagram (Figure 1.1). Nourishment is taken from the intestine via the portal vein to the liver and it transforms this nourishment into blood and distributes it to various parts of the body through the hepatic vein and into the vena cava. The ascending portion of the vena cava supplies the heart, brain, and lungs. The descending portion of the vena cava supplies the rest of the body. The left ventricle and arteries are thought to be devoid of blood. It distributes the pneuma and life spirit to the rest of the body. Both the arteries and veins are thought to be end vessels and diffuse into the tissues. These were the concepts and teachings of circulation at the time. Based upon this, various ailments were treated (Figure 1.1).
Cardiac Tumours
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
Sarcomas which show a predominant smooth-muscle cell differentiation arise both in the left atrium and pulmonary veins. Leiomyosarcoma can begin in the vascular system supplying the heart muscle or in the endothelium lining the cardiac atria. In half of cases, they are situated in the left atrium, resulting in frequent diagnostic confusion with myxoma. When situated in the cardiac cavities, they cause blockage of blood flow in these vessels so it is frequently impossible to determine the initial tumour aetiology – cardiac or vascular – especially as pulmonary vein infiltration is part of atrial leiomyosarcoma growth. The histological appearances show compact bundles of spindle-shaped cells, with oval blunt nuclei. The cytoplasm is often vacuolated and desmin staining is often positive. Myxoid areas and more pleomorphic tumour cells can also be present. The diagnosis is confirmed by positive immunohistochemical reactions with SMA, desmin and vimentin. Vessel invasion and necrosis are especially useful prognostic criteria. Leiomyosarcomas with vascular aetiology are generally situated in the venous system and only exceptionally involve the great vessels. The inferior vena cava is involved most frequently. This difference in predilection to particular vessels is connected with the anatomical structure of its wall and resistance to high pressure. Large veins are composed of a greater amount of smooth muscle.
Electrophysiology
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
The cardiopulmonary system consists of blood vessels that carry nutrients and oxygen to the tissues and removes carbon dioxide from the tissues in the human body (Humphrey & McCulloch, 2003; Alberts et al., 1994). Blood is transported from the heart through the arteries and the veins transport blood back to the heart. The heart consists of two chambers on the top (right ventricle and left ventricle) and two chambers on the bottom (right atrium and left atrium). The atrioventricular valves separates the atria from the ventricles. Tricuspid valve separates the right atrium from the right ventricle, mitral valve separates the left atrium from the left ventricle, pulmonary valve situates between right ventricle and pulmonary artery, which carries blood to the lung and aortic valve situated between the left ventricle and the aorta which carries blood to the body (Bronzino, 2000). Figure 3.9 shows the schematic diagram of heart circulation and there are two components of blood circulation in the system, namely, pulmonary and systemic circulation (Humphrey, 2002; Opie, 1998; Milnor, 1990). In pulmonary circulation, pulmonary artery transports blood from heart to the lungs. The blood picks up oxygen and releases carbon dioxide at the lungs. The blood returns to the heart through the pulmonary vein. In the systemic circulation, aorta carries oxygenated blood from the heart to the other parts of the body through capillaries. The vena cava transports deoxygenated blood from other parts of the body to the heart.
Persistent Left Superior Vena Cava: Why is Prenatal Diagnosis Important?
Published in Fetal and Pediatric Pathology, 2022
Ayşe Keleş, Osman Yılmaz, Gülşah Dağdeviren, Özge Yücel Çelik, Aykan Yücel, Dilek Şahin
Persistent left superior vena cava (PLSVC) is the most common variation of the thoracic venous system [1,2]. It is found in 0.3%–0.5% of the general population and 4%–8% in those with congenital heart disease (CHD) [3,4]. In the embryonic period, anterior cardinal veins perform the venous drainage of the cephalic region and upper extremity. Except for a small part that constitutes the left superior intercostal vein, the left anterior cardinal vein regresses in the eighth week of embryogenesis. Failure of this regression results in PLSVC [4,5]. In most cases, the right and left superior vena cava coexist. The specific combination of a persistent LSVC and non-right superior vena cava was reported to be 0.05% in an autopsy series [6,7]. PLSVC typically empties into the right atrium via the coronary sinus, but may empty directly into the left atrium [8].
The evolution of long-term pediatric ventricular assistance devices: a critical review
Published in Expert Review of Medical Devices, 2021
Louis Marcel, Mathieu Specklin, Smaine Kouidri
The various surgical interventions in young patients result in a modified anatomy of the heart, of the systemic and pulmonary circulation. For instance, the Fontan procedure is a surgical intervention used in children suffering from various CHDs such as triscupid atresias (absence of right atrioventricular connection) or univentricular hearts. The interventions modifies the blood circulation around and inside the heart and is described in Figure 4. The venous blood coming from superior and inferior vena cava is diverted directly to the pulmonary arteries without passing through the ventricle. Pulmonary and systemic circulation are then placed in series with the dingle ventricle. As devices are designed for normal morphology, patients that have completed the Fontan operation present an inferior surival compared to those with bi-ventricular physiology (42% vs 73%) [47]. [48; 49; 50; 51; 52; 53; 54]
Tetralogy of Fallot with isolated levocardia in a young female
Published in Journal of Community Hospital Internal Medicine Perspectives, 2019
Zeeshan Sattar, Hafez Muhammad Abdullah, Sohaib Roomi, Waqas Ullah, Adnan Khan, Ali Ghani, Asrar Ahmad
Preoperative echocardiography revealed the anatomy of levocardia, a large subpulmonary ventricular septal defect (VSD), and severe subvalvular pulmonic stenosis with a gradient of 80 mmHg. It also revealed atrioventricular (AV) discordance with right anterior aorta arising from morphologically left sided right ventricle and left posterior pulmonary artery arising more than 60% from morphologically left sided right ventricle. There was associated congenitally corrected transposition of the great arteries and a double outlet right ventricle (DORV). The morphologically left sided right ventricle was also hypertrophied. There was a single left sided superior vena cava and an inferior vena cava that drained into right atrium. The interatrial septum was intact. Other findings included a left aortic arch and an intact interatrial septum.