Development of palliative medicine in the United Kingdom and Ireland
Eduardo Bruera, Irene Higginson, Charles F von Gunten, Tatsuya Morita in Textbook of Palliative Medicine and Supportive Care, 2015
SVCS results from the compression of the superior vena cava by the tumor arising in the mediastinum or in the right main or upper lobe bronchus or by large-volume mediastinal nodes (most commonly from the right paratracheal or precarinal lymph nodes). The superior vena cava carries blood to the heart from the head, arms, and upper torso. It is formed by the junction of the left and right brachiocephalic veins in the mid-third of the mediastinum and extends caudally for 6-8Â cm, coursing anterior to the right main-stem bronchus and insert into right atrium. It is joined posteriorly by the azygos vein as it loops over the right main-stem bronchus. It is a thin-walled vessel and the blood flows with relatively low intravascular pressure in it (2-8mmHg). Thus, when the superior vena cava is compressed, it leads to an increase in the pressure (to 20-40mmHg ) and it slows or even interrupts local flow. In this case, blood flows through a collateral vascular network to the inferior vena cava or the azygos system. This collateral flow dilates with the time and may accommodate to the flow of the superior vena cava after a few weeks.
The heart
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella in Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
The route of blood flow through the heart begins with the venae cavae, which return blood from the peripheral tissues to the right side of the heart (see Figure 7.1). The superior vena cava returns blood from the head and arms to the heart and the inferior vena cava returns blood from the truck of the body and the legs to the heart. Blood in the vena cavae has already passed through the tissues of the body and is low in oxygen. This deoxygenated blood first enters the right atrium and flows into the right ventricle. Contraction of the right ventricle propels this blood to the lungs through the pulmonary circulation by way of the pulmonary artery. As it flows through the lungs, the blood becomes enriched with oxygen and eliminates carbon dioxide to the atmosphere. Blood then returns to the heart through the pulmonary veins. The oxygenated blood enters the left atrium and then the left ventricle. Contraction of the left ventricle propels the oxygen-rich blood back to the peripheral tissues through the systemic circulation, passing first through the aorta, the largest arterial vessel.
Autopsy Cardiac Examination
Mary N. Sheppard in Practical Cardiovascular Pathology, 2022
Cut the inferior vena cava just above the diaphragm and lift the heart by the apex, reflecting it anteriorly and upwards to facilitate exposure of the pulmonary veins at their pericardial reflection. After confirming that the left and right pulmonary veins enter normally into the left atrium, the pulmonary veins are cut (Fig. 1.3). Then, the superior vena cava is opened to check for thrombosis or occlusion and opened up into the left and right brachiocephalic veins before being cut across. Following removal of the heart from the pericardial cavity, and before weighing the specimen, post-mortem blood clots should be removed by doing a midventricular slice through the ventricles and incising the atria. If one sees aneurysmal dilatation of the right ventricular wall, be aware of the possibility of right ventricular cardiomyopathy, Ebstein's abnormality of the tricuspid valve, pulmonary thrombi and pulmonary disease. Right ventricular hypertrophy usually points to pulmonary disease; look carefully in the pulmonary arteries for atheroma which indicates pulmonary hypertension. Left ventricular hypertrophy may be obvious externally. Aneurysm formation in the left ventricle is usually associated with a previous infarct. Flexibility is called for when dissecting the heart since each disease process requires a different approach. When one notes left ventricular hypertrophy, check for a history of hypertension, check for coarctation of the aorta and check the aortic valve carefully. Look for an impact lesion in the left ventricular outflow tract in cases of hypertrophic cardiomyopathy.
Anatomy-based characteristics of far-field SVC electrograms in right superior pulmonary veins after isolation
Published in Scandinavian Cardiovascular Journal, 2022
Wentao Gu, Weizhuo Liu, Jian Li, Jun Shen, Jiawei Pan, Bangwei Wu, Haiming Shi, Xinping Luo, Nanqing Xiong
It is universally agreed that complete pulmonary vein (PV) isolation is the cornerstone of catheter ablation in patients with atrial fibrillation (AF) [1,2]. Careful evaluation of PV isolation, including differentiating near-field from far-field electrograms originating from adjacent extra-PV structures by using mapping and pacing maneuvers, can help avoid futile ablation [3,4]. Superior vena cava (SVC) is one of the contributing sources of far-field signals appearing commonly in anterior aspects of right superior pulmonary veins (RSPVs) for their close anatomical relationship [5–7]. According to an early study, SVC potentials, recorded with circular mapping catheter with the help of venography, appeared in RSPVs in 23% patients during sinus rhythm right after successful PV isolation [8]. However, the anatomical difference accounted for the presence or absence of SVC potentials has not been clearly described. Currently, PV isolation is routinely performed with the assistance of a high-density 3-dimensional (3 D) mapping system, and computed tomography (CT) scan is widely used as pre-procedural guidance for understanding the procedural-related anatomy. In this study, we analyzed the detailed characteristics of far-field-SVC potentials in RSPV after PV isolation using 3 D mapping system and studied the relationship between the CT-based local anatomy and the presence of far-field-SVC electrograms.
Coronary Sinus Defect, Premature Restriction of Foramen Ovale and Cysto-Colic Peritoneal Band
Published in Fetal and Pediatric Pathology, 2023
The coronary sinus is formed by coalescence of venous tributaries comprised of a small, middle, great, and oblique cardiac vein; the left marginal vein; and the left posterior ventricular vein [5,6]. Together with the vena cavae (superior and inferior), the coronary sinus delivers deoxygenated blood to the right atrium [6]. Unroofed coronary sinus is a congenital cardiac anomaly first described by Raghib et al [1]. There is an overwhelming association of this anomaly with persistent left superior vena cava that drains the left internal jugular and subclavian veins into the coronary sinus [7]. A persistent left superior vena cava occurs in 0.1–0.5% of the general population, with 8% draining into the left atrium [2]. The morphologic type of unroofed coronary sinus have been classified as Kirklin and Barratt-Boyes types whereby (1) type I is completely unroofed with persistent left superior vena cava; (2) type II is completely unroofed but without persistent left superior vena cava; (3) type III shows partially unroofed midportion; and (4) type IV shows partially unroofed terminal portion [2,8,9].
Changes in CYP2D enzyme activity following induction of type 2 diabetes, and administration of cinnamon and metformin: an experimental animal study
Published in Xenobiotica, 2018
Ali Taheri, Hoda Lavasani, Sara Kasirzadeh, Behjat Sheikholeslami, Yalda H. Ardakani, Mohammad-Reza Rouini
The isolated liver perfusion study was conducted in rats. Animals were anesthetized using an intraperitoneal injection of xylazine/ketamine (15/75 mg/kg). The portal vein and superior vena cava were catheterized with an intravenous 16–18 gauge catheter, respectively. Five hundred units of heparin was injected into the inferior vena cava. Freshly prepared Krebs–Henseleit buffer containing 500 ng/ml tramadol was passed through the portal vein with a constant flow rate of 10 ml/min using a peristaltic pump. Thus, perfusion medium passed through the liver; then collected from the superior vena cava. The total volume of the reservoir was 200 ml. Temperature (37 °C), pH (7.4) and perfusion pressure (14 mmHg) were periodically monitored and kept unchanged through the study. Liver viability was proved by monitoring the liver enzymes activities, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), in perfusate samples by measuring the decrease in absorbance at 340 nm resulting from the oxidation of NADH because of the enzymatic reactions and its macroscopic appearance (uniformly pink to brown). Perfusate samples were collected at five minutes intervals up to 30 minutes and then at 10 minutes intervals up to 60 minutes. Samples were centrifuged at 10 000 rpm for 10 minutes. The supernatant was separated and stored at –20 °C until HPLC analysis was carried out.
Related Knowledge Centers
- Central Venous Catheter
- Inferior Vena Cava
- Vein
- Venae Cavae
- Blood
- Circulatory System
- Atrium
- Heart
- Thoracic Diaphragm
- Mediastinum