Electrophysiology
A. Bakiya, K. Kamalanand, R. L. J. De Britto in Mechano-Electric Correlations in the Human Physiological System, 2021
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.
Lung Microcirculation
John H. Barker, Gary L. Anderson, Michael D. Menger in Clinically Applied Microcirculation Research, 2019
The pulmonary circulation consists of the output of the right ventricle which, via the pulmonary artery and its branches, sends mixed venous blood to the pulmonary capillaries where it undergoes gas exchange, and returns it via the pulmonary veins to the left atrium. Gas exchange is the primary function of the lungs and is achieved by the close approximation of pulmonary capillaries and alveoli. The other blood supply to the lungs is the bronchial circulation, which is a small fraction of the output of the left ventricle. It branches from the thoracic aorta or intercostal arteries and supplies arterial blood to the conducting airways and other structures such as the visceral pleura, esophagus, large blood vessels and nerves, and lymph nodes. Bronchial veins drain into pulmonary veins and also into systemic veins (the azygos and hemiazygos veins, which drain into the superior vena cava). Anastomoses between the bronchial and pulmonary circulations have been found in larger vessels between bronchial and pulmonary arterial branches, and at the microcirculatory level between bronchial and pulmonary capillaries. Further discussion of the pulmonary and bronchial circulation is beyond the scope of this chapter, and the reader is referred to other articles.9,14
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 middle layer is the myocardium, which is the muscular layer of the heart. This is the thickest layer although the thickness varies from one chamber to the next. Thickness of the myocardium is related to the amount of work that a given chamber must perform when pumping the blood. The atria, which serve primarily as receiving chambers, perform little pumping action. Under normal resting conditions, most of the blood (75%) moves passively along a pressure gradient (higher pressure to lower pressure) from the veins, into the atria and into the ventricles where the pressure is close to zero. Therefore, it follows that the atria have relatively thin layers of myocardium, as powerful contractions are not necessary. On the other hand, when the ventricles contract, they must develop enough pressure to force open the semilunar valves and propel the blood through the entire pulmonary or systemic circulations. Under normal resting conditions, between heartbeats, the pressure in the pulmonary artery is approximately 8 mmHg and the pressure in the aorta is approximately 80 mmHg. Therefore, to eject blood into the pulmonary artery, the right ventricle must generate a pressure greater than 8 mmHg. However, to eject blood into the aorta, the left ventricle must generate a pressure greater than 80 mmHg. Because the left ventricle performs significantly more work, its wall is much thicker than that of the right ventricle.
Investigating the risk of deep vein thrombosis with JAK inhibitors: a disproportionality analysis using FDA Adverse Event Reporting System Database (FAERS)
Published in Expert Opinion on Drug Safety, 2023
Shefin Mytheen, Anju Varghese, Jismol Joy, Anakha Shaji, Antriya Annie Tom
Deep vein thrombosis (DVT) is a severely devastating disease affecting several million people worldwide, resulting in blood clot formation in deep veins. These clots can migrate to the lungs and obstruct pulmonary artery, leading to a clinical entity known as pulmonary embolism (PE). Factors biasing to DVT include conditions such as hereditary factors, hypercoagulability states, and connective tissue diseases mainly anti phospholipid syndrome, cancer, pregnancy, and trauma. Long-term immobility immediately reduces blood flow, predisposing to thrombus formation and contributing to the development of idiopathic DVT. Certain medications may also vary subtle balance between coagulation and fibrinolysis, thus predisposing to thrombosis [20]. Based on the completed FDA review of large randomized safety clinical trial on 1 September 2021, tofacitinib (XELJANZ and XELJANZ XR) was found to have increased risk of thromboembolic events (DVT and PE).
Management of congenitally corrected transposition from fetal diagnosis to adulthood
Published in Expert Review of Cardiovascular Therapy, 2023
Congenitally corrected transposition of the great arteries (ccTGA) is a complex congenital heart disease first described from an autopsy by a Bohemian pathologist working in Vienna, Karl von Rokitansky, in 1875 [1]. The anomaly is characterized by atrioventricular and ventriculo-arterial discordance [2]. Deoxygenated blood from the right atrium flows through the mitral valve into the morphological left ventricle, which gives rise to the pulmonary artery. Then, oxygenated blood flows into the left atrium that communicates with the morphological tricuspid valve and right ventricle, that is connected to the aorta. The aorta is located usually anterior and to the left. Consequently, the double discordance results in hemodynamic compensation, but the morphologically right ventricle works as systemic ventricle (systemic right ventricle, sRV). The most common anomalies are ventricular septal defect, pulmonary or subpulmonary stenosis, and systemic atrioventricular (morphological tricuspid) valve abnormalities [3] (Table 1). Additionally, cardiac malposition (dextrocardia or mesocardia) occurs in up to one-third of the patients. Associated malformations, especially the Ebstein-like anomaly of the systemic atrioventricular valve, have a significant impact on the clinical course of the disease. Conduction disturbances, including complete atrio-ventricular block, are another common cause of increased morbidity in ccTGA patients and might be the first manifestation of the disease.
Data-driven monitoring in patients on left ventricular assist device support
Published in Expert Review of Medical Devices, 2022
Lieke Numan, Mehran Moazeni, Marish I.F.J. Oerlemans, Emmeke Aarts, Niels P. Van Der Kaaij, Folkert W. Asselbergs, Linda W. Van Laake
In addition to noninvasive tools, invasive or implantable devices may be used to remotely monitor LVAD patients. Although not frequently used in combination with LVADs, the safety and feasibility of the CardioMEMS (Abbott Inc, Atlanta, GA, USA) in LVAD patients have been demonstrated [54]. The CardioMEMS, which measures pulmonary artery pressure, provides daily insight into a patient’s fluid status, enabling optimization of patients prior to LVAD implantation. In addition, pulmonary artery pressure lowering medication can be monitored. Several complications such as tamponade, aortic valve regurgitation, pump thrombosis, right heart failure or significant hemodynamic arrhythmias will lead to either congestion or reduced pulmonary artery pressure, which may be detected using the CardioMEMS sensor [55]. Likewise, it allows for telemonitoring after LVAD implantation. Zhou et al. incorporated a pressure sensor into the LVAD inlet in an experimental set-up. This enables a direct measure of the left ventricle function during LVAD support [56]. They stated that this is the start of a closed loop speed control based on left ventricular pressure. Although pressure sensors or flow probes may provide valuable information, durability, and reliability should be tested extensively in-vivo. The more components a device includes, the more prone it is to malfunction and failure. Future studies are warranted to prove its added value. Noteworthy, cost-effectiveness is not touched upon yet, and we may need to focus on more accessible and noninvasive telemonitoring tools first.
Related Knowledge Centers
- Arteriole
- Pulmonary Circulation
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- Lung
- Circulatory System
- Heart
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- Blood Vessel
- Artery
- Pulmonary Alveolus