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Unformatted text preview: Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. BME 501 FINAL EXAM STUDY GUIDE 12/07 1. Chapter 1 Blood Flow Name the 5 different types of leukocytes and their specific role(s). Which one is most abundant in the circulation? Which one is responsible for the humoral response in organ rejection? B lymphocyte What are the cells involved in rejecting implantable device? Lymphocytes What are the cells involved in rejecting stem cell transplant? Lymphocytes Hemostasis Following injury to a blood vessel, all of the systems are activated. The hemostatic process is divided into 2 components; primary hemostasis Primary hemostasis depends upon the response of the platelet and blood vessel wall to the injury. When the small blood vessels are injured, blood platelets adhere and aggregate at the site of injury, reducing and finally arresting bleeding. secondary hemostasis Secondary hemostasis starts when the cascade system of coagulation is activated by substances released at the time of blood vessel injury. Clinical application: PT The Prothrombin Time or PT is a laboratory screening test used to detect coagulation disorders. It measures the activity of the factors of the extrinsic pathway including factors II, V, VII, X, and fibrinogen. The extrinsic factors not measured in the PT test are Factors III (Thromboplastin), and IV (Calcium). The PT is also used to monitor oral anticoagulant therapy such as warfarin. Our California governor is taking Warfarin (Coumadin) to prevent hemostasis II for his aortic mechanical valve. If Arnold received an Edward Science pericardial valve, is chronic anticoagulation therapy indicated? No During CABG (cardiac aortic bypass graft) surgery, the patient is put on the heart lung by-pass machine, why is anticoagulation indicated? How is the perfusionist monitor whether the dosage is within the therapeutic range? Heparin dosage to its effect on Activated coagulation time. (aPTT) Navier-Stokes Equations 3-D unsteady flow In equation 2, describe the individual terms. For Newtonian fluid at a constant density, viscosity, and at steady state, what terms are cancelled? Derive Womersley's and Reynolds numbers. where u = velocity vector field, = thermodynamic internal energy, p = pressure, T = temperature, = density, = viscosity, KH = heat conduction coefficient, F = external force per unit mass, and 1 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. If the Womersley's number is zero and Reynolds' number is less than 500, draw the velocity profile in a 2-D channel. Reynolds' number is less so the flow is not turbulent also its the same for both the cases so the diameter has not changed. If the Womersley's number is 11 and Reynolds' number is less than 500, draw the velocity profiles in one cardiac cycle. What is the range of Reynolds number for capillary surrounding alveolar sacs? 0.001 to 0.01 What is the range of Reynolds number for blood flow across the aortic valve? 2000-3000 Chapter 4 By-Pass Name two commonly used by-pass grafts. Saphenous and Radial The valves in the vein grafts affect blood flow, how is the surgeon anastomose the vein graft to bypass the coronary artery with atherosclerosis. The graft is anastomose between the aorta and the coronary artery after bypassing the block. Chapter 6 Atherosclerosis Name RCA, LCA, LAD, and left circumflex arteries. What is the number one cause of death in the US? Atherosclerosis What is the pathogenesis of atherosclerosis in a vessel? lumen atheroma If you are smoker, and have a history of hypertension, diabetes, and hypercholesterolemia, your risk for have acute coronary syndrome is high! What are the some components inside the atheroma? Pieces of plaque in the internal carotid artery can break free, travel to the brain, and block blood vessels that supply blood to the brain. This is called brain attack or stroke. Patient can develop paralysis, speech, memory, visual, cognitive, or equilibrium deficits. 2 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. The high hydrostatic pressure on the arterial side squeezes water and nutrients out of the capillaries. Water leaving the capillaries builds up the osmotic pressure because since the blood components become more concentrated. Towards the venal end, water and waste materials are sucked into capillaries by the osmotic pressure. What is the ratio of inertia force to viscous force in the above region? Reynolds' number: 0.001 to 0.01. Reference: Cardiovascular Physiology by Berne and Levy. Also the inertial force is very low as compared to viscous force. Note that we did not have time to cover the concept of hydrostatic and oncotic pressures in the capillary. However, the following information would enhance your understanding of blood pressure in the capillaries and venules in which exchanges of nutrients and waste product take place. Diffusion is the key factor in providing exchange of gases, substrates, and waste products between the capillaries and the tissue cells. The net transfer of fluid across the capillary and venule endothelium is mainly attributable to diffusion and absorption. The process of diffusion is described by the Fick's law: What term is missing in this equation to describe the crosssectional area of the diffusion pathway? Hydrostatic pressure is the principal force in capillary filtration. The hydrostatic pressure (blood pressure) within the capillaries is not constant and depends on the arterial pressure, venous pressure, and pre- and post-capillary venous resistance. Which term in the NavierStokes equation describes "hydrostatic force"? The direction and magnitude of the movement of water across the capillary wall are determined by the algebraic sum of hydrostatic and osmotic pressures that exist across the membrane. The key factor that restrains fluid loss from the capillaries is the osmotic pressure of the plama proteins-usuallytermed colloid osmotic pressure or oncotic pressure. 3 The British physiologist Starling first identified the interrelationship between the hydrostatic pressure and the oncotic forces within the capillary.Hydrostatic pressure tends to cause fluid to leave the plasma, and oncotic pressure pulls it back. These two forces tend to balance each other. The hydrostatic forces, however, are gradually decreasing over the length of the capillary, while the oncotic pressure remains constant. If these pressures were graphed, they would look approximately like the following figure: On the arteriole end, the hydrostatic pressure is higher than the oncotic, so there is fluid movement from plasma to interstitium. The magnitude of this water flow is indicated by the light blue area on the left (downward arrows). On the venule end, the hydrostatic pressure has dropped below the oncotic. Fluid moves back from the interstitium to the plasma. The magnitude of this reverse flow is indicated by the green area on the right (upward arrows). In a normal capillary bed, fluid gain and loss from the plasma are closely balanced, so there is little or no net change in plasma and ISF volumes. Note that this can be seen graphically, since the blue and green (right and left) regions have equal areas. Starling's hypothesis states that the fluid movement due to filtration across the wall of a capillary is dependent on the balance between the hydrostatic pressure gradient and the oncotic pressure gradient across the capillary. The four Starling's forces are: hydrostatic pressure in the capillary (Pc) hydrostatic pressure in the interstitium (Pi) oncotic pressure in the capillary (pc ) oncotic pressure in the interstitium (pi ) The balance of these forces allows calculation of the net driving pressure for filtration. Net Driving Pressure = [ ( Pc - Pi ) - ( pc - pi ) ] Net fluid flux is proportional to this net driving pressure. In order to derive an equation to measure this fluid flux several additional factors need to be considered: the reflection coefficient the filtration coefficient (Kf ) An additional point to note here is that the capillary hydrostatic pressure falls along the capillary from the arteriolar to the venous end and the driving pressure will decrease (& typically becomes negative) along the length of the capillary. The other Starling forces remain constant along the capillary. The reflection coefficient can be thought of as a correction factor which is applied to the measured oncotic pressure gradient across the capillary wall. Consider the following: The small leakage of proteins across the capillary membrane has two important effects: the interstitial fluid oncotic pressure is higher then it would otherwise be. not all of the protein present is effective in retaining water so the effective capillary oncotic pressure is lower than the measured oncotic pressure (in the same way that there is a difference between osmolality and tonicity). 4 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Both these effects decrease the oncotic pressure gradient. The interstitial oncotic pressure is accounted for as its value is included in the calculation of the gradient. The reflection coefficient is used to correct the magnitude of the measured gradient to take account of the `effective oncotic pressure'. It can have a value from 0 to 1. For example, CSF & the glomerular filtrate have very low protein concentrations and the reflection coefficient for protein in these capillaries is close to 1. Proteins cross the walls of the hepatic sinusoids relatively easily and the protein concentration of hepatic lymph is very high. The reflection coefficient for protein in the sinusoids is low. The reflection coefficient in the pulmonary capillaries is intermediate in value: about 0.5. Starling Equation The net fluid flux (due to filtration) across the capillary wall is proportional to the net driving pressure. The filtration coefficient (Kf) is the constant of proportionality in the flux equation which is known as the Starling's equation. The filtration coefficient consists of two components as the net fluid flux is dependent on: the area of the capillary walls where the transfer occurs the permeability of the capillary wall to water. (This permeability factor is usually considered in terms of the `hydraulic conductivity' of the wall.) The filtration coefficient is the product of these two components: Kf = Area x Hydraulic conductivity A `leaky' capillary (eg due to histamine) would have a high filtration coefficient. The glomerular capillaries are naturally very leaky as this is necessary for their function; they have a high filtration coefficient. Typical values of Starling Forces in Systemic Capillaries (mmHg) Arteriolar end of capillary Capillary hydrostatic pressure Interstitial hydrostatic pressure Capillary oncotic pressure Interstitial oncotic pressure 25 -6 25 5 Venous end of capillary 10 -6 25 5 The net driving pressure is outward at the arteriolar end and inward at the venous end of the capillary. This change in net driving pressure is due to the decrease in the capillary hydrostatic pressure along the length of the capillary. During a hot summer day, you are perspiring. Your capillary bed dilates and fluid leak out. What is the relation between hydrostatic and oncotic pressures? The hydrostatic pressure increases while the oncotic pressure decreases. So that the net fluid flux defined by the above equation is a positive number. (write the eqn.) 5 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Patients with liver failure fail to synthesis protein. As a result, intracellular protein concentration is low. This leads to a low intracellular oncotic pressure. Why do these patients suffer from fluid accumulation in the extracellular space (that is, why does fluid fail to be reabsorbed in the venules?) What is their oncotic pressure? The oncotic pressure inside the capillary towards the venal end decreases thus the net driving force will be outside n not inside. (Draw that diagram). Blood pressure in the capillaries The pressure of arterial blood is largely dissipated when the blood enters the capillaries. Capillaries are tiny vessels with a diameter just about that of a red blood cell (7.5 m). Although the diameter of a single capillary is quite small, the number of capillaries supplied by a single arteriole is so great that the total cross-sectional area available for the flow of blood is increased. Therefore, the pressure of the blood as it enters the capillaries decreases. Why does the surface tension in the capillary bed exponentially increase? Why is the Reynolds number so low in this region? What is the Womersley's number in this region? 1. Due to decrease in radii & increase in 2. viscous > inertial ; 3. Wormersley no. 0.75 surface area. Blood pressure in the veins When blood leaves the capillaries and enters the venules and veins, little pressure remains to force it along. Blood in the veins below the heart is helped back up to the heart by the muscle pump. This is simply the squeezing effect of contracting muscles on the veins running through them. One-way flow to the heart is achieved by valves within the veins. Why is the vast majority of effect body volume remain in the venous system (the remaining 85 % resides in the low pressure side of the vascular system)? File 1 Why did War World I pilots experience block-out when ascending against a several-fold increase in G-force?Coz the blood from the heart has to move up against that high G-force which takes time so there's a temporary black out. Why does prolonged flight across the Pacific or Atlantic Oceans predispose individuals to hemostasis and DVT? Coz the movement of the venous blood back to the heart is not facilitated by the muscles not contracting. Chapter 8 Excitation-Contraction Coupling Mechanistically, digoxin inhibits the Na/K ATPase pump. Digoxin probably competes with potassium for the K binding site on the pump. Referring back to the basic physiologic function of a myocardial cell, recall that this pump exchanges intracellular Na for extracellular K. Also recall that extracellular Na is exchanged for intracellular Ca by a non-energy dependent facilitated diffusion countertransport mechanism. THEREFORE, if the Na/K pump is inhibited, intracellular Na will INCREASE. This obliterates the concentration gradient that drives the Na/Ca exchange mechanism. This, in turn, results in an increase in intracellular Ca. This Ca may then be used to directly or indirectly (by causing the release of additional Ca from the SR) cause prolonged excitation-contraction coupling, thereby prolonging the contraction of the muscle fibres (hence a positive inotropic effect). The mechanism, illustrated and discussed above, is responsible for the beneficial pharmacodynamic response of positive inotropy. However, cardiac glycosides possess other pharmacodynamic actions that contribute other effects that may also influence cardiac function. These agents will stimulate both the adrenergic and vagal neurones that control cardiac function. Stimulation of these nerves is presumed to result from a similar action on the neurone (inhibition of ATPase). These effects are somewhat dose dependent, with myocardial tissues affected at low doses, the vagus nerve affected at slightly higher doses, and sympathetic stimulation not clinical evident until toxic doses are attained. 6 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Recalling the normal physiology of cardiac control, it is evident that stimulation of the vagus nerve at therapeutic doses of digoxin can result in a negative chronotropic effect, slowing heart rate (bradycardia). Excessive action by this mechanism can ultimately result in second or third degree heart block that may be characterisic of digoxin toxicity. (Another contributor to this bradycardia is the effect of digoxin at the AV node specifically, where the refractory period may be prolonged, delaying impusle conduction from the AV node to the ventricle.) How does digitalis increase in intracellular Calcium? See above. Is it true that digitalis has a positive ionotropic effect? Yes How does digitalis induce a vagal effect in cardiac conduction fiber? Is it true that digitalis has a negative chronotropic effect? Yes Negative feedback mechanism. Chapter 9 The Cardiac Conduction System The adrenergic receptors that subserve the responses of the sympathetic nervous system have been divided into two discrete receptor types: alpha adrenergic receptors and beta adrenergic receptors. Beta Receptors have been further subdivided into beta1 and beta2 receptors. The ability of epinephrine, norepinephrine and isoproterenol to increase the force of myocardial contraction was examined and the dose response curves presented below were obtained. These electrophysiologic factors contribute to the orderly, rhythmic electrical activity that assures the efficient contractile activity of the heart. In response to beta receptor activation, these parameters increase and the heart beats at a faster rate. Autonomic Innervation of the Heart Left Parasympathetic The Cardiac Conduction System SA AV RV Effect of Beta Receptor Activation on Myocardial Electrophysiology 1.Increase slope of phase 4 spontaneous depolarization. 2. Increase in maximal rate (dVm/dt) of phase 0 depolarization. 3. Increase conduction velocity. 4. Decrease refractory period. How does parasympathetic system (vagal nerve) decrease the upstroke slope (slew rate) of the slow action potential? Word File 1 How does sympathetic system affect the slew rate of fast response curve? -Which ionic channel is affected? Na ion channel -Which toxin markedly depresses the phase 0 repolarization decreasing Vmax? 7 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Chapter 10 Autonomic Nervous System Sympathetic stimulation speeds up the sinus node (sinus tachycardia) and vagal activity slows the node (sinus bradycardia). Increased concentration of the sympathetic transmitter noradrenaline, and of adrenaline from the adrenal glands, cause positive inotropic state (increased contractility), positive chronotropic state (increased frequency), positive dromotropic state (increased conduction velocity), and positive bathmotropic state (increased irritability) on the heart. Noradrenaline activates a-adrenergic constrictor receptors in the coronary vessels, whereas adrenaline activates badrenergic vasodilatator receptors. In response to a fight or flight state, is your sympathetic system dominating your parasympathetic system? What are the neurotransmitters for pre- and post-synaptic junctions, respectively? What is the neurotransmitter for neuron-effector junction for the parasympathetic system? Chp 10 Slide 9. Ans: Sympathetic. Pre= Acetylcholine & Noradrenaline. Acetylcholine and Nitric Oxide. The release of noradrenaline (or norepinephrine) -stimulates heartbeat -raises blood pressure -dilates the pupils -dilates the trachea and bronchi -stimulates the conversion of liver glycogen into glucose -shunts blood away from the skin and viscera to the skeletal muscles, brain, and heart -inhibits peristalsis in the gastrointestinal (GI) tract -inhibits contraction of the bladder and rectum In short, stimulation of the sympathetic branch of the autonomic nervous system prepares the body for emergencies: for "fight or flight". The release of ach (acetylcholine) results in an opposite effect to the above organ systems. -You are burning the night oil for the BME 501 final exam. It is already 1 am, you are low in sugar! Your roommates just ordered the pizza. You begin to salivate! Which CNS system is inducing salivation? Parasympathetic -To remain awake, you are drinking coffee. How does coffee affect your sympathetic system? Coffee has caffeine which stimulates the sympathetic nervous system. Plasma, renin activity. (File 1) The heart is innervated by vagal and sympathetic fibers. The right vagus nerve primarily innervates the SA node, whereas the left vagus innervates the AV node; however, there can be significant overlap in the anatomical distribution. Atrial muscle is also innervated by vagal efferents, whereas the ventricular myocardium is only sparsely innervated by vagal efferents. Sympathetic efferent nerves are present throughout the atria (especially in the SA node) and ventricles, including the conduction system of the heart. -After the heart transplant, how are the donor hearts responding to an increase in sympathetic tone? No, so plan B -Does digitalis work on the heart transplant individual? Yes 8 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Baroreceptor reflex Baroreceptors are sensors found in the major arteries of the body, including the carotoid arteries and the aorta. When the arterial pressure is increased, the sensors are stretched, signals are transmitted into the central nervous system. Feedback signals are sent back to reduce arterial pressure downward toward the normal level. This is a process of negative feedback. The effect of different arterial pressures on the rate of impulse transmission in a Hering nerve. Note that the baroreceptors are not stimulated at all by pressures between 0 and 60 mm. Hg, but above 60 mm. Hg they respond progressively more rapidly and reach a maximum at about 180 mm. Hg. How do the baroreceptors respond to a sudden decrease in arterial pressure and how do they alter cardiovascular control? Many Sunday morning church goers pass out after being inspired by the priests. This experience usually induces peripheral vasodilation by the complex interplays between higher centers in the brain and medullary cardiovascular center. The peripheral vasodilation in the venous system causes a drop in venous return, thus a decrease in stroke volume (SV) and a drop in cardiac output (CO). Consequently, the blood pressure drops and the individuals feel dizzy or experience a fainting spell and fall. How do the carotid baroreceptors respond to a drop in BP and restore CO? Firing rate decreases. Sympathetic tone increases. Some priest claims to possess holy spirits. The believers fall when the priest lays his hand around the victims' necks. What are these voodoo priests doing to the gullible believers' carotid body? Does an increase in venous return affect the Bainbridge reflex? Yes Chemoreceptors Breathing is stimulated by a fall in PaO2, a rise in PaCO2 and a fall in arterial pH. These changes are detected by chemoreceptors. They are structures that are sensitive to the partial pressure of oxygen (PO2), the partial pressure of carbon dioxide (PCO2), and the pH of the blood. They are also sensitive to certain drugs such as acetylcholine and nicotine. They are involved primarily with the regulation of respiration, but also they are involved in complex interactions with a number of cardiovascular reflexes and responses. The directional change in heart rate is evoked by the peripheral chemoreceptors related to the enhancement of pulmonary ventilation (Text: Figure 4-14). Summary: Baroreceptor Reflex The baroreceptor reflex is the body's rapid response system for dealing with changes in blood pressure. In the diagram green lines denote inhibitory effects and red lines indicate excitatory effects. The alterations in the heart rate are achieved by reciprocal changes in vagal and sympathetic neural activity. The high heart rate is achieved by intense sympathetic activity and virtually absence of vagal activity. After a strenuous work out, your chemoreceptors sense hypoxia and hypercapnea. To remove CO2 in exchange for O2, what is happening to your respiratory and heart rates (increase or decrease)? Why? Ans: Increase. Primary-> heart rate; secondary-> Respiratory. 9 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Chapter 16 Mechanical Aspects of Cardiac Performance How is the PCW (pulmonary capillary wage) pressure measured (Hint: refer to figure 20 on page 215)? Varghese Page 1 PCW is used as a surrogate for preload. What is the reading for PCW? Varghese Page 2 Draw a pressure volume loop (P-V loop) and label 1, 2, 3, and 4. Which numbers correspond to preload and afterload, respectively? 1,2 3,4 Label the diastolic pressure-volume curve? When there is a decrease in compliance during diastole, is the slope shifting upward or downward? upward Varghese File Page 3 Refer to figure 6 in your textbook, is it possible for digitalis to increase contractility on the pressure-volume loop while maintaining preload and afterload? Yes Draw a P-V for the effect of acute increase in afterlaod while maintaining normal contractility and preload (Fig. 7 in your textbook)? What happens to SV? Can this P-V loop represent patients with hypertension or aortic stenosis? How is restoration of SV established? Decreses; Yes; by increasing contractility. Varghese File Page 3. Draw the Frank-Starling relationships in response to (1) digitalis, and (2) a toxin to block phase 0 of the action potential. Varghese File Pg 4. Note that SV depends on preload, afterload, and cardiac contractility. Derive cardiac output by FIck's principle (Refer to lecture note and Berns and Levy). Varghese File Pg 4. 10 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Derive cardiac output by indicator dilution. Varghese File Pg 5 Derive cardiac output by thermodilution. Varghese File Pg 5 Fick vs Indicator dilution Methods Fick measurement is accurate for low output states and irregular heart beats (Rhythms) CO = O2 consumption/[(A-V)O2 X hemoglobin concentration x(vol10%) x10] Disadvantages: simultaneous measurement of oxygen consumption logistic problem with a tight gas exchange coupling at bed site If patient has a mitral valve regurgitation, which method is more accurate? Thermodilution Indicator dilution is accurate for high output states Inaccurate in the presence of irregular heart rates or rhythms and coexistent regurgitation of a valve between the ejection site and sampling site Thermodilution-current methods in cardiology practice If a patient has atrial fibrillation, why is Fick's method better? Irregular heart beat. Group Presentations Group 1 Tissue Engineering Cardiac Progenitor Cells (refer to chapter 31) Cyrus Arman and Anna Zhu Where are potential sources of stem cells? Blastocytes, Bone marrow. They are stem cells derived from the inner cell mass of an early stage embryo known as a blastocyst. Are pluripotent hence can differentiate into three germ layers. Unlimited self-renewable capacity. (Wikipedia) What is embryonic stem cell (SC)? What is hematopoetic stem cell? Why is stem cell pluripotent? They are stem cells which give rise to all blood cell types & are self-renewable. Found in the bone marrow of adults.(Wikipedia) Because it has the potential to differentiate into any od the three germ layers: endoderm, mesoderm & ectoderm.(Wikipedia) 11 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. What is differentiation vs. proliferation? How is fluid shear stress influencing embryonic stem cell differentiation into vascular cells? How do ones identify successful differentiation of stem cell into contractile cardiomyocyte? Understand the tissue engineering approaches for embryonic stem cell differentiation into cardiomyocytes (Scaffold, biomemetic bioreactor systems). Group Presentation 2 Pacemakers Steven Woods, Vikram Verghese, and Lam Mai Distribution of Blood to the Heart A patient suffers from acute coronary syndromes presents to the Emergency Room with bradycardia (Heart rate ~30's), which coronary artery is more likely involved? RCA On EKG, you discover that this patient has heart block. What are the possible conduction structures affected by ischemia or depletion of blood perfusion as a result of atherosclerosis? 4 Bundle of His and AV node. How does the Pacemaker restore normal sinus rhythm? Where are the pacing leads located? Refer Varghese File. File 2 Power Supply Voltage (V) Based on this diagram, learn how to calculate power supply for battery design (refer to presentation on biventricular pacing). Battery Li-I Battery Elective Replacement Indicator Lifespan (10-15 Years) Increased by improved lead design 10 Group Presentation 3 AICD (Refer to Chapter 23) Kate Nelson, Krunal Patel Manishaben Patel An Automatic Implantable Cardioverter Defibrillator (AICD) is a small battery powered electrical impulse generator which is implanted in patients who are at risk of sudden cardiac death due to ventricular fibrillation and ventricular Tachycardia. Ventricular fibrillation Normal Sinus rhythm Ventricular Tachycardia 12 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. What is the CO when the patient is in ventricular fibrillation and ventricular tachycardia? Zero and decreases EF <30% resply. What does AICD do to restore CO? It delivers electric impulse when it detects arrythmia which causes cardiac conduction sys to resync What are the functions of the "leads" and "pulse generator" in an AICD?Give ele. impulse;houses battery, C n circuitry. How is battery life calculated?Slide 16 and 17. Arrythmia detection intervals When to shock? Group Presentation IV Biventricular Pacing Joanne Olecko and Michael Breninford (Refer to Chapter 24) Define congestive heart failure (CHF). In patient with CHF, what is the left ventricular ejection fraction (LVEF)? What is the SV, what is the CO? SV(Decreases)= EDV-ESV ; CO (decreases)=HR*SV ; LVEF (decreases)= SV / EDV (30%); Show a normal P-V loop. Show a P-V in patient with CHF. Show the P-V loop after biventricular pacing. In presentation page 11. What is the role of coronary sinus? For passage of Lead to place it in the LV. Describe the lead placement for biventricular pacing. How is it different from those of pacemakers and AICD? BVP: Atrial Lead, RV Lead & LV Lead ; Pacemakers: Group Presentation 5 Cardiac Prosthetic Valves Brian McGee, Anshul Shah, and Nivedita Rao Refer to Chapter 27 Anatomy Human heart has 4 cardiac valves ~ 40 million beats/year or ~ 3 billion beats/lifetime Allows blood flow in one direction only Atrioventricular (AV) valves Mitral: 2 leaflets Tricuspid: 3 leaflets Pulmonic & aortic are outflow valves Both have three leaflets 13 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. What are the main parameters associated with valve replacement (pressure gradient and EOA)? What is aortic stenosis? It is the constriction or incomplete opening of the aortic vavle due to the aging factors like calcification wear and tear,etc. It may lead to atherosclerosis too. Draw a LV pressure tracing and aortic tracing in an 89 individual with aortic stenosis? Show pressure gradient. Slide 11. Using the Bernoulli's principle, derive EOA. Slide 9. When the peak pressure gradient is greater than 50 mHg and EOA less than 1 cm2, the cardiologist needs to monitor the patient's symptoms such as shortness breath, chest pain, and most importantly, fainting spell (due to high afterload, decrease in SV, CO, and BP). Draw this individual's P-V loop? Show the afterload. Draw this individual's P-V loop after aortic valve replacement with pericardial valve. What is chronic anticoagulation not indicated in this individual? Biocompatible. If a 50 year old active individual with congenital biventricular aortic valve presents to you with a severe aortic stenosis (peak pressure gradient > 50 mmHg, EOA=0.5 cm2), why is artificial valve considered a more viable option? Why is chronic anticoagulation indicated? Because it lasts longer. Which is better for young individuals. Group 6 Cardiac MRI (Chapter 19) Mechanism: Draw a single magnetic dipole moment in a static magnetic field of strength (Bo). After excitation, the protons realign to their equilibrium state which generate a signal that is captured by MRI RF coils (Fig. 2). What are T1 and T2 relaxation times able to differentiate tissues, blood, and air? They differ in their T1 & T2 relaxation times. Define T1 and T2 weighted image? T1 W- Short TE and TR T2 W- Long TE and TR Why are individuals with pacemakers, AICD's, or Biventricular Pacing unable to undergo MRI scan? It may induce some magnetic and electric fields in the machines which will hamper its working. Why are blood and fluid in the pericardial sac exhibiting a bright signal than that of the septum and left ventricular wall? we are trying to use gradient recall echo which gives a higher signal intensity to the moving fluids than surrounding structures. We apply smaller flip angels. 14 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. Group 7 Echocardiogram Chapter 18 VIvek Thakkar, Tushar Bansal, Stphen Sin What is the ultrasound frequency range for cardiovascular application? (2-10 MHz) The ability of cardiac ultrasound to resolve anatomic structures depends on the wavelength, defined as: =c/f, where c is the speed of sound in the medium, f is the frequency of wave in Hz, and is wavelength. For pediatric ultrasound, a 7.5 MHz transducer, =0.43 mm, or an axial resolution of 0.86 mm. What is the angle between the beam path (transducer) and the direction of RBC flow to achieve the maximal Doppler shift? 0 (degrees). Group 8 IABP Harshet Thakkar, Harshet Busa, and Camilo Shiwa IABP is indicated in patients with cardiogenic shock, a dire condition in which LVEF is very low (<25%) as a result of a massive heart attach (usually affecting the left coronary artery). Draw the P-V loop in patients with cardiogenic shock. Draw the P-V loop in patients who receive IABP. How does counter-pulsation by IABP reduce preload? During which phase of the cardiac cycle is the balloon inflated? 15 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. EFFECTS OF IABP Aortic pressure Cardiac Blood Flow LV Pressure Left Ventricular How does IABP improve CO? Augmented Diastolic Pressure Increase in Coronary Flow Systolic (Vacuum effects due to deflation) Afterload (Due to vacuum effect upon deflation) Coronary blood flow (Due to CounterPulsation mechanism) Systolic (Due to the vacuum effect upon deflation) Volume (Due to vacuum effect upon deflation) Diastolic (Due to inflation) Preload (Frank-Starling Law reduced workload since less tension) Cardiac output (Due to increase in SV) Enddiastolic (FrankStarling Law reduced workload since less tension) Wall tension (Frank-Starling Law reduces workload) CO (Due to increase in SV) Group 9 Drug Eluting-STENTS Rohan Desai, Rui Zhu, Yifan Zhang Drug-Eluting Stents (DES) Why is a bare stent immunogenic? As its a foreign object & not native to the body, Stainless Steel, Gold, Tantalum, Nitinol, Polymer materials. (For pros and cons look in the Varghese file) What are the materials used to fabricate stents? What is Nitinol? it incites an immune response. This may cause cell proliferation on the stent. In addition, there is a strong tendency for clots to form at the site where the stent damages the arterial wall. Shape-memory nickel-titanium alloy. (Transformation temperature) Can you propose a biodegradable and biocompatible stent? Among the polymers suggested for bioabsorbable stents are Poly-L-lactic acid (PLLA), polyglycolic acid (PGA), poly (D, L-lactide/glycolide) copolymer (PDLA), and polycaprolactone (PCL). Where are the mechanisms of action for drug eluting stent in the growth cycle? Group 10 Stem Cells for Myocardial Regeneration Matthew Gehl, Rakesh Patel Has stem cell therapy demonstrated the possibility to shift P-V loop to the left (green to red)? Yes Where is hamtatopoietic harvested? Bone Marrow. stem cell (HSC) What is the one of the differences between embryonic and hematopoietic stem cells? Human studies by Stephen Demeler and Zeiher's group published in American Journal of Cardiology demonstrated that an increase in LV ejection fraction following acute myocardial infarction (AMI) through 4 months for both injected Cardiac Progenitor Cells (CPC) and Bone Marrow Cells (BM). On average, EF increased from 50% to 58%. -What was the duration of the study? 4 -12 months -How many subjects were recruited to this study? 59 patients. N=30 received CPC. N=29 received BM. Embryonic cells are pluripotent & have unlimited renewable capacity.Embryonic->embryo Hemato. cells are multipotent and limited self-renewable.(Wikipedia).Hema. ->Adult cells 16 Edited by Foxit Reader Copyright(C) by Foxit Software Company,2005-2007 For Evaluation Only. -What was the cell transplant protocol? CPC or BM were delivered via the balloon catheter to the stented coronary arteries. -Is the improvement in LVEF due to drug therapy or stem cell transplant? Group 11 Heart-Lung Bapass Machine (Chapter 26) Nanda Srendra, Ross Leung, and Khoa Tran Due to stem cell transplant. Name the key components in the heart lung bypass machine. Vena Cava--> Suction pump, Filter, Reservoir, Oxygenator, Heat Exchanger, Pump, Filter --> Aorta What is the indication for this device? open heart surgeries and CABG How are the heart lung bypass machine connected to the cardiovascular system to bypass the pulmonary circulation? De-oxygenated blood is taken out from the right atrium and oxygenated blood is given to the aorta. What is the operating principle of the counter-exchange system for the membrane oxygenator? Same as was in AKD. Thin membrane and high surface area of the membrane. You have made it! Happy Holidays! 17 ...
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