Hypothalamic Control

Afferent Fibers Parasympathetic Nervous

The autonomic control of the heart is highly modulated by activity within the portion of the brain known as the hypothalamus. Afferent fibers from the brain stem (medulla oblongata) and spinal cord convey information via the autonomic afferent system to the hypothalamic nuclei within the central nervous system (10), whereas impulses that leave the hypothalamus travel along efferent fibers to the various sympathetic and para-sympathetic ganglia as noted above. Most parasympathetic response...

Some Basic Interpretation Of The Ecg Trace

Cross Section The The Heart

The ECG waveform and mean electrical axis are quite useful in the clinical setting. The ECG is considered one of the most important monitors of a patient's cardiovascular status and is commonly used for measurements as basic as the heart rate. Most ECG monitoring devices used today include automated systems that detect changes in durations between subsequent QRS complexes (i.e., the duration of one cycle). Simply, determination of the PR intervals provides information regarding whether a...

Physical Principles Of Echocardiography

Echocardiography uses the properties of sound waves to differentiate tissues of varied density in the human body. Sound travels in mechanical waves with a speed dependent on the density and elastic properties of the medium in which they are traveling (2). This property of tissue is termed its acoustic density. Ultrasound waves, which are used in medical applications, have frequencies that are higher than those audible to the human ear. ultrasound frequencies are generally over 20,000 cycles per...

Of Anatomy And Animal Research

Anatomy is one of the oldest branches of medicine, with historical records dating back at least as far as the 3rd century bc animal research dates back equally as far. Aristotle (384-322 bc) studied comparative animal anatomy and physiology, and Erasistratus of Ceos (304-258 bc) studied live animal anatomy and physiology (1). Galen of Pergamum (129-199 ad) is probably the most notable early anatomist who used animals in research to attempt to understand the normal structure and function of the...

Info

0, no change +, increased ++, more increased +++, most increased -, decreased , more decreased ---, most 0, no change +, increased ++, more increased +++, most increased -, decreased , more decreased ---, most Anesthetic uptake is determined by its blood solubility, cardiac output, and the difference between alveolar and venous partial pressure (2). The greater the uptake of anesthetic gas, the slower is the rate of induction. Inhalational anesthetics with lower blood gas solubility (i.e.,...

And Bioenergetics In The Normal Heart

Glucose Phosphate Heart Failure

Carbon Substrate Selection The primary carbon substrates (Fig. 4) taken up and metabolized by the myocardium are free fatty acids and glucose. The heart readily takes up and metabolizes pyruvate, lactate and ketone bodies, but the generally low blood concentrations of these substrates limit their utilization. However, under certain conditions such as exercise, which can markedly elevate the blood lactate content, or during periods when blood levels of ketone bodies are elevated,...

Abdominal Defibrillator

Epicardial Medtronic Icd Patches

Antiarrhythmic agents can also be proarrhythmic, which may lead to an increased requirement for ICD therapies. Predisposing factors to proarrhythmias are (1) electrolyte imbalances such as hypomagnesemia or hypokalemia, (2) underlying ventricular arrhythmias, (3) ischemic heart disease, and (4) poor left ventricular function. One of the most dangerous forms of proarrhythmia is considered torsade de pointes or twisting of the points. Specifically, torsade is a rapid form of polymorphic...

Failure And Transplantation

Alexis Carrel reported the first heterotopic transplantation (Table 4) of a canine heart connected to the neck vessels of another dog in 1905 the animal succumbed to massive clotting and survived for only 2 hours. Over the next 55 yr, Drs. Richard R. Lower and Norman E. Shumway ultimately perfected an orthotopic transplantation in the canine. In contrast to Carrel's original work, transplants in Shumway's laboratory research were placed orthotopically, and animals survived for up to 21 days...

Lead Placement In The Clinical Setting

In a clinical setting, not all 12 leads are displayed at the same time, and most often, not all leads are measured simultaneously. A common setup used is a five-wire system consisting of the two arm leads, which are actually placed on the shoulder areas, two leg leads placed where the legs join the torso, and one chest lead. This arrangement allows display of any of the limb leads (I, II, III, aVR, aVL, and aVF) and one of the precordial leads, depending on where the chest electrode is placed....

Output To Organs

Cardiac Output Percent Organ System

Relaxed skeletal muscles Contracted skeletal muscles Fig. 3. Contractions of the skeletal muscles aid in returning blood to the heart this is termed the skeletal muscle pump. While standing at rest, the relaxed vein acts as a reservoir for blood contractions of limb muscles not only decrease this reservoir size (venous diameter), but also actively force the return of more blood to the heart. Note that the resulting increase in blood flow caused by the contractions is only toward the heart...

Introduction To Implantable Pacing And Defibrillation Systems

Defibrillation Heart Failure

Implantable pacing and defibrillation systems require multiple components, as well as external instruments, for proper function and programming. The implantable portion of the system is composed of the implantable pulse generator (IPG, or pacemaker) or an implantable cardioverter-defibrillator (ICD, or defibrillator) and the pacing and or defibrillation leads. The IPG and ICD are most commonly implanted in a subcutaneous location in the left pectoral region. Typically, depending on the...

Training Systems

Medtronic Loop Recorder

As technologies have become more and more advanced, so has the need to teach students, residents, and physicians how to use them. New products to enhance medical training are rapidly entering the marketplace. The most impressive new systems incorporate computerized mannequins, complex graphics, and sophisticated operator controls in state-of-the-art patient simulators. Students, residents, or physicians learn both medical concepts and manual procedures on life-size, interactive equipment that...

Pathway Hemothorax

Heart Failure Electrocardiogram

Measurements in the His bundle electrogram for evaluation of atrioventricular conduction. AH interval, measured from the earliest reproducible rapid deflection of the atrial electrogram in the His recording to the onset of the His deflection, represents conduction time from the low right atrium at the interatrial septum through the atrioventricular node to the His bundle (atrioventricular node function). The HV interval, measured from the beginning of the His deflection to the earliest...

Optimal Pacing Configuration

Left Ventricular Conduction Delay

Right ventricular pacing by itself is considered suboptimal today, although several studies have shown that pacing from the high right ventricular septum or right ventricular outflow tract may be associated with better cardiac function compared to pacing within the right ventricular apex (8,35,36). However, this observation was not confirmed by other investigators (37,38). It appears that pacing in a position that results in the greatest reduction in QRS durations may be associated with the...

Excitation-contraction Coupling Of Cardiac Cells

Relative Refractory Period

Eion, the equilibrium potential calculated from the Nernst equation. Eion, the equilibrium potential calculated from the Nernst equation. Action Potential Duration Atrium 150 ms Fig. 14. Ionic conductance changes during the ventricular cardiac action potential. See text for details. Cardiac action potentials occur because of transient changes in the cellular permeability to sodium, calcium, and potassium. A brief increase in sodium permeability depolarizes the cell and drives the membrane...

References

American Society of Anesthesiologists (October 2003) ASA Standards, Guidelines and Statements. American Society of Anesthesiologists, Park Ridge, IL. 2. Eger, E.I., II (1974) Uptake of inhaled anesthetics the alveolar to impaired anesthetic difference, in Anesthetic Uptake and Action (Eger, E.I., II, ed.), Williams and Wilkins, Baltimore, MD, p. 77. 3. Stevens, W., Cromwell, T., Halsey, M., et al. (1971) The cardiovascular effects of a new inhalation anesthetic, Forane, in human volunteers at...

Cmc Closed Mitral Commissurotomy

Valve Sparing Aortic Root Replacement

Ventricular septal defects with aortic cusp prolapse left ventricular dilation to accommodate a larger volume without changing filling pressures and by ventricular hypertrophy, allowing ejection of a larger total stroke volume (31). The majority of such patients remain asymptomatic for prolonged periods of compensation, during which time they maintain forward stroke volume within the normal ranges. Once the left ventricle can no longer compensate, patients may present with symptoms of dyspnea...

The Cardiac Skeleton

Passing transversely through the base of the heart is a fibrous framework or skeleton made of dense connective tissue, not bone as the name might suggest. The purpose of this tough, immobile scaffold is to (1) provide an attachment for the atrial and ventricular myocardium, (2) anchor the four valves of the heart, and (3) electrically insulate the myocardium of the ventricles from the atria. The supporting framework of the cardiac skeleton (Figs. 15 and 18) provides immobile support for the...

What If Heart Beat Goes Fast Frequently And Qt And Pr Intervals Are Not Normal

What Ventricular Fibrillation

The normal heartbeat is initiated by specialized cardiac cells (so-called pacemaker cells) located in the right atrium adjacent to its junction with the superior vena cava. These cells make up a specialized, albeit somewhat diffuse, region of the right atrium called the sinus node. The rate and regularity of activity in the sinus node (the cardiac pacemaker) is determined by both the intrinsic firing rate (automaticity) of the cells within the node and the influence of extrinsic factors on...

P3 Heart Disease

Primary G protein Tissue distribution Primary effector in heart tissue Vessels, heart, lung, kidney Adenylyl cyclase, L-type calcium channel cAMP PKA, MAPK cAMP, cyclic adenosine 3',5'-monophosphate Gi, inhibitory G protein Gs, stimulatory G protein MAPK, mitogen-activated protein kinase PKA, protein kinase A. been made to classify them according to different subtypes. For example, common a-subunits include (1) as (stimulatory), which activates adenyl cyclase (AC) (2) (inhibitory), which...

Uws

Donald Ross Bunker Drawings

Heart lung machine developed at the University of Minnesota Fig. 4. Drs. Richard Varco and F. John Lewis standing with a cooling by Dr. C. Walton Lillehei and Dr. Richard DeWall. Photo courtesy of device used during open heart surgery. Photo courtesy of the Lillehei Anticoagulation After Prosthetic Heart Valves First 3 months postimplantation First 3 months postimplantation Source From ref. 7. INR, international normalized ratio. Tissue Valve Graft Options Classification of...

Ekg Hegzaaxial System

Lead Sagittal Plane The Heart

The amplitudes of the lead I and II R waves are plotted along the corresponding leg of Einthoven's triangle starting at the midpoint and drawn with a length equal to the height of the R wave (units used to measure the amplitude can be arbitrary because the direction, not the magnitude, of the axis is important). The direction of the plot is toward the positive end of the lead if the R wave has a positive deflection and negative if it has a negative deflection. Perpendiculars from each...

And Techniques Of Cardiac

Transverse Plane Images Mri

Felix Bloch and Edward Purcell discovered independently, in 1946 (1,2), that nuclei with a magnetic dipole moment gave rise to a resonance phenomenon when immersed in a magnetic field and subjected to a pulsed or continuous radiofrequency excitation. MR is based on the interaction of nuclear magnetic moments with externally applied magnetic fields, both static fields and time-varying fields. For the sake of simplicity, we can think of atomic nuclei having an intrinsic angular momentum called...

Animal Models In Valve Disease

Cory Swingen

The significant morbidity and mortality associated with heart valve disease has produced a highly lucrative and competitive market for manufactured prosthetic valves. Efforts to develop the ideal replacement heart valve have focused on producing a product that functions like the native valve Table 2 . The dynamics of blood flow through a tube with its specific viscosity is such that the flow is greatest in the center of the tube. Thus, any structure in the center of the valve i.e., mechanical...

I

Late Stages Heart Failure

Little or No Recovery of Contractile Function Fig. 2. Consequences of myocardial ischemia. The stunned myocardium usually results from a transient coronary occlusion followed by prompt reperfusion however, it may also occur following prolonged ischemia in the preconditioned heart. Preconditioning may lessen the infarct area following a sustained coronary occlusion however, the relationship between preconditioning and the maimed myocardium is unknown. Modified from ref. 15. 1995, with permission...

Physiologic Effects Of Acupuncture

Acupuncture involves stimulation of specific anatomical locations on the skin to alter energy flow patterns throughout the body. The skin can be stimulated by manual or electrical stimulation or the more typical placement of small metallic needles. Acupuncture has been used in China for thousands of years there has been a surge of interest in these nontraditional methodologies in the United States. Acupuncture has been utilized for treatment and prevention of multiple health conditions, such as...

Myocardial Blood Flow

Subendocardial Plexus

Blood containing carbon substrate and oxygen is delivered to the heart by two main coronary arteries that originate from the proximal aorta and course over the surface of the heart epi-cardium . These arteries arborize into progressively smaller branches that turn inward to penetrate the epicardium and supply blood to the myocardium Fig. 2 . In the left ventricle, the heart muscle is typically subdivided into transmural layers these are termed the subepicardium outer layer , the midmyo-cardium,...

Cells

Harvesting Embryonic Stem Cells

A decision of primary importance in cell transplantation is the selection of cell type. Presented in this section is a survey of the major cell types investigated by various laboratories to date. 3.1.1. Fetal and Neonatal Heart Muscle Cells The transplantation of fetal or neonatal cardiomyocytes into myocardial scar tissue is intended for directly restoring contractile function to tissue deficient in its own cardiomyocytes. The motivating hypothesis is that healthy, young cardiomyocytes can...

Surface Anatomy

Sternal Angle Surface Anatomy

Landmarks of the Thoracic Wall There are several defined vertical lines that demark regions of the anterior and posterior thoracic wall Fig. 23 . These lines are used to describe the location of surface landmarks and the locations of injuries or lesions on or within the thorax. The anterior median line runs vertically in the midline. It is also referred to as the midsternal line. The midclavicular line bisects the clavicle at its midpoint and typically runs through or close to the nipple....

Mechanical Effects Of The Pericardium

The degree to which the pericardium alters wall movement varies depending on the ratio of cardiac to pericardial size, loading conditions, and the degree of active and passive filling. Closure of the pericardial sac following open heart surgery has been proposed to 1 avoid possible postoperative complications, 2 reduce the frequency of ventricular hypertrophy, and 3 facilitate future potential reoperations by reducing fibrosis 1 . Differences in ventricular performance dependent on the presence...

Resuscitation Systems And Devices

Handhelp Lifepack Lead

Even before the cardiac patient enters the emergency or operating room, there are many new technologies being developed to aid in the resuscitation of an individual who has suffered from cardiovascular failure. Such devices range from improvements of existing tools e.g., the automated application of cardiopulmonary resuscitation or CPR to novel mechanisms that accomplish improved outcomes e.g., an impedance threshold valve . Furthermore, automated external defibrillators have become commonplace...

Cardiac Defibrillation

Implantable Cardioverter Defibrillator

Today, sudden cardiac arrest death is one of the most common causes of mortality in developed countries 3 million people experience sudden cardiac arrest worldwide, and the annual incidence in the United States is 300,000. Sudden cardiac arrest claims more lives in the United States each year than the combination of deaths from acquired immunodeficiency syndrome AIDS , breast cancer, lung cancer, and stroke 31 . Several studies have identified the primary risk factors for sudden cardiac arrest,...

Introduction

In previous chapters, authors provided brief histories of cardiac device development and several fairly thorough discussions of currently employed devices or assessment technologies. To gain insight into how rapidly innovations in the area of cardiac disease are progressing, a search of the US Patent and Trademark Office Website www.uspto.gov can simply be searched. Such a search produces an impressive number of companies or individuals attempting to secure intellectual property protection in...

Mri Pulse Sequence Diagrams

Mri Haste Pulse Sequence Diagram

Mx i My p x, y exp -ikxx p cos kxx i sin kxx Fig. 5. Waveforms that are applied along the radiofrequency R.F. and one gradient channel during a slice-selective radiofrequency excitation. The gradient channels are typically given logical names, such as slice-select and readout. The direction for the slice selection gradient can be arbitrary and is achieved by using three equivalent gradient coil sets for gradients in the x, y, and z directions and applying a combination of waveforms on all...

Animal Models In Myocardial Ischemia

Animal Model

Despite tremendous advances in treatment options, atherosclerotic coronary vascular disease remains the leading cause of death worldwide. As a result, this disease continues to be an active area of cardiovascular research. Originally defined by the Greeks as a lack of blood flow, the modern definition of ischemia emphasizes both the imbalance between oxygen supply and demand and the inadequate removal of waste products. Impaired oxygen delivery results in a reduction in oxidative...

Perfusion Analysis

Artifacts Myocardial Perfusion Imagin

Myocardial perfusion is a measure of blood flow e.g., mL min per unit mass of myocardial tissue. Myocardial perfusion should ideally match the demand for oxygen in the myocardium. Perfusion is commonly assessed at both rest and with induced stress to evaluate the capacity of the coronary circulation to increase blood flow above its baseline level and thus match increases in oxygen demand. A ratio of the perfusion parameters, measured at stress and divided by the value for rest, will give a...

Reperfusion Injury

Picture Reperfusion Arrythmias

Although immediate restoration of blood flow and oxygen to ischemic tissue is ultimately a beneficial and important therapy, it should be noted that additional myocardial damage can occur on myocardial reperfusion. In what has been termed the oxygen paradox, the resupply of oxygen to a hypoxic cell simultaneously activates two intracellular processes of particular interest the membrane-bound calcium pumps and the contractile apparatus. Resumption of contractile activity in the presence of...

What Is A Pdo Of The Heart

The temporal evolution of left ventricular shortening measured by magnetic resonance imaging tagging under different pacing protocols right atrial pacing top row , biventricular pacing middle row , and right ventricular apex pacing bottom row . Blue, contraction red, reference state yellow, stretch. Data are shown for late diastole after tagging first column , early systole second column , midsystole third column , and late systole last column . These measurements give precise...

A

Info About Heart Failure

I rvTiilcrv nudution cyeJe minus two earhon atoms If the long chain fatty acid being metabolized has an even number of carbon atoms, then the acyl CoA produced during Una cycle through i-lipid oxidation is acetyl CoA, which enters the TCA cycle to be metabolized. Il'lhe long-chain fatty acid being metabolized has an odd number of carbon atoms, then the acvl-CoA produced during final cycle through Gr beta -lipid oxidation is propionyl CoA. 1'ropionyl CoA is converted to succinyl CoA. The latter...

Lv

Where EF is ejection fraction, LV EDV is left ventricular end-diastolic volume, and LV ESV is left ventricular end-systolic volume. Normal values for ejection fraction are approx 55-65 , and cardiac output can be estimated by multiplying the volume ejected with each beat stroke volume by the heart rate using the equation where CO is cardiac output, HR is heart rate, and SV is stroke volume. The Doppler principle, described by Christian Johann Doppler in 1843, states that the frequency of...

Cardiac Pacing 41 History

First Degree Atrioventricular Block

Discoveries relating to the identification of the electro-physiological properties of the heart and the ability to induce cardiac depolarization through artificial electrical stimulation are relatively recent. Gaskell, an electrophysiologist, coined the phrase heart block in 1882, and Purkinje first described the ventricular conduction system in 1845. Importantly, Gaskell also related the presence of a slow ventricular rate to disassociation with the atria 2 . The discovery of the bundle of His...

Blood Pressure

Fundamental to providing comprehensive care to patients is the ability to obtain an accurate medical history and carefully perform and interpret a physical examination. The optimal selection of further tests, treatments, and use of subspecialists depends on well-developed skills for taking patient history and a physical diagnosis. An important part of a normal physical examination is obtaining a blood pressure reading and auscultation of the heart tones, which both represent critical...

Cardiac Muscle Electrical Activity

Cardiac Myocyte Gap Junction

Sarcomeres are linked end to end into assemblies known as myofibrils, which run the length of the long axis of the cardiac cell and are also placed side to side to fill most of the internal volume of the cell. The nucleus of a mature cardiac cell is found on the periphery of the cell along with the sarcoplasmic reticulum. The sarcoplasmic reticulum is a vesicular structure that acts as an internal calcium-store and is an analog of the endo-plasmic reticulum of other cells. Cardiac cells are...

Cardiopulmonary Bypass

Right Atrial Cannulation

Extracorporeal circulation and cardiopulmonary bypass are synonymous terms denoting a method by which the blood that usually returns directly to the heart is temporarily drained from the superior and inferior venae cavae. The blood is diverted into a reservoir, where it is oxygenated and subsequently returned to the patient's arterial circulation. This process effectually excludes the heart from the general circulation and leaves it empty so that it can accommodate surgical intervention Fig. 1...

Importance Of Anatomy And Animal Research

Anatomy remains as quite possibly one of the most important branches of medicine. To diagnose and treat medical conditions, normal structure and function must be known because it is the basis for determining what is abnormal. Furthermore, structure typically has a great impact on the function of an organ, such as with the heart. For instance, a stenotic aortic valve will usually cause functional impairment of the left ventricle and lead to further pathological conditions e.g., hypertrophy ....

Summary

The pericardium is a unique structure that surrounds the heart and serves several important physiological functional roles. Removal of the pericardium or the buildup of fluids within this space will alter hemodynamic performance. Yet, often following open heart surgery, the pericardium is not repaired or closed the rationale for this is under evaluation. Therapeutic approaches have been directed to exploit the access space that exists between the pericardium and the epicardial surface of the...

Life Pak 500 Remove Battery

Medtronic Cardiac Magnet

Include attempts to correct the underlying complication, such as coronary reperfusion in the presence of a myocardial infarction ischemia antiarrhythmic drugs to restore and maintain normal sinus rhythm electrical therapies such as antitachy-cardia pacing, cardioversion, defibrillation and ablation performed surgically or with the assistance of a catheter. The role of medical devices in the management of these arrhythmias will become clear as device function is described in the remainder of...

In Cardiac Ultrasound

Right Ventricle Dimensions

The use of ultrasound for cardiac imaging and investigation of hemodynamics has been revolutionary in the diagnosis and treatment of heart disease. Currently, ultrasound techniques available for use on a limited clinical or investigational basis include intravascular ultrasound, 3D and 4D imaging, and embryonic cardiac imaging. Intravascular ultrasound uses catheters with ultrasound transducers mounted on the tips. These transducers are capable of cross-sectional imaging or true sector imaging...

Yo2

SvO2 SaO2 - VO2 DO2 DO2 Volume of O2 delivered per minute CO x CaO2 x 10 C a-v O2 x CO x 10 SaO2 Arterial O2 saturation 1.0 CaO2 1.39 x Hgb x SpO2 0.003 x PaO2 where VO2 is oxygen consumption, CaO2 is arterial oxygen content, CvO2 is venous oxygen content, CO is cardiac output, DO2 is oxygen delivery, SaO2 is arterial oxygen saturation, Hgb is hemoglobin, SpO2 is oxygen saturation, and PaO2 is partial pressure of arterial oxygen. Accurate measurement of SvO2 requires that vasoregulation be...

Octopus Tissue Stabilizer

Placement Coronary Sinus Catheter

Utilizing standard cardiac surgery procedures, the heart from a 70-kg swine was explanted to an isolated heart apparatus and reanimated. This preparation utilized a clear, crystalloid perfusate that allowed intracardiac visualization. Following in vitro stabilization, the heart was instrumented with 6-mm videoscopes Olympus Industrial, Tokyo, Japan and a 12-French 3D intracardiac echocardiography ICE catheter Duke University, Durham, NC via access ports in the superior vena cava, left...

Afterload

Increased Afterload Heart Graphics

Afterload is another vital component of stroke volume and therefore blood pressure. Afterload is most often equated with ventricular wall tension. Wall tension is also considered as the pressure the ventricle must overcome to eject a volume of blood past the aortic valve. In most normal clinical situations, afterload is assumed to be proportional to systemic vascular resistance. Wall tension is greatest at the moment just before opening of the aortic valve. Wall tension is described by...

Contents

Soon J. 31 Experimental Cell Transplantation for Myocardial Repair and Jianyi 32 Genomics-Based Tools and Technology Jennifer L. 33 Emerging Cardiac Devices and Technologies Paul A. Atsushi Asakura, PhD Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, MN Robert J. Bache, md Cardiovascular Division, Department of Medicine, and Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN Vincent A. Barnett, PhD Department of Physiology,...

Cardiac Cycle

Normal Valve Diagram

The normal electrical and mechanical events of a single cardiac cycle of the left heart are correlated in Fig. 1. The mechanical events of the left ventricular pressure-volume curve are displayed in Fig. 2. During a single cardiac cycle, the atria and ventricles do not beat simultaneously the atrial contraction Fig. 1. Electrical and mechanical events of a single cardiac cycle of the left heart see text for details . ECG, electrocardiogram. Fig. 1. Electrical and mechanical events of a single...

Dipole Cells Heart

Electrocardiogram Lead Placement

Typically, the ECG is measured from the surface of the skin, which can be done by placing two electrodes directly on the skin and reading the potential difference between them. This is possible because these signals are transmitted throughout the body. Again, as stated above, the detected waveform features depend not only on the amount of cardiac tissue involved, but also on the orientation of the electrodes with respect to the dipole in the heart. In other words, the ECG waveform will look...

Baroreceptors

Arterial Baroreceptors Location

The autonomic nervous system plays a vital role in the regulation of blood pressure throughout the body. Specialized receptors sensitive to changes in arterial diameter are located at various strategic locations within the upper thoracic cavity and neck. These specialized nerve clusters are commonly known as arterial baroreceptors. Substantial groupings of such baroreceptors can be found at the arch of the aorta and in the internal carotid arteries just distal to where the common carotid...

Best Position To Auscultate For S4

Info About Heart Failure

Normal heart physiology introducing the third heart sound see text for details . S1, first heart sound S3, third heart sound A2, aortic valve closure P2, pulmonic valve closure. Fig. 1. Normal heart physiology introducing the third heart sound see text for details . S1, first heart sound S3, third heart sound A2, aortic valve closure P2, pulmonic valve closure. Fig. 2. Normal heart physiology introducing the fourth heart sound see text for details . S1, first heart sound S4, fourth...

Ecg Devices

Charles Wolferth And Francis Wood

The invention of electrocardiography has had an immeasurable impact on the field of cardiology. It has provided insights into the structure and function of both healthy and diseased hearts. The ECG has evolved into a powerful diagnostic tool for heart disease, especially for the detection of arrhythmias and acute myocardial infarction. The use of the ECG has become a standard of care in cardiology, and new advances using this technology are continually introduced. The discovery of intrinsic...

Muscles Of The Thoracic Wall

Diaphram And Its Origins

Several muscles of the thoracic wall, including the most superficial ones that create some of the contours of the thoracic wall, are muscles that act on the upper extremity. Some of these muscles form important surface landmarks on the thorax, and others have relationships to vessels that communicate with the thorax. In addition to moving the upper extremity, some of these muscles also can play a role in movement of the thoracic wall and participate in respiration. The pectoralis major muscle...

Overview Of The Thorax

Thoracic Outlet First Rib Resection

Anatomically, the thorax is typically divided into compartments there are two bilateral pulmonary cavities each contains a lung with its pleural covering Fig. 1 . The space between the pleural cavities is the mediastinum, which contains all the other structures found in the thorax. The mediastinum is divided into the superior and inferior compartments by a plane referred to as the transverse thoracic plane it passes through the mediastinum at the level of the sternal angle and the junction of...

Nerves Of The Thoracic Wall

Nerve Pericardium

The wall of the thorax receives its innervation from intercostal nerves Fig. 8 . These nerves are the ventral rami of segmental nerves leaving the spinal cord at the thoracic vertebral levels. Intercostal nerves are mixed nerves that carry both somatic motor and sensory nerves and autonomics to the skin. The intercostal nerves pass out of the intervertebral foramina and run inferior to the rib. As they reach the costal angle, the nerves pass between the innermost and the internal intercostal...

Cardiac neural crest

Initial Septation Atrium

Origin of the cardiac neural crest within a 34-h chick embryo. Green dots represent cardiac neural crest cells in the neural folds of hindbrain rhombomeres 6-8 the region of the first three somites up to the midotic placode level . Fb, forebrain Mb, midbrain. fuse with the atrioventricular cushions, which also divide the left and right atrioventricular canals and serve as the source of cells for the atrioventricular valves. Prior to septation, the right atrioventricular canal and right...

Nerve Supply Of Interventricular Septum

Interventricular Septum Blood Supply

Arterial supply to the interventricular septum. The right coronary artery supplies the posterior one-third of the interventricular septum, and the left coronary supplies the anterior two-thirds. The artery to the atrioventricular node commonly branches off the posterior interven-tricular artery. AV, atrioventricular LAD, left anterior descending. Adapted from T.N. James and G.E. Burch 1958 Blood supply of the human interventricular septum. Circulation 17 3 , pp. 391-396. Fig. 25....

The Electrocardiogram

Electrocardiogram Action Potentials

An electrocardiogram ECG in German, the electrokardio-gram, EKG is a measure of how the electrical activity of the heart changes over time as action potentials propagate throughout the heart during each cardiac cycle. However, this is not a direct measure of the cellular depolarization and repolarization with the heart, but rather the relative, cumulative magnitude of populations of cells eliciting changes in their membrane potentials at a given point in time it shows electrical differences...

Quantitative Analysis

Cardiac Mri Myocardium

OF FUNCTION, PERFUSION, AND VIABILITY Postprocessing of cardiac MRI studies represents the stage at which the full potential of the cardiac MRI examination may be best realized. Postprocessing is composed of two major steps image postprocessing and data postprocessing. The first step largely involves segmentation algorithms to delineate and extract features and structures of interest from the collected images. The second step consists mainly of applying mathematical and statistical methods to...

Doctor John Lewis Hypothermia

Heart Lung Machine From The 1950

Clarence Dennis with the first heart-lung machine at the University of Minnesota. Fig. 3. Clarence Dennis with the first heart-lung machine at the University of Minnesota. called, was a bright he completed his master's and doctoral degrees during this time also and impulsive maverick, always pushing to the next level of care for his clinical patients, for whom he had great empathy. Lillehei and his team launched many surgical innovations during this period, primarily because of their...

Clinical Applications Of Cardiac Ultrasound

Suprasternal Notch Ultrasound

Transvaginal and Transabdominal Fetal Echocardiography The human fetal heart is fully developed and functional by 11 wk after conception. Using transvaginal ultrasound, the structure and functional characteristics of the fetal heart can be observed as early as 9 wk of gestational age 8 . This technique remains the most useful type of fetal cardiac imaging until approx 16 wk of gestation. At that time, transabdominal imaging becomes the preferred method Fig. 1 . Fetal imaging is routinely...

Effects Of Manipulating The Aorta

Mammory Vessel Heart Surgery

Coronary artery disease is often considered a component of systemic vascular disease. The same risk factors that contribute to coronary artery disease, such as smoking, diabetes, hypertension, and hyperlipidemia, also contribute to carotid artery disease and atherosclerotic changes in the aorta this is especially true for the ascending aorta. Atheroma in the aorta can present with calcified plaques or with cheeselike soft plaques, which can be disrupted dislodged during 1 cannulation of the...

Gdp

Exercice Program Heart Failure

G protein receptor activation and coupling with adenylyl cyclase AC during -adrenergic receptor activation. A The receptor is inactive GDP guanosine diphosphate is bound to the a-subunit of stimulatory G protein. B The agonist binds to receptor, which leads to receptor G protein interaction GTP guanosine triphosphate binds to stimulatory G proteins a-subunit, Gas . C The G-subunits dissociate, and Gas stimulates adenylate cyclase, with subsequent formation of cAMP cyclic adenosine...

Cardiac Catheters Diagrams

Heart Diagram With Oxygen Saturations

An incompetent tricuspid valve tricuspid regurgitation abolishes the x descent and causes cannon v waves as volume from the right ventricle backflows into the right atrium during ventricular systole. CVP, central venous pressure ECG, electrocardiogram. S1, heart sound 1 S2, heart sound 2. Fig. 17. Cannon v waves. An incompetent tricuspid valve tricuspid regurgitation abolishes the x descent and causes cannon v waves as volume from the right ventricle backflows into the...

Effect Of Epinephrine On Cardiac Output Volume

Increased Stroke Volume

As the end-diastolic volume increases, the cardiac output also increases. Excessive preload may eventually result in decreased cardiac output. Fig. 3. Frank-Starling relationship. As the end-diastolic volume increases, the cardiac output also increases. Excessive preload may eventually result in decreased cardiac output. Fig. 4. Effect of acutely increasing preload on the pressure-volume loop. Increasing preload while maintaining normal afterload and...

Examples Of Current Pharmacological Cardioprotective Therapies

Listed in this section are current examples of pharmacological therapies targeted at protecting the myocardium from damage caused by ischemia and reperfusion injury. Although activation of the Na H exchanger NHE in response to acidosis is a feedback mechanism that enables the myocardial cell to maintain a fairly stable pH range, NHE activation may not always be beneficial. During ischemia, there is often a buildup of metabolic products that is caused by the anaerobic breakdown of ATP the...

Pacing On Mechanical Remodeling

Cardiac myocytes are known to adapt to changes in hemody-namic load. Ventricular remodeling refers to changes in left ventricular geometry, mass, or volume in response to myocar-dial injury or alterations in load e.g., hypertension . The extent of left ventricular dilation or remodeling in both ischemic and nonischemic cardiomyopathy is a strong predictor of both morbidity and mortality. Angiotensin-converting enzyme inhibitors and p-adrenergic blockers inhibit left ventricular remodeling and...

In Cardiac Electrophysiology

Nonfluoroscopic Electroanatomical Cardiac Mapping and Noncontact Endocardiac Activation Mapping cardiac mapping is essential for understanding mechanisms of cardiac arrhythmias and for directing curative ablation procedures. Traditional endocardial mapping techniques are time consuming, produce significant X-ray exposure, and are limited by lack of three-dimensional 3D spatial information. Among the most important new advances in cardiac electro-physiology are 3D mapping systems, such as...

Eccentric Device Design

Left Ventricular Gram

Amplatzer devices designed for closing secundum atrial septal defects, patent ductus arteriosus, and muscular ventricular septal defects are concentrically symmetrical because there are no valves near the edges of the defects they are designed to close. It is noteworthy that perimembranous ventricular septal defects are different in an important way the aortic and tricuspid valves are close to the defect margins. Previous attempts to close perimembranous ventricular septal defects with the...

Internodal System

Internodal Tracts

Orderly contractions of the atria and ventricles are regulated by the transmission of electrical impulses that pass through modified cardiac muscle cells the cardiac conduction system interposed within the contractile myocardium. This intrinsic conduction system is composed of specialized subpopulations of cells that spontaneously generate electrical activity pacemaker cells or preferentially conduct this activity throughout the heart. Following an initiating activation or depolarization within...

Mixed Venous Saturation Monitoring

Spectrophotometric Catheter

Mixed venous oxygen saturation monitoring SvO2 typically utilizes reflective spectrophotometric technology to measure the amount of oxygen in mixed venous blood. Yet, a true mixed venous blood sample is measured in the pulmonary artery. Systemic venous blood with different oxygen extraction ratios returns to the right atrium via the superior and inferior venae cavae, mixes and equilibrates in the right ventricle, and flows out past the pulmonic valve to the pulmonary artery. As blood travels...

Cardiac Conduction Overview

Normal Cardiac Conduction Pathway

The sinoatrial node in the right atrium normally serves as the natural pacemaker for the heart Fig. 1 . These pacemaker cells manifest spontaneous depolarizations and are respon sible for generating the cardiac rhythm such a rhythm would be classified as an intrinsic, automatic one. The frequency of this earliest depolarization is modulated by both sympathetic and parasympathetic efferent innervation. In addition, the nodal rate is modulated by the local perfusion and chemical environment i.e.,...

Autonomic Innervation Of The Heart

The sinoatrial node produces a regular series of impulses and is called the pacemaker of the heart. The sinoatrial node spontaneously produces an impulse for contraction of the atrial myocardium, depolarizes the atrioventricular node, and sends an impulse through the bundle fibers to the ventricular myocardium. In addition to the pacemaker activity of the sinoatrial node, the heart is also under autonomic, or involuntary, control. The autonomic nervous system is separated into the sympathetic...

Coronary Arteries

Heart Sinus Venous Anatomy

Oxygenated blood is pumped into the aorta from the left ventricle. This is where it enters the right and left main coronary arteries, and subsequent branching feeds the myocardial tissue of all four chambers of the heart. The ascending portion of the aorta is where the origins ostia of the right and left coronaries reside specifically, they exit the ascending aorta immediately superior to the aortic valve at the sinus of Valsalva. Blood flow into the coronary arteries is greatest during...

Sympathetic Anatomy

Presynaptic Sympathetic Fiber Pathway

Cell bodies of presynaptic sympathetic efferent neurons are found in the paired lateral horns of the spinal cord, an area identifiable between the T1 and L2 or L3 vertebrae. The axons, or nerve fibers of these cells, exit the interior of the spinal cord through ventral rootlets, which coalesce to form the larger ventral roots and eventually become the ventral rami. sympathetic fibers almost immediately divert into white rami communicantes Fig. 1 , branching from these spinal nerves, which...

Cardiovascular Physiology At The University Of Minnesota

The Department of Physiology at the University of Minnesota has a rich history of performing basic cardiovascular research and establishing clinical collaborations within the institution. Not only have these individuals published many important basic research papers, but they also have been integrally involved in the training of many generations of cardiac physiologists, surgeons, and biomedical engineers. One of the more notable chairs of the Department of Physiology was Maurice Visscher, who...

Engineering Parameters And The Coronary System

Placement Coronary Sinus Catheter

When faced with the task of designing and testing the devices used in these types of interventional procedures, a thorough understanding of the structural and geometric parameters of the coronary system is crucial for success. The main purpose of the following text is to summarize, at a basic level, the important anatomical parameters needed to design interventional devices and or associated delivery procedures related to the coronary system. From an engineering perspective, for the predesign...

Ligament Pericardium

Pericardium

Mechanical Effects of the Pericardium Isolated Pericardial Hemodynamic Effects and Transplantation Anatomical Animal Comparisons of the Pericardium Intrapericardial Therapeutics and Diagnostics Summary The pericardium is a fibroserous conical sac structure encompassing the heart and roots of the great cardiac vessels. In humans, it is located within the mediastinal cavity posterior to the sternum and cartilages of the third, fourth, fifth, sixth, and seventh ribs of the left thorax and is...

Comparative Cardiac Anatomy

Thebesian Valve Heart

In general, the hearts of large mammals share many similarities, and yet the sizes, shapes, and positions of the hearts in the thoracic cavities can vary considerably between species 6 . Typically, the heart is located in the lower ventral part of the mediastinum in large mammals 7 . Most quadruped mammals tend to have a less-pronounced left-sided orientation and a more ventrally tilted long axis of the heart compared to humans 7 Fig. 2 . In addition, hearts of most quadruped mammals tend to be...

Of The Cardiovascular System

Microcirculation Capillary Leak Syndrome

The principal components considered to make up the cardiovascular system include the blood, blood vessels, heart, and lymphatic system. From Handbook of Cardiac Anatomy, Physiology, and Devices Edited by P. A. Iaizzo Humana Press Inc., Totowa, NJ Blood is composed of formed elements cells and cell fragments suspended in the liquid plasma fraction. Blood, considered the only liquid connective tissue in the body, has three general functions 1 transportation e.g., O2, CO2, nutrients, wastes,...

Blood Pressure Monitoring

Arterial Pressure Waveform

The cardiovascular system is most commonly assessed by monitoring arterial blood pressure. Blood pressure is proportional to the product of cardiac output and systemic vascular resistance BP CO x SVR CO HR x SV MAP 1 3 SBP 2 3 DBP where BP is blood pressure, CO is cardiac output, SVR is systemic vascular resistance, HR is heart rate, SV is stroke volume, MAP is mean arterial pressure, SBP is systolic blood pressure, and DBP is diastolic blood pressure. Stroke volume is dependent on preload,...

Cardiac Action Potentials

Although cardiac myocytes branch and interconnect mechanically via the intercalated disk and electrically via the gap junctions see Section 5 , under normal conditions they should be thought to form two separate functional networks the atria and the ventricles. The atrial and ventricular tissues are separated by the fibrous skeleton of the heart the central fibrous body . This skeleton is composed of dense connective tissue rings that surround the valves of the heart, fuse with one another, and...

Pressure Transducer System

Underdamped Line Waveform

In clinical settings, arterial and venous blood pressures and waveforms are displayed using a pressure transducer monitoring system. A typical pressure transducer monitoring system includes 1 an indwelling intravascular catheter 2 pressure tubing 3 a pressure transducer 4 a stopcock and flush valve 5 a high-pressure fluid bag and 6 a graphical display monitor and microprocessor Fig. 12A,B . The pressure wave derived from the transducer system is a summation of sine waves at different...

Types of Solutions

Cardioplegic Solution

Crystalloid solutions generally can be divided into two categories based on their formulations extracellular or intracellular. Extracellular solutions contain calcium and sodium, the primary determinants of transcellular calcium exchange. Cardioplegic cardiac arrest can still be achieved by extracellular solutions containing only moderate amounts of potassium or magnesium. The cold blood cardioplegia solution 28-34 , the most common, is considered an extracellular ionic formula. The principal...

Central Venous Pressure Monitoring

Rapid Flush Test

An estimate of intravascular volume status and right heart function can be assessed with a central venous pressure catheter. Central venous pressure is ideally considered as the mean venous blood pressure at the junction of the right atrium and the inferior and superior venae cavae. The central venous pressure Tables 2 and 3 is an estimate of right heart filling pressures and may be used to assess both right heart function and the circulating blood volume. The central venous pressure is...

Recent Developments

Electroanatomical Mapping

In an effort to overcome the limitations associated with conventional electrophysiological mapping techniques, considerable advances have been made by a number of companies and such progress is ongoing. More specifically, several highly technical mapping systems have been developed that can function in a complementary role to conventional mapping techniques, or they can be used independently. These techniques can broadly be grouped into two primary technology categories, each possessing their...

Other Universityaffiliated Medical Devices

Angel Wings Device Closure

Many of the major breakthroughs in cardiac device development at the University of Minnesota occurred in associated collaborations with the Surgery Department. In more recent times, several more cardiovascular medical devices have been invented in departments other than the Department of Surgery, specifically the Departments of Medicine and Radiology. Several areas of cardiovascular devices are described in the following sections. 6.1. Active Compression Decompression Cardiopulmonary...

Continuous Systems

Endocardial Solution Ensite

Basket Catheter Mapping Technology The limited mapping resolution of conventional catheters may be overcome via the use of a multielectrode basket catheter. Basket catheter mapping was developed in the 1990s, and typical catheters contain 32-64 nickel or titanium electrodes 35,36 that are 1-2 mm long and 1 mm in diameter Fig. 5 . Depending on the basket catheter shape and radius, the interelectrode distance varies between 3 and 10 mm. Accuracy in the reconstruction of the chamber's...

Introduction To Human Heart Embryology And Development

The primary heart field, secondary heart field, cardiac neural crest, and proepicardium are the four major embryonic regions involved in the process of vertebrate heart development Fig. 1 . They each make an important contribution to overall cardiac development, which occurs with complex developmental timing and regulation. This chapter describes how these regions interact to form the final structure of the heart in relationship to the generalized developmental timeline of human embryology...

Cardiac Denervation

Cardiac Enurvation

Denervation can be divided into two categories pregangli-onic and postganglionic. Preganglionic denervation is caused primarily by disease or injury of the vasomotor centers in the brain or spinal cord above Tj0 it leaves intact the postgangli-onic nerve fiber and many reflexes that occur at the ganglionic level. Preganglionic denervation not only results in loss of centrally mediated cardiac reflexes, but also leads to dysfunctions in the control of peripheral vascular tone and inability to...

And Linear Heart Tube Formation

Heart Chick Embryo

The cells that will become the heart are among the first cell lineages formed in the vertebrate embryo 6,7 . By day 15 of human development, the primitive streak has formed 8 , and the first mesodermal cells to migrate gastrulate through the primitive streak are cells fated to become the heart 9,10 Fig. 2 . These mesodermal cells migrate to an anterior and lateral position where they form bilateral primary heart fields Fig. 1A 11 . Studies of chick development have not supported the previously...

Comparative Anatomy

Bundle His

All large mammalian hearts are considered to have a very similar conduction system with the following main components the sinoatrial node, the atrioventricular node, the bundle Fig. 13. Histological section through the bundle of His in a canine heart. The section was prepared using a modified Masson's trichrome stain collagen nuclei stain blue, muscle keratin cytoplasm stain red . Ao, aorta HB, His bundle IVS, interventricular septum LA, left atrium LV, left ventricular endocardium RA, right...

The Atrioventricular Node

AND BUNDLE OF HIS SPECIFIC FEATURES As mentioned in Section 3, the atrioventricular node and the bundle of His play critical roles in the maintenance and control of ventricular rhythms. In addition, both structures are frequently accessed during cardiac catheterization procedures 1 as anatomical landmarks, 2 to allow insight into atrial-ventricular conduction behaviors, or 3 to ablate these structures or the surrounding tissues to terminate aberrant behaviors e.g., reentrant tachycardias or to...

Right Trigone Heart

Trigone Aorto Mitral

The function of the heart is to circulate blood in closed circuit to the lungs, where blood is oxygenated, and out to the body, where oxygen provides fuel for cellular metabolism. To accomplish this task, blood is pumped by the right heart system from the body to the lungs. Once oxygenated in the lungs, blood is returned to the left heart, where it is then pumped out to the body. Although described as a biological pump, the heart is actually two biological pumps in series, composed of a right...

Effector Pathways To The Heart

Pacemaker Cell Sympathetic

Within the myocardium, parasympathetic nerve fibers release acetylcholine when stimulated. Cardiac cells contain muscarinic receptors embedded within their lipid bilayer, which can activate G proteins found in the cytoplasm upon binding with acetylcholine. Activation occurs when a bound GDP gua-nosine diphosphate molecule is replaced by a GTP guanosine triphosphate structure. Subsequently, this response allows the altered protein to bind with potassium channels in the membrane and causes them...