This lessens the tendency to adhe- ity until they burst glucophage sr 500 mg low cost, but the pressure in the bags will stay sion between the disc and seating due to the surface below 60 cm H20 purchase glucophage sr 500mg without prescription. This is thought to be a safety feature tension of condensed water from the expired air order glucophage sr 500mg free shipping, or after that prevents barotrauma to a patient’s lungs should the washing or sterilizing. The disc has a stem that is located exhalation pathway in a breathing system containing this in a guide, in order to ensure that it is correctly positioned bag become occluded. These bags should that when the valve top is screwed fully ‘open’ there is be ftted only to breathing systems that have a pressure minimal pressure on the disc when seated. Screwing factors, such as its shape, size, degree of flling, the tension down the valve top produces progressively increasing of the expiratory valve and the fresh gas fow rate, as well tension in the spring. The valve should always be the patient’s tidal volume cannot be made simply by used in the vertical position so that the disc is seated by watching the bag. Here, the valve disk so as to detect even the smallest movement when used in is attached to a red-coloured spindle that extends through paediatric anaesthesia. The inside of the valve body has a small funnel through which the disk has to move before signifcant gas can escape. This initial movement of 5 mm 1 accentuates the bobbing action of the spindle which is 5 useful particularly in paediatric anaesthesia. This has a number of advantages: • As there is no leak from the valve during inspiration, the patient’s lung compliance may be more accurately assessed. This is without doubt true when the valve resistance is high (due to sticky valves, narrow valve apertures) or where the respiratory effort is severely compromised (e. However, modern valve design (with wider valve apertures, lighter valve discs, more delicate springs, better screw threads) minimizes this resistance. This could still fail, for instance if the bag were trapped under the wheel of an anaesthetic B machine, a dangerously high pressure could develop within the breathing system and be passed on to the Figure 5. As the valve is gradually closed, the expiratory fow resistance A increases and in sophisticated examples this resistance can be calibrated and displayed on the valve body. When the valve top is screwed down fully, both valves are closed and in this position the outer one is pushed against the inner so that is has no movement of its own (Fig. An excess pressure is now required to move the more powerful spring on the outer valve which will begin to open at 3 kPa (30 cm H2O) and be fully open between 6 and 7 kPa (60–70 cm H2O) when the gas fow is 50 l min−1 (Fig. It is now possible to simplify the design so that the spring and the valve disc are replaced by a neoprene fap valve (1) (Fig. When positive pressure is required, the valve top (2) operates a screw threaded insert (3) that lowers an overpressure relief valve (4). As the valve top is screwed shut, the insert lowers the second valve (4) onto the fap valve housing, gradually occluding the expiratory pathway until complete occlusion occurs (Fig. The second valve is ftted with a spring (5) which is strong enough to maintain the occlusion up to a pres- sure of 60 cm H2O, but weak enough for the valve to lift (Fig. Breathing hoses D The hoses connecting the components of a breathing system must be of such a diameter as to present a low Figure 5. They 132 Breathing systems and their components Chapter | 5 | A 2 3 (i) 5 4 1 Figure 5. The disadvantages are that the irregular wall must cause turbu- lence and being opaque may harbour dirt and infection unseen. They are also heavy and, if unsupported, may drag on a facemask or endotracheal tube. Smooth bore breathing hose produces less turbulence than the corrugated variety at similar gas fows. It can also be produced so that it resists kinking (by the attachment of a reinforcing spiral of a similar material to its external surface). One will ft the bag mount (male to female) but the Reuse of breathing other will not ft the bag (female to female). Also, if the tapers used in the construction may either wear with frequent use (see above) are made from materials that are easily dis- (most plastics and rubber) or become distorted by damage torted with repeated connection they will be designated (metal connectors). Some items that nection can be minimized by giving the components of might be designated as single use because they are not the joint a slight twist following their insertion. Pro- Conversely some metal connectors made from alumin- vided that these items are protected by a high-quality ium alloys may stick together by the phenomenon of cold bacterial flter, some manufacturers will accept product welding produced by the recommended twist above, and liability if the item is used on a number of patients as long may be very diffcult to separate. The parallel Lack fresh gas fow requirements of Classifcation of anaesthetic breathing system. Br J Anaesth Resistance to airfow in anaesthetic semi-closed anaesthetic systems’. A new anaesthetic semiclosed anaesthetic breathing breathing system combining Mapleson A systems systems. Anaesth Patient Saf Found presence of carbon monoxide from Anaesth 1960;32:298–309. The enfurane, isofurane, halothane, low-fow anesthesia is affected by fresh-gas fow sequence at the start and sevofurane by soda lime type of anesthetic machine. Rate of change in Funk W, Gruber M, Wild K, Hobbhahn Abnormal heat generation in gas concentrations in a charged circle J. Fresh gas fow is Small carbon monoxide formation exothermic Baralyme(R)–sevofurane not the only determinant of volatile in absorbents does not correlate reaction. Anesthesiology 2004;101: agent consumption: a multi-centre with small carbon dioxide 531–3. The use of the fexible fbreoptic endoscope (fbrescope) Tracheal tubes 158 for intubation continues to increase and to emerge from Subglottic devices 176 being the domain of a few to becoming a mainstream Laryngoscopes 179 activity at which anaesthetic trainees rightly feel they must Aids for intubation/tube exchange 196 be adept. Technological developments are apparent here too with an increasing shift towards miniaturized digital Miscellany 199 video-based devices rather than optical glass-fbre image Standards, techniques (and fashions) in airway manage- transmission. In the last few years, we have also seen the prolifera- Although the most basic principle of anaesthesia is the tion of a new generation of crossover devices for laryn- maintenance of a patent airway aimed at providing ade- goscopy which combine features of both fbrescopes and quate oxygenation and ventilation, the range of devices traditional rigid (lighted retractor type) laryngoscopes. Of the developments in the last on fbreoptics, prisms and mirrors or digital camera tech- decade several are notable. The laryngeal mask in its various forms has continued The standard technique of direct laryngoscopy for tracheal to expand both within and beyond routine airway man- intubation is being challenged. These devices which sit outside the larynx and niques, and harm, albeit rare, may be seen with this aim to provide a gas-tight seal are now generally referred technology too. This trend, whether based on science or not (of which more later) The term ‘rubber’ accurately refers to the product extracted has meant that the majority of airway devices now being from the rubber plant, but is now used generically to developed are at least in part single-use. Production and describe an elastic solid and may be prefxed by a more material costs and hence price, as well as storage and stock- specifc adjective to describe the material used in its pro- ing issues, are ultimately more signifcant considerations duction. Natural latex rubber is extracted from the bark sap for single-use items and this is already affecting the range of rubber plants as the monomer C5H8. Although cheap and versatile, it degrades easily and proliferation of devices and techniques.
In the same way buy discount glucophage sr 500mg on-line, Se-defcient mice were more susceptible to infuenza virus infection than Se-adequate mice (Beck et al buy glucophage sr 500mg free shipping. Iron Iron defciency has been considered the most common micronutrient defciency in the world cheap glucophage sr 500 mg otc, particularly in the tropics. Iron accumulation has been shown to increase infection rates, whereas low iron concentrations are associated with an impaired immune system because critical immune cells such as macrophages are unable to produce microbial killing enzymes such as hydroxy radicals. It is important to note the existence of a protein called natural resistance associ- ated macrophage protein-1, which is located in the membrane of the phagolysosome of macrophages, monocytes, and neutrophils, and has the function of transporting divalent metals, including Fe2+, providing protection against intracellular microor- ganisms such as Leishmania, Mycobacterium, and Salmonella (Bellamy, 1999). In fact, experimental studies in vitro and animal studies suggest that the growth of intracellular organisms such as plasmodia, mycobacteria, and invasive Salmonella may be enhanced by iron therapy. Although iron exerts important modulatory effects on the immune system, a clinically important relation between states of iron defciency and susceptibility to infection remains controversial. Zinc Zinc is an important antioxidant that plays an essential function in immune protec- tion, particularly in the elderly. The contribution of zinc is crucial for the activity of superoxide dismutase and participates in T-cell division, maturation, and dif- ferentiation. Zinc defciency results in a marked atrophy of the thymus involving an increase in lymphopenia. Similarly, zinc defciency affects the development of acquired immunity by prevent- ing several functions of T lymphocytes, such as activation, Th1 cytokine production, and B-lymphocyte functions such as immunoglobulin G production. It is important to note that zinc defciencies are characterized by an increased susceptibility to a diverse variety of infectious agents, including Listeria monocytogenes (Carlomagno et al. However, these changes were partially reversible by zinc supplementation (Falutz et al. Hence, these observa- tions indicate the need to carefully consider therapeutic options, and immune status should be evaluated after identifying a benefcial role of zinc supplementation in these patients (Baum et al. A recent review reports that low zinc status impairs immune function, impairs resistance to pathogens, and is associated with increased incidence and duration of pneumonia, resulting in augmented use and duration of antimicrobial treatment and increased mortality in the elderly (Barnett et al. Although copper defciency has been related with the reduction of several param- eters in certain animal studies, human studies have reported inconclusive results. Indeed, copper supplementation has increased the numbers of neutrophils in periph- eral blood and reduced the incidence of respiratory tract infections in infants recover- ing from marasmus, who were neither anemic nor neutropenic (Castillo-Duran et al. On the other hand, a recent study has demonstrated that a high intake of copper reduces some parameters of immune functions against the Beijing strain of infuenza virus. These results indicate that under highly controlled conditions, long-term high copper intake affects several indices of immune function (Turnlund et al. In plants, polyphenols, besides providing color and favor, have a defense function against ultraviolet radia- tion, pathogens, and other damage (Korkina et al. Polyphenols are separated from essential nutrients because a defciency state has not been detected; nevertheless, these phytochemicals play an important biological role. Nowadays, a number of stud- ies have shown that polyphenols are natural compounds with an interesting range of biological effects, including anti-infammatory (González-Gallego et al. Despite the strong evidence about the effect of polyphenols on the immune system, the mechanisms implied in these actions are not fully understood currently. Recent studies have shown that polyphenols may act by modify- ing these epigenetic mechanisms in immune cells. Interestingly, the same study showed an increase in the Treg subpopulation in different immune organs, with function- ally active cells, in mice fed with this polyphenol (Wong et al. In the next paragraphs, the main dietary polyphenols and the effects on immune function and resistance to infection will be described. This dietary antioxidant may be found in olive oil, which is an important source of vitamins (e. Olive oil has benefcial effects on human health, and it is implicated in the resolution, attenuation, or prevention of diverse pathologies. Among them, olive oil is characterized by modulating immune system functions (Puertollano et al. These regulatory functions in the immune system appear to be involved in an increase of host resistance to microorganisms after administration of diets containing olive oil (Puertollano et al. Studies in vitro have suggested that phenolic components from olive oil possess radical scavenging activity at least as strong as that of other relevant dietary antioxidants, such as ascorbic acid and α-tocopherol (Visioli et al. In addition, data from animal studies have suggested that oleuropein may act as an anti-Toxoplasma compound, evidencing the action of this polyphenol on infection resistance of animals infected with this parasite (Jiang et al. Traditionally, green tea consumption has been related to a positive effect on human health, such as toxin elimination and improvement of resistance to infection. Indeed, several investigations have revealed that tea polyphenols are capable of modulating Nutrition–Infection Interactions and Potential Therapeutic Strategy 99 proinfammatory signals in certain in vitro and in vivo models, suggesting that green tea may be considered as an adjuvant treatment in some infammatory disorders (Pajonk et al. Regarding antimicrobial effects, green tea has been shown to inhibit the growth of bacteria responsible for upper respiratory tract infections (Hamilton-Miller, 1995; Yam et al. In addition, tea polyphe- nols and extracts delay or inhibit the growth of a wide variety of pathogenic strains of Enterobacteriaceae (Yam et al. This property may be useful in a concomitant treatment with antiretroviral drugs (Hauber et al. Resveratrol is the main polyphe- nol contained in red wine and grapes and has shown a relevant immunomodulatory activity (Gao et al. Although the exact mechanism by which resveratrol exerts immunomodulatory activity has not clearly been defned, it appears to inhibit cell proliferation, cell-mediated cytotoxicity, and cytokine pro- duction (Docherty et al. In addition, resveratrol is able to modulate T-cell differentiation (Petro, 2011). As a result of its immunomodulatory properties, it has been demonstrated that resveratrol protects mice from infection with herpes simplex viruses (Docherty et al. These antimicrobial effects may be attributed, at least in part, to the potent antioxidant and anti-infammatory effect of this polyphenol. Finally, recent researches are focusing on the effect of cocoa on the immune sys- tem. Cocoa favonoids, including catechins and procyanidins, have been shown to be able to modulate different mechanisms of the immune system such as secretion of cytokine and other infammatory molecules in different in vitro studies (reviewed in Perez-Cano et al. Different studies from this laboratory have pointed out that a cocoa diet is able to modify the different lymphocyte subsets. A biological role for ascorbate in the selective neutralisa- tion of extracellular phagocyte-derived oxidants. Selenium and interleukins in persons infected with human immunodefciency virus type 1. The natural resistance-associated macrophage protein and susceptibility to intracellular pathogens. Trypanosoma cruzi: The effects of zinc supplementation during experi- mental infection. Chronic zinc defciency and lis- teriosis in rats: Acquired cellular resistance and response to vaccination. Nutrition–Infection Interactions and Potential Therapeutic Strategy 101 Cerqueira, A.
Many dental offices had been destroyed in the hurricane purchase glucophage sr american express, and records were either lost entirely or the loss of dental records from destroyed dental offices discount glucophage sr 500mg mastercard, too damaged by water to be usable order discount glucophage sr line. Only a minority and the socioeconomic and cultural situation that pre- of victims has been identified by any of the available cluded many people from visiting a dentist and having techniques. Figures 12-11 through 12-13 provide three addi- On August 29, 2005, Hurricane Katrina, which tional examples of dental evidence that was useful for had slightly weakened from a Category 5 to Category identifying the victim of a mass disaster. Figure 12-11 4 storm, struck the New Orleans, Louisiana area of shows a denture, Figure 12-12 shows a two-tooth jaw the Gulf Coast of the United States. At least 1386 fragment with a unique restoration, and Figure 12-13 people lost their lives. This link in the dental identification process (subsequent to short chapter could only provide a brief overview of the locating the antemortem dentist of record) is the qual- importance of dental anatomy as a foundation for the ity of the dental written and radiographic record. All dental profession- records are the first step in the practice of forensic den- als must maintain accurate and comprehensive dental tistry by every dental professional. This includes written records, radiographs, and involved in forensic dentistry, the probability is that models that accurately describe or reproduce the oral eventually he or she will be contacted regarding ques- anatomic and anthropologic forms in detail. Person identification by means of a bite mark, and by helping to properly preserve crucial single unique dental feature. Symposium ed: skeletal attribution of race— Other chapters of this text describe in more detail some methods for forensic anthropology. Carabelli on a maxillary first molar will identify a per- Guidelines for bite mark analysis by the American Board of son as Caucasian heritage. Forensic odontology and the role of the dental forensic identification of an individual or for assessing hygienist. Forensic odontol- Trade Center disaster, the ability to identify a single ogy in solving crimes: dental techniques and bite mark tooth as a maxillary versus mandibular premolar was evidence. Bitemarks in forensic dentistry: a review of legal, the key to the ability to search the database of antemor- scientific issues. Symposium on forensic dentistry: offered within this chapter were selected to give the legal obligations and methods of identification for the prac- novice a practical and representative introduction to titioner. Mass fatality incidents: are California den- Journal of the California Dental Association. This manual can be obtained from the American Society of Forensic Odontology at http://www. A precise drawing on graph paper of a model of a mandibular right canine by a first-year dental hygiene student. Remember that almost all teeth taper toward the narrower lingual sur- Draw these two boxes in the lower left and right face, but the overall outline from the lingual is the same corner of the page (Fig. Professional drawing (by medical artist) of a model of a maxillary canine based on dimensions given in Table 1-7. Mark the faciolingual width of the ber of the squares of the mesiodistal crown measure- cervix. Hold the tooth facial side down the four-square border at each side and below these and in such a position that you are looking exactly in views. Be sure that the tooth crown The cingulum is normally centered on, or slightly distal is not tilted up or down. The incisal edge of on any tooth other than those lines that have been pro- the tooth will normally have a slight lingual twist of the duced by attrition? Labeling the grooves, the fossae, lingual to the center (in the same position it is shown and the ridges on the occlusal surfaces of the posterior on your drawings of the mesial and distal aspects). It is not specified view as might be expected during a conver- expected that a student will remember the exact sation with an instructor or a patient. On maxillary central incisors, the root is quickly sketch a specific tooth and view from memory. Based on this In order to sketch a facial view of a recognizable fact, three parallel horizontal lines can be drawn to tooth from memory, the drawer must have knowledge denote the distance of the crown length from incisal of the following characteristics related to the tooth edge to the cervical line relative to the root length being drawn: (a) approximate crown-to-root ratio (i. For this maxillary central incisor, the crown the crown heights of contour (crests of curvature), (d) length is on the bottom. If one consid- to memorize that the average crown width for this ers each of these tooth characteristics in the appropri- tooth is 8. Five steps involved in sketching the facial view of a tooth (in this case, a right maxillary central incisor). Chapter 13 | Guidelines for Drawing, Sketching, and Carving Teeth 367 knowledge, two parallel vertical lines can be placed crown box. If a sketch of the crown were all that you perpendicular to the horizontal lines to establish are reproducing, you would be finished. We know that the apex of the the formation of two boxes: a crown box that will root is near the center of the tooth root axis (a ver- surround the crown and a root box that will enclose tical line in the center of the root at the cervix). At this time, label the mesial (M) and distal We also know that roots are broadest in the cervical (D) surfaces of the crown box that is dependent on third (but not very much narrower than the width whether you are viewing a right or left incisor. For of the crown), may be nearly parallel in the cervi- this right incisor, the mesial surface is on the right cal third, and taper toward the rounded apex. Based side of the box, and the distal is on the left side, as if on this knowledge, you can finish the sketch. Since these the rounded apex just touches the apical line of the two points are the widest parts of the tooth crown root box. When the teeth are in ideal alignment, “boxes” and crests of curvature, and refer to the Appendix they are the location of the proximal contacts. On all pages for tooth traits when sketching the actual tooth incisors, the proximal heights of contour (contacts) outlines. Also, on this surface is not until this step is complete that you actually of anterior teeth, there is normally evidence of a nar- begin sketching the tooth crown shape (outline). On maxil- example, on a maxillary central incisor, we know lary molars, the lingual root is now in the foreground. The facial crest of curvature is similar for all line from the facial view is broad and curves toward teeth: in the cervical third. Based on this knowledge, begin sketching ture is in the cervical third on the cingulum for anterior the crown outline by placing subtle convexities that teeth but in the middle third for most posterior teeth. See the student sketch of a mandibular the mesial and distal crown walls, and these walls second molar from the mesial view in Figure 13-5B. The Posterior teeth from the occlusal view are viewed proximal convexities also curve incisally to blend looking directly down along the axis of the root. The the incisal line of the crown box in the mesial half and crown outline box is developed for this view by using tapers shorter (farther from the box outline) toward the mesiodistal and faciolingual crown proportions. Finally, the cervical line appears as a con- On mandibular premolars, the crown proportions are tinuation of the mesial and distal walls and curves slightly longer buccolingually than mesiodistally, but toward the apex, just touching the cervical line of the close to square. Four sketches of teeth by first- quarter dental and dental hygiene students: although not perfectly drawn, each sketch is recog- nizable as the tooth being drawn.
J Am Coll Cardiol 61(22): Ischemia-Causing Stenoses Obtained Via Noninvasive Fractional 2233–2241 Flow Reserve) study proven glucophage sr 500mg. A crucial element is a user interface that permits to correct misalignment between datasets buy genuine glucophage sr online. Current sofware packages allow fusion of images from diferent modalities T e backbone of cardiac hybrid imaging is noninvasive and even diferent manufacturers purchase glucophage sr toronto. Tus, two main fac- tors are the reason why hybrid imaging was accepted in T e increasing global interest in hybrid imaging from clinical practice and is now a routine technique in many a variety of medical specialties has prompted manufac- specialized imaging centers: the excellent image quality turers to launch a number of hybrid imaging devices. In the latter case, recting for the lower matrix size and larger voxel size) image fusion is accomplished through rapid automated using dedicated fusion sofware (Fig. Terefore, cardiac hybrid imaging can eas- ily be performed by acquiring datasets on standalone scanners with subsequent sofware-based fusion, and 20. This ﬁrst step is crucial and allows the user to align the often times imperfect correlation (Panels A and C) on images in three dimensions in order to obtain optimal matching of structural and functional information (Panels B and D). Overall, the diagnostic accuracy of hybrid imaging is very high with a sensitivity, specifcity, positive and negative predictive value of 88–96 %, 92–100 %, 77–97 %, and 97–99 %, respectively. Recommendations for hybrid imaging However, a number of limitations apply to these early pilot studies such as the small sample sizes, the heteroge- 1. Tere is also tration and correction of dataset misalignment evidence of an incremental prognostic value from com- (Fig. A number of desirable as it improves patient comfort and small studies suggest that hybrid imaging provides diag- speeds up the total examination nostic information about the hemodynamic relevance of 6. This is able if the scanners are run for other (non-cardiac) particularly true in patients with multivessel disease and examinations patients with inferior or inferolateral perfusion defects. Terefore, patients should be carefully selected where an added value of hybrid imaging may be anticipated. In equivocal lesions, hemodynamic relevance could be conﬁrmed in 35 % and excluded in 25 % Santana et al. Trend towards increased sensitivity (by 17 %) in patients with multivessel disease Slomka et al. However, the majority of perfusion defect in the territory of a stenosed coronary artery) the patients with angiographic 3-vessel disease turn out to revascularization rate was 41 %, while it was signiﬁcantly lower in have considerably less fow-limiting lesions than deemed patients with unmatched (11 %) or normal (0 %) ﬁndings (With from the angiograms. Terefore, proof of myo- Side branches are ofen regarded as prognostically insig- cardial ischemia in the territory of the occluded vessel nifcant but may be associated with signifcant angina. On one hand, hybrid imaging generally smaller, they may be difcult to distinguish from may accurately detect a perfusion defect located in the main branch disease. A 74-year old diabetic patient, who underwent coronary artery bypass grafting 15 years ago, presented with left bundle branch block, new-onset dyspnea, and stress-induced hypotension. Furthermore, the a higher in-plane spatial resolution and avoids ionizing use of other modalities (e. A number of acquired in three distinct short axes of the lef ventricle, novel hybrid imaging approaches hold promise to make not enough to extrapolate onto a volumetric perfusion their way into clinical practice or are used already in very dataset. This approach emission tomography/computed tomography imaging accurately may allow visualization of venous morphology and identify- detects anatomically and functionally signifcant coronary artery ing candidate veins for percutaneous lead insertion (Chap. It is likely that patients in whom the lef ventricular imaging: frst fusion of three-dimensional magnetic resonance per- lead is placed in a non-viable territory may not respond to fusion and low-dose coronary computed tomographic angiography. J Nucl Cardiol 16:201–211 emission computed tomography in patients with suspected coro- Sato A, Nozato T, Hikita H et al (2010) Incremental value of combining nary artery disease. J Am Coll Cardiol 53:623–632 64-slice computed tomography angiography with stress nuclear Wijns W, Kolh P, Danchin N et al (2010) Guidelines on myocardial myocardial perfusion imaging to improve noninvasive detection of revascularization: the Task Force on Myocardial Revascularization coronary artery disease. Eur Heart J with or without percutaneous coronary intervention to reduce 31:2501–2555 2 1 Electrophysiology Interventions R. It is also associ- explained, focusing on preprocedural planning and ated with important clinical consequences, including postprocedural follow-up. More specifcally, these ostia is reserved for patients with symptomatic and drug- foci are located near the entrance sites of these veins into refractory paroxysmal or persistent atrial fbrillation. Terefore, the rationale behind catheter-based cryo- or radiofrequency transcatheter ablation of these sites is to 21. During the intervention, be used to acquire the required preoperative informa- the ablation catheter is brought into the lef atrium tion. The choice between these two imaging modalities through a percutaneous venous femoral access and sub- ofen depends on the local expertise and available sequent transseptal puncture from right to lef atrium equipment. After traditionally percutaneous venous femoral access, a transseptal catheter puncture is performed to gain access to the left atrium (Panel A). Next, the catheter with an ablation electrode at its tip is placed at the level of an atriopulmonary venous junction – in this case the upper left pulmonary vein (Panel B). Finally, ablation is performed: a 21 circular Lasso catheter is used for electrical mapping guidance at the atriopulmonary venous junction (the wall of which has myocardial tissue extending from the left atrium), while a linear catheter with ablation electrode performs a radiofrequency ablation at a speciﬁc point (Panel C ). Panel D shows a three-dimensional fast anatomic mapping image of the left atrium acquired by dragging a mapping catheter over sites of interest along the atrial endocardial wall. The ﬁnal ablation points (red in Panel B) surround the pulmonary vein entrances into the left atrium in a circular fashion, achieving as such electrical isolation (Panels A–C) (With permission from Ghaye et al. The device is also seen on frontal (arrow in Panel C ) and lateral (arrow in Panel D) conventional chest radiographs. Since the left atrial appendage is a major source of thrombus formation due to circulatory stasis, the use of an occluder device here can dramatically reduce the risk of thromboembolic stroke. In this particular patient, anticoagulation therapy could be stopped after device placement. However, this approach is currently controversial, as some investigators argue that there are also other potential sources of emboli, including the atrial septum, left-sided valves, and the aorta. Occurring especially in large atria and in patients with atrial ﬁbrillation, slow blood ﬂow can range from moderate to very pronounced (asteriskinPanel A). In this patient, absence of a thrombus was conﬁrmed by delayed-phase imaging (asterisk in Panel B). Therefore, diagnosis of a left atrial appendage thrombus should only be retained after a ﬁlling defect has been conﬁrmed on delayed-phase imaging or with transesophageal ultrasound. In the second patient, the left atrial appendage is completely ﬁlled with a hypodense mass on arterial-phase imaging (asterisk in Panel C ), which persists on delayed-phase imaging (asterisk in Panel D) with only discrete further opaciﬁcation surrounding the thrombus. The normal three-dimensional anatomy of the pulmonary veins is illustrated, which includes the right superior (green ), right inferior (purple), left superior (red), and left inferior (blue ) pulmo- nary veins. The right superior pulmonary vein drains the right upper and middle lobe, with the left superior pulmonary vein draining the left upper lobe and lingula. The right and left inferior pulmonary veins drain the lower lobes of their respective lungs. A por- tion of the left atrial appendage (yellow) can be seen anterior to the left pulmonary veins B atrium and its pulmonary veins, providing an anatomic overview unmatched by ultrasound (Fig. An accessory vein (purple) is present in both cases, cen- tered on the posterior atrial wall in Panel A and between the upper and lower left pulmonary veins in Panel B. Furthermore, they have veins and lef atrium, specifcally mentioning important often small ostia (as especially illustrated inPanel B), making them anatomic variations that can alter the procedural strat- more at risk for complications such as stenoses.