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Cialis Super Active

Insertion of an endobronchial valve designed for the treatment of emphysema may be considered in selected patients [106] order cialis super active canada. Nonoperative therapy provides an alternative to the surgical approaches in patients who are poor operative candidates buy cialis super active 20mg low cost. Nutritional status must be maintained buy genuine cialis super active, appropriate antibiotics used for the infected pleural space, and the space adequately drained. The chest tube is initially necessary, can be detrimental later, and may play a role more important than that of a passive conduit. A chest tube with too small diameter can lead to lung collapse and tension pneumothorax in the setting of a mobile mediastinum. Not only can the chest tube be used to drain pleural air, it can also be used to limit the air leak in certain situations. Synchronized closure of the chest tube during the inspiratory phase has also been used to limit air leak [110,111]. These techniques pose potential hazards, including increased pneumothorax and tension pneumothorax [110,112], necessitating extremely close patient monitoring when such manipulations are used. No adverse effects were encountered from the instillation of tetracycline in patients with persistent air leaks. The gas escaping through the chest tube represents part of the minute ventilation delivered to the patient and makes maintenance of an effective tidal volume problematic. Maintenance of a specific level of ventilation is not only affected by the amount of gas escaping through the fistula. The chest tube is a potential source of infection, both at the insertion site and within the pleural space. The size of the air leak and the flow that the drainage system can accommodate are necessary considerations. When the air leak reached 4 to 5 L per minute, use of the Thora-Klex or Sentinel Seal became clinically impractical. The Pleur-Evac can handle flow rates up to 34 L per minute, but its use with rates greater than 28 L per minute is impractical owing to intense bubbling in the suction control chamber. Thus, the goal of management is to maintain adequate ventilation and oxygenation while reducing the fistula flow [112]. Using the greatest number of spontaneous breaths per minute, thereby reducing use of positive pressure, may also be advantageous. The use of differential lung ventilation with conventional ventilation may be of benefit for some patients [122]. Proximal fistulas, such as those associated with lobectomy or pneumonectomy or stump breakdown, can be directly visualized through the bronchoscope. Distal fistulas cannot be visualized directly and require bronchoscopic passage of an occluding balloon to localize the bronchial segment leading to the fistula [132,133]. Once the fistula has been localized, various materials can be passed through a catheter in the working channel of the bronchoscope and into the area of the fistula [129–137]. Direct application of a sealant through the working-channel catheter onto the fistula site is the method generally used for directly visualized proximal fistulas. These include fibrin agents cyanoacrylate-based agents, absorbable gelatin sponge (Gelfoam, Pfizer), blood tetracycline, and lead shot [131–133]. The cyanoacrylate-based and fibrin agents have received the most attention but still have had less than 20 total cases reported. These patients have had at least a 50% reduction of fistula flow, and most had closure of the fistula subsequent to sealant application, although multiple applications were necessary in some patients. These agents appear to work in two phases, with the agent initially sealing the leak by acting as a plug and subsequently inducing an inflammatory process with fibrosis and mucosal proliferation permanently sealing the area [129]. They are not useful with large proximal tracheal or bronchial ruptures or multiple distal parenchymal defects [132]. Kelbel C, Borner N, Schadmand S, et al: Diagnosis of pleural effusions and atelectasis: sonography and radiology compared. Lichtenstein D, Goldstein I, Mourgeon E, et al: Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Yu C-J, Yang P-C, Chang D-B, et al: Diagnostic and therapeutic use of chest sonography: value in critically ill patients. Estenne M, Yernault J-C, Detroyer A: Mechanism of relief of dyspnea after thoracentesis in patients with large effusions. Mattison L, Coppage L, Alderman D, et al: Pleural effusions in the medical intensive care unit: prevalence, causes and clinical implications. Maringhini A, Ciambra M, Patti R, et al: Ascites, pleural, and pericardial effusions in acute pancreatitis: a prospective study of the incidence, natural history, and prognostic role. Iverson L, Mittal A, Dugan D, et al: Injuries to the phrenic nerve resulting in diaphragmatic paralysis with special reference to stretch trauma. Wheeler W, Rubis L, Jones C, et al: Etiology and prevention of topical cardiac hypothermia-induced phrenic nerve injury and left lower lobe atelectasis during cardiac surgery. Monla-Hassan J, Eichenhorn M, Spickler E, et al: Duro-pleural fistula manifested as a large pleural transudate. D’Souza R, Doshi A, Bhojraj S, et al: Massive pleural effusion as the presenting feature of a subarachnoid-pleural fistula. Anzueto A, Frutos-Vivar F, Esteban A: Incidence, risk factors and outcome of barotrauma in mechanically ventilated patients. The clinical manifestations of these disorders are varied, and the final pathophysiologic consequences depend on where the gas bubbles obstruct the circulation and how they impact the function of the surrounding tissue. Clinicians must depend on a high level of suspicion in the appropriate settings to rapidly identify the problem, prevent further gas entry into the circulation, and begin effective treatment. Each of these entities is discussed in more detail based on the predominant location of the gas collections, although they are not always separate and distinct. Air may also enter the venous system via the occipital emissary veins, the dural sinuses, the diploic veins, the veins of tumors, or through burr holes. During pregnancy, the veins of the uterus are exposed and fixed; when traumatized; they remain open and may serve as a portal of entry for gaseous emboli. The presumptive mechanism of embolization involves the forcible entry of air into the venous circulation through vascular openings of the bony medulla of the femur as a result of the high pressures generated in the distal shaft when the prosthesis is inserted. Emboli are the result of intraosseous irrigation with water or air under pressure (at least 80 cm water). Diagnostic and Therapeutic Procedures Air embolism in the setting of central venous catheterization has an unknown overall incidence, probably because the diagnosis is made only with large emboli. Air can enter the central venous system in several different ways: (a) during needle/wire/catheter insertion; (b) with fracture of the catheter, malfunction of a self-sealing diaphragm, or detachment of external connections; (c) after removal of a catheter that has been in place for several days, such that air is “sucked” into an open subcutaneous tissue tunnel that has formed a skin tract; and (d) as a result of a piggyback infusion running dry [1]. Lung biopsy by percutaneous or bronchoscopic techniques creates a direct traumatic opening at the blood–air interface. To minimize this risk, the volume of gas introduced, the pressure resulting within the cavity, and the rate of injection should always be as low as possible. The underlying mechanism relates to the rich plexus of veins of the epidural space, mostly anterior and lateral to the spinal cord.

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Many pregnant women are symptomatic from tion but this normally recovers rapidly after delivery purchase generic cialis super active online. Most Endocarditis prophylaxis women with symptomatic episodes of dizziness purchase cialis super active 20 mg without a prescription, syncope and palpitations do not have arrhythmias [41] buy 20mg cialis super active otc. Fatal cases of underlying pathology such as blood loss, infection, heart endocarditis in pregnancy have occurred antenatally, failure, thyrotoxicosis or pulmonary embolus. The com­ rather than as a consequence of infection acquired at the monest arrhythmia encountered in pregnancy is time of delivery [2]. As always, the baby should be delivered if nodal re‐entrant) is rare in pregnancy but exacerbation viable before the maternal operation. These women have an increased Emergency caesarean section may be required to aid risk of bleeding, particularly after delivery. References 1 Knight M, Tuffnell D, Kenyon S, Shakespeare J, Gray R, Deaths and Morbidity 2009–13. Mitral valve disease in pregnancy: before, during and after the first and subsequent outcomes and management. Prospective 24 Sadler L, McCowan L, White H, Stewart A, Bracken M, multicenter study of pregnancy outcomes in women North R. Predictors of pregnancy complications in 25 Cotrufo M, De Feo M, De Santo L, Romano G, Della women with congenital heart disease. Use of therapeutic dose low molecular for pregnant women with congenital heart disease. Outcome of pregnancy limb anomalies in case reports of first‐trimester statin after surgical correction of tetralogy of Fallot. Best Pract Res Clin Obstet Gynaecol 2001;15: cardiomyopathy: a position statement from the Heart 903–911. Pregnancy Cardiology Working Group on peripartum outcome after gestational exposure to amiodarone. Maternal and the prevention of endocarditis: report of the Working fetal outcomes of subsequent pregnancies in women Party of the British Society for Antimicrobial with peripartum cardiomyopathy. The risk of diabetes to Optimal glycaemic control prior to conception and pregnancy outcome increases with increasing maternal throughout pregnancy improves pregnancy outcome hyperglycaemia [5,6], and thus the risk from pre‐gesta­ [6,16,17]. In 1989 the St Vincent Declaration pledged to improve This chapter covers the clinical management of preg­ pregnancy outcomes for women with diabetes to those nancies complicated by pre‐gestational diabetes, as well of non‐diabetic women [8]. Finally, the obstetric, neonatal and diabetic care, this has not hap­ long‐term health consequences for the child of a diabetic pened. The main types of diabetes seen in tion and belonging to non‐white ethnic minority groups obstetric practice are shown in Table 9. Type 1 diabetes Absolute insulin deficiency due to autoimmune destruction of the pancreatic β‐cell. Presents typically under the age of 20 years old, and only 10% have a first‐degree relative affected. Accounts for approximately 5% of all diabetes outside pregnancy Type 2 diabetes Relative insulin deficiency and decreased insulin sensitivity. Presents typically over the age of 20 years, and >50% have a first‐degree relative affected. Results from a single gene mutation causing defects in pancreatic β‐cell insulin secretion. Autosomal dominant with approximately 95% having a first‐degree relative affected. Associated with a number of other medical problems including neural sensory deafness, a tendency for stroke and lactic acidosis. Accounts for less than 1% of all diabetes outside pregnancy Secondary diabetes Diabetes due to other medical conditions, i. The intervention group ● Diabetes in pregnancy poses major health risks to had a 10% higher rate of induction of labour with a both the mother and the growing fetus, and influences similar caesarean section rate compared with women the future health of the child. This observa­ tional study analysed over 23 000 non‐diabetic pregnant Diagnosing diabetes and gestational women between 2000 and 2006 from nine countries. Maternal and social risk criteria diagnose women with a fasting glucose between factors that can impact on pregnancy do nonetheless 5. This risk can be further increased between peri‐conception glycaemic control and congen­ by the presence of obesity [39]. The association between pre‐pregnancy levels of glycaemia and congenital malformations begins at the 35 32. In order 20 to significantly limit early fetal loss and congenital 15 abnormalities women need optimal glycaemic control 8. In A dilated retinal examination should be performed prior the future, advances in the technologies of closed‐loop to pregnancy, in early pregnancy and again at 28 weeks’ insulin delivery, which combines real‐time continuous gestation if no retinopathy was detected initially. While met­ should not be considered a contraindication for rapid formin can be continued in pregnancy, women previ­ optimization of glycaemic control in pregnancy or a ously on other oral hypoglycaemic agents, such as contraindication to pregnancy or a vaginal birth. Laser set for women with pre‐existing diabetes if achievable treatment before pregnancy protects against retinopathy without problematic hypoglycaemia. This may change as the onset of atinine clearance and protein excretion rate [62]. Pre‐pregnancy counselling with normal or mild renal impairment before pregnancy Diabetes in Pregnancy 105 usually preserve their renal function post partum and Hypoglycaemia can anticipate a successful pregnancy outcome. When Hypoglycaemia affects up to 70% of pregnant women microalbuminuria is present that is not attributable to a with pre‐existing diabetes and is associated with excess urinary tract infection, serial urinary protein/creatinine maternal mortality. Hypoglycaemic symptoms change in ratios should be performed throughout the remaining pregnancy, especially if autonomic neuropathy is pre­ pregnancy to quantify the degree of proteinuria. The risk of hypoglycaemia is greatest in the first 20 with moderate to severe diabetic nephropathy [serum weeks of pregnancy and immediately post partum. If accel­ erated progression of nephropathy occurs in pregnancy, Diabetic ketoacidosis renal intervention with dialysis may be required [61,63]. Cardiac involvement is associ­ include infection, vomiting, use of beta‐mimetic agents ated with overall mortality while gastrointestinal and insulin pump failures. Although the suggestion that autonomic neuropathy causes hypoglycaemia unawareness has recently been challenged [66], the intensity of autonomic symptoms in Screening for non‐diabetic response to hypoglycaemia decreases with duration comorbidities of diabetes and this reduces the threshold at which hypoglycaemic symptoms occur [67]. All women should be screened prior to nausea and vomiting is common in women with auto­ pregnancy for thyroid disease; if they are already being nomic gastroparesis, is challenging and hypoglycaemia treated for thyroid disease, this should be repeated in is frequent. There should be a high level of suspi­ cion to screen for other autoimmune diseases if clinically indicated. Review of all medications Folic acid 5 mg once daily Screening for diabetic complications, including treatment of diabetic retinopathy Risks to the fetus of a diabetic First trimester pregnancy Referral to a combined multidisciplinary diabetic obstetric antenatal clinic Maternal glucose crosses the placental barrier but insu­ Dating scan at 6–8 weeks, confirming viability and gestational age lin does not, so increases in maternal glucose stimulate Screening for diabetic complications fetal insulin production and hyperplasia of insulin‐ Screening for non‐diabetic comorbidities Assessment and optimization of glycaemia sensitive tissues [74,75]. Maternal hyperglycaemia also Advice on hypoglycaemia prevention enhances production of human placental growth Second trimester hormone, fetal insulin‐like growth factor and tumour Optimization of glycaemic control necrosis factor. As with insulin, these hormones act as Screening for diabetic complications fetal growth factors, resulting in accelerated fetal growth, Repeat digital retinal assessment at 16 weeks if initial retinal macrosomia and organomegaly. Cardiac malformations include ultrasonographic examination of the fetal heart at 18–22 weeks transposition of the great vessels, ventricular septal Assessment of fetal growth defect and dextrocardia, while the central nervous sys­ Third trimester tem anomalies include anencephaly, spina bifida, hydro­ Optimization of glycaemic control cephaly and holoprosencephaly; malformations of the Screening for diabetic complications, with repeat digital retinal genitourinary system and the skeleton also occur [76]. The long‐term effects of a diabetic pregnancy on the child are only now being evaluated.

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How does the avian influenza virus differ from other influenza viruses purchase online cialis super active, and why should we worry? Chickenpox is a manifestation of primary infection; zoster is caused by reactivation of latent infection buy 20mg cialis super active overnight delivery. By 2005 generic cialis super active 20mg online, dramatic reductions in chickenpox occurred, with the incidence declining by approximately 85%. Nevertheless, 10% of the adult population is estimated to be at risk of infection, and the majority of cases in the United States now occur in adults. The virus circulates exclusively in humans, and no other reservoirs of infection are known. The disease becomes epidemic in the susceptible population in winter and early spring, affecting both sexes and all races equally. Transmission occurs via the respiratory route and requires close contact even though the virus is highly infectious, with attack rates of 70–90% in susceptible family members. Zoster occurs in up to 1% of people over 60 years of age, and 75% of cases occur in those over the age of 45 years. The development of zoster is not associated with exposure to other people with chickenpox or zoster, although patients with zoster may themselves be capable of transmitting the virus to susceptible individuals. Zoster occasionally occurs in younger individuals, particularly those who are immunosuppressed. She had noted the onset of the skin lesions and low-grade fever 2 days before admission. Aside from the rash, she had been feeling well until the day of admission, when she began experiencing a dry cough and increasing shortness of breath. A chest X-ray revealed bilateral lower lobe infiltrates with a fine reticulonodular pattern. New crops of skin lesions were noted over the first 24 hours; however, the patient then defervesced, and her respiratory status slowly improved. Pathophysiology and Clinical Manifestations Chickenpox is popularly felt to be a benign childhood rite of passage. Nevertheless, from 1990 to 1994, approximately 100 deaths each year in the United States were attributed to chickenpox and its complications. The overall risk of death is about 15 times higher in adults than in children, being estimated at more than 3 per 10,000 cases. Most deaths in adults are a result of the development of visceral complications as discussed later in this subsection. The virus then replicates at local sites (which have not been clearly identified) and infects the reticuloendothelial system. Viremia ensues, followed by diffuse seeding of the skin, internal organs, and nervous system. Replication of the virus occurs in the dermis, leading to degenerative changes and the formation of multinucleated giant cells, producing the characteristic diffuse vesicular rash. It begins as small erythematous papules less than a centimeter in diameter that rapidly evolve into vesicles. As viral replication proceeds and infiltration by polymorphonuclear leukocytes occurs, the lesions appear purulent. A hallmark of chickenpox is that lesions at all stages of development—maculopapules, vesicles, and scabs —are all found together. Successive crops of lesions occur over several days, with complete healing by 10-14 days in uncomplicated cases. Zoster presents as a localized eruption along the course of one or more dermatomes, most commonly the thoracic or lumbar. The rash, which is often preceded by localized pain, begins as erythematous papules that evolve into vesicles. The vesicles may coalesce into large, confluent blisters with a hemorrhagic component. Healing occurs over the course of 2 weeks, although permanent skin changes such as discoloration and scarring may occur. When zoster affects the first branch of the trigeminal nerve, herpes zoster ophthalmicus may occur, with involvement of the cornea and potentiallysightthreatening complications. Involvement of other branches of the trigeminal or facial nerves may result in unusual presentations with intra- oral vesicles. The constellation of lesions in the external auditory canal, loss of taste, and facial palsy is termed Ramsay Hunt syndrome. Diagnosis the diagnosis of chickenpox can usually be made on clinical grounds, based on the characteristics described earlier. Since the eradication of all known natural human reservoirs of smallpox and the discontinuation of universal smallpox vaccination, the clinical diagnosis of chickenpox has been relatively straightforward. Nevertheless, the possibility of smallpox as a biologic weapon and resumption of vaccination of larger segments of the population may necessitate considering smallpox (see below) or disseminated Vaccinia in the differential diagnosis of a diffuse vesicular rash in an adult. A diffuse vesicular eruption, Kaposi varicelliform eruption, occasionally occurs in patients with eczema. The diagnosis can be made on the basis of the history and identification of the virus in vesicle fluid. Occasionally, enteroviral infection may cause diffuse cutaneous vesicular lesions that mimic early chickenpox. These lesions are often found on the palms, soles, and oral mucosa and do not progress like those of chickenpox. Chickenpox infected 3–4 million people annually (10% adults) in the United States before vaccine availability; zoster, 500,000 annually. Highly infectious, spreads person to person by air droplets; zoster represents reactivation. Antibody-based assays performed on lesion scrapings or vesicle fluid may also be useful if available. Complications the major complications of varicella result from involvement of the pulmonary and nervous systems. Varicella pneumonitis is more common in adults and immunocompromised patients than in children. It has been estimated that as many as 1 in 400 adults with chickenpox have some pulmonary involvement, although most cases appear to be subclinical. When clinical varicella pneumonitis occurs in adults, it may be associated with high morbidity and mortality. The disease can be particularly severe in pregnant women during the later stages of pregnancy, possibly because of both the respiratory impairment resulting from a gravid uterus and the immunologic changes associated with pregnancy. Smoking and the presence of a large number of skin lesions have been identified as risk factors for the development of varicella pneumonia.

A longitudinal incision is made along the entire length of the confluence and extended into a pulmonary vein orifice buy 20 mg cialis super active, if necessary buy cheap cialis super active, to create a patulous opening cheap cialis super active 20mg without prescription. A matching incision is made on the posterior aspect of the top of the left atrium, placing gentle traction leftward on the left atrial appendage. The suture line is started at the leftward extent and carried along the superior edge of the atriotomy and the inferior edge of the venous confluence. Closure of the Atrial Septal Defect A patent foramen ovale or a small atrial septal defect, which is invariably present, must be closed in the usual manner through a right atrial incision. Ligation of the Ascending Vertical Vein the ascending vertical vein is encircled with a heavy tie during cooling. After stable hemodynamics are achieved, the vein is ligated as far away from the venous confluence as possible. It may be limited to an anastomotic stenosis between the pulmonary venous confluence and the left atrium, or it may involve the ostia of one or more of the pulmonary veins themselves. Magnetic resonance imaging can be especially useful in visualizing patent pulmonary veins with atretic ostia. Conventional Technique An isolated anastomotic stenosis is approached through a right atriotomy and vertical incision on the atrial septum. The narrowed anastomosis is enlarged by removing as much of the tissue as possible between the posterior left atrium and the pulmonary veins. However, if there is any question about the integrity of the adhesions, the endocardium of the left atrial wall and pulmonary venous confluence should be reapproximated with a running 6- 0 or 7-0 Prolene suture. If ostial stenosis of one or more pulmonary veins is present, it has been traditionally repaired by endarterectomy excision of the scar tissue or by incising and patching the pulmonary vein using pericardium, Gore-Tex, or atrial tissue. Sutureless Technique the operation requires that the adhesions between the left atrium and pericardium be left intact. The superior vena cava is cannulated as high as possible and standard aortic and inferior vena caval cannulation is performed. Following aortic cross- clamping and cardioplegia delivery, a left atrial incision is made just posterior to the interatrial groove. For right pulmonary venous involvement, as much scar tissue as possible is completely excised from the left atrium and by transecting the pulmonary veins beyond the narrowed area. This creates a neo-left atrial pouch, allowing unobstructed drainage of the open right pulmonary veins into the left atrium. Resection of scar tissue between the left atrium and pulmonary venous confluence results in an unobstructed communication. When left pulmonary veins are involved, the repair can be performed from within the left atrial cavity. Through the resultant opening, the pulmonary vein(s) is dissected out to the left pericardium and divided beyond the stenosed segment. If there are adequate pericardial adhesions, no suturing is required and the left pulmonary vein(s) drains into the left atrium through the closed posterior pericardial cavity. When pericardial adhesions are insufficient, the pericardium must be sutured to the left atrial wall away from the pulmonary venous ostium. This can be performed from inside the left atrium or from the outside by elevating the apex of the heart toward the right side. Alternatively, the left pulmonary veins can be dealt with from the outside by elevating the apex of the heart and opening the left atrium and stenotic pulmonary veins as described for right pulmonary vein stenosis. A pericardial flap is mobilized and sewn to itself and the left atrial wall as described in the preceding text. Identifying Pulmonary Venous Ostia the orifices of the stenotic pulmonary veins may be reduced to pinholes and can be difficult to identify. Phrenic Nerve Injury the suture lines for both the right-sided repair and the outside approach for left pulmonary vein repair come close to the phrenic nerves. Often in a reoperation, the course of the phrenic nerve cannot be appreciated from within the pericardial space. Therefore, it is best to open the pleural space(s) to check the location of the nerve before placing the sutures in the pericardium. Superficial bites over the nerve may be taken, or in some cases, the nerve with its pedicle can be mobilized away from the pericardium. Sutureless Technique as Primary Procedure Many have advocated for sutureless repair as a primary approach toward total anomalous pulmonary venous return, in particular for patients with heterotaxy syndrome, mixed total anomalous pulmonary venous return, and those with unusual orientation of the common confluence. Here, the development of a pericardial well around the confluence and veins affords an adjustment for orientation abnormalities. The plane between the pericardium and the pulmonary veins must be developed carefully, as this provides exposure to the veins as well as limits the borders (“well”) of the “neo-atrium”. Bleeding Suture line bleeding can be difficult to identify with the sutureless technique, in part because lifting the heart P. In addition, inadvertent entry into the left pleural space, even if deemed trivial, can be the source of considerable hemorrhage and difficult to control. A: Through a standard left atriotomy, the stenotic ostia are identified and the scar tissue either totally excised (dashed lines) or incisions made across the narrowed areas (dotted lines). The upper chamber may or may not communicate with the right atrium through an atrial septal defect or foramen ovale. Surgical Technique Complete correction is usually performed on continuous cardiopulmonary bypass using bicaval cannulation. The transatrial incision is extended across the right atrium and then across the atrial septum to the fossa ovalis (see Transatrial Oblique Approach section in Chapter 6). A: If the orifice of the appendage is easily visualized, the diaphragm may represent a supravalvar mitral ring. B: Removing the diaphragm to demonstrate the orifice of the appendage (the diaphragm separates the appendage from the veins) suggests this is cor triatriatum. The incision on the atrial septum can then be closed primarily or more often with a patch of autologous pericardium prepared with glutaraldehyde using a running 5-0 or 6-0 Prolene suture. The incisions on the right superior pulmonary vein and right atrium are then closed with a running 5-0 or 6-0 Prolene suture. The patient is rewarmed, the aortic cross-clamp is removed, and deairing is carried out in the usual manner. Anderson divides ventricular septal defects into perimembranous, subarterial-infundibular, and muscular types. The perimembranous variety of ventricular septal defects encompasses subgroups of defects that occur near the membranous segment of the interventricular septum and includes those septal defects commonly seen in tetralogy of Fallot and atrioventricular septal defects. Because the path of the conduction tissue is intimately related to the inferior rim of these defects, an accurate knowledge of the surgical anatomy of this region is most helpful. The atrioventricular node is situated in its usual position at the apex of the triangle of Koch, whose boundaries consist of the septal attachment of the tricuspid valve, tendon of Todaro, and the coronary sinus as its base.