Defects with High Pulmonary Blood Flow

Defects in which left-to-right shunting is continuous or predominant are associated with high pulmonary blood flow, and affected patients may eventually develop irreversible pulmonary vascular disease. The pressure and volume of flow, together with low oxygen saturations, are important determinants of structural changes in the lung vessels. These defects include persistent ductus arteriosus, aortopulmonary window, atrial and ventricular septal defects, atrio-ventricular septal defects,...

Generator Pocket

This pocket can be constructed in the prepectoral or subpectoral area, or in the axilla. If the former is chosen, the box pocket can be made before the wire is placed with an incision 3 cm below the clavicle, and the pocket created by a blunt dissection downward and medially onto the prepectoral fascia. The needle can then be inserted into the subclavian vein through the top of this incision and thus no tunnelling is required. If the axilla is chosen, an incision is made horizontally in the...

Testing the Pulmonary Vascular Response

Historically, the determination of resistance and reactivity of the pulmonary vasculature has implications for treatment and prognosis in patients with pulmonary vascular disease (Barst etal., 1999). Various inhaled or injected agents have been considered for reactivity testing, including oxygen, nitric oxide, calcium antagonists, adenosine and prostacycline. Many workers describe the construction of dose-response curves to multiple vasodilator agents, during long-catheter studies (Jolliet...

Transposition ofthe Great Arteries

Patients with this defect have a combination of severe cyanosis and increased pulmonary blood flow. In patients with simple transposition, a Rashkind's balloon septostomy is performed as soon after birth as possible to increase mixing at atrial level, although severe desaturation may persist. If a small ventricular septal defect or persistent ductus arteriosus is present, systemic oxygenation is usually higher. In most cases an arterial switch operation is performed in the first 2 weeks of life...

Blood Pumps

There are currently two types of blood pumps in use. The roller pump consists of a rotating arm which compresses silastic tubing between the parallel wall of the roller and a backing plate, causing positive forward displacement of blood in a continuous flow. It is therefore occlusive. Rate of flow is dependent upon the speed of rotation of the rotor arm. Careful adjustment of the rotating arm is required to provide forward blood flow and yet minimize damage to the cellular components of the...

Relations And Cardiac Position

These may need to be specified, particularly if they are unpredictable from knowledge of atrial situs and segmental connections. Although an unpredictable relation or position may affect the surgical approach, it does not alter the nature of the operation in the way that abnormal connections do. For example, if the atrio-ventricular connections are discordant, whilst the ventriculo-arterial connections are concordant, it is fundamental to appreciate that the pulmonary and systemic circulations...

Cardiopulmonary Exercise Testing In Children And Adolescents

In adult practice, exercise testing has largely focused on the evaluation of symptoms of ischaemic heart disease. Only a small subgroup of children have congenital or acquired reasons to suspect myocardial ischaemia (Kawasaki disease, cardiac surgery to the coronary arteries). Another subgroup of children may require investigation to assess inducible arrhythmia, including inherited arrhythmia syndromes such as Long QT and Brugada syndromes. There are numerous published protocols for exercise...

References

Allen ML, Peters MJ, Goldman A et al. Early postoperative monocyte deactivation predicts systemic inflammation and prolonged stay in pediatric cardiac intensive care. Crit Care Med2002 30 1140-1145. Andersen LW, Baek L, Thomsen BS et al. Effect of methyl-prednisolone on endotoxemia and complement activation during cardiac surgery. J Cardiothorac Anesth 1989 3(5) 544-549. Aoki M, Nomura F, Stromski ME et al. Effects of pH on brain energetics after hypothermic circulatory arrest. Ann Thorac Surg...

Acknowledgements

Figure 8.33 was photographed by Dr L. H. S. Van Mierop of Gainesville, FL, USA, and is reproduced with Figure 8.33 was photographed by Dr L. H. S. Van Mierop of Gainesville, FL, USA, and is reproduced with his permission. We are indebted to all our friends who have collaborated and contributed to the formulation of the concepts expressed herein, particularly James L. Wilkinson, Melbourne, Australia the late Andre Moulaert, Utrecht, The Netherlands Benigno Soto, Birmingham, AL, USA Simcha Milo,...

Anatomy Of Isolated Ventricular Septal Defects

We use the term ''isolated'' ventricular septal defect to describe a hole between the ventricles in a heart with concordant atrio-ventricular and ventriculo-arterial connections, and normally positioned chambers and arteries, in other words otherwise normal hearts, with no other major associated lesions. The defect itself is considered to represent the margin around which the surgeon must place a patch so as to separate the pulmonary and systemic circulations, which before correction would have...

Figure 347

Echocardiographic surveillance is equally important after apparently definitive procedures. Progressive obstruction of an extracardiac valved conduit is almost inevitable and should be monitored. Other anticipated late complications might include recurrent aortic arch obstruction, pulmonary regurgitation after repair of tetralogy of Fallot (Colour Plate 2), venous pathway narrowing after atrial repairs for TGA, obstruction of pulmonary venous flow, either within the...

Transposition of the Great Arteries

Transposition of the great arteries (TGA) is defined as ventriculo-arterial discordance with an aorta arising from the RV (Figure 5.13), and the pulmonary artery arising from the LV. Surgical therapy for this condition was revolutionized with the introduction of intra-atrial switch procedures, which produce a physiologically normal circulation. The arterial switch operation produces both a physiological and anatomically normal circulation. In cases of TGA associated with a VSD and subpulmonary...

Univentricular Heart

Surgical management involves the Fontan procedure or one of its variations, such as the total cavopulmonary connection (TCPC). For success, the procedure, which is classified as definitive palliation and which involves passive pulmonary blood flow, relies on good function of the sole ventricle and low normal pulmonary vascular resistance. The procedure may be staged, starting with a Glenn shunt (SVC to right PA) followed by a completion of TCPC at a later date. Sometimes a fenestration between...

Redo Surgery

Many patients undergo reoperation at some stage in their lives. Those whose lesions required the use of a homograft conduit, such as truncus arteriosus, Rastelli procedure or correction of pulmonary atresia, will need conduit replacement, either because they have grown out of the size originally used or because the conduit has become progressively narrowed with calcification. The conduit may lie just beneath the sternum or even attached to it. The greatest care is required during the opening of...

Hybrid Approaches

Interventional cardiology has been generally considered as competitive to surgery, since some lesions are now ''curable'' without the need for surgery. Elsewhere, catheter treatments have been adjuvant to surgical treatment. However, a collaborative approach between surgeons and interventional cardiologists might be more appropriate in order to decrease cumulative morbidity and mortality and improve outcome of certain congenital heart defects. Various collaborations could be beneficial for the...

Ventricular Pacing

The electrode with its curved stilette is passed to the right atrium, often a loop is formed with the stilette pulled back, and it passes across the tricuspid valve and out into the right ventricular outflow tract and pulmonary artery. In small children the curve of the stilette needs to be within 2 cm of the end. The entry into the pulmonary artery may be difficult, particularly in corrected transposition of the great arteries or in transposition after atrial surgery. In these cases the use of...

Valvuloplasty for Congenital Valvular Diseases

Since the first description of balloon dilatation of a valvar pulmonic stenosis by Kan etal. in 1982, this Surgery for Congenital Heart Defects, Third Edition. Edited by J. F. Stark, M. R. de Leval and V. T. Tsang 2006 John Wiley & Sons, Ltd procedure is now considered to be first-line treatment. Pulmonary valve relief is usually indicated when the systolic gradient between the right ventricle and the pulmonary artery is higher than 50mmHg. A routine right heart catheterization is first...

The Atrioventricular Junctions

The most vulnerable and complicated regions of the normal heart are the atrio-ventricular junctions, because they contain the origins of the leaflets of the atrio-ventricular valves, the atrio-ventricular conduction system and the major branches of the coronary arteries (Anderson et al., 2000). The areas are further complicated anatomically because the junction of the right heart chambers occupies a spatial plane different from that of the left heart chambers, the attachment of the leaflets of...

Atria and Atrial Septum

The two atria are normally of similar sizes. Bowing of the atrial septum into the right (Figure 3.24a) or left atrium (Figure 3.24b) suggests volume overload, pressure overload or both of the left or right atrium, respectively. A secundum atrial septal defect (Colour Plate 5) is the most common type of interatrial communication. This is usually best visualized in children from a subcostal position. Delineation of the margins of the defect in relation to other structures is crucial in the...

Intraoperative Echocardiography

Both epicardial and trans-oesophageal ultrasonic windows may be used for intraoperative echocardiography. When the epicardial approach is used, the ultrasound transducer is enclosed in a sterile plastic sleeve, contact being maintained between the face of the scan head and the plastic by ultrasound jelly. The pericardial cavity may be filled with saline, and the transducer is held gently against the epicardial surface. Epicardial and trans-oesophageal echocardiography may be of complementary...

Hypothermic Circulatory Arrest And Lowflow

Each individual operation imposes its own constraints on the surgeon and the perfusion practice. The use of circulatory arrest, low flow, full flow, and high or low perfusion pressures is based on a combination of patient size, anatomy, surgical procedure, collateral blood flow and personal (surgeon) preference, as opposed to predetermined protocols. There is a trend towards less use of deep hypothermia and circulatory arrest, with a move towards more physiological parameters. Currently, the...

Oxygenators

There is currently no role for the bubble oxygenator in paediatric practice, unless there are strong economic reasons for its use. In comparison to membrane oxygenators, they are associated with increased production of gaseous microemboli, protein denaturation, increased haemolysis and complement activation (van Oeveren etal., 1985). In addition to gaseous exchange, membrane oxygenators also remove gaseous microemboli from the circuit (Jones et al., 2002a). Of the membrane oxygenators...

Heparin Dosage and Heparin Neutralization

Heparin is given prior to cannulation at a dose of 3 mg kg of body weight. More heparin may be added, depending on the activated clotting time (ACT), which is monitored at frequent intervals during bypass to maintain an ACT of more than 450 seconds. A baseline ACT measurement is performed before heparinization and a second measurement before the institution of bypass, in order to ensure adequate anticoagulation. Heparin binds to and activates antithrombin III. It is not a uniform substance, and...

Hypothermia

In non-cardiac surgical patients, the deleterious effects of intraoperative hypothermia with regard to increased infection, morbid cardiac events, blood loss, protein loss and length of hospital stay have been well documented. In contrast, during cardiac surgery, hypothermia has been used to reduce metabolic activity while preserving high-energy phosphate stores and increase tolerance to reductions in pump flow rates (cardiac output). It has also been used as a kind of insurance policy,...

Generator Placement

This approach is frequently used in small infants and thin children because the pacemaker can be buried very deeply (Figure 9.10). An incision is made below and lateral to the 12th rib and dissection is carried down onto the muscle, which is split to reveal the extraperitoneal space above the kidney. The wire is tunnelled subcutaneously and connected to the box, the muscle edges are brought together with Dexon and the wound closed in layers. A vertical incision is created down onto the...

Aortic Valve Stenosis

Balloon dilatation valvuloplasty for congenital aortic valve stenosis was developed in the mid-1980s (Lababidi etal., 1984), and experience has been gained in most large centres. Dilatation is indicated in all patients with Doppler peak gradient greater than 70 mmHg, in patients with left ventricular strain on the ECG and peak gradient greater than 60 mmHg, and regardless of the gradient in patients with syncope, low cardiac output, severe left ventricular dysfunction or duct-dependent systemic...

Twodimensional Gradientecho Imaging

One advantage of newer gradient-echo sequences is that they are partially flow-compensated and thus the blood pool signal is homogenous. However, high velocity blood flow will lead to signal loss, which allows qualitative analysis of blood flow jets. Thus, single-slice imaging allows qualitative assessment valvular dysfunction and dynamic vascular anatomy. Multi-slice two-dimensional (2D) gradient-echo imaging represents the gold standard for ventricular volumetry (Bellenger etal., 2002), as it...

Left Superior Vena Cava

The special circumstances of cannulation for the various procedures are covered in the individual operations described in this book however, the management of a left SVC is common to many conditions and is considered separately here. It can be difficult to determine in advance whether it is necessary to cannulate a left SVC. However, if pressure-monitoring cannulae have been inserted into the neck above both right and left SVCs, the decision can be made during CPB. When full flow is established...

Electrode Dislodgement

Electrode dislodgement may occur with endocardial leads, although it has become significantly rarer since active fixation leads have been routinely used. The patient may require a temporary trans-venous system to main cardiovascular stability while the permanent system is revised. The box pocket is opened and the pacing wire disconnected from the generator. The anchoring suture on the sleeve is removed if necessary, a subclavicu-lar incision would have to be opened. A new stilette is advanced...

Catheter Placement and Haemodynamic Measurement

Resistance calculations require the measurement of cardiac output and mean trans-pulmonary pressure difference (pulmonary artery pressure left atrial pressure). Of the methods of cardiac output measurement, there are known limitations. Thermodilution can be unreliable in small children when the proximal injectate port for the cold fluid injection may not lie in the right atrium, or where intracardiac shunts exist. Dye dilution is not commonly used for practical reasons. The Fick principle is...

Postoperative Assessment

Bedside echocardiography in the intensive care unit provides key information for postoperative management. Surgical dressings, drains, pressure-monitoring catheters, pacing wires, prosthetic material inserted at operation, and hyperinflation of the lungs in ventilated patients may limit access and image quality. Infection is a potential concern, especially in neonates in whom the sternum may be splinted for a while postoperatively. Nevertheless, acceptable examinations can be obtained in most...

Arrhythmias And Pacing

Postoperative arrhythmias, a relatively common complication following cardiac surgery (Hoffman et al., 2002), Prolonged ACT, normal heparinase ACT APTT > 2 x control, PT < 1.5 x control APTT, activated partial thromboplastin time ACT, activated clotting time PT, prothrombin time. APTT, activated partial thromboplastin time ACT, activated clotting time PT, prothrombin time. result from a variety of causes, including injury or oedema to the cardiac conduction system, changes in myocardial...

Myocardial Preservation

Since the publication of the first edition of this book, a wealth of literature has been generated concerning intraoperative protection of the paediatric myocardium. A majority of the work reported in this literature is experimental and includes various modifications of crystalloid cardioplegic solutions, blood cardioplegia and, more recently, reperfusion solutions. Despite extensive literature, there remains no generally accepted strategy for the intraoperative protection of the paediatric...

Practical Difficulties with the Wire Position

A left superior vena cava to the coronary sinus can be used for both atrial and ventricular pacing, with either a tined lead or a screw-in lead. It is relatively easy to enter the tricuspid valve on an atrial loop. 2. In a small heart, the bend between the right atrium and the pulmonary artery is too tight to take a straight stilette. In this case, the lead is withdrawn, leaving the stilette within the atrium, and the stilette is only advanced when the electrode has become almost horizontal....

Biventricular Pacing Cardiac Resynchronization Therapy

In association with heart failure, there are electromechanical abnormalities of prolonged atrio-ventricular, interventricular and intraventricular delay. This combination allows for poor ventricular filling, diastolic mitral regurgitation, delayed activation of the free wall of the left ventricle in comparison to the right ventricle, and finally dysynchrony between different segments of the left ventricle, particularly the septum and the free wall, all of which produce inefficient cardiac...

Atrioventricular Connection

Once atrial situs has been defined, it is necessary to recognize ventricular structure in order to assess the atrio-ventricular connection. When there is a biventricular atrio-ventricular connection, the morphological right ventricle can be recognized by the coarse apical and septal trabecular pattern and from the fact that the septal origin of the tricuspid valve is positioned slightly more apically than that of the mitral valve (Figure 3.17, (a) concordant and (b) discordant atrio-ventricular...

Ventricles and Ventricular Septum

Ventricular volumes, wall thickness and wall movement demonstrate the haemodynamic consequences of structural abnormality. For example, there is reduced cavity volume and increased wall thickness of the right ventricle in pulmonary atresia with intact ventricular septum (Figure 3.24b) and of the left ventricle in hypoplastic left-heart syndrome. Right ventricular volume overload occurs most commonly in left-to-right shunting at atrial level (Colour Plate 5), but is increasingly seen during late...

Haemodilution

Before the extracorporeal circulation can be connected to the patient's circulation, it must be primed with fluid and de-aired to reduce the possibility of gaseous macro- and microemboli being delivered to the patient. Initiation of CPB therefore results in haemodilution, with a reduction in the plasma colloidal oncotic pressure that may result in a movement of fluid from the intravascular space into the inter- and intracellular spaces, causing tissue oedema. An increase in interstitial fluid...

Colourflow Doppler Interrogation

Colour-flow Doppler interrogation is performed over a selected portion of the anatomical 2D image, whereby pulsed Doppler sampling occurs at many points on each line of the ultrasound beam within this chosen portion. The mean velocities at each sampling site are colour-coded according to the direction and velocity of flow. Normally, shades of red are assigned for flow toward the transducer, and shades ofblue are assigned for flow away from the transducer. This spatially orientated colour-flow...

Summary

Cardiac catheterization and associated angiocardiography is no longer the principal mode of investigation of heart disease. It is but one of a number of investigations into the form and function of the heart. It has its own particular strengths, but because of its invasive nature carries an inherent risk. Thus, the importance of the specific data must be balanced with the risk of the procedure. The indications revolve around the need for precise haemodynamic measurements, particularly pressure,...

Intracardiac Suction

Typically, three suction heads are used to provide three suction lines to the patient. One of these acts as a vent, and the other two are available for intracardiac or pericardial suction. A sump sucker is connected to one of these, and a hand-held metal-tipped sucker is connected to the other. The tubing to these suction devices should be as short as possible. For neonates, we use only two suction lines to reduce such prime loss. It is important to use low-pressure suction to avoid haemolysis.

Coronary Arteries

Knowledge of coronary artery anatomy is important in the assessment of many congenital heart defects. In complete TGA (Pasquini etal., 1987), the coronary arteries normally arise separately from the aortic sinuses that face the pulmonary trunk. The most important variant to identify is an intramural proximal coronary artery course this is usually first suspected by identifying the proximal left coronary artery coursing between the aorta and pulmonary trunk (Figure 3.38) adjustment of the...

Perimembranous VSD

Before the availability of the new perimembranous Amplatzer device, several authors have tried to close perimembranous VSDs using devices originally designed for ASD or PDA closure. The rates of complications (i.e. embolization, aortic insufficiency) and residual shunt were high. Following animal experiments, Hijazi et al. (2002) and Bass et al. (2003) recently reported their human experience with perimembranous VSD closure, using a specifically designed device, the Amplatzer perimembranous...

Abbreviations

This is a list of abbreviations which occur frequently in the text. Those less commonly used are explained where they occur. CPAP continuous positive airway FiO2 fraction of inspired oxygen IPPV intermittent positive pressure LVOT left ventricular outflow tract LVOTO left ventricular outflow tract

Atrial Septal Defect ASD

Supraventricular arrhythmias, particularly atrial flutter, are very common in patients with an ASD. In those who have not had surgical correction, arrhythmias are seen in 30-40 of patients by the age of 35 years. Atrial flutter in these patients is often ''typical'', i.e. dependent on conduction through a critical isthmus between the tricuspid annulus and inferior vena cava, and the activation wavefront may circle in either a counterclockwise or clockwise direction (Chan et al., 2000). In the...

Tetralogy of Fallot TOF

Most patients with TOF survive into adulthood with palliative or corrective surgery (Murphy etal., 1993). Patients with repaired TOF are at risk for both atrial and ventricular arrhythmias (Roos-Hesselink et al., 1995 Lucron etal., 1999). Following surgery, patients may have scarring of the right atrium from an atriotomy, and right ventricular scar from a ventriculotomy or ventricular outflow tract patch. In addition, residual haemodynamic lesions, such as RV dilatation caused by chronic...

Functional Single Ventricle and Fontan Operation

The Fontan procedure offers surgical palliation to patients with a functional single ventricle. The primary arrhythmia following the atriopulmonary Fontan operation is IART, with atrial fibrillation also seen, but less frequently (Triedman, 2002). Retrospective studies from large cardiac surgical centres indicate that 25-50 of patients who have undergone the Fontan procedure will have clinical documentation of IART by 10 year follow-up. Frequently identified risk factors for IART include older...

Case Selection And Preparation

Knowledge of individual anatomy is essential when planning electrophysiological intervention. Review of the surgical case notes will allow assessment of the potential anatomical barriers for arrhythmia circuits and central obstacles for re-entry, such as atriotomy scars and patches. Documentation of clinical tachycardias via 12 lead electrocardiograms or Holter recordings is required to determine arrhythmia mechanisms and allow effective targeting of the arrhythmia substrate. Imaging...

Ventricular Tachycardia

Patients with ventricular dilatation, fibrosis or previous operative intervention are at risk of developing ventricular tachycardia. This is particularly seen in the patients with TOF who have undergone patch reconstruction of the right ventricular outflow tract (Lucron et al., 1999). Advanced mapping techniques are used to identify re-entry loops and corresponding channels between areas of scarring. Complex circuits may require ablation at several sites around the re-entrant zone to block all...

Surgical Procedures

16 Systemic-to-Pulmonary Artery Shunts, C. vanDoorn and M. R. de Leval . . . 251 Indications, 251 Disadvantages, 251 Surgical Technique, 251 Classical Blalock- Taussig Shunt, 251 Potts Shunt and Waterston Shunt, 254 Prosthetic Systemic-Pulmonary Artery Shunt, 255 Results, 259 17 Pulmonary Artery Banding, V. T. Tsang and J. Stark 261 Classical Indications, 261 Current Indications, 261 Ventricular Septal Defect, 261 Transposition of the Great Arteries, 262 Double-inlet Ventricle and Tricuspid...

Pulmonary Atresia

Pulmonary atresia is defined as a lack of continuity between the RVOT and the central pulmonary arteries, with a variable degree of hypoplasia of these structures. Pulmonary atresia is separated into two groups those with and those without a VSD. As the diagnosis and subsequent management of these two groups is different, it is useful to consider them separately. Pulmonary atresia with a VSD is the most common variant and is considered by some to be a severe form of ToF, with a subaortic VSD,...

Arterial Cannulation

The site of arterial cannulation will vary, depending on the requirements of the individual operation and the morphology of the circulation. Some situations are obvious, e.g. if the surgeon is to operate on the aortic root, the cannula should be positioned as distally as possible. However, more subtle positioning is also helpful. In an operation for tetralogy of Fallot, most of the surgical procedures take place on the right ventricular outflow tract or the pulmonary arteries, to the left of...

Pericardial Cavity

The heart is enclosed by a firm, fibrous sac, the pericardium. In functional terms, the pericardium consists of a tough bag that encloses the heart. The heart is placed into it from the base toward the apex, and the bag is subsequently closed by the fibrous layer merging at the cardiac base with the adventitial layers of the veins that enter and the arteries that leave the heart. In anatomical terms, the pericardium is a much more complex structure. This is because a second sac, the serous...

Congenitally corrected transposition ccTGA

This rare disorder is characterized by atrio-ventricular and ventricle-arterial discordance (right atrium to left ventricle to pulmonary artery and left atrium to right ventricle to aorta). Congenitally corrected transposition may be asymptomatic and in some patients is an incidental finding (Figure 5.17). However, the majority of patients with ccTGA have associated cardiac lesions (Bjarke and Kidd, 1976), such as VSDs, pulmonary stenosis or tricuspid valve abnormalities. Even without...

Straddling Left Atrioventricular Valves

A straddling left atrio-ventricular valve can be found in two distinct situations. The first is when the valve is of mitral structure, and is connected to a left-sided morphologically left ventricle and also to a right-sided morphologically right ventricle. This arrangement is basically that of concordant atrio-ventricular connections, but when the straddling valve is committed mostly to the ventricle receiving the other valve, then there is effective double-inlet right ventricle with...

Closed Cardiac Operations

Approximately 25 of cardiac surgery for congenital disease is performed without bypass, usually via a thoracotomy for procedures such as ligation of persistent ductus arteriosus, relief of coarctation of the aorta, formation of Blalock-Taussig shunts and banding of the pulmonary artery. Many of the patients are very cyanosed and or in severe heart failure. Some may require preoperative intensive care with respiratory and cardiac support. Levels of monitoring, vascular access and induction and...

R H Anderson and A E Becker

The purpose in this chapter is to show the anatomical variation that can exist in communications between ventricles, and to show how this variation relates to the atrio-ventricular and ventriculo-arterial connections that are present. In each example, we will describe the surgical anatomy of the conduction tissues. The key for various parts of the conduction tissues as they are superimposed on photographs is illustrated in Figure 8.1. Note the different conventions used for the right and left...

Angioplasty

Experiments establishing the basis for balloon angioplasty were performed in the early 1980s (Lock et al., 1981,1982). In those experiments, the balloon dilatation of experimental pulmonary artery stenoses was responsible for medial and intimal tearing, leading to the increase of vessel size, which reflects the efficacy of the procedure. Since then, balloon catheters have been used to dilate various vascular lesions, either congenital or postoperative. Balloon dilatation of aortic coarctation...

The Cardiac Skeleton

The fibrous skeleton is variably developed around the atrio-ventricular junctions, being strongest at the central fibrous body (Figure 2.37). There, the attachments of the leaflets of the mitral, tricuspid and aortic valves all meet together. Part of the fibrous body in this position also forms the membranous portion of the cardiac septum. Because of the differing positions of attachments of the leaflets of the mitral and tricuspid valves to the central fibrous body, and because of the wedge...

Velocityencoded Phase Contrast MR

Quantification of blood flow and velocity is an important tool in the management of congenital heart defects. Quantification of the pulmonary to systemic blood flow ratio (Qp Qs), valvular regurgitation fraction or vascular stenosis is used to assess disease progression, suitability for surgery and timing of surgery. Velocity-encoded phase contrast MR enables non-invasive quantification of blood flow and velocity in major vessels. Cardiac output and Qp Qs measured using this technique compare...

Ultrafiltration Uf

Modified Ultra Filtration Circuit

The increasing use of CPB in the neonatal period with haemodilution has exposed the tendency toward massive capillary leakage in these patients. Such capillary leakage can result in organ oedema and dysfunction and potentially fatal results. This problem reawakened interest in ultrafiltration, which was used in adult cardiac surgery for some time for removal of water from patients in chronic heart failure or for haemoconcentration towards the end of bypass. In conventional ultrafiltration...

Atrial Flutter and IART

If the typical flutter isthmus is involved in the reentry circuit, the area between the tricuspid valve (TV) and IVC is targeted for ablation (Figure 10.3). It is relatively narrow and in most patients good ablation catheter-tissue contact is achievable, although furrows and ridges may reduce tissue penetration with RF energy. Complete bidirectional conduction block across the flutter isthmus is the end point for ablation. IART may be re-entrant around a right atriotomy scar or, less usually,...

Junctions Between The Cardiac Segments

Types of Atrio-ventricular Connection There are several ways in which the atrial chambers can be joined to the underlying ventricular mass (Tynan et al, 1979), as illustrated in Figure 1.5. We describe the way in which the atrial and ventricular muscles masses are joined together as the ''types of atrio-ventricular connection''. In this respect, it should be noted that the normal heart, and many malformed hearts, possess two atrio-ventricular junctions. Thus, connections are usually plural....

Table 136 Basic principles of arrhythmia management for the intensivist

Ensure preoperative and immediate postoperative 12-lead ECGs have been recorded for later comparison Discuss patients with complex arrhythmia histories with an electrophysiologist prior to surgery Discuss any incidents of perioperative arrhythmias and precipitating factors with surgeon and anaesthetist Ensure abnormalities of plasma electrolytes are corrected Obtain a 12-lead ECG of arrhythmia prior to antiarrhythmic drug administration Record ECG after any subsequent interventions including...

Permanent Systems

The procedure requires X-ray fluoroscopy with a C arm and is performed in a catheter laboratory or a pacing theatre. Sterility is paramount and it is important to empower all members of the multidisciplinary team to point out areas of concern. We perform our procedures under general anaesthesia with a 24 hour course of anti-staphylococcal antibiotics starting at induction. Adult centres use basal sedation and local anaesthesia. Use of antibiotic cover is not universal but is very common....

In Doubleoutlet Ventricle

In hearts with double-outlet ventriculo-arterial connection, the hole between the ventricles forms the only egress for one of them. This hole, however, is not the space around which the surgeon secures a patch. It is important to appreciate this fundamental difference between interventricular communications in hearts in which each ventricle gives rise to a separate arterial trunk, and those in which there is a double-outlet ventriculo-arterial connection. The crucial feature in surgical repair...

Venous Reservoirs and Venous Drainage

Reservoir Pressure Heart

Blood drains from the patient via venous cannula into a venous reservoir before being pumped through the circuit. The reservoir acts as a holding tank, allowing fluctuations in the patient's circulatory volume to be tolerated. Figure 11.1 shows a diagram of the cardiopulmonary bypass circuit used at our department. Line 1 is the venous line from the right atrium or superior vena cava (SVC) to the venous cardiotomy reservoir (A). Line 2 is the venous line from the reservoir to the arterial pump...

Tetralogy of Fallot

Tetralogy of Fallot (ToF) is caused by malalignment of the infundibular septum, which leads to right ventricular outflow tract (RVOT) obstruction, a subaortic VSD with aortic override (Figure 5.6) and right ventricular hypertrophy. Current management consists of early single-stage reconstructive surgery, which has the benefit of leaving the patient acyanotic and has good survival rates. However, staged reconstruction may still be required under special circumstances (see Chapter 29). MR imaging...

Defects with Fibrous Continuity Between the Leaflets of the Aortic and Tricuspid Valves

These defects have conventionally been termed ''membranous defects'', but this can be a misleading term. As Becu et al. (1956) indicated, the defect is rarely caused by a deficiency of the interventricular component of the membranous septum. Indeed, during the development of the heart, the interventricular component is frequently not formed until after birth (Allwork and Anderson, 1979). The defect with fibrous continuity between the leaflets of the aortic and tricuspid valves results instead...

Identification Of The Cardiac Segments

Crista Supraventricularis

Atrial Situs (Atrial Arrangement) and Morphology Sequential segmental analysis can only work if structures are defined morphologically (Van Praagh, 1972 Anderson and Ho, 1997). This presents a problem only in relation to nomenclature of ventricles and the atrial chambers. Strict clarity demands that the words morphologically ''left'', or ''right'', ''ventricle'' or ''atrium'' should be used whenever these chambers are discussed and described, but this is somewhat cumbersome. For this reason,...

Anatomy Of The Ventricular Septal Defect In Tetralogy Of Fallot

Although the various types of ventricular septal defects found in tetralogy are comparable with isolated perimembranous, muscular or juxta-arterial defects that open to the outlet of the right ventricle, tetralogy is such a well-defined entity that the defects warrant separate consideration. We define ''tetralogy'' as the combination of a ventricular septal defect, subpulmonary infundibular stenosis, aortic overriding and right ventricular hypertrophy. The essence of the anomaly is cephalad...

Straddling Right Atrioventricular Valve

As with straddling of the left valve, this condition can also exist in two basic forms, each of which may produce basically univentricular or biventricular atrio-ventricular connections, depending on the degree of override of the atrio-ventricular junction. The first represents a spectrum between concordant atrio-ventricular connections with straddling tricuspid valve, and double-inlet left ventricle with right-sided rudimentary right ventricle and straddling right valve. The straddling valve...

Venous Cannulation

This is usually the method of choice for operations certain to involve circulatory arrest, or those in which the left side of the heart requires attention in the absence of intracardiac shunts. However, it is also preferred by some teams when low-flow bypass is required or when surgery on the inside of the heart is minimal e.g. the situation in the arterial switch procedure with intact ventricular septum . The choice of cannula is important for facilitating positioning within the right atrium...

Pulmonary Hypertension

Children with L-R shunts leading to pulmonary overcirculation or obstruction to pulmonary venous drainage pulmonary venous obstruction, mitral valve stenosis are at risk of developing pulmonary hypertension PHT Wessel, 2001 . PHT increases right ventricular afterload, potentially resulting in acute right ventricular failure, and may occur despite technically successful cardiac surgery. Pulmonary vascular reactivity has been related not only to the presence of preoperative pulmonary hypertension...

Quantitative Measurement

Atrioventricular Septal Defects And Echo

Echo measurement of ventricular shortening, wall thickness and cavity size remains a cornerstone of the assessment of ventricular function, hypertrophy or volume load. Figure 3.4, parasternal long axis in diastole, left, and systole, right, showing systolic apposition of the mitral valve and the septum as the mechanism of left ventricular outflow obstruction in hypertrophic cardiomyopathy . Contemporary clinical surgical decision making in many situations relies heavily on relatively simple...

Basic Rules Regarding Disposition Of The Conduction System

In any heart with a communication between two ventricles, application of a few basic rules enables fairly accurate prediction of the course of the conduction system. First, the regular atrio-ventricular node is always located at the apex of the triangle of Koch. Second, the branching atrio-ventricular bundle is positioned astride the crest of the muscular ventricular septum, regardless of whether that septum is aligned or malaligned relative to the atrial and muscular outlet septal structures....

Anatomy Of Cardiac Chambers

Triangle Koch Anatomy

To understand the spatial relationships of the different cardiac chambers, three basic rules of cardiac anatomy should be remembered. First, because of the orientation of the cardiac long axis, the ventricles are more or less to the left of their corresponding atrial chambers. Second, the right atrium and the right ventricle are relatively anterior to their left counterparts. Third, because of the anterior position of the chambers of the right heart, the aorta and its valve have a central...

P G Rees

Lillehei and colleagues devised a system of leaving at operation a wire attached to the ventricular epicardium and used it to pace the heart with a small external pacemaker system developed by Bakken Weirich etal., 1958 . In 1959, Elmquist and Senning described the first completely implantable pacing system involving the use of epicardial electrodes. At about that time, Furman and Robinson 1958 used endocardial leads introduced trans-venously. During the next few years...