|
|
| (170 intermediate revisions by 12 users not shown) |
| Line 1: |
Line 1: |
| {{Infobox_Disease | | | __NOTOC__ |
| Name = Atrial septal defect |
| | {{Atrial septal defect}} |
| Image = Gray468.png |
| | '''For patient information click [[Atrial septal defect (patient information)|here]]''' |
| Caption = Heart of human [[embryo]] of about thirty-five days |
| |
| Width = 180px |
| |
| DiseasesDB = 1089 |
| |
| ICD10 = {{ICD10|Q|21|1|q|20}} |
| |
| ICD9 = {{ICD9|745.5}}-{{ICD9|745.6}} |
| |
| ICDO = |
| |
| OMIM = 108800 |
| |
| MedlinePlus = |
| |
| eMedicineSubj = med |
| |
| eMedicineTopic = 3519 |
| |
| MeshName = Atrial+Septal+Defects |
| |
| MeshNumber = C14.240.400.560.375 |
| |
| }}
| |
| {{SI}}
| |
| {{WikiDoc Cardiology Network Infobox}}
| |
|
| |
|
| '''Editors-In-Chief:''' Claudia Hochberg, M.D.; [[User:C Michael Gibson |C. Michael Gibson, M.S., M.D.]] [mailto:mgibson@perfuse.org] Phone:617-525-6884 | | {{CMG}}; '''Associate Editor(s)-In-Chief:''' [[Priyamvada Singh|Priyamvada Singh, M.D.]] [mailto:psingh13579@gmail.com]; {{KD}} '''Assistant Editor(s)-In-Chief:''' [[Kristin Feeney|Kristin Feeney, B.S.]] [mailto:kfeeney@elon.edu] |
|
| |
|
| '''Associate Editors-In-Chief:''' {{CZ}}; [[User:KeriShafer|Keri Shafer, M.D.]] [mailto:kshafer@bidmc.harvard.edu]
| | {{SK}} ASD |
|
| |
|
| {{Editor Join}}
| | ==[[Atrial septal defect overview | Overview]]== |
|
| |
|
| ==Overview== | | ==[[Atrial septal defect anatomy|Anatomy]]== |
| '''Atrial septal defects''' (ASD) are a group of congenital heart diseases that involve the inter-atrial septum. The inter-atrial septum is the tissue that separates the [[right atrium|right]] and [[left atrium|left]] atria from each other. This tissue prevents arterial and venous blood from mixing with each other. If there is a defect in this septum, a direct communication between the atria can occur, which allows shunting, resulting in mixing of arterial and venous blood. It is possible for blood to travel from the left side of the heart to the right side of the heart, or vice versa. The direction of shunting will depend on a variety of factors, notable the patient's [[hemodynamics]].
| |
|
| |
|
| It should be noted however, that a "Right-to-left-shunt" typically poses the more dangerous scenario (See Pathophysiology below). Since the right side of the heart contains venous blood with a low oxygen content, and the left side of the heart contains arterial blood with a high oxygen content, right to left shunts can cause [[hypoxia]] and result in [[cyanosis]]. Additionally, a communication between the two atria may allow blood clots to pass from the venous system to the arterial system and result in a [[stroke]] or peripheral embolism.
| | ==[[Atrial septal defect classifications | Classification]] == |
| | [[Atrial septal defect ostium secundum | Ostium Secundum Atrial Septal Defect]] | [[Atrial septal defect ostium primum | Ostium Primum Atrial Septal Defect]] | [[Atrial septal defect sinus venosus | Sinus Venosus Atrial Septal Defect]] | [[Atrial septal defect coronary sinus | Coronary Sinus]] | [[Atrial septal defect patent foramen ovale | Patent Foramen Ovale]] | [[Atrial septal defect common or single atrium | Common or Single Atrium]] |
|
| |
|
| == Embryology == | | ==[[Atrial septal defect pathophysiology | Pathophysiology]]== |
| During development of the [[fetus]], the interatrial septum develops to eventually separate the [[left atrium|left]] and [[right atrium|right]] atria. The ''[[Foramen ovale (heart)|foramen ovale]]'' ([[International Phonetic Alphabet|pronounced]] {{IPA|[fərˈamən əʊˈvɑːli]}}) remains open during fetal development to allow blood from the venous system to bypass the lungs directly and enter the circulatory system. This is so, as prior to birth, the oxygenation of the blood is provided via the mother's [[placenta]] as the lungs of the fetus are not breathing air. A layer of tissue begins to cover the foramen ovale during fetal development, in which typically, after birth, the pressure in the pulmonary circulatory system drops, thus causing the [[foramen ovale]] to close entirely. In approximately 25% of adults, the foramen ovale does not entirely seal. In this case, elevation of pressure in the pulmonary circulatory system (ie: [[pulmonary hypertension]] due to various causes, or transiently during a [[cough]]) can cause the foramen ovale to remain open. This is known as a '''[[patent foramen ovale]]''' ('''[[PFO]]''').
| |
|
| |
|
| ==Pathophysiology== | | ==[[Atrial septal defect epidemiology and demographics|Epidemiology and Demographics]]== |
| In unaffected individuals, the chambers of the left side of the heart make up a higher pressure system than the chambers of the right side of the heart. This is because the [[left ventricle]] has to produce enough pressure to pump blood throughout the entire body, while the [[right ventricle]] only has to produce enough pressure to pump blood to the [[lung]]s.
| |
|
| |
|
| In the case of a large [[ASD]] (>9mm), which may result in a clinically remarkable ''[[left-to-right shunt]]'', blood will shunt from the [[left atrium]] to the [[right atrium]] causing excessive interatrial communication (In the case of hemodynamically significant [[ASD]] (Qp:Qs > 1.5:1), the patient is often found to be notably symptomatic and [[ASD]] repair may be indicated). This extra blood from the left atrium may cause a volume overload of both the [[right atrium]] and the [[right ventricle]], which if left untreated, can result in enlargement of the right side of the heart and ultimately heart failure.
| | ==[[Atrial septal defect risk factors|Risk Factors]]== |
|
| |
|
| Any process that increases the pressure in the [[left ventricle]] can cause worsening of the left-to-right shunt. This includes [[hypertension]], which increases the pressure that the [[left ventricle]] has to generate in order to open the [[aortic valve]] during ventricular [[systole]], and [[coronary artery disease]] which increases the stiffness of the [[left ventricle]], thereby increasing the filling pressure of the left ventricle during ventricular [[diastole]].
| | ==[[Atrial septal defect natural history|Natural History and Prognosis]]== |
|
| |
|
| The [[right ventricle]] will have to push out more blood than the [[left ventricle]] due to the left-to-right shunt. This constant overload of the right side of the heart will cause an overload of the entire pulmonary vasculature. Eventually the pulmonary vasculature will develop [[pulmonary hypertension]] to try to divert the extra blood volume away from the lungs.
| | ==[[Atrial septal defect complications|Complications]]== |
|
| |
|
| The [[pulmonary hypertension]] will cause the [[right ventricle]] to face increased [[afterload]] in addition to the increased [[Preload (cardiology)|preload]] that the shunted blood from the left atrium to the right atrium caused. The [[right ventricle]] will be forced to generate higher pressures to try to overcome the [[pulmonary hypertension]]. This may lead to [[heart failure|right ventricular failure]] (dilatation and decreased [[systole|systolic]] function of the right ventricle) or elevations of the right sided pressures to levels greater than the left sided pressures.
| | ==[[Atrial septal defect diagnosis | Diagnosis]]== |
| | | [[Atrial septal defect history and symptoms|History and Symptoms]] | [[Atrial septal defect diagnosis physical examination | Physical Examination]] | [[Atrial septal defect chest x-ray | Chest X Ray]] | [[Atrial septal defect electrocardiogram | Electrocardiogram]] | [[Atrial septal defect echocardiography | Echocardiography]] | [[Atrial septal defect transcranial doppler ultrasound | Transcranial Doppler Ultrasound]] | [[Atrial septal defect MRI | MRI]] | [[Atrial septal defect CT | CT]] | [[Atrial septal defect cardiac catheterization |Cardiac Catheterization]] | [[Atrial septal defect exercise testing|Exercise Testing]] | [[ACC/AHA guidelines for evaluation of unoperated patients with atrial septal defects|ACC/AHA Guidelines for Evaluation of Unoperated Patients]] |
| When the pressure in the right atrium rises to the level in the left atrium, there will no longer be a pressure gradient between these heart chambers, and the left-to-right shunt will diminish or cease.
| |
| | |
| If left uncorrected, the pressure in the right side of the heart will be greater than the left side of the heart. This will cause the pressure in the right atrium to be higher than the pressure in the left atrium. This will reverse the pressure gradient across the [[ASD]], and the shunt will reverse; a '''right-to-left shunt''' will exist. This phenomenon is known as [[Eisenmenger's syndrome]].
| |
| | |
| Once right-to-left shunting occurs, a portion of the oxygen-poor blood will get shunted to the left side of the heart and ejected to the peripheral vascular system. This will cause signs of [[cyanosis]].
| |
| | |
| ==Epidemiology== | |
| As a group, atrial septal defects are detected in 1 child per 1500 live births. PFO are quite common (appearing in 10 - 20% of adults) but asymptomatic and therefore undiagnosed. ASDs make up 30 to 40% of all congenital heart disease that is seen in adults.<!--
| |
| --><ref>{{cite journal | author = Kaplan S | title = Congenital heart disease in adolescents and adults. Natural and postoperative history across age groups. | journal = Cardiol Clin | volume = 11 | issue = 4 | pages = 543-56 | year = 1993 | id = PMID 8252558}}</ref>
| |
| | |
| The [[ostium secundum atrial septal defect]] accounts for 7% of all congenital heart lesions. This lesion shows a female preponderance, with a male : female ratio of 1:2.<!--
| |
| --><ref>{{cite journal | author = Feldt R, Avasthey P, Yoshimasu F, Kurland L, Titus J | title = Incidence of congenital heart disease in children born to residents of Olmsted County, Minnesota, 1950-1969. | journal = Mayo Clin Proc | volume = 46 | issue = 12 | pages = 794-9 | year = 1971 | id = PMID 5128021}}</ref>
| |
| | |
| [[Patent foramen ovale|Patent Foramen Ovale]]s (PFOs) are quite common (appearing in 10 - 20% of adults) but are asymptomatic and therefore undiagnosed. [[ASD]]s make up 30 to 40% of all congenital heart disease that is seen in adults and are the most common form of congenital heart defect in adults besides [[bicuspid aortic valve]] and [[mitral valve prolapse]].
| |
| | |
| == Genetics ==
| |
| [[ASD]]s are often associated with other malformations. There is a well described asssociation with primum or secundum ASDs with [[Down syndrome]]. Other associated lesions include partially anomalous pulmonary venous return, [[pulmonary valve stenosis]], [[mitral stenosis]] or [[mitral valve prolapse]], [[ventricular septal defects]] and [[coarctation of the aorta]]. There are a small group of [[ASD]]s that may have a familial occurence. | |
| | |
| == Types of atrial septal defects ==
| |
| The different types of atrial septal defects originate in different parts of the septum and are named according to their origins.
| |
| | |
| There are many types of atrial septal defects. They are differentiated from each other by whether they involve other structures of the heart and how they are formed during the developmental process during early [[fetus|fetal]] development.
| |
| | |
| ===Ostium secundum atrial septal defect===
| |
| The '''ostium secundum atrial septal defect''' is the most common type of atrial septal defect (it accounts for 60%-70% of ASDs), and comprises 6-10% of all congenital heart diseases.
| |
| | |
| The secundum atrial septal defect usually arises from an enlarged foramen ovale, inadequate growth of the septum secundum, or excessive absorption of the septum primum. 10 to 20 percent of individuals with ostium secundum ASDs also have [[mitral valve prolapse]] .<!--
| |
| --><ref>{{cite journal | author = Leachman R, Cokkinos D, Cooley D | title = Association of ostium secundum atrial septal defects with mitral valve prolapse. | journal = Am J Cardiol | volume = 38 | issue = 2 | pages = 167-9 | year = 1976 | id = PMID 952260}}</ref>
| |
| | |
| Most individuals with an uncorrected secundum ASD don't have significant symptoms through early adulthood. About 70% develop symptoms by the time they are in their 40s. Symptoms are typically decreased exercise tolerance, easy fatigueability, [[palpitation]]s, and [[fainting|syncope]].
| |
| | |
| Complications of an uncorrected secundum ASD include [[pulmonary hypertension]], right-sided [[congestive heart failure|heart failure]], [[atrial fibrillation]] or [[atrial flutter|flutter]], [[cerebrovascular accident|stroke]], and [[Eisenmenger's syndrome]].
| |
| | |
| While [[pulmonary hypertension]] is unusual before 20 years of age, it is seen in 50% of individuals above the age of 40. Progression to [[Eisenmenger's syndrome]] occurs in 5 to 10% of individuals late in the disease process.
| |
| | |
| ===='''Patent foramen ovale'''====
| |
| A '''[[foramen ovale (heart)|patent foramen ovale]]''' (PAY-tent for-amen oh-VALL-ee) ('''PFO''') is a small channel that has little hemodynamic consequence. Clinically it is linked to [[decompression sickness]], paradoxical embolism and [[migraine]]. On echocardiography, there may not be any shunting of blood noted except when the patient coughs.
| |
| | |
| There is a debate within the neurology and cardiology communities about the role of a PFO in cryptogenic (ie of unknown cause) neurologic events, e.g. strokes and transient ischemia attacks (TIAs) without any other potential cause. In addition, there is some data to suggest that PFOs may be involved in the pathogenesis of some migraine headaches. Several clinical trials are currently underway to investigate the role of PFO in these clinical situations..
| |
| | |
| ==='''Ostium primum atrial septal defect'''===
| |
| The '''ostium primum atrial septal defect''' (also known as an '''endocardial cushion defect''') is a defect in the atrial septum at the level of the [[tricuspid valve|tricuspid]] and [[mitral valve|mitral]] valves. This is sometimes known as an endocardial cushion defect because it often involves the [[endocardial cushion]], which is the portion of the heart where the atrial septum meets the ventricular septum and the mitral valve meets the tricuspid valve.
| |
| | |
| Endocardial cushion defects are associated with abnormalities of the atrioventricular valves (the [[mitral valve]] and the [[tricuspid valve]]). These include the cleft mitral valve, and the single atrioventricular valve (a single large, deformed valve that flows into both the right ventricle and the left ventricle).
| |
| | |
| Endocardial cushion defects are the most common congenital heart defect that is associated with [[Down's syndrome]].
| |
| | |
| ==='''Sinus venosus atrial septal defect'''===
| |
| A [[sinus venosus ASD]] is a type of atrial septum defect in which the defect in the septum involves the venous inflow of either the [[superior vena cava]] or the [[inferior vena cava]].
| |
| | |
| A [[sinus venosus ASD]] that involves the [[superior vena cava]] makes up 2 to 3% of all interatrial communication. It is located at the junction of the [[superior vena cava]] and the [[right atrium]]. It is frequently associated with anomalous drainage of the right-sided [[pulmonary vein]]s into the right atrium (instead of the normal drainage of the pulmonary veins into the left atrium).<!--
| |
| --><ref>{{cite journal | author = Davia J, Cheitlin M, Bedynek J | title = Sinus venosus atrial septal defect: analysis of fifty cases. | journal = Am Heart J | volume = 85 | issue = 2 | pages = 177-85 | year = 1973 | id = PMID 4569755}}</ref>
| |
| | |
| ===Common or single atrium===
| |
| | |
| [[Common atrium|Common (or single) atrium]] is a failure of development of the embryologic components that contribute to the atrial septal complex. It is frequently associated with heterotaxy syndrome <ref>{{cite book | author=Valdes-Cruz LM, Cayre RO | title=Echocardiographic diagnosis of congenital heart disease | location=Philadelphia | year=1998}}</ref>
| |
| | |
| [[Image:ASD.png|center|thumb|350px|Schemating drawing showing the location of different types of ASD, the view is into an opened right atrium. ''HV'': right ventricle; ''VCS'': superior caval vein; ''VCI'': inferior caval vein; ''1'': upper sinus venosus defect; ''2'': lower sinus venosus defect; ''3'': secundum defect; ''4'': defect involving coronary sinus; ''5''; primum defect.]]
| |
| | |
| ==Diagnosis==
| |
| ===Diagnosis in children===
| |
| Most individuals with a significant ASD are diagnosed [[in utero]] or in early childhood with the use of [[ultrasonography]] or [[auscultation]] of the [[heart sounds]] during [[physical examination]].
| |
| | |
| ===Diagnosis in adults===
| |
| Some individuals with an [[ASD]] will have undergone surgical correction of their [[ASD]] during childhood. The development of signs and symptoms due to an [[ASD]] are related to the size of the intracardiac shunt. Individuals with a larger shunt tend to present with symptoms at a younger age.
| |
| | |
| Adults with an uncorrected [[ASD]] will present with symptoms of dyspnea on exertion (shortness of breath with minimal exercise), [[congestive heart failure]], or [[cerebrovascular accident]] (stroke). They may be noted on routine testing to have an abnormal [[chest x-ray]] or an abnormal [[EKG]] and may have [[atrial fibrillation]].
| |
| | |
| ====[[Physical examination]]====
| |
| =====[[Auscultation]] of the heart=====
| |
| The physical findings in an adult with an [[ASD]] include those related directly to the intracardiac shunt, and those that are secondary to the [[congestive heart failure|right heart failure]] that may be present in these individuals.
| |
| | |
| Upon [[auscultation]] of the [[Heart sounds|heart sounds]], there may be an ''ejection systolic murmur'' that is attributed to the pulmonic valve. This is due to the increased flow of blood through the pulmonic valve rather than any structural abnormality of the valve leaflets.
| |
| | |
| In unaffected individuals, there are respiratory variations in the splitting of the [[Heart sounds|second heart sound]] (S<sub>2</sub>). During respiratory inspiration, the negative intrathoracic pressure causes increased blood return into the right side of the heart. The increased blood volume in the right ventricle causes the pulmonic valve to stay open longer during ventricular [[systole]]. This causes a normal delay in the P<sub>2</sub> component of S<sub>2</sub>. During expiration, the positive intrathoracic pressure causes decreased blood return to the right side of the heart. The reduced volume in the right ventricle allows the pulmonic valve to close earlier at the end of ventricular systole, causing P<sub>2</sub> to occur earlier.
| |
| | |
| In individuals with an [[ASD]], there is a '''fixed splitting of S<sub>2</sub>'''. The reason why there is a fixed splitting of the second heart sound is that the extra blood return during inspiration gets equalized between the left and right atrium due to the communication that exists between the atria in individuals with [[ASD]].
| |
| | |
| ===Chest X-ray===
| |
| | |
| [[Chest X ray]] may show an enlarged right atrial border or cardiomegaly if significant pulmonary hypertension is present.
| |
| | |
| <div align="left">
| |
| <gallery heights="175" widths="175">
| |
| Image:Atrial septal defect 001.jpg|Enlarged right atrial border and mild cardiomegaly.
| |
| Image:Atrial septal defect 002.jpg|Lateral view
| |
| </gallery>
| |
| </div>
| |
| | |
| | |
| <div align="left">
| |
| <gallery heights="175" widths="175">
| |
| Image:Atrial septal defect 003.jpg|Post repair. Enlarged right atrial border and mild cardiomegaly.
| |
| Image:Atrial septal defect 004.jpg|Post repair. Lateral view
| |
| Image:ASD.xray.jpg|ASD. Another patient. Enlarged right atrial border and advanced cardiomegaly.
| |
| </gallery>
| |
| </div>
| |
| | |
| ====Electrocardiography====
| |
| | |
| The [[ECG]] findings in atrial septal defect vary with the type of defect the individual has. Individuals with [[atrial septal defect]]s may have a prolonged [[PR interval]] (a [[first degree heart block]]). The prolongation of the [[PR interval]] is probably due to the enlargement of the atria that is common in [[ASD]]s and the increased distance due to the defect itself. Both of these can cause an increased distance of internodal conduction from the [[SA node]] to the [[AV node]].<!--
| |
| --><ref>{{cite journal | author = Clark E, Kugler J | title = Preoperative secundum atrial septal defect with coexisting sinus node and atrioventricular node dysfunction. | journal = Circulation | volume = 65 | issue = 5 | pages = 976-80 | year = 1982 | id = PMID 7074763}}</ref>
| |
| | |
| Other EKG findings include the following:
| |
| # Incomplete and less frequently complete [[Right Bundle Branch Block]] ([[RBBB]]) is often present.
| |
| # [[Right Ventricular Hypertrophy]] ([[RVH]]) with strain suggests onset of [[pulmonary hypertension]] or associated [[pulmonic stenosis]].
| |
| # 2 out of 3 patients with an [[ostium secundum ASD]] have [[right axis deviation]].
| |
| # Patients with [[ostium secundum ASD]]s often develop [[atrial fibrillation]] or [[atrial flutter]], and this occurs with a higher incidence with increasing age and with [[pulmonary hypertension]].
| |
| # [[Sinus venosus ASD]]s are often associated with low atrial and [[junctional rhythm]]s.
| |
| # [[Ostium primum ASD]]s are associated with a marked left axis deviation.
| |
| # Individuals with a [[sinus venosus ASD]] exhibit a left axis deviation of the [[P wave]] (not the [[QRS]] complex).
| |
| | |
| [[Image:ASDPrimum.jpg|300px|left|thumb|12 lead EKG shows the rSR' pattern in V1 (R' greater than S with T wave inversion which is commonly seen in volume overload in Right Ventricular Hypertrophy)]]
| |
| <br clear="left"/>
| |
| | |
| ====Echocardiography====
| |
| | |
| In transthoracic [[echocardiography]], an [[atrial septal defect]] may be seen on color flow imaging as a jet of blood from the [[left atrium]] to the [[right atrium]].
| |
| | |
| If agitated saline is injected into a peripheral [[vein]] during [[echocardiography]], small air bubbles can be seen on echocardiographic imaging. It may be possible to see bubbles travel across an [[ASD]] either at rest or during a cough. (Bubbles will only flow from [[right atrium]] to [[left atrium]] if the RA pressure is greater than LA).
| |
| | |
| [[Image:ASD.jpg|thumb|300 px|left|[[Echocardiography|Ultrasound picture]] of the heart, seen in a subcostal view. The apex towards the right, atria to the left. ASD secundum seen as a discontinuation of the white band of the atrial septum. Enlarged [[right atrium]] below. Enlarged pulmonary veins seen entering left atrium above. <small>(Image courtesy of Kjetil Lenes)</small>]]
| |
| <br clear="left"/>
| |
| See '''[[Echo in Atrial Septal Defect]]''' for more info/images
| |
| | |
| Because better visualization of the atria is achieved with transesophageal [[echocardiography]], this test may be performed in individuals with a suspected [[ASD]] which is not visualized on transthoracic imaging.
| |
| | |
| Newer techniques to visualize these defects involve intracardiac imaging with special catheters that are typically placed in the venous system and advanced to the level of the heart. This type of imaging is becoming more common and involves only mild sedation for the patient typically.
| |
| | |
| If the individual has adequate echocardiographic windows, it is possible to use the echocardiogram to measure the [[cardiac output]] of the left ventricle and the [[right ventricle]] independently. In this way, it is possible to estimate the shunt fraction using [[echocardiography]].
| |
| | |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A
| |
| <googlevideo>8637172269944067306&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A2
| |
| <googlevideo>-2527268983131571055&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A3
| |
| <googlevideo>1536009221252381368&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A4
| |
| <googlevideo>4718874950603401633&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A5
| |
| <googlevideo>-2711509694247706297&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A6
| |
| <googlevideo>2754627930396522386&hl=en</googlevideo>
| |
| *Atrioventricular septal defects (AVSDs) Rastelli Type A7
| |
| <googlevideo>-8214352524179603182&hl=en</googlevideo>
| |
| | |
| ==== Trans-Cranial Doppler (TCD) Ultrasound ====
| |
| This is a less invasive protocol for finding [[PFO]] or other [[ASD]]s, involves highly-sensitive versions of Trans-Cranial Doppler, or "through the head" doppler ultrasound devices. There is debate as to whether this protocol is the Gold Standard for Finding [[PFO]] and also testing for successful closure of [[PFO]] after closure procedures. The protocol has been adopted as the testing standard in clinical trials of [[PFO]] closure devices and other investigations of the relationship between [[PFO]]-stroke-migraine. This protocol requires no sedation and besides a simple intravenous injection of saline. It is otherwise entirely non-invasive and can be administered by clinicians trained in the protocol and using the appropriately sensitive TCD technology, in well under one hour. At least one clinical study has shown this protocol with the appropriate TCD technology, to be highly accurate in comparison to other current standards of care for finding [[PFO]]. It is also dramatically less expensive than other tests for [[PFO]].
| |
| | |
| ==== MRI====
| |
| Cardiac MRI can be helpful in diagnosing [[ASD]]s and can be used to determine defect size, quantify the shunt fraction and detect associated anomalous pulmonary venous connections.
| |
|
| |
|
| ==Treatment== | | ==Treatment== |
| Once an individual is found to have an [[atrial septal defect]], a determination of whether it should be corrected has to be made.
| |
|
| |
|
| Criteria for closure include right ventricular dilatation, [[pulmonary artery]] pressures of 50% or less than systemic pressures, history of a cryptogenic stroke.
| | [[Atrial septal defect medical therapy|Medical Therapy]] | [[Atrial septal defect indications for surgical repair in adults| Indications For Surgical Repair]] | [[Atrial septal defect surgical closure | Surgical Closure]] | [[Atrial septal defect minimally invasive repair| Minimally Invasive Repair]] | [[Atrial septal defect percutaneous closure | Percutaneous Closure]] | [[Atrial septal defect robotic repair | Robotic ASD Repair]] | [[Atrial septal defect post surgical follow up|Post Surgical Follow Up]] |
|
| |
|
| Surgical mortality due to closure of an [[ASD]] is lowest when the procedure is performed prior to the development of significant pulmonary hypertension. The lowest mortality rates are achieved in individuals with a pulmonary artery systolic pressure of less than 40 mm Hg.
| | ==Special Scenarios== |
|
| |
|
| If [[Eisenmenger's syndrome]] has occurred, there is significant risk of mortality regardless of the method of closure of the [[ASD]]. In individuals who have developed [[Eisenmenger's syndrome]], the pressure in the [[right ventricle]] has raised high enough to reverse the shunt in the atria. If the [[ASD]] is then closed, the [[afterload]] that the [[right ventricle]] has to act against has suddenly increased. This may cause immediate [[heart failure|right ventricular failure]], since it may not be able to pump the blood against the [[pulmonary hypertension]].
| | [[Atrial septal defect pregnancy|Pregnancy]] | [[Atrial septal defect decompression sickness |Diving and Decompression Sickness]] | [[Atrial septal defect paradoxical emboli | Paradoxical Emboli]] | [[Atrial septal defect pulmonary hypertension|Pulmonary Hypertension]] | [[Atrial septal defect Eisenmenger's syndrome|Eisenmenger's Syndrome]] | [[Atrial septal defect atmospheric pressure|Atmospheric Pressure]] |
|
| |
|
| Closure of an [[ASD]] in individuals under age 25 has been shown to have a low risk of complications, and individuals have a normal lifespan (comparable to a healthy age-matched population). Closure of an [[ASD]] in individuals between the ages of 25 and 40 who are asymptomatic but have a clinically significant shunt is controversial. Those that perform the procedure believe that they are preventing long-term deterioration in cardiac function and preventing progression of [[pulmonary hypertension]].
| | ==Case Studies== |
|
| |
|
| Methods of closure of an [[ASD]] include surgical closure and percutaneous closure.
| | [[Atrial septal defect case study one|Case #1]] |
|
| |
|
| ===Evaluation prior to correction=== | | ==Related Chapters== |
| Prior to correction of an [[ASD]], an evaluation to determine if [[pulmonary hypertension]] is present and whether it is reversible. Closure of an [[ASD]] may be recommended for prevention purposes, to avoid such a complication in the first place. [[Pulmonary Hypertension]] is not always present in adults that are diagnosed with an [[ASD]] in adulthood.
| | * [[Atrioventricular septal defect]] |
| | * [[Congenital heart disease]] |
|
| |
|
| If there is a suspicion that [[pulmonary hypertension]] is present, the evaluation may include a right heart catheterization. This involves placing a catheter in the venous system of the heart and measuring pressures and oxygen saturations in the [[superior vena cava|SVC]], [[inferior vena cava|IVC]], [[right atrium]], [[right ventricle]], [[pulmonary artery]], and in the wedge position. Individuals with a [[pulmonary vascular resistance]] (PVR) of less than 7 wood units show regression of symptoms (including [[New York Heart Association Functional Classification|NYHA functional class]]). On the other hand, individuals with a [[pulmonary vascular resistance|PVR]] of greater than 15 wood units have increased mortality associated with closure of the [[ASD]].
| | {{WikiDoc Help Menu}} |
| | | {{WikiDoc Sources}} |
| If the pulmonary arterial pressure is more than 2/3 the systemic systolic pressure, there should be a net left-to-right shunt of at least 1.5:1 or evidence of reversibility of the shunt when given pulmonary artery vasodilators prior to surgery. If [[Eisenmenger's]] physiology has developed, it must be demonstrated that the right-to-left shunt is reversible with pulmonary artery vasodilators prior to surgery.
| | [[CME Category::Cardiology]] |
| | |
| ===Surgical ASD closure===
| |
| Surgical closure of an [[ASD]] involves opening up at least one [[atrium (anatomy)|atrium]] and closing the defect with a patch under direct visualization.
| |
| | |
| ===Percutaneous ASD closure===
| |
| | |
| Percutaneous closure of an [[ASD]] is currently only indicated for the closure of ostium secundum [[ASD]]s with a sufficient rim of tissue around the septal defect so that the closure device does not impinge upon the [[superior vena cava|SVC]], [[inferior vena cava|IVC]], or the [[tricuspid valve|tricuspid]] or [[mitral valve|mitral]] valves. The Amplatzer Septal Occluder is commonly used to close [[ASD]]'s. The ASO consists of two self-expandable round discs connected to each other with a 4-mm waist, made up of 0.004–0.005´´ nitinol wire mesh filled with Dacron fabric. Implantation of the device is relatively easy. The prevalence of residual defect is low. The disadvantages are a thick profile of the device and concern related to a large amount of nitinol (a nickel-titanium compound) in the device and consequent potential for nickel toxicity.
| |
| | |
| Percutaneous closure is the method of choice in most centers.<!--
| |
| --><ref>{{cite journal | author = Bjørnstad P | title = Is interventional closure the current treatment of choice for selected patients with deficient atrial septation? | journal = Cardiol Young | volume = 16 | issue = 1 | pages = 3-10 | year = 2006 | id = PMID 16454871}}</ref>
| |
| | |
| [[Image:ASD-ampatzl-anim.gif|left|Amplatzer Septal Occluder]]
| |
| <br clear="left"/>
| |
| | |
| ==Associated conditions==
| |
| Due to the communication between the atria that occurs in [[ASD]]'s, disease entities or complications from the condition, are possible.
| |
| | |
| ===Decompression sickness===
| |
| [[ASD]]s, and particularly [[PFO]]s, are a predisposing risk factor for [[decompression sickness]] in divers because a proportion of venous blood carrying inert gases, such as [[helium]] or [[nitrogen]] does not pass through the lungs.<!--
| |
| --><ref>{{cite journal | author = Lier H, Schroeder S, Hering R | title = [Patent foramen ovale: an underrated risk for divers?] | journal = Dtsch Med Wochenschr | volume = 129 | issue = 1-2 | pages = 27-30 | year = 2004 | id = PMID 14703578}}</ref><!--
| |
| --><ref>{{cite journal | author = Saary M, Gray G | title = A review of the relationship between patent foramen ovale and type II decompression sickness. | journal = Aviat Space Environ Med | volume = 72 | issue = 12 | pages = 1113-20 | year = 2001 | id = PMID 11763113}}</ref>
| |
| The only way to release the excess inert gases from the body is to pass the blood carrying the inert gases through the [[lung]]s to be exhaled. If some of the inert gas-laden blood passes through the [[PFO]], it avoids the lungs and the inert gas is more likely to form large bubbles in the arterial blood stream causing ''decompression sickness''.
| |
| | |
| ===Paradoxical emboli===
| |
| Venous [[thrombus|thrombi]] (clots in the [[vein]]s) are quite common. Embolization (dislodgement of thrombi) normally go to the lung and cause [[pulmonary embolism|pulmonary emboli]]. In an individual with [[ASD]], these emboli can potentially enter the arterial system. This can cause any phenomenon that is attributed to acute loss of blood to a portion of the body, including [[cerebrovascular accident]] (stroke), infarction of the [[spleen]] or [[intestine]]s, or even a distal extremity (i.e.: finger or toe).
| |
| | |
| This is known as a ''paradoxical'' embolus because the clot material paradoxically enters the arterial system instead of going to the lungs.
| |
| | |
| ===Migraine===
| |
| Some recent research has suggested that a proportion of cases of [[migraine]] may be caused by [[Patent foramen ovale|patent foramen ovale]]. While the exact mechanism remains unclear, closure of a [[PFO]] can reduce symptoms in certain cases.<!--
| |
| --><ref>{{cite journal | author = Adams H | title = Patent foramen ovale: paradoxical embolism and paradoxical data. | journal = Mayo Clin Proc | volume = 79 | issue = 1 | pages = 15-20 | year = 2004 | id = PMID 14708944}}</ref><!--
| |
| --><ref>{{cite journal | author = Azarbal B, Tobis J, Suh W, Chan V, Dao C, Gaster R | title = Association of interatrial shunts and migraine headaches: impact of transcatheter closure. | journal = J Am Coll Cardiol | volume = 45 | issue = 4 | pages = 489-92 | year = 2005 | id = PMID 15708691}}</ref>
| |
| This remains controversial. 20% of the general population have a [[PFO]], which for the most part, is asymptomatic. 20% of the female population have migraines. And, the [[placebo effect]] in migraine typically averages around 40%. The high frequency of these facts makes statistically significant relationships between [[PFO]] and migraine difficult (i.e., the relationship may just be chance or coincidence).
| |
| | |
| ==See also==
| |
| *[[Atrioventricular septal defect]]
| |
| *[[Cardiac output]]
| |
| *[[Congenital heart disease]]
| |
| *[[Heart sounds]]
| |
| *[[Pulmonary hypertension]]
| |
| *[[Vascular resistance]]
| |
| **[[Pulmonary vascular resistance]]
| |
| *[[Ventricular septal defect]]
| |
| | |
| ==References==
| |
| {{Reflist|2}}
| |
| | |
| ==External links==
| |
| * [http://heartcenter.seattlechildrens.org/conditions_treated/atrial_septal_defect.asp Atrial Septal Defect information] from Seattle Children's Hospital Heart Center
| |
| | |
| {{Congenital malformations and deformations of circulatory system}}
| |
| {{Electrocardiography}}
| |
| {{SIB}}
| |
|
| |
|
| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Congenital heart disease]] | | [[Category:Congenital heart disease]] |
| | | [[Category:Pediatrics]] |
| [[tr:Atriyal septal defekt]] | | [[Category:Embryology]] |
| | | [[Category:Disease]] |
| {{WikiDoc Help Menu}}
| |
| {{WikiDoc Sources}}
| |