Atrial septal defect

Atrial septal defect

Last Reviewed : 12/24/2020
Atrial septal defect

Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Normally, the atria are separated by a dividing wall, the interatrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart, or vice versa. This can lead to lower-than-normal oxygen levels in the arterial blood that supplies the brain, organs, and tissues. However, an ASD may not produce noticeable signs or symptoms, especially if the defect is small.

A "shunt" is the presence of a net flow of blood through the defect, either from left to right or right to left. The amount of shunting present, if any, determines the hemodynamic significance of the ASD. A "right-to-left-shunt" typically poses the more dangerous scenario.

During development of the fetus, the interatrial septum develops to separate the left and right atria. However, a hole in the septum called the foramen ovale, allows blood from the right atrium to enter the left atrium during fetal development. This opening allows blood to bypass the nonfunctional fetal lungs while the fetus obtains its oxygen from the placenta. A layer of tissue called the septum primum acts as a valve over the foramen ovale during fetal development. After birth, the pressure in the right side of the heart drops as the lungs open and begin working, causing the foramen ovale to close entirely. In approximately 25% of adults, the foramen ovale does not entirely seal. In these cases, any elevation of the pressure in the pulmonary circulatory system (due to pulmonary hypertension, temporarily while coughing, etc.) can cause the foramen ovale to remain open. This is known as a patent foramen ovale (PFO), a type of atrial septal defect.


We researched this topic for you and found the following best online resources. They are categorized into basic, advanced, and research level based on the extent of information you need. You will be taken to the respective websites by pressing on the links below.


Basic information: mayo clinic atrial septal defect kids health what is an atrial septal defect? medline plus atrial septal defect clevelnd clinic atrial septal defect merck manuals(professional version) atrial septal defect web md atrial septal defect newyork times atrial septal defect aurora health care atrial septal defect


Advanced information: medscape atrial septal defect congenital heart defects uk atrial septal defect (asd) national organisation for rare diseases atrial septal defect patient atrial septal defect radiopedia atrial septal defect guidelines for the echocardiographic assessment of atrial septal defect and patent foramen ovale: from the american society of echocardiography and society for cardiac angiography and interventions by frank e. silvestry, md, fase, et al., (j am soc echocardiogr 2015;28:910-58. anaesthesia for percutaneous closure of atrial septal defects by patrick a calvert bch ma mrcp,andrew a klein mbbs frca



sinha r, thangaswamy cr, muthiah t, chandra p, subramaniam r. prolonged postoperative desaturation in a child with down syndrome and atrial septal defect. indian j anaesth [serial online] 2011 [cited 2016 jul 29];55:608-10. available from:

singh sp, chauhan s, talwar s. sinus venosus atrial septal defect in a patient with pentalogy of fallot. ann card anaesth [serial online] 2012 [cited 2016 jul 29];15:166-8. available from: arq. bras. cardiol. vol.81 no.5 são paulo nov. 2003 original article:initial experience in brazil with the helex septal occluder for percutaneous occlusion of atrial septal defects by carlos a.c. pedra et al., transcatheter closure of atrial septal defect in a patient with noonan syndrome after corrective surgery by ljupco mangovski, mihajlo farkic, ljiljana jovovic vojnosanit pregl 2015; 72(6): 557–560

desai pm, umbarkar sr, sarkar ms, lohiya r. conscious sedation using dexmedetomidine for percutaneous transcatheter closure of atrial septal defects: a single center experience. ann card anaesth [serial online] 2016 [cited 2016 jul 29];19:463-7. available from: sinus venosus atrial septal defect in a 31-year-old female patient: a case for surgical repair by m.a. gatzoulis, g. giannakoulas european respiratory review 2010 19: 340-344; doi: 10.1183/09059180.00007610 chodchanok vijarnsorn, kritvikrom durongpisitkul, prakul chanthong, et al., “transcatheter closure of atrial septal defects in children, middle-aged adults, and older adults: failure rates, early complications; and balloon sizing effects,” cardiology research and practice, vol. 2012, article id 584236, 9 pages, 2012. doi:10.1155/2012/584236 post-traumatic fulminant paradoxical fat embolism syndrome in conjunction with asymptomatic atrial septal defect: a case report and review of the literature by franz mueller et al., journal of medical case reports20115:142 doi: 10.1186/1752-1947-5-142

adiele dk, chinawa jm, arodiwe io, gouthami v, murthy k s, eze jc, obidike eo, ujunwa fa. atrial septal defects: pattern, clinical profile, surgical techniques and outcome at innova heart hospital: a 4-year review. niger med j [serial online] 2014 [cited 2016 jul 29];55:126-9. available from: anatomy of a wrong diagnosis: false sinus venosus atrial septal defect by nicola gaibazzi et al., cardiovascular ultrasound20031:15 doi: 10.1186/1476-7120-1-15 atrial septal defects in the adult recent progress and overview by gary webb and michael a. gatzoulis migraine prevalence in patients with atrial septal defect by yuji kato et al., the journal of headache and pain201314:63 doi: 10.1186/1129-2377-14-63 a comparison of surgical and medical therapy for atrial septal defect in adults by stavros konstantinides, m.d. et al., n engl j med 1995; 333:469-473august 24, 1995doi: 10.1056/nejm199508243330801


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Presentations/quiz/newspaper articles: atrial septal defect by ramachandra barik, cardiologist at aiims,bhubaneswar,odisha

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