The Gerbode defect describes a rare abnormal left-to-right shunt between the left ventricle and right atrium through a defect in the atrioventricular septum, usually congenital in etiology.
Clinical presentation varies depending on the size and resultant severity of the defect 1,2,4-6. Small lesions with minimal shunting may be asymptomatic, however large lesions with ample shunting may cause signs of heart failure such as exertional dyspnea, raised jugular venous pressure, hepatomegaly, peripheral edema, or failure to thrive in pediatric patients 1,2,4-6. Cyanosis is generally not seen in patients with Gerbode defects 1,2,4-6. Praecordial auscultation is indistinguishable to that of ventricular septal defects, with a pansystolic murmur heard over the left sternal border 1,2,4-6.
A defect between the left ventricle and right atrium results in a left-to-right shunt 1,4-6. Similar to other left-to-right shunts, significant shunting can result in increased pressure in the right side of the heart, and eventual cardiac compromise (heart failure, etc.) 1,4-6.
Classically, a Gerbode defect is considered to be a congenital lesion whereby there is an abnormal perforation of the septal leaflet of the tricuspid valve, near the edge of the leaflet or its attachment 1,4,7. A perforation in this location, the atrioventricular (membranous) portion of the interventricular septum (just inferior to the posterior and right cusps of the aortic valve), allows for a communication between the left ventricle and right atrium 1,4,7.
In addition to having a congenital etiology, Gerbode defects are increasingly being described as acquired 1,4,7. These are most commonly acquired iatrogenically through surgery performed near the atrioventricular (membranous) portion of the interventricular septum, but there are numerous causes 1-7:
- valve replacement
- atrioventricular node ablation
- tricuspid annuloplasty
Gerbode defects can be classified according to location 1,6:
- supravalvular (direct): defect is superior to the septal leaflet of the tricuspid valve
- infravalvular (indirect): defect is inferior to the septal leaflet of the tricuspid valve
- intermediate: both inferior and superior defects are present in relation to the septal leaflet of the tricuspid valve
Supra- and infravalvular types are the most common 1,6.
The chest radiograph can be normal with a small Gerbode defect, and may only be abnormal with large defects. In these cases, cardiomegaly and pulmonary plethora may be appreciated on the plain radiograph 8.
Transthoracic echocardiography is generally the imaging modality of choice 1-4,7. It allows direct visualization of the Gerbode defect and resultant right atrial dilatation 1-4,7. In particular, color flow Doppler revealing high-velocity systolic flow originating from the upper atrioventricular (membranous) portion and directed into the right atrium, is characteristic 1-4,7.
Electrocardiographically-gated CT and cardiac MRI (CMR) allow for further direct visualization of the defect 1,9. CMR in particular, is able to provide detailed shunt anatomy and quantification of shunt severity 1,9.
Treatment and prognosis
Although some small Gerbode defects may close spontaneously, most do not 1,6. Treatment may be required for defects causing symptoms, with surgical closure being the management of choice 1,6. However, some authors argue that all Gerbode defects should be surgically-closed due to an inherent risk of infective endocarditis 1.
- cardiac failure
- infective endocarditis
- Eisenmenger phenomenon is a theoretical complication, and has not yet been reported in the literature (as of December 2018)
History and etymology
The defect is named after Frank A Gerbode (1907-1984), an American cardiothoracic surgeon, who described the surgical closure of the defect in a series of patients in 1958 10. However, the first description of the defect was over a century prior to this, in 1838 by John Thurnam (1810-1873), an English physician 11.
- 1. Saker E, Bahri GN, Montalbano MJ, Johal J, Graham RA, Tardieu GG, Loukas M, Tubbs RS. Gerbode defect: A comprehensive review of its history, anatomy, embryology, pathophysiology, diagnosis, and treatment. Journal of the Saudi Heart Association. 29 (4): 283-292. doi:10.1016/j.jsha.2017.01.006 - Pubmed
- 2. Taskesen T, Prouse AF, Goldberg SL, Gill EA. Gerbode defect: Another nail for the 3D transesophagel echo hammer?. The international journal of cardiovascular imaging. 31 (4): 753-64. doi:10.1007/s10554-015-0620-3 - Pubmed
- 3. Wasserman SM, Fann JI, Atwood JE, Burdon TA, Fadel BM. Acquired left ventricular-right atrial communication: Gerbode-type defect. Echocardiography (Mount Kisco, N.Y.). 19 (1): 67-72. Pubmed
- 4. Yuan SM. Left ventricular to right atrial shunt (Gerbode defect): congenital versus acquired. Postepy w kardiologii interwencyjnej = Advances in interventional cardiology. 10 (3): 185-94. doi:10.5114/pwki.2014.45146 - Pubmed
- 5. Battin M, Fong LV, Monro JL. Gerbode ventricular septal defect following endocarditis. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 5 (11): 613-4. Pubmed
- 6. Tidake A, Gangurde P, Mahajan A. Gerbode Defect-A Rare Defect of Atrioventricular Septum and Tricuspid Valve. Journal of clinical and diagnostic research : JCDR. 9 (9): OD06-8. doi:10.7860/JCDR/2015/14259.6531 - Pubmed
- 7. Kelle AM, Young L, Kaushal S, Duffy CE, Anderson RH, Backer CL. The Gerbode defect: the significance of a left ventricular to right atrial shunt. Cardiology in the young. 19 Suppl 2: 96-9. doi:10.1017/S1047951109991685 - Pubmed
- 8. Mateescu AD, Coman IM, Beladan CC, Radulescu B, Ginghina C, Popescu BA. A Congenital Gerbode Defect associated with a Rare Structural Abnormality of the Mitral Valve Diagnosed in an Adult Patient. Korean circulation journal. 46 (5): 739-742. doi:10.4070/kcj.2016.46.5.739 - Pubmed
- 9. Cheema OM, Patel AA, Chang SM, Shah DJ. Gerbode ventricular septal defect diagnosed at cardiac MR imaging: case report. Radiology. 252 (1): 50-2. doi:10.1148/radiol.2521082186 - Pubmed
- 10. Gerbode F, Hultgren H, Melrose D, Osborn J. Syndrome of left ventricular-right atrial shunt; successful surgical repair of defect in five cases, with observation of bradycardia on closure. Annals of surgery. 148 (3): 433-46. Pubmed
- 11. Thurnam J. On aneurisms of the heart with cases. Medico-chirurgical transactions. 21: 187-438.9. Pubmed
Related Radiopaedia articles
Congenital heart disease
There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorized, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt