Gerbode ventricular septal defects type I, II and III

Gerbode ventricular septal defects type I, II and III

Though congenital left ventricle to right atrium connections have been described as early as 1838 at autopsy [1, cited in 2], the description by Frank Gerbode and colleagues was in 1958, in their surgical series [3]. They described three varieties of communications:

1. Fusion of the septal leaflet of the tricuspid valve to the edges of the ventricular septal defect associated with a perforation of the leaflet. Shunt occurs from left ventricle directly into right atrium.
2. A defect or cleft of tricuspid valve close to its point of attachment directly overlying the VSD.
3. A combination of these two lesions.

They also described the finding of bradycardia and rise in systemic blood pressure while closing the defect manually at surgery. This they mentioned, was similar to the Branham reflex described in case of a peripheral arteriovenous fistula [4]. The rise in blood pressure due to increase in systemic blood flow stimulates carotid sinus receptors and causes reflex vagally mediated bradycardia.

Though the initial descriptions were of congenital defects, later the terminology has been expanded to include acquired LV-RA shunts as well. Possible reasons are invasive cardiac procedures, endocarditis, trauma and myocardial infarction [5]. Advanced cardiac imaging techniques like computed tomography, magnetic resonance imaging and real-time 3D echocardiography have been useful in definitive diagnosis and anatomic characterization of the shunt. In the initial descriptions, oxygen step up on cardiac catheterization at the right atrial level was noted and sometimes even mistaken for atrial septal defect [3].

Different types of classifications have been in use for Gerbode VSD. Classification by Moss AJ et al was into two types: Direct and Indirect. Direct defect involves the membranous septum from LV to RV while indirect defect involves a VSD with accompanying tricuspid regurgitation [6].

Sakakibara S had classified LV-RA communications into 3 types [7]. Type I was a direct communication from LV to RA across the atrioventricular part of the membranous septum.  In type II, defect develops in the interventricular part of the membranous septum and just opposite, in the septal leaflet of the tricuspid valve. These two openings adhere to each other and communication from LV to RA is thus possible. Type III is a combination of a large membranous septal defect with fissure, and thickened and shortened septal tricuspid leaflet.

In a more recent publication, type I is considered as direct and acquired with direct shunt through the atrioventricular part of the membranous septum, while type II is indirect and congenital with indirect LV-RA shunt through a perimembranous VSD and a defect in the septal tricuspid leaflet [8]. A case report describes closure of Gerbode defect Type II post transcatheter aortic valve replacement with Amplatzer muscular VSD occluder [9].

References

1. Thurnam J. On aneurisms of the heart with cases. Med Chir Trans. 1838;21:187-438.9. doi: 10.1177/095952873802100114. PMID: 20895656; PMCID: PMC2116819.
2. 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. J Saudi Heart Assoc. 2017 Oct;29(4):283-292. doi: 10.1016/j.jsha.2017.01.006. Epub 2017 Feb 16. PMID: 28983172; PMCID: PMC5623025.
3. 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. Ann Surg. 1958 Sep;148(3):433-46. doi: 10.1097/00000658-195809000-00012. PMID: 13571920; PMCID: PMC1450812.
4. Branham HH. Aneurismal Varix of the Femoral Artery and Vein Following a Gunshot Wound. Intemat. J. Surg. 1890; 3:250.
5. Taskesen T, Prouse AF, Goldberg SL, Gill EA. Gerbode defect: Another nail for the 3D transesophagel echo hammer? Int J Cardiovasc Imaging. 2015 Apr;31(4):753-64. doi: 10.1007/s10554-015-0620-3. Epub 2015 Feb 14. PMID: 25680357.
6. Riemenschneider TA, Moss AJ. Left ventricular-right atrial communication. Am J Cardiol. 1967 May;19(5):710-8. doi: 10.1016/0002-9149(67)90476-6. PMID: 6023467.
7. Sakakibara S, Konno S. Left ventricular-right atrial communication. Ann Surg. 1963 Jul;158(1):93-9. doi: 10.1097/00000658-196307000-00018. PMID: 14042644; PMCID: PMC1408381.
8. Panduranga P, Mukhaini M. A rare type of Gerbode defect. Echocardiography. 2011 Jul;28(6):E118-20. doi: 10.1111/j.1540-8175.2010.01356.x. Epub 2011 Mar 23. PMID: 21426390.
9. Deleanu D, Platon P, Chioncel O, Iliescu VA, Parasca CA. Percutaneous Closure of Gerbode Defect Type II Post-TAVR With Amplatzer Muscular VSD Occluder. JACC Cardiovasc Interv. 2021 Sep 13;14(17):e229-e230. doi: 10.1016/j.jcin.2021.06.026. Epub 2021 Aug 11. PMID: 34391711.