Multiple muscular ventricular septal defects are also called swiss cheese VSD. Swiss cheese VSDs are associated with left axis deviation on ECG. Swiss cheese VSDs are difficult to close surgically. It is difficult to locate the openings of the VSD from the right ventricular side. Some may have multiple right ventricular openings for a single left ventricular orifice. When one right ventricular orifice is closed, the VSD may be seen puffing from another orifice.
These VSDs may require left ventriculotomy for closure, which is a problem in a small infant. Special techniques using a thread passed from the right atrium across the interatrial septum, through the mitral valve has also been described, with good success documented by intraoperative transesophageal echocardiography and on follow up.
Intraoperative injection of fluorescein saline into the left ventricle has been used to identify multiple swiss cheese VSDs and facilitate surgical closure. Fluorescein saline injection was done through an infant feeding tube introduced through the fossa ovalis and right ventricular side of the septum was observed for the dye leak, thus obviating left ventriculotomy. This technique was useful in identifying the swiss cheese VSDs and ensuring the completeness of closure.
Pulmonary artery banding in multiple swiss cheese VSD
Due to the difficulty for surgical closure, often pulmonary artery banding is all that is done in these cases, to control the excessive pulmonary blood flow and development of pulmonary arterial hypertension. Adjustable pulmonary artery bands have been used in several cases. Some of them may need tightening on follow up while a few need release of the band with patient's growth. Sometimes the pulmonary artery band can be removed when the VSDs close spontaneously.