Response

Abstract

In response to our case report, Dr Sheikh wrote that the interatrial communication described in our article is wrongly labeled as a patent foramen ovale (PFO). Dr Sheikh stated that the definition of PFO is the presence of a 1-way valve that can only allow a right-to-left shunt. Therefore, the presence of a left-to-right shunt rules out PFO and proves the existence of a septum secundum defect.A widely open PFO can be considered an acquired form of an atrial septal defect, especially when disproportion exists between size of a PFO and effective length of its valve allowing a left-to-right shunt to develop. However, it should be distinguished from a true ostium secundum atrial septal defect.1Friedman W.F. Congenital heart disease in infancy and childhood.in: Braunwald E. Heart Disease. Saunders, Philadelphia, PA1997: 896Google Scholar PFO is defined as a central opening in the septum secundum covered by the tissue of septum primum, forming the valve of foramen ovale; whereas, the definition of a septum secundum defect is the deficiency of septum secundum to cover and seal multiple perforations in the anterior-superior portion of the septum primum. PFO does not become an ostium secundum defect simply because it has a leaky valve. It has different anatomic characteristics and can be distinguished from a septum secundum defect during routine transesophageal echocardiography in the majority of cases using the right ventricular inflow-outflow view. In a PFO, separation between septum primum and septum secundum is usually seen with the flow between them almost parallel to both septa. In contrast, in the presence of a septum secundum defect, interatrial septum interruption is usually seen on 2-dimensional echocardiography and a color Doppler shows flow perpendicular to the interatrial septum. In response to our case report, Dr Sheikh wrote that the interatrial communication described in our article is wrongly labeled as a patent foramen ovale (PFO). Dr Sheikh stated that the definition of PFO is the presence of a 1-way valve that can only allow a right-to-left shunt. Therefore, the presence of a left-to-right shunt rules out PFO and proves the existence of a septum secundum defect. A widely open PFO can be considered an acquired form of an atrial septal defect, especially when disproportion exists between size of a PFO and effective length of its valve allowing a left-to-right shunt to develop. However, it should be distinguished from a true ostium secundum atrial septal defect.1Friedman W.F. Congenital heart disease in infancy and childhood.in: Braunwald E. Heart Disease. Saunders, Philadelphia, PA1997: 896Google Scholar PFO is defined as a central opening in the septum secundum covered by the tissue of septum primum, forming the valve of foramen ovale; whereas, the definition of a septum secundum defect is the deficiency of septum secundum to cover and seal multiple perforations in the anterior-superior portion of the septum primum. PFO does not become an ostium secundum defect simply because it has a leaky valve. It has different anatomic characteristics and can be distinguished from a septum secundum defect during routine transesophageal echocardiography in the majority of cases using the right ventricular inflow-outflow view. In a PFO, separation between septum primum and septum secundum is usually seen with the flow between them almost parallel to both septa. In contrast, in the presence of a septum secundum defect, interatrial septum interruption is usually seen on 2-dimensional echocardiography and a color Doppler shows flow perpendicular to the interatrial septum.