Patent Foramen Ovale

ASDs

• One of the least complex CHDs, one of the first types to be repaired surgically.

• Classified according their to location relative to the fossa ovalis.

• Associated with other congenital heart disease in 30-40% of cases.

• 5 to 10 % of all CHD, as isolated anomaly.

• More common in females (male to female ratio 1:2) 

Ostium Secundum ASD

• Most common,50-70% of all ASDs.
• Located in the area of the fossa ovale, located centrally.
• Excessive reabsorption of septum primum or deficiency in growth of septum secundum.
• Can be associated with MV prolapse, w/wo MR.  

Ostium Primum ASD

• Located anterior and inferior to fossa ovale, located  by AV valves.
• Associated with Cleft MV, (anterior leaflet).
• Failure of endocardial cushions to close ostium primum.
• 20% of all ASDs.
• Associated with Atrioventricular Septal Defects(AVSD), Cleft MV/TV & Down's Syndrome.

Unrestricted Shunt

• Any shunt that is less than 3.5-4m/s.
• Usually means a larger shunt. 

Sinus Venosus ASD

• Least common, 6% to 8% of ASDs.
• Associated with Anomalous Right Upper Pulmonary Vein. (PAPVR where RPV or LPV can drain into RA with or without ASD).
• Right upper pulmonary vein abnormally goes to the SVC or directly into the RA.
• Faulty or incomplete reabsorption of sinus venosus.
• SVC type: defect is superior and posterior to fossa ovale .
• IVC type: defect is located inferior and posterior to fossa ovale.
• Both types associated with Anomalous RUPV.

Coronary Sinus ASD

• Extremely Rare.

• Includes unroofed coronary sinus and Left SVC to LA.
• Associated with Total Anomalous Pulmonary Veins and Situs Ambiguous (Asplenia).

   

   

   

Iatrogenic ASD

• Physician induced defect (Septostomy).
• Blalock-Hanlon; Surgical creation of ASD.
• Park; Blade Atrial Septostomy- creation by blade catheter.
• Rashkind; Balloon Atrial Septostomy.

   

   

   

Findings of Long Term ASDs

• Arrhythmia SVT, A-flutter, RBBB.
• CHF in 3rd or 4th decade of life.
• CVA due to paradoxical embolism.
• RAE, RVE (RV volume overload).
• MPA dilated, Pulmonary Veins mildly dilated.
• PI/TR.
• Paradoxical septal motion.
• D-shaped LV in SAX due to RV volume overload.
• If long-standing shunt, PHTN can occur which can cause the shunt to become right to left. 

Hemodynamics of ASDs

• LV remains normal, "extra" blood shunts back to the right side in L-R shunt.
• RAE, RVE, dilated PA, dilated Pulmonary veins.

ASDs & Echo

•  Avoid calling ASD from the Apical 4, view can have false drop out in atrial septum area.
• Sometimes seen from SAX.
•  Gold standard view is from Subcostal or RSB.
• Measure in end diastole.
• RV size by M-mode and 2-D from all views.
• Image and Doppler Pulmonary Valve for PS.
• Color in Apical and Subcostal views for shunt direction.
• Size ASD in subcostal and Apical views by 2D and Color.
• Evaluate location of ASD by 2-D and Color from all views.
• Evaluate PVs – R/O anomalous venous drainage by Color.
• Evaluate A-V Valves in the setting of a primum defect for abnormal attachments (ie Endocardial Cushion Defect).

ASDs and Doppler

• PW will be a biphasic pattern.

• One peak in late ventricular systole.
• Second peak in atrial systole.
•  Peak velocity across unrestrictive ASD can be 0.25-1.0 m/s.

•  Velocity will decrease with inspiration and will help differentiate from venous flow from which increases with inspiration.

   

   

   

Qp:Qs

• Qp= .785 x (RVOT diameter)2 x VTI RVOT

• Qs= .785 x (LVOT diameter)2 x VTI LVOT

   

Surgical Management of ASDs

• Open surgical repair: dacron or pericardial patch or direct suture.
• Transcatheter closure (double umbrella device):
•  Helex Device, Amplatzer Device, CardioSeal.
•  Tunnel repair for sinus venosus ASD.  

   

   

   

Post Device Echo of ASDs

• R/O Obstruction of: SVC flow, Pulmonary Vein flow, and MV/TV apparatus.