Atrial Septal Defect Flashcards
(31 cards)
Definition
an opening between the left and right atria at the interatrial septal level
Prevalence
-6-10% of all congenital heart disease
- female to male ration 1.5:1 to 3.5 to 1
-possible familial incidence
Embryology
- Osmium Secundum : excessive resorption of the septum premium of a deficiency in the growth of the septum secundum, resulting in a defect in the area of the fossa ovalis
- Osmium Primum: Failure of endocardial cushions to close ostium primum, resulting in a defect anterior to the fossa ovalis
- sinus venous: faulty or incomplete resorption of the sinus venosus, resulting in a defect posterior to the fossa ovalis
-coronary sinus may be a part of a complex that includes an unroofed coronary sinus, left atrial connection, and a persistent left SVC.
Ostium Secundum
- most common
-70%
-defect in the area of the fossa ovalis
-associated with MVP with or without MR
Ostium Primum
- 20%
-deect anterior and inferior to the fossa ovalis - associated with atrioventricular septal defects, cleft MV/TV, Downs syndrome
Sinus Venosus
- 6-8%
-There are 2 types: SVC type where the defect is superior and posterior to the fossa ovalis
IVC type where the defect is located posterior and inferior
- both types are associated with partial anomalous pulmonary venous return
Coronary Sinus
- least common
-part of a complex that includes unroofed coronary sinus and persistent left SVC connected to the right atrium or coronary sinus
-associated with total anomalous pulmonary venous return, situs ambiguus (asplenia)
Common atrium
associated with cleft MV, partial anamolous pulmonary venous return, persistent LT SVC, Ellis van Creveld syndrom
Atrial Septal Aneurysm
redundancy of fossa ovalis tissue which is often fenestrated
Pathology/Physiology
- The size of the defect has less effect on shunting than does the relative resistance of the ventricles to filling
-normally, the predominant shunt is left to right because lt atrial pressures are higher than rt and the rt ventricle is a thin walled compliant ventricle
-a slight reversal of flow may occurs during early ventricular systole
-there is a volume overload of the right atrium and the right ventricle with increased pulm blood flow
-PHTN may develop by adult life
- the pulmonic and tricuspid valve annuli are dilated, resulting in valvular regurgitation.
Associated Conditions
- Ellis van Creveld syndrome (common atrium)
-Lutembacher syndrom (MS and ASD)
-Holt-oram syndrom ( cardiac limb)
-functional pulmonary ejection murmur
- mild PS
-Ebsteins anomaly
-partial anomalous pulmonary venous return
History
- asymptomatic
- familial recurrence
- fatigue
-dyspnea
-CHF
- recurrent pulm infections
Physical Examination
- slender habitus
-precordial bulge
-rt ventricular thrust
- cyanosis ( represents several of left to right shunt )
- Hepatomegaly (older pt)
- Pulmonary vascular occlusive disease (rare)
Cardiac Auscultation
- S1 loud and closely split at times
-fixed wide split of S2 (lt upper sternal border)
-Soft mid systolic crescendo-decrescendo ejection murmur at the left upper sternal border
-low pitched early diastolic murmur near the xyphoid (due to increased diastolic tv flow)
-Thrill (25%)
-P2 may be accentuated (indicating pulm htn)
EKG
- prolonged PR interval (20%)
-RSR in lead V1 (incomplete RBBB)
-rt axis deviation
-lt axis deviation (septum primum defect)
-rt atrial enlargement
-RVH
- Afib/flutter (most often in adults)
Chest xray
- cardiomegaly (rt atrial and rt ventricular enlargement)
-prominent main and pulmonary branch arteries
-increased pulmonary vascular markings
-relatively small aortic knob
-dilated main pulmonary artery with clear lung fields (PVOD)
Cardiac Cath
- Oxygen saturation step up of > 10% in the RA, RV, and MPA, as compared with the vena cava
-Systolic pressure gradient of 22 mmHg or less across right ventricular outflow tract
-Pulmonary arterial and right ventricular pressures are normal to slightly elevated
-Determine Qp/Qs (>1.5:1 is significant)
Natural history/ complications
-spontaneous closure ( rare after 2 yrs of age)
- CHF (3rd to 4th decade of life)
-Pulm HTN (3rd to 4th decade of life)
-atrial arrhythmias (adult like usually)
- infective endocarditis (very rare)
-cerebrovascular accident due to paradoxical embolism (very rare)
medical management
-treatment of chf (digoxin, diuretics)
-infective endocarditis prophylaxis (if mv disease is present)
surgical management
-open repair (dacron or pericardial patch or direct suture) under cardiopulmonary bypass
- transcatheter closure (button, double-umbrella device)
-increased pulmonary vascular resistance is. contraindication
-tunnel repair for sinus vensosus asd
views (echo)
- subcostal (preferred)
- parasternal short axis of the av
-AP4 (limited)
-rt parasternal
M-mode/2D
- Direct visualisation of the defect (sweep beam superiorly and inferiorly to detect and size defect)
- RA/RV dilation
-main pulmonary artery/pulmonary artery branch dilation
- RV volume overload pattern (V dilation with paradoxical septal motion)
- D-shaped LV due to right heart diastolic volume overload
-T sign at outer edges of defect
- mild LA enlargement
- MVP (secundum)
-Cleft MV (Primum)
-Partial anomalous pulmonary venous return ( sinus venosus)
-Coronary sinus dilation (Persistent LSVC)
-RVH (w increased pulmonary vascular resistance)
-Saline contrast may demonstrate a negative contrast effect in the right atrium or may demonstrate contrast crossing ASD from right to left
- Measure the diameter of the defect in two orthogonal views at end diastole
1. small defect less than 3 mm
2. mod defect 3-5 mm
3. mod-large 5-8 mm
4. large greater than 8 mm
-determine the presence of associated lesions (cleft valve, vsd, pda, mvp,…)
PW/CW/Color doppler
- color flow provides information concerning location, direction, and magnitude of shunt
-PW demonstrates left to right shunt (usually low velocity)
-low velocity (peak 0.25 to 1.3 m/s), biphasic pattern (peaks in late systole, atrial systole) with flow reversal in early ventriclar systole w decreased flow upon inspiration
-Increased TV/MV peak velocity ration (normal 0.6)
-Increased pulmonary/aorta peak velocity (normal 0.6)
-turbulent flow across the pulmonary valve/ MPA
-Determine the presence and severity of MR/TR/PR
-determine peak/mean pressure gradient across defect
PostOP responsibilities
- Thickened interatrial septum due to repair
-Flat/paradoxical septal motion (normal postop)
-Evaluate the integrity of the patch repair (residual shunting, patch aneurysm)
-Evaluate MV repair (ex: repair of cleft mv)
-evaluate right atrial dimension
-evaluate for the pressure and severity of valvular regurgitation
- determine RV/LV dimensions, thickness, and systolic/diastolic function
-determine SPAP/MPAP/PAEDP
