Dr Ranjith MP Senior Resident Department of Cardiology Government Medical college Kozhikode
Dr Ranjith MPSenior Resident
Department of CardiologyGovernment Medical college
Kozhikode
Atrioventricular Septal Defects are characterized by complete absence of AV septum
Additional features
A common atrioventricular ring
A five leaflet valve that guards the common AV orifice
An unwedged left ventricular outflow tract
LV mass characterized by longer distance from apex to aortic valve than from apex to left AV valve
Also known as Endocardial cushion defect, AV canal defect, canalisatrioventricularis communis, persistent atrioventricular ostium
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AVSDs account for 4% to 5% of congenital heart disease
New England Regional Infant Cardiac Program - 0.118/1000 livebirths
Baltimore–Washington Infant study defined a prevalence of 0.362
The Alberta Heritage study the prevalence was 0.203 and 0.242 per 1000 live births using invasive or noninvasive methodology for the diagnosis respectively
Gender distribution is approximately equal or may show a slight female preponderance
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Rogers, Edwards : Recognised morphology of 10ASD in 1948
Wakai, Edwards : Term of partial and complete AV canal defect in 1956
Bharati & Lev : Term of Intermediate & Transitional in 1980
Rastelli: Described the of common anterior leaflet in 1966
Lillehei : 1st repair of AVSD in 1954
Kirklin, Watkin, Gross: Open repair using oxygenator
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Result from Faulty development of the endocardial cushions and of the atrioventricular septum
In partial AVSDs, incompletefusion of the superior andinferior endocardial cushions results in a cleft in the midportion of the AML , often associated with MR
Complete AVSD associated with lack of fusion between the superior and inferior cushions
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Mitral & tricuspid valves achieve the same septal insertion level because the mitral annulus is displaced toward the apex
The distance from mitral annulus
to the left ventricular apex is less
than the distance from the aortic
annulus to the apex
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In the normal heart, the aortic valve is wedged between the mitral and tricuspid annuli. In AVSD the aortic valve is displaced anteriorly and creates an elongated, so-called gooseneck deformity of the LVOT
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Based on the relationships of the anterior bridging leaflets to the crest of the ventricular septum or RV papillary muscles
Rastelli type A : the anterior bridging leaflet is tightly tethered to the crest of the IVS, occurring in 50% to 70%
Rastelli type B : (3%), the anterior bridging leaflet is not attached to the IVS; rather, it is attached to an anomalous RV papillary muscle and is almost always associated with unbalanced AV canal with right dominance
Rastelli type C : (30%) a free-floating anterior leaflet is attached to the anterior papillary muscle.
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Kiyoshi suzuki et al J Am Coll Cardiol 1998;31:217–23
Partial AVSD Most common 20 ASD & LSVC to CS
Less frequently- PS, TS or atresia, cor triatriatum, CoA, PDA, membranous VSD, PV anomalies, and HLV
Complete AVSD Type A usually is an isolated defect and is frequent in patients
with Down syndrome.
Type C – TOF, DORV, TGA and heterotaxy syndromes
The combination of type C complete AVSD with TOF is observed Down's syndrome, whereas DORV is a feature of patients with asplenia
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M. Cristina Digilio et alCardiogenetics 2011; 1:e7
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M. Cristina Digilio et alCardiogenetics 2011; 1:e7
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M. Cristina Digilio et alCardiogenetics 2011; 1:e7
Anatomy of AVSD expected to demonstrate one or more of the following hemodynamic changes Shunting across the atrial septal defect
Shunting through the ventricular septal defect
Mitral regurgitation
Tricuspid regurgitation
Patterns of shunting: obligatory shunting
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Greater proportion of SVC blood with a low oxygen saturation may cross the IAS to the LA
If AV insufficiency were present blood being ejected from LV to RA
Increase the PO2 of blood in RA, RV, PA
Slightly higher PO2 of blood perfusing the lungs would decrease pulmonary vasoconstriction and increase pulmonary blood flow
It is possible that the lesser degree of constriction of the pulmonary arterioles may retard the development of a thick medial muscle layer, so that a more rapid decrease in PVR may occur after birth
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Fetal physiology
Infants with ostium 10 defect usually present the same hemodynamic features as those with 20 ASD
As PVR falls after birth, RV after load falls & RV stroke volume increases and exceeds that of the LV. The RV fills preferentially and thus left-to right shunting occurs through the ASD
MR and LV to RA shunting are not usually prominent features in infants with 10 defect
If MR present, in early infancy cardiac failure develops within weeks after birth
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Early infancy
Pulmonary blood flow is increased even though PVR may still be high, because shunting occurs from a high-pressure to a low-pressure chamber
The increased pulmonary blood flow and PA pressure interfere with the normal postnatal maturation of the pulmonary arterioles
The thick medial muscle layer is maintained and the fall in PR is delayed
An interesting association may develop in some infants of an obligatory left-to-right shunt through the atrioventricular septal defect and simultaneous right-to-left shunting through the ductus arteriosus
Pulmonary vascular resistance may be increased above systemic arterial resistance
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later infancy
Partial AVSD
Patients with 10 ASD are usually asymptomatic during childhood.
Dyspnea, easy fatigability, recurrent RTI and growth retardation may be present early in life if associated with major MR or common atrium
Patients with 10 ASD usually have earlier and more severe symptoms than patients with 20 ASD
Complete AVSD
Tachypnea and failure to thrive invariably occur early in infancy & virtually all patients have symptoms by 1 year of age.
If these symptoms do not develop early on, the clinician should suspect premature development of pulmonary vascular obstructive disease
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Usually undernourished and have signs of CHF
Hyperactive precordium with a systolic thrill at the lower left sternal border is common
S1 is accentuated. S2 narrowly splits, P2 increases in intensity.
A grade 3 to 4/6 holosystolic murmur
ECG Superior” QRS axis with the QRS axis between -40 and -1500
Most of the patients have a prolonged PR interval
More than 50% have atrial enlargement
RVH or RBBB is present in all cases (2/3rd have rsR, RSR or Rr in lead V1, and the rest have a qR or R pattern) & many have LVH
Chest X-ray
In 10 ASD findings are same as 20 ASD except for enlargement of the LA & LV when MR is significant
In complete AVSD cardiomegaly is always present and involves all four cardiac chambers. Pulmonary vascular markings are increased, and the main PA segment is prominent
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Primary imaging technique for diagnosing AVSD
The internal cardiac crux is the most consistent imaging landmark
Apical four-chamber imaging plane clearly visualizes the internal crux
The 10 ASD is seen as an absence of the lower IAS
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Several echocardiac features are shared by all forms of AVSD: Deficiency of a portion of the inlet ventricular septum
Inferior displacement of the AV valves
Attachment of a portion of the left AV valve to the septum
The two separate AV valve orifices are equidistant from the cardiac apex
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The most common left AV valve abnormality, a cleft, is best visualized from the parasternal and subcostal short-axis imaging planes.
Rarely parachute mitral valve and double-orifice mitral valve also occur
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In the transitional form of partial AVSD, there is aneurysmalreplacement of a portion of the inlet ventricular septum
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Rarely required for diagnosis
In older patient it may have a role in assessing the degree of pulmonary vascular obstructive disease or CAD
A large Lt to Rt shunt at the atrial level demonstrated by a significantly higher oxygen saturation sampled from the RA compared with the blood in the IVC & SVC
In complete AVSD the PASP is invariably at or near systemic level, while in partial AVSDs, the PASP is usually <60% of systemic pressure
LV angiography - gooseneck deformation of the LVOT
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Left to-right shunting increases the oxygen saturation in RA
Sample from high in the SVC usually represents the best
mixed venous oxygen saturation (normal or 40 to 50%)
Usually a further increase in oxygen saturation in the RV
Pulmonary venous oxygen saturation is frequently reduced to 93–95% in older individuals with very large L to R shunts
LA & LV O2 saturation is often decreased to as low as 86–88%
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The LV angiogram shows features characteristic of AVCD& are best revealed in the hepatoclavicular orientation
The LV outflow tract is elongated and appears narrow
A concavity of the medial border LV that extends along the outflow region to the aorta due to the abnormal attachment of the AML. If it attaches to the ventricular septum or right papillary muscle, LVOT obstruction may be evident
Detect AV valve regurgitation
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The outcome of live-born patients with AVSD depends on the
specific morphology of the defect
The size of the ventricular septal defect
Degree of ventricular hypoplasia
Degree of AV valve regurgitation
Presence or absence of LVOT obstruction
Presence or absence of coarctation of aorta
Associated syndromes (cardiac and noncardiac)
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Patients with the complete form of AVSD and large VSD not undergoing repair die in infancy with CHF & PAH
Those who survive without surgery into childhood usually develop pulmonary vascular obstruction and eventually die with Eisenmenger’s syndrome
Berger and his colleagues found that only 54% of patients born with a complete form of AVSD were alive at 6 months of age, 35% at 12 months, 15% at 24 months, and 4% at 5 years of age
This data would support surgical intervention in the first 3–6 months of age
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Berger TJ,et al Ann Thorac Surg 1979; 27: 104–11.
Infants with 10 ASD presenting in infancy have a poor outcome, mainly because of the associated risk factors that bring these infants to early attention
Those with the partial form of AVSD and minimal left AV valve regurgitation seem to fare the best without surgery, although there is still likely considerable morbidity and mortality
According to Somerville, 50% die before 20 years of age and only 25% survive beyond 40 years of age
Atrial fibrillation in these patients was an important cause of late morbidity and mortality
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The complete form of AVSD is the most frequent type of CHD associated with trisomy 21
70% of children with complete AVCD display this aneuploidy
Children with Down syndrome show a simple form of AVCD which is usually complete & rarely associated with additional cardiac anomalies (with the only notable exception of TOF)
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Left-sided obstructive lesions are significantly rare in children with AVCD and Down syndrome compared to patients with AVCD without Down syndrome
Accordingly, some types of situs abnormalities such as l-loop of the ventricles, atresia of the AV valves and TGA are virtually absent in subjects with Down syndrome
Surgical correction of AVCD in individuals with Down syndrome results in lower mortality and morbidity rates, compared to the children without trisomy (12.6% Vs 17.8%)
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Patients are at increased risk for the development of pulmonary vascular obstructive disease
These patients have a greater degree of elevation of pulmonary vascular resistance in the first year of life and more rapid progression to fixed pulmonary vascular obstruction than patients without Down syndrome
Chronic upper airway obstruction with macroglossia and an inherently small hypopharynx, hypotonia, the predisposition to chronic infection, an abnormal capillary bed morphology, and the suggestion of pulmonary hypoplasia can all adversely affect the pulmonary vascular bed
surgical correction should be carried out by 6 months
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Incidence 1% in unoperated cases
Higher incidence in operated cases
10% may require reoperation to relieve LVOT obstruction
more common in partial than in complete AVSD
Etiology Attachments of SBL to ventricular septum
Extension of the anterolateral papillary muscle into LVOT
Discrete fibrous subaortic stenosis
Tissue from an aneurysm of the membranous septum bowing into the LVOT
Septal hypertrophy
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Systolic (left) and diastolic (right) echocardiographics demonstrating LVOT obstruction in a 17-year-old who had repair of a partial AVSD at age 15 months
PA banding is now performed infrequently in infants with AVSD because the surgical risks of intracardiac repair are not significantly greater than the palliative procedure
Perioperative mortality is about 5%
It is reserved for those few patients in whom intracardiac repair is likely to be associated with a high risk like Single papillary muscle
Severe left ventricular outflow obstruction
Unbalanced commitment of the AV valve to the ventricles
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Objectives - closure of the interatrial communication and restoration and preservation of left AV valve competence
These objectives can be accomplished by careful approximation of the edges of the valve cleft with interrupted nonabsorbable sutures
The repair is completed by closure of the interatrial communication (usually with an autologous pericardial patch), avoiding injury to the conduction tissue
This repair results in a two-leaflet valve
Alternatively, if the left AV valve is to be considered a trileaflet valve, with the cleft viewed as a commissure, surgical repair demands that this commissure be left unsutured and that various annuloplastic sutures be placed to promote coaptation of the three leaflets
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A: Surgical exposure
B: Closure of the mitral valve cleft
C: Prosthetic patch closure of an 10 defect
D: Repair completed
Surgical repair of complete forms of AVSD is indicated earlier in life than for the partial forms of AVSD
Repair should be done electively before 6 months of age & earlier repair should be considered for infants with failure to thrive
For the symptomatic infant, surgical options include palliative pulmonary artery banding and complete repair of the anomaly
In the modern era complete repair appears to be the procedure of choice
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Closure of interatrial and interventricular communications, construction of two separate and competent AV valves from available leaflet tissue, and repair of associated defects
Techniques are based on the use of a single patch or double patch (separate atrial and ventricular patches) to close the ASD and VSD and then reconstruction of the left AV valve as a bileaflet valve
Some surgeons consider the cleft of the left AV valve, a true commissures and envision this valve as a trileaflet valve. This is the basis for Carpentier technique for repair of complete AVSD
The two-patch technique has become the method of choice
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52Carpentier technique for repair of complete AVSD with the double-patch technique.
Concept of a trileaflet left atrioventricular valve
The risk of hospital death for repair is 3%
Determinants of hospital mortality include CHF , cyanosis, failure to thrive, age at operation of <4 years, and moderate to severe MR
20- and 40-yr survivals after repair is 87% and 76% respectively
Closure of the mitral cleft and age <20 years at time of operation is associated with better survival
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Partial AVSD: Regurgitation or stenosis of the left AV valve Subaortic stenosis Residual recurrent ASD
Reoperation for MR occurs in 10% to 15% of survivors of primary repair of partial AVSD
Risk factors for reoperation include significant residual MR as assessed intraoperatively at the time of initial repair, the presence of a severely dysplastic mitral valve, and failure to close the cleft in the AML
Repeat repair is possible if valve dysplasia is not severe or when the mechanism of regurgitation is through an unsutured cleft
Replacement of the mitral valve may be required in the presence of a severely dysplastic valve
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Complete AVSD
Needed in 17% of patients during the first 20 years after surgical repair
Lesions requiring reoperation include - left and right AV valve regurgitation, left AV valve stenosis (native and prosthetic), and residual/recurrent ASDs or VSDs
Residual left AV valve regurgitation may result from inadequate surgical reconstruction
Right AV valve regurgitation requiring reoperation is rare . It is more apparent with the presence of PAH or in association with TOF with RV dysfunction owing to persistent RVOT obstruction or PR
Residual shunts are rare causes for late reoperation55
Parachute Deformity of the Mitral Valve Closure of the mitral cleft at the time of repair may result in an
obstructed mitral orifice
If the patient has significant AV valve regurgitation, valve replacement may be the only suitable option
Double-Orifice Mitral Valve The surgeon must resist the temptation of joining the two
orifices by incising the intervening leaflet tissue. The combined opening of both orifices is satisfactory for adequate mitral valve function
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Right or Left Ventricular Hypoplasia The only option for definitive surgical treatment is the modified
Fontan's procedure preceded by adequate pulmonary artery banding in infancy
Subaortic Stenosis If discovered at the time of initial preoperative evaluation,
subaortic stenosis tends to be of the fibromuscular membrane type and should be treated by appropriate resection during surgical repair
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Common atrium is characterized by near absence of the atrial septum
In the presence of two ventricles, it always is associated with an AVSD
Most patients with common atrium present in infancy with symptoms of excess pulmonary blood flow
These patients are symptomatic earlier in life than patients with only a 10 ASD
The precordium is hyperactive with a prominent RV impulse. S2 is widely split and fixed
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P2 intensity proportionate to the severity of pulmonary hypertension
An ESM present over the upper left sternal border. A distinct holosystolic murmur of MR may be heard at the apex. A middiastolic murmur commonly is detected over the lower left sternal border resulting from an increase in right atrial to right ventricular blood flow
The radiographic and electrocardiographic characteristics of patients with common atrium are indistinguishable from those with other forms of AVSD
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Echocardiography Subcostal four-chamber view is most suitable for accurate diagnosis
A muscle bundle or band coursing through the atrium should not be interpreted as an atrial septum
Cardiac Catheterization and Angiography The hemodynamic diagnosis of common atrium depends on the
demonstration of complete mixing of systemic and pulmonary venous blood
The oxygen saturations of pulmonary and systemic arterial blood are nearly identical
Pulmonary blood flow exceeds systemic flow, except in patients with PAH
Right ventricular pressure is increased more often than in 20 ASD or partial AVSD 60
If definitive repair is delayed, significant pulmonary vascular obstructive disease may develop more easily than in patients with secundum ASD or partial AVSD
Treatment Medical therapy -Digoxin and diuretic therapy are traditional
forms of therapy
Surgical repair, which should be performed early in life because the patient usually has symptoms and is at risk for developing pulmonary vascular obstructive disease
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One ventricle and its corresponding AV valve are hypoplasticwhile the other ventricle receives the larger portion of the common AV valve
The most common arrangement is a dominant right ventricle with a hypoplastic left ventricle
The left-sided component of the common AV valve may be stenotic after two-ventricle repair has been performed
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1. Down syndrome most commonly associated with Type A
2. Most common form complete AVCD is Type B.
3. Free interventricular communication exists in type A
4. In type A anterior bridging leaflet has been described as free floating
1. Sinus rhythm is present in most patients with a 1⁰ ASD
2. P-wave changes indicating right atrial, left atrial, or biatrialenlargement are seen in 54% of patients.
3. The mean QRS axis ranges from +30⁰ to +120⁰
4. ventricular volume overload results in the rsR or RSR pattern in the right precordial leads in 84%.
1. Single papillary muscle
2. Severe left ventricular outflow obstruction
3. Unbalanced commitment of the AV valve to the ventricles
4. Associated TOF
1. The only option for definitive surgical treatment in Right or Left Ventricular Hypoplasia is the modified Fontan's procedure preceded by adequate pulmonary artery banding in infancy
2. In double-orifice Mitral Valve, better results by joining two orifices by incising the intervening leaflet tissue
3. Closure of the mitral cleft at the time of repair may result in an obstructed mitral orifice in Parachute Deformity of the Mitral Valve
4. If discovered at the time of initial preoperative evaluation, subaorticstenosis tends to be of the fibromuscular membrane type & should be treated by appropriate resection during surgical repair
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1. Oxygen saturation step up from RA to RV
2. Mixed venous sample best represented by low SVC sample
3. Oxygen saturation 93 to 95 in pulmonary vein
4. Left atrial and left ventricular oxygen saturation is often decreased to as low as 86–88%
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1. Noonan syndrome
2. Down syndrome
3. CHARGE syndrome
4. Ellis-van creveld syndrome
1. 20- and 40-yr survivals after repair is 87% and 76% respectively
2. Closure of the mitral cleft and age <20 years at time of operation is associated with better survival
3. Right AV valve regurgitation requiring reoperation is rare
4. The risk of hospital death for repair is 12- 16%
1. Gender distribution is approximately equal or may show a slight female preponderance
2. A five leaflet valve that guards the common AV orifice
3. An wedged left ventricular outflow tract
4. LV mass characterized by longer distance from apex to aortic valve than from apex to left AV valve
1. Inferior displacement of the AV valves
2. The two separate AV valve orifices are not equidistant from the cardiac apex
3. The internal cardiac crux is the most consistent imaging landmark
4. Deficiency of a portion of the inlet ventricular septum
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1. Reoperation for MR occurs in 10% to 15% of survivors of primary repair of partial AVSD
2. Replacement of the mitral valve may be required in the presence of a severely dysplastic valve
3. Residual shunts are common causes for late reoperation
4. The risk of hospital death for repair is 3%
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1. Down syndrome most commonly associated with Type A
2. Most common form complete AVCD is Type B.
3. Free interventricular communication exists in type A
4. In type A anterior bridging leaflet has been described as free floating
1. Sinus rhythm is present in most patients with a 1⁰ ASD
2. P-wave changes indicating right atrial, left atrial, or biatrialenlargement are seen in 54% of patients.
3. The mean QRS axis ranges from +30⁰ to +120⁰
4. ventricular volume overload results in the rsR or RSR pattern in the right precordial leads in 84%.
1. Single papillary muscle
2. Severe left ventricular outflow obstruction
3. Unbalanced commitment of the AV valve to the ventricles
4. Associated TOF
1. The only option for definitive surgical treatment in Right or Left Ventricular Hypoplasia is the modified Fontan's procedure preceded by adequate pulmonary artery banding in infancy
2. In double-orifice Mitral Valve better results by joining two orifices by incising the intervening leaflet tissue
3. Closure of the mitral cleft at the time of repair may result in an obstructed mitral orifice in Parachute Deformity of the Mitral Valve
4. If discovered at the time of initial preoperative evaluation, subaorticstenosis tends to be of the fibromuscular membrane type & should be treated by appropriate resection during surgical repair
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1. Oxygen saturation step up from RA to RV
2. Mixed venous sample best represented by low SVC sample
3. Oxygen saturation 93 to 95 in pulmonary vein
4. Left atrial and left ventricular oxygen saturation is often decreased to as low as 86–88%
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1. Noonan syndrome
2. Down syndrome
3. CHARGE syndrome
4. Ellis-van creveld syndrome
1. 20- and 40-yr survivals after repair is 87% and 76% respectively
2. Closure of the mitral cleft and age <20 years at time of operation is associated with better survival
3. Right AV valve regurgitation requiring reoperation is rare
4. The risk of hospital death for repair is 12- 16%
1. Gender distribution is approximately equal or may show a slight female preponderance
2. A five leaflet valve that guards the common AV orifice
3. An wedged left ventricular outflow tract
4. LV mass characterized by longer distance from apex to aortic valve than from apex to left AV valve
1. Inferior displacement of the AV valves
2. The two separate AV valve orifices are not equidistant from the cardiac apex
3. The internal cardiac crux is the most consistent imaging landmark
4. Deficiency of a portion of the inlet ventricular septum
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1. Reoperation for MR occurs in 10% to 15% of survivors of primary repair of partial AVSD
2. Replacement of the mitral valve may be required in the presence of a severely dysplastic valve
3. Residual shunts are common causes for late reoperation
4. The risk of hospital death for repair is 3%
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