Cardiac Defects and Corrective Procedures Flashcards
Atrial Septal Defect (ASD) ANATOMY
- most common?
- least common?
- Most common= defects in septum primum w/in the fossa ovalis (secundum ASD’s)
- Less common= defect involving septum secundum near the SVC (sinus venosus ASD’s), or the coronary sinus.
Atrial Septal Defect (ASD) PATHOPHYSIOLOGY
- Type of shunt?
- What does it cause?
- What can large shunts cause?
The LEFT to RIGHT shunt over time results in right A+V dilatation.
- -RA fibrosis can occur and then act as a substrate for late occurring atrial arrhythmia’s.
- -RV dilatation can cause tricuspid annular dilation which results in tricuspid insufficiency
- -Large shunts cause pulmonary congestion, which can (less commonly) cause pulmonary HTN which can cause right to left shunting and cyanosis to occur [risk for emboli and stoke]
Atrial Septal Defect (ASD) SURGICAL CORRECTION
Surgical closure (direct suture anastamosis or patch using autologous pericardium or synthetic material) --majority of secundum ASD's use a transcatheter device
Ventricular Septal Defect (VSD) ANATOMY
- Location and number?
- Small vs Large?
- What is special about supracristal VSD’s?
- May occur in multiple locations in ventricular septum (inlet, muscular, perimembranous, or supracristal)
- May be single or multiple
- Small defects usually close in the 1st few yrs of life
- Large defects have a significant LEFT to RIGHT shunt (with dilation of the PA and left A+V), systemic RV pressures, and a diameter similar to the aortic annulus
- Supracristal VSD’s can spontaneously close and cause prolapse of the right coronary cusp of the aortic valve which can cause aortic insufficiency
Ventricular Septal Defect (VSD) PATHOPHYSIOLOGY
- Type of shunt and what it causes?
- Type of murmur heard and its location?
- Large shunts effects?
- A large LEFT to RIGHT shunt can cause excessive pulmonary blood flow which causes pulmonary edema and tachypnea. The increased pulmonary VR results in left A+V enlargement.
- A holistic murmur is heard at the lower left sternal border from the turbulent flow crossing the defect. Small shunts have a high pitch.
- Large shunts may interfere with a child’s feeding and growth and cause rapid breathing, irritability, excessive sweating, poor weight gain, irreversible pulmonary HTN, pulmonary vascular obstructive disease and a resultant RIGHT to LEFT shunting (Eisenmengers Syndrome).
Ventricular Septal Defect (VSD) SURGICAL CORRECTION
- Describe infant care?
- How are they closed?
- What are the special considerations for muscular VSD’s?
- Infants w/ CHF from volume overload use diuretics. As their metabolic requirements increase, high calorie formulas are given. If impaired growth persists then surgery is indicated to close the VSD.
- Closed with a patch repair
- Small VSD’s may only need suturing of the edge
- Muscular VSD’s can be difficult if obscured by the trabeculations of the RV
Patent Ductus Arteriosus (PDA) ANATOMY
- What does it connect and why?
- When does it close normally?
- When is a PDA common?
Connects the main PA to the descending aorta. In the fetus, it is open to shunt blood from the PA to the descending aorta to bypass the nonaerated lungs. It normally closes hours after birth leaving the fiber like ligamentum arteriosum.
-PDA is common in premature infants.
Patent Ductus Arteriosus (PDA) PATHOPHYSIOLOGY
- Type of shunt created?
- Large vs Small?
- What type of murmur is heard and its location?
- Describe ductal dependent lesions
After birth, PVR is lower in the lungs which can cause the PDA to make a LEFT to RIGHT shunt from the aorta to the PA.
- Large PDA can cause HF from pulmonary over circulation and pulmonary HTN.
- Small PDA can be insignificant w/ only endocarditis as a risk.
- PDA’s are heard as a continuous murmur at the upper sternal border.
- Ductal Dependant Lesions= PDA’s may be necessary after birth to provide pulmonary or systemic BF for patients w/ Pulmonary Atresia or Hypoplastic Left Heart Syndrome.
Patent Ductus Arteriosus (PDA) SURGICAL CORRECTION
Premature Infants vs. Older Infants/Children
Premature Infant= pharmacological treatment w/ indomethacin or ibuprofin. If that fails, surgical intervention is needed.
Older infants/children= the PDA is closed in the cardiac catheterization lab by coil embolization.
Double Outlet Right Ventricle (DORV) ANATOMY
-two descriptions
Both the aorta and PA arise from the RV.
- Described as the presence of muscular conal tissue under the aorta and PA w/ fibrous discontinuity btwn the aortic and mitral valves.
- Described as a VSD (can be sub-aortic, sub-pulmonary, doubly-committed, or in a remote location). The great vessels may be normally related or transposed. Rarely there can be hypoplasia of the mitral valve and LV
Double Outlet Right Ventricle (DORV) PATHOPHYSIOLOGY
- What does it depend on?
- What can be seen in infants?
Depends on position of VSD and degree of pulmonary stenosis.
Infants= may show spectrum from pulmonary over circulation to transposition like physiology (occurs w/ inadequate circulatory mixing due to streaming of oxygenated blood across the VSD from the LV back to the PA [Taussig-Bing Anomaly]).
Double Outlet Right Ventricle (DORV) SURGICAL CORRECTION
-Describe the 3 different cases
- Normally related great vessels and sub-aortic VSD= patching the VSD to the aorta
- If aorta is remote from VSD= Rastelli-like procedure is performed to baffle the LV output to the aorta and a conduit is placed to route systemic venous blood from the RV to the PA.
- Hypoplasia of the left heart= single ventricular surgical palliation
A-P Window ANATOMY
-Describe what it is and what it may occur with
There is a connection btwn the aorta and the main or right PA. Can occur as an isolated defect or in association with an interrupted aortic arch
A-P Window PATHOPHYSIOLOGY
- What type of shunt is created?
- What may be present with a large defect?
results in a LEFT to RIGHT shunt w/ pulmonary over circulation and left heart dilatation. With large defect, pulmonary HTN mat be present.
A-P Window SURGICAL CORRECTION
-What type of treatment and when must it be performed and why?
Surgery- must be performed early to prevent irreversible pulmonary HTN
Tetrology of Fallot (TOF) ANATOMY
-Describe the 4 anomalies
- Large anteriorly malaligned VSD of the conal septum
- Stenosis of the RV outflow tract (infundibular stenosis) w/ associated pulmonary valve stenosis
- Aorta is enlarged and displaced to the right such that it overrides the VSD
- RV Hypertrophy
Tetrology of Fallot (TOF) PATHOPHYSIOLOGY
- What is cyanosis dependent on?
- Describe effects on minimal stenosis in infants
- Describe effects of severe RV outflow tract stenosis in infants
- Describe Hypercyanotic
- Describe micro deletion of chromosome 22
- Degree of cyanosis is dependent on the degree of obstruction to pulmonary blood flow.
- Infants with minimal stenosis may have a large LEFT to RIGHT shunt across the VSD w/ little to no cyanosis (pink Tetralogy)
- Infants w/ severe RV outflow tract stenosis will be severely cyanotic w/ ductal dependent pulmonary blood flow.
- Hypercyanotic episodes may be fatal (leads to increased RIGHT to LEFT shunting)
- Micro deletion of 22q11 is associated with cono-truncal congential heart defects
Tetrology of Fallot (TOF) SURGICAL CORRECTION
- What do they do for severely cyanotic infants?
- What is used in selected cases?
- When is TOF repaired?
- Severly cyanotic infants= Prostaglandin E1 infusion to maintain ductal patency and pulmonary perfusion
- Selected cases= modified Blalock-Taussig shunt-provides adequate pulmonary BF to the lungs
- Depending on anatomy- they might repair the defect successfully in neonatal period but is usually repaired btwn 4-6 months or as cyanosis progresses
Transposition of the Great Arteries (TGA) ANATOMY
D Type vs L Type
D Type= Aorta is anterior and to the right relative to the PA and arises from the RV. The PA arises from the LV
L Type= Right A+V are connected by the mitral valve and the Left A+V are connected by the tricuspid valve
Transposition of the Great Arteries (TGA) PATHOPHYSIOLOGY
D Type vs L Type
D Type= Aorta returns deoxygenated blood to systemic circulation while the PA returns oxygenated blood to the pulmonary circulation
L Type= May be asymptomatic. May have significant tricuspid insufficiency and systemic ventricular dysfunction
Transposition of the Great Arteries (TGA) SURGICAL CORRECTION
D Type vs L Type
D Type= Initially given prostaglandin E1 to maintain patency- if foramen ovale is restrictive then it must be enlarged by a Balloon Septostomy. Surgery then occurs in the 1st week via a Arterial Switch Operation
L Type= Tricuspid valve replacement for those with tricuspid insufficiency and systemic ventricular dysfunction. Some may have a double switch (Senning procedure w/ an arterial switch procedure)
Truncus Arteriosus (TA) ANATOMY
Aorta and PA leave the heart as a common trunk. There is a large VSD that the Truncus Arteriosus overrides. The PA arise from the Truncus Arteriosus as either confluent or (more commonly) separate origins.
Truncus Arteriosus (TA) PATHOPHYSIOLOGY
Complete intracardiac mixing of the systemic and pulmonary VR causes systemic desaturation. As PVR goes lower than SVR, pulmonary over circulation and CHF occurs.
Truncus Arteriosus (TA) SURGICAL CORRECTION
Closure of the VSD w/ detachment of the PA from the common trunk and incorporating them into a RV to PA conduit
Total Anomolous Pulmonary Venous Return (TAPVR) ANATOMY
All pulmonary veins are abnormal in how they connect to the heart. Oxygenated blood from the lungs are carried by the pulmonary veins back to the right side of the heart rather than the LA. Therefore, systemic BF requires RIGHT to LEFT shunting across an ASD.
Total Anomolous Pulmonary Venous Return (TAPVR) PATHOPHYSIOLOGY
-Obstruction vs no obstruction
Children show varying degrees of cyanosis.
- If there is no obstruction to BF, infants/children have obligate mixing of saturated and desaturated blood in the RA ans RIGHT to LEFT shunting of partially deoxygenated blood across the ASD
- If there is an obstruction to pulmonary VR, there may be severe cyanosis w/ rapid development of acidosis
Total Anomolous Pulmonary Venous Return (TAPVR) SURGICAL CORRECTION
Surgery. An anastamosis is made btwn the pulmonary venous confluence and the LA. The anomalous connection (vertical vein or infracardiac vein) should then be ligated to prevent LEFT to RIGHT shunting, and the ASD is closed.
Partial Anomolous Pulmonary Venous Return (PAPVR) ANATOMY
At least 1, but not all, pulmonary veins connect anomalously to the right heart. Frequently, the right pulmonary veins drain into the right heart via the SVC. This defect can occur with an ASD and lung abnormalities
Partial Anomolous Pulmonary Venous Return (PAPVR) PATHOPHYSIOLOGY
usually asymptomatic and may be identified serendipitously. The draining into the RA presents the same as an ASD (volume overload and chamber dilation).
-The greater the # of veins draining= a larger shunt=significant right A+V dilation.
Partial Anomolous Pulmonary Venous Return (PAPVR) SURGICAL CORRECTION
Surgery. The anomalous pulmonary veins are redirected to the LA
Ebstein’s Anomoly ANATOMY
- Descripton
- What kind of shunt can form
The tricuspid valve is abnormally formed and more apically displaced which creates atrailization of a portion of the RV. If significant it can be regurgitant, leading to further dilation of the RA.
-In the presence of an atrial communication, RIGHT to LEFT shunting can occur and cause cyanosis
Ebstein’s Anomoly PATHOPHYSIOLOGY
- Mild cases
- Severe cases
- Severe tricuspid valve insufficiency
Mild cases= asymptomatic
Severe cases= infants present at birth w/ severe cardiomegaly and cyanosis
Severe tricuspid valve insufficiency= the RV is unable to generate antegrade flow to open the pulmonary valve- leading to functional atresia and ductal dependency.
Ebstein’s Anomoly SURGICAL CORRECTION
Infants vs Older patients
Infants= Blalock-Taussig shunt to ensure adequate pulmonary BF
Older patients= reparative procedures on the tricuspid valve or full replacement
Aortic Stenosis (AS) ANATOMY
Aortic valve leaflets are thickened. There can be associated defects such as PDA, sub-aortic stenosis, mital stenosis, or coarchtation of the aorta.
-Mild stenosis- compensatory LV hypertrophy is present
Aortic Stenosis (AS) PATHOPHYSIOLOGY
Evolves slowly and causes increased afterload on the LV- resultant hypertrophy, increased myocardial O2 demand and subendocardial ischemia.
Aortic Stenosis (AS) SURGICAL CORRECTION
Severe cases (>70mmHg or >50mmHg w/ symptoms)= balloon vavuloplasty or valve replacement (biologic/mechanical valve replacement or Ross procedure).
Pulmonary Stenosis ANATOMY
Describe the 3 types
Pulmonary valve opening from the RV is restricted
- Supraventricular stenosis= PA lumen above the valve opening is narrowed
- Valvular pulmonary stenosis= The leaflets of the pulmonary valve are abnormally thickened and fused at their edges so the valve does not open fully
- Subvalvular or infundibular stenosis= Outflow tract of RV below pulmonary valve is dynamically obstructed by muscular tisssue
Pulmonary Stenosis PATHOPHYSIOLOGY
- Moderate vs Severe
- Where is the murmur located
- Often well tolerated and asymptomatic
- Severe stenosis= right sided heart failure.
- With an ASD= stiff hypertrophied RV leads to decreased compliance and RIGHT to LEFT shunting and cyanosis.
- Moderate stenosis= increases RV pressure which causes hypertrophy of the RV
- Can be heard via a murmur at the left mid to upper sternal border. Higher the pitch=greater stenosis
Pulmonary Stenosis SURGICAL CORRECTION
-Mild vs Severe
Mild stenosis= may require no intervention
Severe stenosis= balloon valvuloplasty, angioplasty, stent insertion, or surgical repair
Coarctation of the Aorta ANATOMY
Narrowing of the lumen of the aorta. May consist of a posterior shelf life obstruction in the juxtaductal region or complete tubular hypoplasia of the aorta.
Coarctation of the Aorta PATHOPHYSIOLOGY
Main 2 effects and what they cause
Causes increased afterload to the LV, higher BP proximal to the obstruction and lower BP distal.
- The increased afterload after ductal closure can cause LV failure and pulmonary HTN
- The differences in BP can cause a limb systolic BP discrepancy or the distal organ perfusion can be compromised.
Coarctation of the Aorta SURGICAL CORRECTION
Infants vs adults
Infants= Initially give prostaglandins to open/maintain ductal patency. Then surgical repair- extended end to end anastomosis
Adults- Same surgical repair, transcatheter, balloon angioplasty