11- Cardiac Defects Flashcards
Acyanotic heart defects
-Any structural abnormality that does not cause right-tot-left intra-cardiac shunting
-Pt should have normal O2 sats
Types of Acyanotic heart defects
-Septal wall defects (2) (holes in septum of hear that vary in location)
-Aortic stenosis
-Pulmonic stenosis
-Coarctation of the aorta
-Double aortic arch
Septal wall defects
-Atrial septal defects (ASD)
-Ventricular septal defects (VSD)
-Represent the 2 most common types of (CHD)
Atrial septal defects (ASD)
-Opening in the intra-atrial septum- This creates an anatomical connection between 2 uppermost chambers of the heart
-Rarely cause symptoms in infancy- undiagnosed
-Forms when the fusion of septum primum and septum secundum occurs.
Clinical manifestations of ASD
-Increased workload on the right ventricle
-Increased blood flow to the lungs
-These are secondary to a large defect >6mm in diameter and only if symptoms are present
Symptoms of ASD
-Fatigue
-Exercise intolerance
-Failure to thrive- not growing
-Poor weight gain
-Tachypnea
How to diagnose ASD?
Echocardiogram
Management and treatment of ASD
-No symptoms: Managed by a cardiology clinic for years
-Small ASD <6mm in diameter: Usually spontaneously close by the age of 2
-ASD>6mm: Usually require closure prior to the child starting school
Indication for closure includes….
-Symptoms of heart failure
-Pulmonary hypertension
-Risk or history of paradoxical embolus
-History of arrhythmia
Ventricular Septal Defects (VSD)
-Most common congenital heart lesion
-Causes a connection btw right and left ventricle
-Can occur as a single lesion or with other heart defects
Other defects VSD can occur with
-Tetralogy of Fallot (TET)
-Pulmonary atresia
-Complete atrioventricular canal
-Transposition of the great arteries (TGA)
-Patent ductus arteriosus (PDA)
Clinical Manifestations of VSD
-Small defect with little intra-cardiac shunting will usually remain asymptomatic
-With larger defects:
—Increased pulmonary blood flow
—Increased pulmonary venous return to the left side of the heart
—Subsequent left ventricular volume overload.
Symptoms of VSD
-Tachypnea
-Poor feeding
-Failure to thrive
-Sweating
-Irritability
-Auscultation of the lungs may reveal rales secondary to pulmonary edema.
How do you diagnose VSD?
-Echocardiogram
Management and treatment of VSD
-Asymptomatic requires none
-With symptoms: Diuretics, Systemic afterload reduction (ACE inhibitors and Inotrops)
-Pts with failure to thrive may need a higher calorie formula to accommodate for increased caloric need
Surgical indications for VSD
-Heart failure despite medical management
-PPHN- persistent pulmonary hypertension
-Subpulmonic or membranous VSD with aortic valve regurgitation
Atrioventricular septal defects
-Spectrum of abnormalities that involve defects in the portion of the atrial and/or ventricular septum directly adjacent to the atrioventricular valves (tricuspid and mitral).
-Common in children with Trisomy 21 (Down syndrome).
3 types of atrioventricular septal defects
-Partial
-Transitional
-Complete
Treatment of atrioventricular septal defects
-Asymptomatic: Treated similarly as those with VSD
-Definitive therapy involves surgical repair
Aortic stenosis
-Any discrete narrowing that occurs btw the left ventricle and the aorta
-Most common cause: Bicuspid aortic valve (Aortic valve consists of 2 functional leaflets instead of 3)
Severity of aortic stenosis depends on
-The degree of obstruction, which is a calculated measurements from an ECHOCARDIOGRAM
Aortic stenosis severity
-Mild: <25 mmHg gradient
-Moderate: 25-50 mmHg gradient
-Severe: 50mmHg gradient. CO is usually maintained. There is an increase workload on the left ventricle and myocardial ischemia can develop
Symptoms of aortic stenosis
Infants: Tachypnea, poor feeding, growth failure
Children: Syncope, progressive exercise intolerance, fatigue, and chest pain
How can you diagnose aortic stenosis?
Echocardiogram
Management and treatment of aortic stenosis
-Therapy depends on severity
-Neonates with shock: Placed on PGEI to help ductus open to improve circulation
-Mild to moderate: Outpatient cardiology with serial echocardiograms
-Sever: Reduce obstruction and create an exit of blood across the left ventricular outflow tract
Surgeries for aortic stenosis
-Valvuloplasty: A balloon tip is passed into the valve orifice and inflated to enlarge the opening
-Valvotomy: Division of the valve leaflets of valve replacement
What happens when aortic stenosis is left untreated?
-Risk of sudden cardiac death
-Infective endocarditis
-Inflammation of heart valves
Pulmonic stenosis
-A narrowing in the right ventricular outflow tract between the right ventricle and the main pulmonary artery.
-It results from abnormally formed valve leaflets that may be dysplastic or form an abnormal dome shape.
-Can result form obstruction in the R ventricular outflow tract: increases the workload on R ventricle, which can cause right ventricular hypertrophy
Classifications of Pulmonic stenosis
-Mild: no symptoms
-Moderate to sever: Increase R ventricular afterload.
——Dyspnea on exertion
——Fatigue
——Cyanosis
How to diagnose pulmonic stenosis?
Echocardiogram- Look at anatomy, size and degree of obstruction
Treatment for pulmonary stenosis
-Mild: no therapy
-Moderate: Transcatheter ballon valvuloplasty, surgical valvotomy, or valve replacement
Coarctation of the aorta
-A discrete narrowing of the descending thoracic aorta, usually distal to the takeoff of the left subclavian artery.
-Involves the extension of a shelf-like structure into the lumen of the aorta.
-The “shelf” represents thickening of the first two layers of the aortic vessel. (Intima and Media)
Clinical manifestation of coarctation of aorta
-Obstruction to blood in descending aorta. Blood is diverted to brachiocephalic, left carotid, and left subclavian artery (Results in difference in BP btw upper and lower extremities)
-Upper extremity systolic blood pressure is at least 10 mm Hg higher than lower extremities.
Symptoms of coarctation of aorta
-Older patients may be asymptomatic.
-Diminished or absent femoral pulses
-Brachio-femoral delay
-Continuous flow murmur
Diagnosis of coarctation of aorta
-Echocardiogram
-MRI
Treatment of coarctation of aorta
-Surgical repair: Coarctation segment is removed by the surgeon, and the aorta is reconnected in an end-to-end fashion.
-Alternative: Dilation and widening of the narrowed blood vessel
Patients with coarctation of aorta are susceptible to…
-Persistent hypertension
-Vocal cord paresis or paralysis
-Chylothorax- digestive system lymph accumulates in chest cavity
-Lower extremity paralysis
-Post-coarctectomy syndrome- GI stuff
Double aortic arch
-During the development of the fetus, six symmetrical arches undergo remodeling to form the aortic arch and its major branches. (innomiate artery, left common carotid artery, left subclavian artery)
-Occurs when one of the arches fails to remodel correctly and is included in the class of anomalies.
Double aortic arch is also known as…
-Complete vascular ring
——Encircles and causes compression of both the esophagus and trachea.
——Instead of a single left-sided arch, patients have an arch that bifurcates into a right and left aortic arch.
Clinical manifestations of double aortic arch
-Adjacent to esophagus: Feeding difficulty, Gastroesophageal reflux (GERD), Failure to thrive, and Dysphagia.
-Adjacent to trachea: Intrathoracic upper airway obstruction
Signs and symptoms of double aortic arch
-Cough
-Wheezing
-Stridor
-Persistent infections
-Critical airway obstruction
Diagnosis of double aortic arch
-Barium swallow
-CT angiography
-MRI
Management and treatment of double aortic arch
-Management depends on symptoms
-Severe dysphasia: nasogastric tube feeds
-Sever upper airway obstruction: intubation and MV (PEEP helps stent open airway structures being compressed by anterior aortic arch)
-Child is diagnosed: Should be immediately referred for surgical repair
Surgical interventions for double aortic arch
-The nondominant left aortic arch division and ligation, which leaves the dominant right aortic arch intact. This relieves airway obstruction, however, mild airway symptoms can still be present.
Cyanotic heart defects
Result from structural abnormalities that lead to significant mixing of oxygenated and deoxygenated blood and cause oxygen saturations less that 85%.
Types of cyanotic heart defects
-Tetralogy of Fallot
-Total anomalous pulmonary venous return
-Transposition of the great arteries
-Hypoplastic left heart syndrome
-Truncus arteriosus
Any neonate presenting with O2 sats of 85% to 90% should be assessed for what?
To determine whether the cause of hypoxemia is lung disease or CHD
Measures to determine cardiac defects in neonates
-Chest radiograph
-Electrocardiograph
-Hyperoxia test
-Echocardiogram
-Auscultation (may reveal abnormal heart sounds)
Hyperoxia test
-ABG are obtained on room air and FiO2 100% and compared to assess the pt’s ability to oxygenate.
-Baseline: R radial ABG will give accurate PaO2, directly from the aorta, prior to PDA
-100% FiO2 15 minutes later: PaO2 is assessed
Hyperoxia test PaO2 results from 100% FiO2
-PaO2 >150mmHg: hypoxemia is related to lung disease
-PaO2 <150mmHg: Cyanotic heart defect should be suspected. Low PaO2 is due to shunting and mixing of oxygenated and deoxygenated blood.
Prostaglandin Infusion
Prostaglandin E is given to help with cyanosis.
-Prostaglandin E are hormone-like substances that maintain patency of the PDA.
-May be discontinued after the specific cardiac lesion has been identified
Tetralogy of Fallot
-A combination of four conditions
—-VSD
—-An aorta that overrides the VSD
—-Obstruction of the right ventricular outflow tract (RVOTO)
—-Right ventricular hypertrophy
-The most common form of cyanotic CHD
Tet spell
A sudden increase in RVOTO can cause a period of hypercyanosis.
Treatment for a tet spell
-O2
-Knee to chest manuevers
-Medications ton increase SVR (Phenylephrine)
-Volume administration (increase flow into pulmonary vasculature)
-Sedatives (Morphine, Decrease catecholamines, Decrease spasm at the opening of the pulmonary valve).
Symptoms of tet spells
Mild obstruction: May have no symptoms
Severe RVOTO: Severe pulmonary stenosis or pulmonary atresia
Treatment of tet spell
Severe symptoms: Early treatment to provide pulmonary blood flow: PGE1 infusion, Early surgical palliation, and Repair
Total anomalous pulmonary venous return (TAPVR)
Results when there is no connection between the pulmonary vein confluence (the location where the pulmonary veins come together) and the left atrium.
TAPVR is life-threatening because
-No blood delivery into the left side of the heart
-Impossible for circulation of oxygenated blood to the body without communication between the right and left sides of the heart (Septal defect)
There are 4 types of TAPVR
-Supracardiac TAPVR
-TAPVR to the coronary sinuses
-Infracardiac TAPVR
-Mixed-type TAPVR
-The only difference between these types is the location of the TAPVR
Symptoms of TAPVR
-Asymptomatic at birth
-Cyanosis is often not apparent
-Tachypnea and Feeding difficulties (Develop over the first few weeks of life)
-Failure to thrive.
Transposition of the great arteries (TGA)
Two main arteries leaving the heart have changed places, so that the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle.
Common with TGA
-VSD
-Left ventricular outflow tract obstruction
-Aortic abnormalities (rare)
Symptoms of TGA
If there is inadequate mixing across an associated intracardiac or extracardiac shunt, a neonate with TGA will present with rapidly progressive cyanosis within the first few hours of life.
Diagnosis of TGA
-Rapid diagnosis and emergent intervention are required for survival
-ECHOCARDIOGRAM
-Physical exam is non specific (No cardiac murmur. Unless there is no VSG present; Electrocardiogram is normal; Chest radiograph is often unremarkable.)
Treatment of PGA
-Intracardiac shunt needs to be created immediately in order for the neonate to survive.
-Atrial septostomy- creates a hole in the atrial wall (wide-open-atrial-level shunt allows mixing to occur and sats to stabilize)
-Atrial switch- surgical repair for TGA
Hypoplastic left heart syndrome (HLHS)
-Cyanotic heart disease in which parts of the left side of the heart do not fully develop.
-Left ventricle: small and unable to sustain systemic circulation, small and non-apex forming.
-Left atrium: small in since d/t lack of flow
-Aorta: small until PDA, where flow from the PDA supplies the normal-size descending aorta
-Includes an atrial septal defect, which supplies oxygenated blood flow to the right heart.
Staged repair for HLHS
-Norwood: Combine aorta and pulmonary artery using a shunt
-Bidirectional Glen: Connection of superior vena cava to pulmonary artery, and removal of pulmonary artery shunt.
-Fontan: Connection of inferior vena cava to pulmonary artery
Hypoxic gas delivery
Used for pts who consistently saturate>85% to increase PVR to maintain appropriate systemic blood flow prior to stage 1 repair
-Nitrogen is mixed with room air to achieve an FIO2 of 0.15 to 0.20.
-FIO2 < 0.15 can put patients at risk for tissue hypoxia.
-Delivery devices include: nasal cannula, oxyhood, or ventilator.
-An external oxygen analyzer should be used to ensure the appropriate FIO2 is delivered.
Truncus Arteriosus
-Condition in which a single great vessel leaves the heart and supplies the systemic and pulmonary circulation.
-Usually diagnosed prenatally via ultrasound.
-Neonates without prenatal diagnosis may present with aysmptomatic cyanosis, meaning they may be blue with saturations in the 75% to 85% range without respiratory distress
Truncus Arteriosus
-Murmur may or may not be present depending on the origins and caliber of pulmonary arteries.
-Ausculation: first heart sound is normal and second is loud and single.
-Ausculation of lung fields may demonstrate rales.
Goals of surgical interventions for truncus arteriosus
