DISORDERS OF THE CARDIOVASCULAR SYSTEM PART 2 (AB) Flashcards
What are the five basic questions to answer for congenital heart disease (CHD) diagnosis?
- Is it acyanotic or cyanotic? 2. Is the pulmonary blood flow (PBF) normal, increased, or decreased? 3. Does the malformation originate in the left or right side of the heart? 4. Which is the dominant ventricle? 5. Is pulmonary hypertension present (Eisenmenger Syndrome) or not?
What are the basic diagnostics to request for cyanotic congenital heart disease (CHD)?
Chest X-ray (CXR), ECG, 2D-Echocardiogram, Cardiac Catheterization.
Why is an AP view taken for CXR in infants and children under 2 years old?
Infants and young children cannot stand on their own, so an AP view is taken instead of a PA view.
What is the significance of PA vs. AP view in CXR?
PA view: The film is closer to the chest, and the X-ray beam is from the back, making the heart size radiographically accurate. AP view: The heart appears enlarged due to its distance from the film.
What is the role of ECG in congenital heart disease (CHD) diagnosis?
ECG helps determine heart sidedness, chamber enlargement (RV or LV), and signs of atrial enlargement.
What is the definitive diagnostic tool for cyanotic CHD?
2D-Echocardiogram.
When is cardiac catheterization used in CHD diagnosis?
When ECG or 2D-Echo cannot fully determine anatomy, or in complex CHD cases where pulmonary artery location or pulmonary hypertension needs further assessment.
What is the hyperoxia test used for?
To differentiate between cardiac and pulmonary causes of cyanosis.
What are the steps of the hyperoxia test?
- Patient breathes 100% oxygen for 10 minutes (via hood or ET tube). 2. Oxygen tension is measured in the right radial artery (ABG needed, not pulse oximeter).
What PaO2 values indicate a cardiac vs. pulmonary cause of cyanosis?
PaO2 > 150 mmHg = Pulmonary cause (e.g., pneumonia). PaO2 ≤ 150 mmHg = Cardiac cause or persistent pulmonary hypertension of the newborn (PPHN).
What PaO2 value is seen in truncus arteriosus or single ventricle with PDA?
50 – 150 mmHg.
What PaO2 value is seen in Tetralogy of Fallot, tricuspid atresia, or other CHD with decreased PBF?
<50 mmHg.
What is the purpose of complex congenital heart disease (CCHD) screening?
To detect duct-dependent lesions and other complex congenital heart defects in newborns using pulse oximetry.
When is CCHD screening performed?
At or beyond 24 hours of life, or shortly before discharge.
What are the criteria for failing a CCHD screen?
Oxygen saturation <90% in right hand or foot = immediate referral. 90-95% or >3% difference = repeat test; if still abnormal, refer.
What are the four main components of Tetralogy of Fallot (TOF)?
- Pulmonary stenosis 2. Ventricular septal defect (VSD) 3. Overriding aorta 4. Right ventricular hypertrophy (RVH).
What determines the severity of TOF symptoms?
The degree of right ventricular outflow tract obstruction (RVOTO).
How does TOF typically present in infancy?
Cyanosis may not be apparent at birth but can develop around 6 months with increased activity.
What are the common triggers for hypercyanotic (Tet) spells in TOF?
Crying, feeding, defecating, or stressful procedures like IV insertion.
What is the first-line management for a Tet spell?
Place the child in a knee-chest position to increase systemic vascular resistance (SVR) and reduce right-to-left shunting.
What medications can be used to treat a Tet spell?
Phenylephrine (to increase SVR), propranolol (to reduce RVOTO spasm), and morphine (for hyperpnea and irritability).
What are the classic CXR findings in TOF?
Boot-shaped heart, concave main pulmonary artery segment, right-sided aortic arch, and decreased pulmonary vascularity.
What are the characteristic ECG findings in TOF?
Right axis deviation (RAD) >105° and right ventricular hypertrophy (RVH) with tall R waves in V1/V2 and deep S waves in V5/V6.
What is the definitive treatment for TOF?
Corrective open-heart surgery, ideally between 4-6 months of age.
What palliative procedure is used for severe TOF cases?
Blalock-Taussig shunt (BTS) to increase pulmonary blood flow before corrective surgery.
What are common complications of untreated TOF?
Cerebral thrombosis, brain abscess, bacterial endocarditis.
What congenital heart defects present with increased pulmonary blood flow (PBF)?
Atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), complete atrioventricular septal defect (CAVSD), transposition of the great arteries (TGA), truncus arteriosus, total anomalous pulmonary venous return (TAPVR).
What congenital heart defects present with decreased pulmonary blood flow (PBF)?
Tetralogy of Fallot (TOF), tricuspid atresia, pulmonary atresia, hypoplastic right heart syndrome.
What congenital heart defects present with normal pulmonary blood flow (PBF)?
Aortic stenosis, coarctation of the aorta, hypoplastic left heart syndrome.
What is Eisenmenger Syndrome?
A long-standing left-to-right shunt (e.g., VSD, ASD, PDA) that causes pulmonary hypertension, eventually leading to shunt reversal (right-to-left) and cyanosis.
What are the clinical features of Eisenmenger Syndrome?
Cyanosis, digital clubbing, polycythemia, dyspnea, and paradoxical embolism.
What is the definitive treatment for Eisenmenger Syndrome?
Heart-lung transplantation or lung transplantation with cardiac repair.
What congenital heart defect is associated with Down syndrome?
Atrioventricular septal defect (AVSD).
What congenital heart defect is associated with Turner syndrome?
Coarctation of the aorta, bicuspid aortic valve.
What congenital heart defect is associated with DiGeorge syndrome?
Tetralogy of Fallot (TOF), truncus arteriosus.
What congenital heart defect is associated with maternal diabetes?
Transposition of the great arteries (TGA).
What congenital heart defect is associated with congenital rubella?
Patent ductus arteriosus (PDA).
What is the primary defect in Ebstein anomaly?
Downward displacement of an abnormal tricuspid valve (TV) into the right ventricle (RV), leading to an arterialized RV.
What is the consequence of tricuspid valve displacement in Ebstein anomaly?
The RV becomes smaller functionally, but appears large on X-ray.
What are the pulmonary complications of Ebstein anomaly?
Functional or anatomic pulmonary atresia, leading to decreased pulmonary blood flow.
What determines the severity of symptoms in Ebstein anomaly?
Extent of TV displacement and severity of right ventricular outflow tract obstruction (RVOTO), similar to Tetralogy of Fallot (TOF).
What are the classic imaging findings in Ebstein anomaly?
Chest X-ray: Massive box-shaped cardiomegaly. ECG: May show Wolff-Parkinson-White (WPW) syndrome or supraventricular tachycardia (SVT).
What is the significance of SVT in a patient with suspected Ebstein anomaly?
Any patient presenting with SVT should undergo an echocardiogram to check for congenital heart disease, including Ebstein anomaly.
What are the surgical stages for Ebstein anomaly treatment?
1st stage: Tricuspid valve repair, atrial septectomy, and aortopulmonary shunt placement. 2nd stage: Glenn shunt (SVC to pulmonary artery). 3rd stage: Fontan procedure (IVC baffled to pulmonary artery).
What is the goal of the single ventricle repair pathway in Ebstein anomaly?
To complete the Fontan procedure, which allows systemic venous return to flow directly into the pulmonary circulation.
What congenital heart defect presents similarly to Ebstein anomaly in terms of staged repair?
Tetralogy of Fallot (TOF), as both may require an initial aortopulmonary shunt followed by staged correction.
What is the incidence of Transposition of the Great Arteries (TGA)?
5% of all congenital heart defects (CHD), more common in infants of diabetic mothers, and more frequent in males (Male:Female = 3:1).
What is the normal blood flow in the heart?
Deoxygenated blood enters the RA → RV → pulmonary artery → lungs for oxygenation → LA → LV → aorta → systemic circulation.
What is the main defect in TGA?
The pulmonary artery arises from the LV, and the aorta arises from the RV, creating a parallel circulation with no oxygenated blood reaching the systemic circulation.
What happens to systemic blood flow in TGA?
Deoxygenated blood recirculates through the systemic circulation without reaching the lungs, leading to profound cyanosis.
What happens to pulmonary blood flow in TGA?
Oxygenated blood recirculates between the lungs and left heart without reaching the systemic circulation.
Why is mixing of oxygenated and deoxygenated blood important in TGA?
Without adequate mixing, the baby cannot survive. Mixing can occur at the interatrial, interventricular, or great artery level.
What structures allow mixing in TGA?
Patent ductus arteriosus (PDA), patent foramen ovale (PFO), and ventricular septal defect (VSD).
What happens if no mixing occurs in TGA?
Severe cyanosis and hypoxia, requiring immediate intervention with prostaglandins to keep the ductus open.
What is the characteristic ECG finding in TGA?
Right ventricular hypertrophy (RVH) with a right-sided dominant pattern.
What is the characteristic CXR finding in TGA?
Egg-on-a-side appearance with a narrow pedicle and increased pulmonary blood flow.
What is the initial medical treatment for TGA?
Prostaglandin E1 (PGE1) infusion to keep the ductus arteriosus open and allow some oxygenated blood to reach systemic circulation.
What is the emergency procedure for restrictive PFO in TGA?
Balloon atrial septostomy (Rashkind procedure) to increase interatrial mixing of oxygenated and deoxygenated blood.
Why is balloon atrial septostomy not a corrective procedure?
It only provides temporary relief by improving oxygenation while awaiting definitive surgical correction.
What is the definitive surgical treatment for TGA?
Arterial switch procedure (Jatene operation), which restores normal circulation by switching the great arteries.
What are the key steps in the arterial switch procedure?
The aorta and pulmonary artery are detached and switched, with coronary artery reimplantation onto the neoaorta.
What is the survival rate after an arterial switch procedure?
> 95% in uncomplicated TGA cases.
What was the previous surgical treatment for TGA before the arterial switch?
Atrial switch procedure (Mustard or Senning procedure), which rerouted blood flow but did not correct the anatomical defect.
Why is the atrial switch procedure no longer preferred?
It results in long-term complications such as right ventricular failure, arrhythmias, and pulmonary hypertension.
What are the major long-term complications of the atrial switch procedure?
Sick sinus syndrome, atrial flutter, sudden death, SVC/IVC syndrome, protein-losing enteropathy, and pulmonary hypertension.
Why does right ventricular failure occur in the atrial switch procedure?
The RV, which is not designed for systemic pressure, must pump against high resistance, leading to progressive failure.
What is the incidence of Total Anomalous Pulmonary Venous Return (TAPVR)?
1% to 2% of congenital heart diseases (CHD).
What is the defining feature of TAPVR?
The heart has no direct pulmonary venous connection into the left atrium.
What are the three main locations of pulmonary venous drainage in TAPVR?
Supracardiac, Infracardiac, and Intracardiac.
Where do the pulmonary veins commonly drain in TAPVR?
Commonly into the coronary sinus.
What is the hallmark chest X-ray finding in supracardiac TAPVR?
Snowman appearance or Figure of 8.
What is the hallmark chest X-ray finding in infracardiac TAPVR?
Ground glass appearance due to pulmonary edema and small heart size.
What is the key to differentiating TAPVR locations?
The appearance of chest X-ray results and patient presentations.
What is the main pathophysiologic consequence of TAPVR?
Total mixing of systemic venous and pulmonary venous blood within the heart, producing cyanosis.
Which TAPVR location is most commonly associated with obstruction?
Infracardiac TAPVR (95-100% obstruction rate).
What is the treatment for TAPVR?
Surgical correction during infancy.
What is ECMO used for in TAPVR?
For severely ill newborns when immediate surgery cannot be performed.
What is Truncus Arteriosus?
A congenital defect where a single arterial trunk arises from the heart, supplying systemic, pulmonary, and coronary circulation.
What is usually associated with Truncus Arteriosus?
Ventricular septal defect (VSD).
What is the consequence of no pulmonary stenosis in Truncus Arteriosus?
Increased pulmonary blood flow leading to pulmonary hypertension.
What are the surgical treatments for Truncus Arteriosus?
VSD closure and separation of pulmonary artery from truncus with RV-to-PA homograft conduit.
What is Hypoplastic Left Heart Syndrome (HLHS)?
Underdevelopment of the left side of the heart, including the left ventricle, mitral valve, aorta, and aortic valve.
What is the pathophysiology of HLHS?
Aortic valve (AOV) and mitral valve (MV) atresia or stenosis, with hypoplasia of the left ventricle and ascending aorta.
What is the fatal outcome of untreated HLHS?
The left ventricle cannot pump enough blood to the body, leading to fatality.
What are the three surgical stages for HLHS treatment?
Norwood procedure (newborn), Glenn shunt (2-6 months), and Fontan procedure (2-3 years old).
What is the goal of the Norwood procedure?
To construct a reliable source of systemic circulation from the single right ventricle.
What does the Glenn shunt do?
Connects the superior vena cava (SVC) to the pulmonary artery to bypass the heart.
What is the general principle for mild congenital heart diseases (CHD)?
No activity restrictions; children can live a normal life.
What are the activity recommendations for moderate to severe CHD?
Modify physical activity and restrict competitive sports.
What is the immunization guideline for CHD patients?
Routine immunization should be given to all CHD patients.
What should be assessed preoperatively and postoperatively in CHD patients?
All organ functions should be evaluated.
What should be included in counseling for CHD patients and their families?
Parents and adolescents should receive counseling about the condition and treatment.
