Cardiology - CHD Flashcards
Signs of CHD
- Cardiogenic shock (low CO)
- HF (tachypnoea, tachycardia, failure to thrive, reduced feeding, pulmonary oedema)
- Cyanosis (severe obstruction or mixing of blood)
Congenital Heart Conditions
- Hypoplastic Left Heart Syndrome (HLHS)
- Transposition of the Great Arteries
- Coarctation of the Aorta (CoA)
- Tetralogy of Fallot
- Anomalous Pulmonary Venous Drainage
- Truncus Arteriosus
- Tricuspid Atresia
- ASD
- VSD
- PDA
- Pulmonary & Aortic Stenosis
Hypoplastic Left Heart Syndrome (HLHS)
Left side of the heart (LV, MV, AV, ascending aorta) is underdeveloped.
- LV cannot pump effectively
- Systemic circulation is then dependent on a PDA, when it closes → shock, cyanosis, tachypnoea, death
- Hypoplastic LV (tiny or absent)
- Mitral atresia or severe stenosis
- Aortic atresia or severe stenosis
- Hypoplastic ascending aorta
- Keep PDA open, create new systemic outflow and connect SVC to pulmonary arteries, or heart transplant
Transposition of the Great Arteries
Aorta and pulmonary artery have the opposite origin sites:
- Aorta arises from the RV and PA arises from the LV
- Systemic blood runs in a loop w/o becoming oxygenated
- Pulmonary blood runs in a loop w/o reaching the body
- Severe cyanosis but no respiratory distress (lungs are oxygenated, it’s the body that isn’t), external O2 supply will not work
- PDA/ASD/VSD critical to mix blood
- Arterial switch operation to swap to correct ventricles
Coarctation of the Aorta (CoA)
Narrowing/constriction of a segment of the aorta, usually at the isthmus near the ductus arteriosus.
- Higher pressure at proximal end (upper extremity HTN)
- Lower pressure at distal end (lower extremity hypotension)
- LVH as the heart works harder to overcome constriction
- Weak femoral pulse and cold lower limbs
- Angioplasty w/ or w/o stent, or resection and anastomosis
Tetralogy of Fallot
A combination of 4 heart defects that cause cyanotic heart disease:
1. VSD
2. Pulmonary stenosis
3. Overriding aorta (sits over VSD, gets blood from both ventricles)
4. RVH
- VSD + pulmonary stenosis (tight PV) leads to deoxygenated blood entering the aorta causing cyanosis
- RVH from pumping against obstruction
Anomalous Pulmonary Venous Drainage/Return (APVD/APVR)
Instead of the pulmonary veins draining into the LA as normal, they drain somewhere else. Can be total (all pulmonary veins drain incorrectly) or partial (only some).
- Oxygenated blood gets mixed back into deoxygenated blood
- Less O2 delivered to the body leading to cyanosis/HF
- Can be drained into the SVC (supracardiac type)
Can be drained into the RA and coronary sinus (cardiac type)
- Can be drained into the hepatic/portal veins (infracardiac type)
- Requires surgery to reconnect the pulmonary veins to the LA
Truncus Arteriosus
Instead of a separate aorta and pulmonary artery there is one single large arterial trunk supplying blood to both systemic and pulmonary circuits all at once.
- Mixed blood leading to cyanosis
- Always has a VSD present
- Pulmonary over-circulation leading to HF
- Patch VSD & create new connection b/w RV + pulmonary arteries
Tricuspid Atresia
Complete absence of the tricuspid valve so blood cannot flow from the RA → RV.
- Small RV (hypoplastic)
- Blood needs to find a way through to the left side, usually through an ASD or PFO
- Often has a VSD present too
- Blood mixes in the LA or LV
- Shunt placement for blood to pass from the veins into the pulmonary circulation bypassing the RV
Atrial Septal Defect (ASD)
A hole in the intra-atrial septum between RA & RV.
- Causes left-right shunting (from high pressure to low) causing pulmonary over-circulation & HTN
- Right-heart overload
- Can spontaneously close or will require closure device
Ventricular Septal Defect (VSD)
A hole in the intra-ventricular septum b/w RV & LV.
- Causes left-right shunting (from high pressure to low) causing pulmonary over-circulation & HTN
- Can lead to HF as the oxygenated blood that is shunted into the RV and returns to the lungs, must also loop back around to the LV again so the left heart is being overworked with the large volume it is continuously pumping
Atrioventricular Septal Defect (AVSD)
Both the atrial and ventricular septa do not form correctly, and the AV valves (mitral & tricuspid) do not form correctly.
- Valves may be malformed into one large AV valve or may be abnormal and leaky
- Mixing of blood, HF symptoms (pulmonary HTN)
- Associated with Down Syndrome
- Surgical repair
Patent Ductus Arteriosus (PDA)
The ductus arteriosus (foetal blood vessel connecting the pulmonary artery to the aorta causing blood to bypass the lungs - not needed in foetal development, receiving O2 etc from placenta) remains open after birth when it should normally close (within 24-72h).
- Leads to pulmonary over-circulation as blood passes from the aorta straight into the pulmonary artery
- The left heart is then overworked as it receives extra blood from the lungs and can lead to HF (similar to VSD)
- Surgical closure
Pulmonary Stenosis
Narrowing of the PV or the PA which obstructs and resists flow from the RV to the lungs for oxygenation.
- Causes RVH overtime - right heart must work harder to overcome obstruction
- Features a systolic murmur as a clinical indicator
- Mild cases can be asymptomatic and not require intervention.
- Mod-severe cases can lead to cyanosis, dyspnoea, exercise intolerance and require valvuloplasty or replacement
Aortic Stenosis
Narrowing of the AV which obstructs and resists flow from the LV to the aorta and systemic circulation for O2 delivery.
- Causes LVH and heart failure overtime - left heart must work harder to overcome obstruction
- Features a systolic murmur as a clinical indicator
- Mild cases can be asymptomatic and not require intervention
- Mod-severe cases can lead to angina, syncope, exercise intolerance and require valvuloplasty or replacement
Patent Foramen Ovale (PFO)
A hole between the RA and LA that allows blood to bypass the lungs in foetal development and fails to close after birth.
- Can be asymptomatic and remain open w/o issues.
- Can increase the risks of stroke, TIAs, emboli if clots flow from the RA to the LA, esp. w/ underlying DVT.
- Differs from ASD as it is a right-left shunt
Persistent Pulmonary HTN of the Newborn (PPHN)
Pulmonary circulation remains constricted after birth leading to high pulmonary pressure,
- Prevents normal blood flow to the lungs, affecting gas exchange leading to hypoxaemia (low O2 in blood)
- It’s a result of the pulmonary arteries remaining constricted, resulting in high pulmonary vascular resistance (PVR) and poor blood flow to the lungs, preventing adequate oxygenation.
- Respiratory distress, cyanosis, heart murmur, hypoxaemia, tachycardia
- Can be caused MAS, infections, hypoxia, etc.
- Treated with O2, inhaled NO, ECMO, ventilatory support
