Cardiology Flashcards
1
Q
What are most common causes of acyanotic congential heart disease?
A
- VSD
- ASD
- PDA
- Coarctation of the aorta
- Aortic valve stenosis
2
Q
What are most common causes of cyanotic congenital heart disease?
A
Tetralogy of Fallot
Transposition of the great arteries
Tricuspid atresia
3
Q
Why does fetal circulation have three shunts?
A
To bypass the lungs as they are not yet developed or functional
4
Q
Name the three fetal shunts in fetal circulation
A
Ductus venosus
Foramen ovale
Ductus arteriosus
5
Q
What is the function of fetal shunt: ductus venosus?
A
This shunt **connects the umbilical vein to the inferior vena cava **and allows blood to bypass the liver.
6
Q
What is the function of fetal shunt: foramen ovale?
A
This shunt connects the right atrium with the left atrium so bypass the RV and pulmonary circulation
7
Q
What is the function of fetal shunt: ductus arteriosus?
A
This shunt connects the pulmonary artery with the aorta and allows blood to bypass the pulmonary circulation
8
Q
Describe what happens to the foramen ovale at birth.
A
Foramen ovale:
* baby takes first breath = expands the alveeoli
* this decreases pulmonary vascular resistance
* this causes a fall in pressure in the right atrium
* at this point, L atrial pressure is higher than R atrial pressure
* so this squashes the atrial septum, causing functional closure of the formaen ovale.
* this becomes sealed. Now called fossa ovalis
9
Q
Describe what happens to the ductus arteriosus at birth.
A
Ductus arteriosus closure:
* prostaglandins are needed to keep DA open
* Increased oxygenation causes a drop in circulating prostaglandins
* This causes closure of the ductus arteriosus
* becomes ligamentum arteriosum
10
Q
Describe what happens to the ductus venosus at birth.
A
Ductus venosus closure:
* immediately after birth the DV stops functioing because the umbilical cord is clamped
* therefore there is no flow in the umbilical veins
* The DV structurally closes a few days later, becoming the ligamentum venosum
11
Q
What is the nitrogen washout test (aka hyperoxia test) in CHD?
from passmed on ‘cyanosis in the neonatal period’
A
This test is used to differentiate between cardiac and non-cardiac causes of cyanosis.
* infant is given 100% oxygen for 10mins
* after this, ABG is taken
* a pO2 of less than 15kPa = indicates cyanotic congenital heart disease
12
Q
What is the initial management of cyanotic congenital heart disease?
passmed
A
Supportive care
Prostaglandin E1 e.g alprostadil
* this is used to maintain a patent ductus arteriosus in ductal-dependent congenital heart defect
* this can act as a holding measure until a definite Dx is made and surgical correction is preformed
13
Q
- How many leaflets does normal aortic valve have?
- What is the role of the aortic valve?
- how does number of leaflets differ in a patient with aortic stenosis?
A
- Three leaflets
- Role: allow blood to flow from the LV into the aorta, but prevent blood from flowing back into the left ventricle.
- will have 1, 2, or 4 leaflets.
14
Q
What is the presentation of aortic stenosis?
A
- if mild - can be asymptomatic, discovered as incidental murmer during routine examination
- if significant - can present with fatigue, SOB, dizziness, fainting.
- Symptoms are worse on exertion
- if severe - will present with HF within months of birth
15
Q
Describe murmer heard in aortic stenosis?
A
Ejection systolic murmer
Heard loudest at the aortic area (2nd ICS, right sternal border)
Has crescendo-decrescendo character
Radiates to the carotids
16
Q
What signs may be present on examination of a patient with aortic stenosis?
A
- Ejection systolic murmer heard loudest on the aortic area (2nd ICS, right sternal border) which is crescendo-decrescendo and radiates to the carotids
- Ejection click just before the murmer
- Palpable thrill during systole
- Slow rising pulse and narrow pulse pressure
17
Q
What is gold standard investigation for diagnosing aortic stenosis?
A
Echocardiogram
18
Q
How is aortic stenosis managed?
A
- It is a progressive condition that worsens over time so needs regular follow ups with echos, ECGs and exercise testing to monitor progression
- If aortic stenosis is significant, may need to restrict physical activities
Options for treating stenosis:
* Percutaneous balloon aortic valvoplasty
* Surgical aortic valvotomy
* Valve replacement
19
Q
What are the complications of aortic stenosis?
A
- Left ventricular outflow tract obstruction
- Heart failure
- Ventricular arrhythmia
- Bacterial endocarditis
- Sudden death, often on exertion
20
Q
- How many leaflests does normal pulmonary valve have?
- What is role of pulmonary valve?
- Describe pathophysiology of pulmonary valave stenosis?
A
- three leaflets
- prevent blood from returning to the heart.
- leaflets develop abnormally so can become fused or thickened. this causes a narrow opening between the RV and pulmonary artery = congenital pulm valve stenosis
21
Q
What other conditions can pulonary stenosis be associated to?
A
Tetralogy of Fallot
William syndrome
Noonan syndrome
Congential rubella syndrome
22
Q
How can pulmonary stenosis present?
A
- usually asymptomatic
- found incidentally during routine baby checks
- if significant - fatigue on exertion, SOB, dizziness, fainting
23
Q
Describe the murmer heard in pumonary stenosis
A
Ejection systolic murmer heard loudest at the pulmonary area (2nd ICS, left sternal border)
24
Q
What signs could a patient who has pulmonary stenosis present with?
A
- Ejection systolic murder heard loudest in the pulmonary area (2nd ICS, left sternal border)
- Palpable thrill in the pulmonary area
- Right ventricular heave due to RV hypertrophy
- Raised JVP with giant a waves
25
What is gold standard investigation for diagnosing pulmonary stenosis?
Echocardiogram
26
How is pulmonary stenosis managed?
Mild pulmonary stenosis:
* no intervention
* followed up with cardiologist - "watch and wait" approach
Symptomatic / significant stenosis:
* balloon valvuloplasty via a venous catheter = main treatment choice.
* if this is contraindicated / fails = open heart surgery
27
Describe balloon valvuloplasty via a venous catheter to a patient with pulmonary stenosis
Catheter is inserted under xray guidance into the femoral vein.
Goes through the IVC and right side of the heart to the pulmonary valve
Once here, dialte the valve by inflating the balloon.
28
What is an atrial septal defect?
a defect = a hole in the septum between the two atria
29
Describe the pathophysiology of atrial septal defects
(i.e.how does it happen?)
* during development, the left and right atria are connected.
* normally in the 4th week of gestation, the atrial septum is formed from two spearate endocardial cushions.
* these two walls grow downwards from the top of the heart and fuse with the endocardial cushion in the middle of the heart. This separates the atria.
* defects in these two walls = atrial septal defect.
30
How does an atrial septal defect affect blood flow in the heart?
* ASD leads to a shunt, where blood moves between both atria.
* pressure in the left atrium is higher than pressure in the right atrium - so blood moves from LA --> RA.
* So... blood continues to flow to the pulmonary vessels and the lungs to get oxygenated = pt is acyanotic.
* Increased flow to the right side causes the right side to become overloaded = right heart strain.
* R sided overload = R heart failure and pulmonary hypertension.
31
Initially, what is ASD:
* is it acyanotic?
or
* cyanotic?
Why?
Acyanotic
* blood moves from the L to R as LA pressure is higher than RA pressure.
* So blood still flows to the pulmonary vessels and lungs to get oxygenated and the patient does **not** become cyanotic.
32
What syndrome can ASD lead to?
Eisenmenger syndrome
33
How can ASD lead to Eisenmenger syndrome?
* R heart is becoming overloaded as blood is moving through the ASD via a L --> R shunt.
* This can lead to R sided overload and pulmonary hypertension.
* Pulmonary hypertension causes pulmonary pressure to become GREATER than systemic pressure.
* This reverses the L--> R shunt, so becomes a R --> L shunt across the ASD
* because of this blood bypasses the lungs and pt becomes cyanotic
= Eisenmenger syndrome
34
What are the types of atrial septal defects?
Ostium secondum
Patent foramen ovale
Ostium primum
(Also in TMP = sinus venosus defect and coronary sinus defect but these aren't mentioned by Dr Tom)
35
# Atrial septal defects
What is ostium secondum?
Where the septum secondum fails to fully close, leaving a hole in the wall.
36
# Atrial septal defects
What is ostium primum?
Septum primum fails to close fully, leaving a hole in the wall.
Usually leads to AV valve defects - so can be called a AV septal defect
37
Why might ostium secundum ASD occur?
| there are two reasons!
1. Incomplete occlusion of ostium secundum by septum secundum
2. too much reabsorption of septum primum from the atrium roof.
38
What are RF for ASDs?
Fhx of children with ASD
Autosomal dominance inheritance
Maternal smoking in 1st trimester
Maternal DM
Maternal rubella
Maternal drug use and alcohol use
39
What are complications of atrial septal defects?
Stroke
Atrial fibrillation or atrial flutter
Pulmonary hypertension and R sided HF
Eisenmenger syndrome
40
How do atrial septal defects present?
Asymptomatic
Diagnosed following HF, stroke or TIA in adulthood
Symptoms in childhood:
* poor weight gain
* difficulty feeding
* recurrent chest infections / LRTIs
* tachypnoea
* SOB
41
What type of murmer is caused by an atrial septal defect?
Mid-systolic crescendo-decrescendo murmer
Loudest at the upper left sternal borner (2nd ICS), heard over pulmonary valve region.
Fixed split second heart sound (so can hear closure of aortic valve and pulmonary valve at different times)
42
Why do you get a fixed split second heart sound in ASD?
Blood is flowing from the LA to the RA via the L-->R shunt (the ASD)
This increases volume of blood that the RV has to empty before the pulmonary valve can close.
So it closes later than the aortic valve = fixed split second heart sound.
43
What would be ddx for ASD?
Atrioventricular septal defect
VSD
Innocent murmer
Pulmonary stenosis murmer - more turbulent
44
Explain how ASD can cause stroke in patients with a DVT
| From a Tom Tip on Z2F
Normally - DVT can become an embolus - so travel to the R side of the heart --> lungs --> becomes a pulmonary embolus
In pt with an ASD - remember you have a hole between the atria.
So, clot can travel from RA to the LA across the ASD. It can then travel to the LV --> into the aorta --> brain = cause a large stroke.
Therefore pts with ASD may be asymptomatic their whole life then present later on w/ a stroke.
45
What is goldstandard investigation in suspected ASD?
Transthoracic echocardiogram
* can get info on size of ASD
* understand direction of blood flow through defect
* can approximate pulmonary artery pressure
46
How are ASDs managed?
* If < 5mm = should close spontaneously in 12m
* In adults who have no signs of R HF and small defect = monitor every 2-3yrs with echo
* Anticoagulants - aspirin, warfarin, DOACs to reduce risk of clots and stroke in adults
* Definitive management = surgical closure if larger than 1cm, using transvenous catheter closure (via femoral vein)
47
What is a ventricular septal defect?
* Congenital hole in the septum between two ventricles
* most common cause of CongHD
48
What chromosomal conditions are ventricular septal defects commonly associated with?
* Down's syndrome
* Edward's syndrome
* Patau syndrome
* cri-du-chat syndrome
* Turner's syndrome
49
What are the causes of ventricular septal defects?
* chromosomal disorders - down's, edward's, patau's, turner's
* congenita infections
* aquired causes - post MI
50
1. Does a ventricular septal defect lead to a cyanotic presentation or an acyanotic presentation?
2. why?
1. acyanotic.
2. there is increased pressure in the left ventricule, so blood will flow from left to right through the VSD. Blood is still flowing around the lungs - i.e blood is properly oxygenated - before entering systemic circulation so has an acyanotic presentation.
51
How can VSD lead to a right sided HF?
* The VSD causes a L-->R sided shunt
* more blood than usual is pooling into the RV so the right side becomes overloaded.
* This leads to R sided HF and increased flow into the pulmonary vessels.
52
A VSD can lead to right sided HF due to a L-->R shunt.
How does this cause pulmonary hypertension?
* L-->R shunt leads to R sided overload, R HF and increased flow to the pulmonary vessels.
* extra blood flowing through the RV increases the pressure in the pulmonary vessels over time
* this leads to pulmonary hypertension.
53
In VSD, you can get pulmonary hypertension as a consequence. How does this lead to a cyanotic presentation and Eisenmenger syndrome?
*Recap: *
* in a VSD, have a L-->R shunt due to increased pressure in the R ventricle.
* Increased flow into the R side of the heart leads to R sided overload, R sided HF and you get increased flow of blood into the pulmonary vessels
* increased flow into pulmonary vessels over time causes increased pressure in these vessels = pulmonary hypertension
*Answer to the question:*
* Pulmonary hypertension means that over time the pressure in the right side of the heart can become GREATER than the left side of the heard.
* This causes a shift in the current L-->R shunt, so blood now flows through the hole from R-->L
* Because of this, blood does not pass through the lungs.
* Patient becomes cyanotic as blood flowing round is deoxygenated = Eisenmenger syndrome
54
What are RF for VSDs?
Maternal DM
Maternal rubella infection
Fetal alcohol syndrome
Uncontrolled maternal phenylketonuria during pregnancy
FHx of VSD
Chromosomal disorder
55
What is the presentation of a patient with a VSD?
| Hx and Ex findings. (Murmer description is another card)
* Asymptomatic
* Murmer picked up on antenatal 20 week scan
* failure to thrive
* features of HF - hepatomegaly, tachypnoea, tachycardia, pallor
* SOB/ dyspnoea
* Poor feeding
56
Describe the murmer heard in a VSD
* **Pan systolic murmer** - so starts at S1 and extends all the way to S2.
* Pan systolic murmer is louder in smaller defects, and quieter in larger defects!
* heard more prominently at the **left lower sternal border**, in **3rd and 4th ICS**.
* Systolic thrill on palpation
57
What are differentials for pan-sytolic murmer?
VSD
Mitral regurgitation
Tricuspid regurgitation
58
DDx for VSD?
* Miral regurg
* Tricuspid regurg
* ASD
* PDA
* Pulm stenosis
* Tetralogy of Fallot
59
What is management for VSD?
* small vsd = asymptomatic usually, close spontaneously, need monitoring.
* moderate + large vsd = nutritional support, diuretics for HF, surgical close of the defect (transvenous catheter closure via femoral vein)
60
What are complications of VSD?
* Infective endocarditis
* aortic regurgitation - due to prolapse of valve leaflet through defect.
* Eisenmenger syndrome
* R sided HF
* pulm HTN
* growth failure
61
Complications of surgical repair of VSD?
* Permanent heart block needing a pacemaker
* Wound infection
* Reoperation needed
62
# recap on infective endocarditis
Infective endocarditis is a complication of VSD.
1. How does it present?
2. what microorganims can cause it?
2. What inv would you do?
3. What is management?
4. How can it be preevnted when pt has surgical procedures?
1. persistent low grade fever, splenomegaly, change in heart murmer, petechaie, osler's nodes, janeway lesions, splinter haemorrhages
2. gram positive cocci - staphylococcus aureus, streptococcus viridans, enterococcus.
3. Blood cultures and echocardiography. Inv use Modified Duke's Criteria for diagnosing I.E.
4. IV abx - then abx based on sensitivities from blood cultures. Surgery may be needed
5. should be given prophylactic abx during surgical procedures.
63
What are the four characteristics of Tetralogy of Fallot?
* Ventricular septal defect
* Overriding aorta - is more on the right than usual.
* Pulmonary valve stenosis
* Right ventricular hypertrophy
64
RF for Tetralogy of Fallot?
* Male
* Genetics - DiGeorge syndrome, CHARGE syndrome, VACTERL association (from TMP)
* Rubella infection
* Increased age of mother - over 40
* Teratogens - alcohol consumption in pregnancy, warfarin, trimethadione
* Maternal DM
65
RF for Tetralogy of Fallot?
* Male
* Genetics - DiGeorge syndrome, CHARGE syndrome, VACTERL association (from TMP)
* Rubella infection
* Increased age of mother - over 40
* Teratogens - alcohol consumption in pregnancy, warfarin, trimethadione
* Maternal DM
66
How does Tetralogy of Fallot present?
* picked up in antenatal scans
* newborn baby check picks up an ejection systolic murmer due to the pulmonary stenosis
* cyanosis
* clubbing
* poor feeding
* poor weight gain
* ejection systolic murmer heard loudest in the pulmonary area (L sternal border, second intercostal space)
* 'Tet spells'. (asked about in another BS card)
67
What are Tet spells in Tetralogy of Fallot?
* when do they happen/precipitating factors?
* presentation?
* pathophysiology/ why do they happen?
* intermittent symptomatic periods where the R to L shunt becomes temporarily worsened, so precipitates a cyanotic episode.
* typically happens when infant is upset, in pain or has a fever. Precipitated by walking, physcial exertion or crying.
* Presentation: irritable, cyanotic child with SOB and tachypnoea. LOC, seizures. Can cause death.
* Pathophysiology: pulmonary vascular resistance increases or the systemic resistance decreases.
example by Dr Tom:
* a child physically exerting themselves will generate a lot of CO2. CO2 is a vasodilator that causes systemic vasodilation so will reduce systemic vascular resistance.
* blood flow will choose the path of least resistance, so blood will be pumped from RV to the aorta rather than into the pulmonary vessels. SO the lungs have been bypassed --> deoxygenated blood enters systemic circulation = cyanotic.
68
Describe how these abnormalities in Tetralogy of Fallot affect blood flow in an infant and cause cyanosis.
| Describe pathophysiology of TOF, which way blood shunt is
1. VSD = allows blood to flow between the ventricles.
2. The overriding aorta means the aorta (aortic valve) is placed further to the right. So when the RV contracts, blood moves into the aorta = so more **deoxygenated** blood enters the aorta to move around the body.
3. Pulmonary valve stenosis provides greater resistance against the flow of blood comng from the RV. So blood will flow throigh the VSD and into the aorta instead.
4. So, overriding aorta and having pulmonary stenosis causes blood flow to shunt from R --> L. Blood shunting from R --> L means less blood gets to lungs to be oxygenated.= cyanosis.
5. The RV tries to pump blood against the resistance of the LV and pulmonary valve stenosis = RV has to work harder = get right ventricular hypertrophy.
69
In TOF, what is severity of cyanosis determined by?
The severity of the pulmonary valve stenosis. (i.e. the severity of RV outflow tract obstruction)
70
How can you treat Tet spells in TOF?
* child can squat = to increase vascular systemic resistance - encourage blood to flow into pulmonary vessels.
* young children can do knees to chest position for same reason.
Medical managment:
* supplementary O2 = for hypoxia
* Bblockers = relax RV and improve flow to pulmonary vessels
* IV fluids = increase preload so increse volume of blood to pulm vessels
* Morphine = decrease respiratory drive so breathe effectively
* sodium bicarbonate = buffer metabolic acidosis
* phenylephrine infusion = increase systemic vascular resistance
71
What inv would you do for TOF?
* Echocardiogram = establish Dx. Can look at flow of blood via doppler flow studies during Echo.
* CXR = see characteristic boot shaped heart due to the RV wall thickening.
72
How is Tetralogy of Fallot managed?
Medical:
* in neonates = prostaglandin infusion to help maintain PDA - so blood can flow from the aorta back to the pulm arteries.
Surgical:
* Total surgical repair by open heart surgery. Will then require stabalisation in CICU
73
Complications of TOF?
Polycythaemia
Cerebral abscess
Stroke
Infective endocarditis
CCF
Death - up to 25% in 1st year of life.
After surgery = pulm regurg, arrythmias, exercise intolerance, death.
74
For patients with TOF, what follow up is recommended?
Lifelong follow up
Regular ECGs, Echos, and cardiopulmonary exercise testing (if they have exercise intolerance)
75
AR Tetralogy of Fallot
See schematic from TMP
76
What is transposition of the great arteries?
* The attachment of the aorta and the pulmonary trunk to the heart are swapped = transposed.
* RV pumps blood up to the aorta
* LV pumps blood into pulmonary vessels.
* Have two separate circulations that do not mix
77
What other cardiac conditions is transposition of the great arteries associated to?
Pulm stenosis
VSD
Coarctation of the aorta
78
Is transposition of the great arteries a cyanotic condition or an acyanotic condition, and why?
Cyanotic!!!
No connection between the systemic circulation and the pulmonary circulation
79
Why is transposition of the great arteries immediately life threatening after birth?
(What is different from intrapartum/ why is it not life threatening when in utero?)
As there is no connection between the systemic and pulmonary circulation - the baby does not get any oxygenated blood to the brain/ body.
In pregnancy, this is not life threatening and development of the fetus is normal - as gas and nutrient exchange happens in the placenta, and blood does not flow through the lungs (due to presence of ductus arteriosus and foramen ovale so bypass pulmonary circulation)
80
For transposition of the great arteries, what does immediate survival of the baby depend on?
A shunt between the systemic circulation and the pulmonary circulation.
This will allow blood flowing through the body to get oxygenated in the lungs.
Shunt can be across a patent ductus arteriosus, atriaal septal defect or a ventricular septal defect.
81
Maternal RF for transposition of the great arteries?
* Age over 40
* Maternal DM
* Rubella infection
* Poor nutrition
* Alcohol consumption
82
How does transposition of the great arteries present?
* Usually diagnosed in antenatal scan
If not detected in antenatal scan:
* cyanosis (within 24hrs usually)
* if have a VSD/PDA they may be able to compensate for a few days
* respiratory distress
* tachycardia
* poor feeding
* poor weight gain
* sweating
O/E:
* prominent RV heave
* single second heart sound
83
Ddx for transposition of the great arteries?
(and how would you differentiate between these and TofGA)
Tetralogy of Fallot:
* on cxr see boot shaped heart
* on echo, see pulmonary stenosis, overriding aorta, VSD and right ventricular hypertrophy
Tricuspid atresia:
* ECG shows L axis deviation
84
How is transposition of the great arteries managed?
* if there is a VSD, this allows some time for definitive treatment
* prostaglandin infusion - to maintain the PDA = allows aorta to flow to the pulm arteries for oxygenation
* balloon septostomy = catheter in formaen ovale via the umbilicus and inflate balloon to create a ASD to allow mixing
* Open heart surgery is definitive management = use a cardiopulmonary bypass machine to perform an "arterial switch" within few days of birth.
85
What is coarctation of the aorta?
* where there is narrowing of the aortic arch, usually around the ductus arteriosus.
* The severity of the coarctation (or narrowing) can vary from mild to severe.
* It is often associated with an underlying genetic condition, particularly Turners syndrome.
86
How does coarc of aorta affect blood flow in heart?
* Narrowing of the aorta reduces the pressure of blood flowing to the arteries that are distal to the narrowing.
* It increases the pressure in areas proximal to the narrowing, such as the heart and the first three branches of the aorta.
87
How does coarc of aorta present?
* May only present with weak femoral pulses
* Performing a four limb blood pressure will show **high blood pressure** in limbs supplied by arteries **before the narrowing** of the aorta and lower blood pressure in limbs after narrowing
* systolic murmur heard below the left clavicle (left infraclavicular area) and below the left scapula
* Tachypnoea and increased work of breathing
* Poor feeding
* Grey and floppy baby
Additional signs may develop over time:
* Left ventricular heave due to left ventricular hypertrophy
* Underdeveloped left arm where there is reduced flow to the left subclavian artery
* Underdevelopment of the legs
88
How is coarc of aorta managed?
Depends on severity
In citical coarctation where there is a risk of heart failure and death shortly after birth:
* Prostaglandin E is used keep the ductus arteriosus open while waiting for surgery.
* This allows some blood flow flow through the ductus arteriosus into the systemic circulation distal to the coarctation.
* Surgery is then performed to correct the coarctation and to ligate the ductus arteriosus.
