Cardiology - Heart Shunts

Question 1

What are innocent murmurs?

Answer 1

AKA flow murmurs

Fast blood flow through heart during systole

Question 2

What are the typical features of innocent murmurs?

Answer 2

Soft
Short
Systolic
Symptomless
Stressed
- Quieter when standing, only appears when child unwell or feverish

Question 3

What features of murmurs would need further investigation and referral to a paediatric cardiologist?

Answer 3

• Murmur louder than 2/6
• Diastolic murmurs
• Louder on standing
• Failure to thrive
• Feeding difficulty
• Cyanosis or SOB

Question 4

What investigations would you use to establish the cause of a murmur in children?

Answer 4

ECG
CXR
Echocardiogram

Question 5

Which murmurs are pan-systolic and where are they best heard?

Answer 5

Mitral regurgitation
Mitral area, 5th ICS, mid-clavicular line

Tricuspid regurgitation
Tricuspid area, 5th ICS, left-sternal border

Ventricular septal defect
Left lower sternal border

Question 6

Which murmurs are ejection-systolic and where are they best heard?

Answer 6

Aortic stenosis
Aortic area, 2nd ICS, right sternal border

Pulmonary stenosis
Pulmonary area, 2nd ICS, left sternal border

Hypertrophic obstructive cardiomyopathy
4th ICS, left sternal border

Question 7

What causes splitting of the second heart sound?

Answer 7

Negative intra-thoracic pressure causes right side of the heart to fill faster as blood taken from venous system

Increased volume in RV causes it to take longer for RV to empty in systole

This causes a delay in the pulmonary valve closing

When pulmonary valve closes later than aortic valve, second heart sound is split

Question 8

What are the signs of atrial septal defect?

Answer 8

• Mid-systolic, crescendo decrescendo murmur
• Loudest at upper left sternal border
• Fixed split second heart sound

Question 9

What is a fixed split second heart sound?

Answer 9

Second heart sound does not change with inspiration and expiration

Blood flows from LA into RA

Increased volume in RV before pulmonary valve can close

Does not vary with respiration

Question 10

What murmur is heard in patent ductus arteriosus?

Answer 10

Small may not cause any sounds

Large PDAs cause normal first heart sound with continuous crescendo-decrescendo machinery murmur

Can continue during second heart sound making the second harder to hear

Question 11

What murmur is heard in tetralogy of fallot?

Answer 11

Ejection systolic, heard best in the pulmonary area 2nd ICS, left sternal border

This is due to the pulmonary stenosis

Question 12

When does cyanotic heart disease occur?

Answer 12

When blood is able to bypass pulmonary circulation and lungs

Right-to-left shunt

Question 13

What heart defects can cause a right-to-left shunt?

Answer 13

Ventricular septal defect
Atrial septal defect
Patent ductus arteriosus
Transposition of the great arteries

Question 14

When does blood flow from the right to the left in a shunt?

Answer 14

If pulmonary pressure increases beyond systemic pressure causes increased RA pressure

LA pressure < RA pressure

Blood now flows from the right to the left - Eisenmenger syndrome

Question 15

Why do patients with transposition of the great arteries always have cyanosis?

Answer 15

Right side of the heart directly pumps blood into aorta and systemic circulation

Question 16

When does the ductus arteriosus stop working and when does it close?

Answer 16

1-3 days post birth

Seals completely 2-3 weeks into life

Question 17

What infection causes PDA?

Answer 17

Rubella

Question 18

What is a big key risk factor for PDA?

Answer 18

Prematurity

Question 19

How can asymptomatic patients suddenly present during adulthood?

Answer 19

Heart failure signs

Question 20

What is the pathophysiology in PDA?

Answer 20

Aorta Pa > Pulmonary vessel Pa

Blood flows from aorta to pulmonary artery

Left to right shunt

Increased pressure in pulmonary vessels causing pulmonary hypertension - right sided heart strain as RV struggles to contract against increased resistance

Pulmonary hypertension and right sided heart strain causes right ventricular hypertrophy

Increased blood flowing through pulmonary vessels and returning to left side of heart then causes left ventricular hypertrophy

Question 21

How does PDA present?

Answer 21

• May have continuous crescendo-decrescendo machinery murmur
• SOB
• Difficulty feeding
• Poor weight gain
• LRTI

Question 22

What investigations are used for PDA?

Answer 22

Echocardiogram
Doppler flow studies to assess size of left to right shunt
Echo also assesses effects on the ventricles

Question 23

How are PDAs managed?

Answer 23

Monitored using echocardiograms until 1 year

After 1 year, highly unlikely PDA will close

Trans-catheter or surgical closer can be performed

Question 24

When are patients with PDA treated before 1 year?

Answer 24

Evidence of heart failure or symptomatic

Question 25

What is the pathophysiology of atrial-septal defects?

Answer 25

Septum grows downwards from top of the heart downwards towards **endocardial cushion** and fuse to separate atria Forms **Septum primum** and **Septum secondum** Defects in these septa causes atrial septal defects Foramen ovale is present in septum secondum, closes after birth

Question 26

What are the different types of atrial septal defects, most to least common?

Answer 26

1) **Ostium secondum** Septum secondum 2) **Patent foramen ovale** Foramen ovale 3) **Ostium primum** Septum primum, AV valve defects, atrioventricular septal defect

Question 27

What are the complications of atrial septal defects?

Answer 27

Stroke AF or atrial flutter Pulmonary hypertension and right sided heart failure Eisenmenger syndrome

Question 28

How can strokes occur in patients with ASD?

Answer 28

If a patient has a large DVT that breaks off Usually will go to the right-side of the heart and enter the pulmonary circulation causing a PE If there has been a life-long asymptomatic ASD, this embolus can enter the left side of the heart and travel to the brain causing a large stroke

Question 29

How do ASDs present?

Answer 29

* Mid-systolic, crescendo-decrescendo murmur, heart loudest at upper left sternal border * Fixed split second heart sound * SOB * Difficulty feeding * Poor weight gain * LRTIs

Question 30

What causes fixed split second heart sound in ASDs?

Answer 30

LA Pa > Ra Pa Blood flows from left to right Increased volume in RV, takes longer for pulmonary valve to close during systole, causing a splitting sound

Question 31

How are ASDs managed?

Answer 31

Referral to paediatric cardiologist If small and asymptomatic, watchful waiting Transvenous catheter closure (via femoral vein) Open heart surgery

Question 32

How are ASDs managed in adults?

Answer 32

Anticoagulants e.g. aspirin, warfarin and NOACs To reduce clot and stroke risk

Question 33

What conditions are VSDs associated with commonly?

Answer 33

Down's syndrome Turner's syndrome

Question 34

Why don't patients with VSD become cyanotic?

Answer 34

LV Pa > RV Pa Blood flows from left to right

Question 35

What does a left to right shunt lead to?

Answer 35

Right sided overload Right heart failure Pulmonary hypertension

Question 36

What can happen after a long period of time in VSDs?

Answer 36

Pulmonary hypertension Pressure in right side of the heart becomes greater than life Blood shunted from right to left, leading to cyanosis

Question 37

How do VSDs present?

Answer 37

Poor feeding Dyspnoea Tachynpoea Failure to thrive Can be picked up on antenatal scans or if a murmur is heard during new-born baby check

Question 38

What murmur do patients with VSD typically have?

Answer 38

Pan-systolic, heard at left lower sternal border 3rd and 4th ICS Systolic thrill on palpation

Question 39

How are VSDs treated?

Answer 39

Dealt with by paediatric cardiologist Small VSDs with no symptoms watched over time, they can close spontaneously Transvenous catheter closure via femoral vein Open heart surgery

Question 40

What should be given during surgical procedures to patients with VSDs?

Answer 40

Antibiotic prophylaxis Higher risk of infective endocarditis

Question 41

When does Eisenmenger syndrome occur?

Answer 41

When blood flows from the right to the left of the heart

Question 42

What lesions can cause Eisenmenger syndrome?

Answer 42

Atrial septal defect Ventricular septal defect Patent ductus arteriosus

Question 43

How long does it take Eisenmenger syndrome to develop?

Answer 43

1-2 years with large shunts Adulthood with small shunts Develops more quickly during pregnancy, so women with "hole in the heart" need regular echos and close monitoring

Question 44

What is the pathophysiology of Eisenmenger syndrome?

Answer 44

In shunt defects pressure in the left side of the heart is higher than the right Blood flows from the left to the right Over time extra blood flowing to the right side and lungs increases the pressure in the pulmonary vessels causing **pulmonary hypertension** When pulmonary pressure exceeds **systemic pressure** blood flows from the right to the left, deoxygenated blood enters systemic circulation causing **cyanosis**

Question 45

What does cyanosis lead to?

Answer 45

Reduced oxygen saturation of the blood Bone marrow produces more RBCs and Hb to increase oxygen capacity of the blood This causes **polycythaemia**, leading to a **plethoric** complexion

Question 46

What are patients with polycythaemia more susceptible to?

Answer 46

Blood clots Higher concentration of RBCs and Hb makes the blood more viscous

Question 47

What are the examination findings associated with **pulmonary hypertension**?

Answer 47

Right ventricular heave- RV contracts forcefully against increased pressure in lungs Loud P2- forceful shutting of pulmonary valve Raised JVP Peripheral oedema

Question 48

What are the signs of right to left shunting or chronic hypoxia?

Answer 48

Cyanosis Clubbing Dyspnoea Plethoric complexion

Question 49

What is the prognosis of Eisenmenger syndrome?

Answer 49

Reduced life expectancy by 20 years Main causes of death : - Heart failure - Infection - Thromboembolism - Haemorrhage **Mortality up to 50% in pregnancy**

Question 50

How is Eisenmenger syndrome managed?

Answer 50

Corrected surgically to prevent development Once pulmonary pressure high enough, not possible to reverse it medically **Definitive treatment is heart-lung transplant, high mortality** - Oxygen management- **symptoms only, does not affect outcome** - **Sildenafil** for pulmonary hypertension - Treat arrhythmias - Venesection for polycythaemia - Anticoagulation for thrombosis - Prophylactic abx for infective endocarditis