Cardiac Haemodynamics and CHD

Question 1

What is Kussmaul’s sign?

Answer 1

Increase in RA pressure with inspiration (or lack of decline in RA pressure)
- indicates constriction or RV ischemia

Question 2

What does cannon a wave suggest?

Answer 2

AV dissociation

Question 3

When do you get large/elevated ‘a’ wave?

Answer 3

Mitral stenosis, decreased LV compliance d
Tricuspid stenosis

(Difficulty filling the ventricle)

Question 4

When do you get large ‘v’ wave?

Answer 4

Mitral regurgitation, LV failure, VSD

Tricuspid regurgitation

Question 5

What is normal RA pressure

Answer 5

<10mmHg

Question 6

When is PCWP (=LA pressure) greater than LV end diastolic pressure?

Answer 6

Mitral stenosis
Cor triatriatum
Atrial myxoma
Pulmonary vein stenosis

Question 7

What is the abnormality seen on LV tracing in severe AS?

Answer 7

LV pressure tracing is much higher than the aortic pressure
Severe AS is the commonest cause of LV outflow tract obstruction

Normally just like RV systolic pressure is same as PA systolic pressure - LV systolic pressure should be the same as aortic systolic pressure

Question 8

What is the cause for intracavity gradient?

Answer 8

For example pressure gradient LV cavity —> LV outflow tract —> aorta
Pressure highest in LV then lower as you go to outflow tract/aorta
This is seen in LV outflow tract obstruction
Classic cause ‘hypertrophic cardiomyopathy’

Question 9

What is constrictive disease?

Answer 9

Disease of pericardium - calcified or thickened pericardium
E.g. TB pericarditis, due to previous radiotherapy, uraemia, connective tissue disease

(vs restrictive which is disease of myocardium)

Question 10

What is restrictive disease?

Answer 10

Disease of myocardium
E.g. idiopathic, infiltrative (amyloidosis, sarcoidosis, haemochromatosis), post radiation, endocardial fibroelastosis

(vs constrictive which is disease of pericardium)

Question 11

Echocardiography/CT difference in constrictive vs restrictive?

Answer 11

Both will have diastolic dysfunction
Restrictive - E’ low
Constrictive - E’ >8m/s

CT chest showing thickened pericardium more likely to be constrictive disease

Question 12

What is the best discriminator to distinguish constrictive vs restrictive on right heart catheter?

Answer 12

LV-RV interdependence

Constrictive also has increase in RV pressure with inspiration

Question 13

Role of RHC in pulmonary HT?

Answer 13

Pulmonary hypertension if mPAP >25mmHg

If PCWP high (LA pressure high) then pulmonary HT due to left heart problem

Can also assess vasodilator response

Question 14

What is the equation for calculating PVR?

Answer 14

PVR = PA - LA / Qp

Q is cardiac output
PA is pulmonary artery pressure
LA is PCWP

Question 15

What are the drugs used for pulmonary arterial hypertension (group 1)?

Answer 15

Endothelin receptor antagonist - Bosentan, Macitentan, Ambrisentan
Phosphodiesterase inhibitor - Sildenafil, Tadalafil
Guanylate cyclase stimulant - Riociguat
Prostacyclin receptor agonist - Epoprostenol (IV), Iloprost (inhaled), Selexipag (PO)

Best efficacy is combination of Ambrisentan and Tadalafil
Above meds improve symptoms, 6MWT, slow disease progression
NO clear mortality benefit

Question 16

Left to Right shunt

Answer 16

Qp (pulmonary blood flow) > Qs (systemic blood flow)

Question 17

Qp : Qs ratio

Answer 17

= Ao O2 - MV O2 / PV O2 - PA O2

Question 18

What are the different types of ASD?

Answer 18

Ostium primum - partial AVSD, more common in Downs syndrome
Ostium secundum (commonest 75%)
Sinus venosus - can be overlying SVC (most common) or IVC (not defect of atrial septum
Coronary sinus

Question 19

When would you consider closing atrial septal defect (ASD)?

Answer 19

1. Haemodynamically significant shunt - symptoms, RV enlargement, Qp:Qs >1.5
2. Paradoxical embolism
3. Platypnoea-orthodeoxia syndrome - dyspnoea and hypoxia when changing position from recumbent to upright position

NOT CLOSED in Eisenmenger physiology - if you have longstanding flow you can end up with severe pulmonary HT and reversible flow

Question 20

What is Eisenmenger syndrome?

Answer 20

Requires presence of congenital heart disease
Sequence of events:
1. ‘Left-to-right’ shunt present
2. Increased pulmonary blood flow
3. Endothelial dysfunction and vascular remodeling
4. Increased pulmonary vascular resistance (PVR) leading to pulmonary artery hypertension (PAH)
5. PAH cause reversal of shunt to ‘Right-to-left’
6. Venous blood returning to

Question 21

What is the aim of endothelin receptor antagonist in PAH?

Answer 21

The aim of endothelin receptor antagonist therapy is to reduce pulmonary vascular resistance and hence reduce the strain on the right ventricle