Cardiology

Question 1

What is the Bernoulli equation and how can you use that to determine ventricular pressure

Answer 1

pressure = 4x velocity (squared)

If tricuspid regurgitation is 4 metres/second
Then change in pressure = 4x(4) squared = 64

Ventricular pressure is then 64 + Right atrial pressure

Question 2

Cause of mitral stenosis?

Answer 2

90% rheumatic heart disease
Mitral annular calcification (senile)
Radiation
Methysergide (migraine prophylaxis)
Fabrys, MOS, Whipples, EMF
Carcinoid
SLE/RA

Question 3

Mitral valve size and mild-severe Ms sizes

Answer 3

Normal MV orifice 4-6cm

Mild MS >1.5cm
Moderate 1-1.5cm
Severe <1 cm

Symptoms at rest do not usually occur until orifice less than 1.5

Fusions of the commissures, leaflets get thickened (fish mouth)

Question 4

MS severity

Answer 4

valve area
Pressure gradient
Supporting findings eg :A size, pulmonary artery pressure

Question 5

Mild MS

Answer 5

area >1.5
mean gradient < 5
PASP <30

Question 6

Moderate MS

Answer 6

area 1-1.5
mean gradient 5-10
PASP 30-50

Question 7

Severe MS

Answer 7

area <1.0
mean gradient >10
PASP >50

Question 8

Exercise and MS?

Answer 8

increasing heart rate means decreased filling time and therefore higher pressures to try and maintain filling to ventricle. Can precipitate APO rapidly.
Also need to be careful in AF

Left heart cath, the atrial pressures much higher than ventricle in diastole

Question 9

Balloon valvuloplasty indications MS

Answer 9

moderate or severe MS (<1.5cm)
Suitable valve (pliable, non-calcified, minimal subvalvar fusion)
Symptomatic (>1.5cm, if PAWP >25)

Asymptomatic - new onset AF, PASP >50 at rest, before pregnancy?

Question 10

Contraindications to ballon MS

Answer 10

More than mild MR
LA thrombus (?appendage)
Heavy calcification of both commisures
Predominant subvalvar involvement

Question 11

MS and pregnancy

Answer 11

Increased blood volume 40-50%
Increased cardiac output 30-50$
Peak at 20-24 wees
Active labour additional 50% CO
After delivery increased preload

Bed rest, diuretics, beta blockers
For failed medical Mx for balloon at 22-26 weeks

Question 12

Mitral Regurge causes

Answer 12

Mitral valve prolapse
Rheumatic
Ruptured chordae or papillae
LV dilation causing functional regurge

Question 13

Aortic Valve regurge

Answer 13

Quadcuspid valves
Marfans with root dilatation

in acute severe AR avoid bradycardia - > allows more time for regurge
(endocarditis, dissection)

Question 14

mild Aortic Stenosis

Answer 14

mean Pressure gradient <20
Area >1.5
Velocity ratio >0.5

Question 15

Moderate AS

Answer 15

mean pressure gradient 20-40
Area 1.0-1.5
velocity ratio 0.25-0.5

Question 16

Severe AS

Answer 16

mean pressure gradient >40
Area <1.0
Velocity ratio <0.25

Question 17

low gradient AS

Answer 17

low flow across severe narrowing
pressure gradient might not increase

classical low flow low gradient due to low EF
-> trial dobutamine to see if can increase

Question 18

velocity ratio

Answer 18

velocity LVOT / Velocity valve

if 0.5 it means valve is half the size of normal

Question 19

What are the cardioselective beta blockers?

Answer 19

atenolol, metoprolol, bisoprolol, nebivolol

Question 20

what are the MRI findings of arhythmogenic right ventricular cardiomyopathy

Answer 20

intramyocardial fat
late gadolinium enhancement
ventricular dyskinesia

Question 21

what is the mechanism of action of levosimendan

Answer 21

binds to cardiac troponin C, increases calcium sensitivity, positively inotropic, opens ATP sensitive potassium channels causing vasodilation

Question 22

what is the mechanism of action of hydralazine?

Answer 22

lowers blood pressure through a peripheral vasodilation effect, ? cAMP

acts on resistance arterioles

can cause lupus, headache, tachycardia, palpitations

Question 23

what is the mechanism of action of ivabradine?

Answer 23

selectively inhibiting the If channels in the sinoatrial node

indications: heart failure, not in AF, on maximal beta blocker therapy with HR >70 and EF <35%

No inotropic effect unlike CCB’s

Question 24

What is the effect of noradrenaline on the myocardium?

Answer 24

phosphorylation of calcium channels in myocardium, phosphorylation of troponin I, phosphorylation of phospholamban

mediated through Gs-proteins coupled to beta adrenoreceoptors,
cAMP dependent protein kinase A responsible for the phosphorylation
end result is superior contractility, increased conduction velocity, increased heart rate and increased relaxation rate,

Question 25

what is loafers endocarditis?

Answer 25

eosinophilic invasion of cardiac tissue causing a restrictive endocarditis. can be primary or secondary or idiopathic cause of hyper eosinophilia

Question 26

What is the total tension in stimulated muscle?

Answer 26

the cumulative tension of the cross bridges and elastic limit