Heart

Question 1

preload

Answer 1

Preload is the initial stretching of the cardiac myocytes (muscle cells) prior to contraction

Question 2

4 things that increase stroke volume e

Answer 2

Cardiac size, contractility, preload and afterload are the 4 factors affecting stroke volume

Increased central venous pressure would increase venous return, hence increasing preload.

Question 3

B-type natriuretic peptide (BNP) is a hormone produced mainly by the left ventricular myocardium in response to

Answer 3

strain

Whilst heart failure is the most obvious cause of raised BNP levels any cause of left ventricular dysfunction such as myocardial ischaemia or valvular disease may raise levels. Raised levels may also be seen due to reduced excretion in patients with chronic kidney disease. Factors which reduce BNP levels include treatment with ACE inhibitors, angiotensin-2 receptor blockers and diuretics.

Question 4

Effects of BNP

Answer 4

vasodilator
diuretic and natriuretic
suppresses both sympathetic tone and the renin-angiotensin-aldosterone system

Question 5

4 uses of BNP

Answer 5

Diagnosing patients with acute dyspnoea
a low concentration of BNP(< 100pg/ml) makes a diagnosis of heart failure unlikely, but raised levels should prompt further investigation to confirm the diagnosis
NICE currently recommends BNP as a helpful test to rule out a diagnosis of heart failure

Prognosis in patients with chronic heart failure
initial evidence suggests BNP is an extremely useful marker of prognosis

Guiding treatment in patients with chronic heart failure
effective treatment lowers BNP levels

Screening for cardiac dysfunction
not currently recommended for population screening

Question 6

Varicose veins are dilated, tortuous, superficial veins that occur secondary to incompetent venous valves, allowing blood to flow back, away from the heart. They most commonly occur in the legs due to reflux in the great saphenous vein and small saphenous vein. Whilst extremely common, the vast majority of patients do not require any intervention.

risk factors

Answer 6

ncreasing age
female gender
pregnancy
the uterus causes compression of the pelvic veins
obesity

symtpoms
aching
throbbing
tihing

Question 7

complications of varicose viens

Answer 7

Other patients may present with complications of varicose veins:
a variety of skin changes may be seen:
varicose eczema (also known as venous stasis)
haemosiderin deposition → hyperpigmentation
lipodermatosclerosis → hard/tight skin
atrophie blanche → hypopigmentation
bleeding
superficial thrombophlebitis
venous ulceration
deep vein thrombosis

Question 8

A 2-month-old baby is diagnosed with a ventricular septal defect. This is due to a failure in embryological development of which cardiovascular structure?

Answer 8

endocardial sinus

Development of the heart begins at about day 18 in the embryo from the mesoderm from a group of cells from the cardiogenic area. Signals from the underlying endoderm result in the formation of a pair of elongated strands known as the cardiogenic cords. These cords fuse together resulting in the primitive heart tube.

At day 22, there is the development of five regions in the primitive heart tube: beginning superiorly, the 1) truncus arteriosus, 2) bulbus cordis, 3) primitive ventricle, 4) primitive atrium and the 5) sinus venosus. These later become the 1) ascending aorta and pulmonary trunk, 2) right ventricle, 3) left ventricle, 4) anterior atrial walls and appendages, and the 5) coronary sinus and sino-atrial node respectively.

Over the next week, the embryo’s heart undergoes morphogenesis where it loops and twists from a vertical tube into the premature heart with atrial and ventricular orientation present by day 28. Thickenings of mesoderm in the inner lining of the heart walls (called endocardial cushions) appear and grow towards each other. They fuse and divide the atrioventricular canal into left and right sides. Failure of the endocardial cushions to develop properly will result in a ventricular septal defect.

By the end of the 5th week, the four heart chamber positions are complete. The atrioventricular and semilunar valves form between the 5th and 9th weeks.

Question 9

failure of endocardial cushions to develop rest in what

Answer 9

ventricular septal defect

Question 10

Aetiology of VSD ( ventricular septal defects)

Answer 10

congenital VSDs are often association with chromosomal disorders
Down's syndrome
Edward's syndrome
Patau syndrome
cri-du-chat syndrome
congenital infections
acquired causes
post-myocardial infarction

pan systolic mumur which is louder in smaller defects

Question 11

management of VSD

Answer 11

small VSDs which are asymptomatic often close spontaneously are simply require monitoring
moderate to large VSDs usually result in a degree of heart failure in the first few months
nutritional support
medication for heart failure e.g. diuretics
surgical closure of the defect

Question 12

left ventricular ejection fraction =

Answer 12

stroke volume/end diastolic LV volume

stroke volume = end diastolic volume - ends systolic volume

Question 13

systemic vascular resistance =

Answer 13

mean arterial pressure/cardiac output

Question 14

A teenage boy collapses while playing tennis and is pronounced dead in hospital. The post-mortem reveals heart abnormalities. What is the most likely abnormality?

Answer 14

hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the only condition listed above that typically presents with sudden death, which rules out the other options.

Acute myocarditis may present with chest pain, fever, palpitations, tachycardia and dyspnoea.

Dilated cardiomyopathy may present with right ventricular failure, dyspnoea, pulmonary oedema, and atrial fibrillation.

Restrictive cardiomyopathy presents similarly to constrictive pericarditis, where right heart failure signs predominate: raised JVP, hepatomegaly, oedema, ascites.

Atrial myxoma may present with dizziness, fainting and palpitations, due to obstruction of the conductive pathway.

Question 15

Hypertrophic cardiomyopathy (HCM)

HCM results in obstruction of the left ventricular outflow tract due to asymmetric septal hypertrophy.

signs and symptoms

Answer 15

sudden death; angina, dyspnoea, palpitations, syncope.
typically following exercise
double apex beat
Tests: ECG (will show high Q waves due to left ventricular hypertrophy), echocardiogram (shows hypertrophy)

Question 16

treatment

Answer 16

Treatment: bed rest, diuretics, digoxin, ACE-inhibitors, anticoagulation, biventricular pacing, implantable cardioverter-defibrillator, cardiac transplantation

Question 17

cause of HCM

Answer 17

the most common defects involve a mutation in the gene encoding β-myosin heavy chain protein or myosin-binding protein C
results in predominantly diastolic dysfunction
left ventricle hypertrophy → decreased compliance → decreased cardiac output
characterized by myofibrillar hypertrophy with chaotic and disorganized fashion myocytes (‘disarray’) and fibrosis on biopsy

Question 18

A teenage boy collapses while playing tennis and is pronounced dead in hospital. The post-mortem reveals heart abnormalities. What is the most likely abnormality?

Answer 18

hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the only condition listed above that typically presents with sudden death, which rules out the other options.

Acute myocarditis may present with chest pain, fever, palpitations, tachycardia and dyspnoea.

Dilated cardiomyopathy may present with right ventricular failure, dyspnoea, pulmonary oedema, and atrial fibrillation.

Restrictive cardiomyopathy presents similarly to constrictive pericarditis, where right heart failure signs predominate: raised JVP, hepatomegaly, oedema, ascites.

Atrial myxoma may present with dizziness, fainting and palpitations, due to obstruction of the conductive pathway.

Question 19

Hypertrophic cardiomyopathy (HCM)

HCM results in obstruction of the left ventricular outflow tract due to asymmetric septal hypertrophy.

signs and symptoms

Answer 19

sudden death; angina, dyspnoea, palpitations, syncope.
typically following exercise
double apex beat
Tests: ECG (will show high Q waves due to left ventricular hypertrophy), echocardiogram (shows hypertrophy)

Question 20

treatment

Answer 20

Treatment: bed rest, diuretics, digoxin, ACE-inhibitors, anticoagulation, biventricular pacing, implantable cardioverter-defibrillator, cardiac transplantation

Question 21

cause of HCM

Answer 21

the most common defects involve a mutation in the gene encoding β-myosin heavy chain protein or myosin-binding protein C
results in predominantly diastolic dysfunction
left ventricle hypertrophy → decreased compliance → decreased cardiac output
characterized by myofibrillar hypertrophy with chaotic and disorganized fashion myocytes (‘disarray’) and fibrosis on biopsy

Question 22

most common cause of typical anginal( pain over sternum and shoulder ) pain

Answer 22

atherosclerosis

The pathological process involved in atherosclerosis begins with thickening of the tunica intima(composed of proteoglycan rich extracellular matrix and acellular lipid pools)

Fatty streak int eh subendotheilal space by Low density lipoprotein can be seen

Fibroatheroma starts which is characterized primarily by infiltration of macrophages & T-lymphocytes, with the formation of a well-demarcated lipid-rich necrotic core.

The appearance of foam cells occur relatively early in the disease process and play a major role in the pathogenesis of atheroma formation.

Further progression leads to a thin cap fibroatheroma, wherein the necrotic core becomes bigger and fibrous cap thins out.

Finally, smooth muscle cells from the tunica media start to proliferative and migrate into the tunica intima.

Question 23

the aortic arch is a continuation of what and gives rise to what

Answer 23

The aortic arch is a continuation of the ascending aorta. It gives off the right brachiocephalic trunk, the left common carotid artery and the left subclavian artery in that order, before continuing as the descending aorta.

Question 24

The thyrocervical trunk arises from the

Answer 24

subclavian artery and gives off branches

Inferior thyroid artery
Suprascapular artery
Ascending cervical artery
Transverse cervical artery

Question 25

CABG - coronary artery bypass surgery used to treat coronary artery disease
what vessel do they use

complications

Answer 25

internal mammary artery increasingly used as opposed to the saphenous vein

AF (40%) and stroke (2%)

Question 26

Preload = end diastolic volume
Afterload = aortic pressure

Answer 26

Starlings law
Increase in end-diastolic volume will produce larger stroke volume- this occurs up to a point beyond which cardiac fibres are excessively stretched.

Question 27

2 major risk factors for atherosclerosis

Answer 27

smoking and hyperlipidaemia.

Question 28

ophthalmic artery arises from what

Answer 28

internal carotid

Question 29

A patient with dilated cardiomyopathy presents to his GP with symptoms of heart failure.

Which of the following explains why his heart condition has lead to heart failure?

Answer 29

ventricular dilation due to Laplace law - pressure in the lumen = wall tension/lumen radius

Question 30

Atrial stretch receptors

Answer 30

Located in atria at junction between pulmonary veins and vena cava.
Stimulated by atrial stretch and are thus low pressure sensors.
Increased blood volume will cause increased parasympathetic activity.
Very rapid infusion of blood will result in increase in heart rate mediated via atrial receptors: the Bainbridge reflex.
Decreases in receptor stimulation results in increased sympathetic activity this will decrease renal blood flow-decreases GFR-decreases urinary sodium excretion-renin secretion by juxtaglomerular apparatus-Increase in angiotensin II.
Increased atrial stretch will also result in increased release of atrial natriuretic peptide.

Question 31

Which one of the following pathological explanations best describes the initial pathological processes occurring in an abdominal aortic aneurysm in an otherwise well 65-year-old, hypertensive male?

Answer 31

loss of elastic fibres from the media

Question 32

starling law

Answer 32

as preload progressively increase , stroke volume increases gradually then decrease suddenly

Question 33

complications of MI

Answer 33

cardiac arrest 
cariogenic shock 
chronic HF 
tacky or Bradycardia 
pericarditis 
left ventricular anerursym 
left ventricular free wall rupture 
ventricular spetal defect 
acute mitral regurgitation

Question 34

0-24hr post-MI histology findings: early coagulative necrosis, neutrophils, wavy fibres, hypercontraction of myofibrils. High risk of ventricular arrhythmia, HF and cardiogenic shock

1-3 days post-MI histology: Extensive coagulative necrosis, neutrophils (associated with fibrinous pericarditis)

3-14 days post-MI histology: macrophages + granulation tissue at margins. High risk of free wall rupture, papillary muscle rupture and LV pseudoaneurysm

2 weeks to several months post-MI histology: contracted scar complete. Associated with Dressler syndrome, HF, arrhythmias, mural thrombus

Answer 34

post MI findings

Question 35

A 53-year-old woman is attending her GP for a routine “well-woman check”. At the start of the appointment, the doctor uses an automated sphygmomanometer to measure the patient’s blood pressure, which reads 174/96 mmHg. She is informed that the reading is high, likely because she just walked into the clinic, and will be repeated in a few minutes.

What is the usual physiological mechanism in response to a rise in blood pressure?

Answer 35

Glutamatergic activation of caudal ventrolateral medulla by nucleus tractus solitarii

The vagus nerve regulates the baroreceptor reflex, correcting an acute decrease in arterial blood pressure

Question 36

what is responsible for the closure of the ductus arteriosus at birth

Answer 36

At birth, there is an increased oxygen tension in the blood, and a reduced level of prostaglandins; both of which allow the patent ductus arteriosus to close.

An increased left atrial pressure allows the foramen ovale (connection between left and right atria) to close.

Question 37

when do the coronary arteries fill

Answer 37

ventricular diastole

Question 38

on xray patients with aortic dissection will also have what seen

Answer 38

widened mediastinum

Question 39

Which nerve directly innervates the sinoatrial node?

Answer 39

no particular node

Question 40

What is the expected oxygen saturation levels in the right atrium for a healthy individual?

Answer 40

70% ad deoxygenated

Question 41

atrial flutter characterised by what

Answer 41

sawtooth - narrow complex tachycardia

Question 42

An 82-year-old lady has just been diagnosed with heart failure after 8 months of increasing breathlessness and ankle swelling. She is started on a number of medications, given some lifestyle advice and counselled on the prognosis. Which two types of valve dysfunction will she be most prone to because of her new diagnosis?

what two conditions is she now more prone too

Answer 42

The most common valve dysfunctions secondary to heart failure are functional mitral and tricuspid regurgitations. This is because the enlarged ventricles cause an incomplete seal at the valves during diastole.

The most common valve dysfunctions secondary to heart failure are functional mitral and tricuspid regurgitations. This is because the enlarged ventricles cause an incomplete seal at the valves during diastole.