Cardiac Function 2 (Clinical Problems)

Question 1

What is Cor Pulmonale?

Answer 1

Pulmonary arterial hypertension resulting from _diseases affecting the structure and/or the function of the lung_s; pulmonary arterial hypertension results in right ventricular enlargement (hypertrophy and/or dilatation) and may lead with time to right heart failure.

Question 2

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise.

Physical examination reveals a b_lood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension and peripheral oedema._

Chest x-rays show right ventricular
and proximal pulmonary artery enlargement, but no sign of pulmonary
congestion. An echocardiogram shows normal left ventricular wall thickness
and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole

Answer 2

Cor pulmonale, or _right-sided heart failur_e, is an enlargement of the right ventricle due to high blood pressure in the lungs usually caused by chronic lung disease.

Question 3

Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension and peripheral oedema.

Chest x-rays show right ventricular
and proximal pulmonary artery enlargement, but no sign of pulmonary
congestion. An echocardiogram shows normal left ventricular wall thickness
and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole

Pulmonary hypertension may be caused by….

Answer 3

• Loss of capillary beds (eg, due to bullous changes in COPD or thrombosis in pulmonary embolism)
• Vasoconstriction caused by hypoxia, hypercapnia, or both
• Increased alveolar pressure (eg, in COPD, during mechanical ventilation)
• Medial hypertrophy in arterioles (often a response to pulmonary hypertension due to other mechanisms)

Question 4

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise. Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension, hepatomegaly and peripheral oedema. Chest x-rays show right
ventricular and proximal pulmonary artery enlargement, but no sign of
pulmonary congestion. An echocardiogram shows normal left ventricular wall
thickness and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole.

What is the probable cause of the patient’s dyspnoea with exertion?

Answer 4

• The most obvious cause of dyspnoea with exertion is the impaired lung function that occurs as a result of heavy smoking.
• Smoking causes obstructive airways disease, loss of elastin etc all of which i_ncrease the work of breathing._
• This is exacerbated during exercise.
• The patient’s exercise capacity will also be reduced because he is not able to increase cardiac output sufficiently as his right venticular function is impaired.

Question 5

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise. Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension, hepatomegaly and peripheral oedema. Chest x-rays show right
ventricular and proximal pulmonary artery enlargement, but no sign of
pulmonary congestion. An echocardiogram shows normal left ventricular wall
thickness and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole.

Explain the pulmonic component of the 2nd heart sound in Cor Pulmonale

Answer 5

• The pulmonary valve generally _closes shortly after the aortic valve p_roducing splitting of the second heart sound.
  
  • Since there is an increase in blood volume in the right ventricle during inspiration, the pulmonary valve (P2 component of S2) stays open longer during ventricular systole due to an increase in ventricular emptying time, whereas the aortic valve (A2 component of S2) closes slightly earlier due to a reduction in left ventricular volume and ventricular emptying time.
• Normally splitting of S2 is increased with inspiration and decreased with expiration because the reduced intrathoracic pressures during inspiration lead to increased right heart filling, d_elaying pulmonary closure._
• These effects are reversed during expiration.
• Increased pulmonary arterial pressure leads to f_urther delay_ in closure of the pulmonary valve, and a more vigorous closure.
• Resulting in wider splitting and an accentuated S2.

Question 6

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise. Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension, hepatomegaly and peripheral oedema. Chest x-rays show right
ventricular and proximal pulmonary artery enlargement, but no sign of
pulmonary congestion. An echocardiogram shows normal left ventricular wall
thickness and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole.

Explain the neck vein distension, hepatomegaly and peripheral oedema.

Answer 6

• The neck vein distension (raised JVP), hepatomegaly and peripheral oedema are due to elevated systemic venous pressures as a result of right heart dysfunction.
• Late in the disease there may also be tricuspid regurgitation as a result of RV dilatation.

Question 7

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise. Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension, hepatomegaly and peripheral oedema. Chest x-rays show right
ventricular and proximal pulmonary artery enlargement, but no sign of
pulmonary congestion. An echocardiogram shows normal left ventricular wall
thickness and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole.

What might be present in a 12 lead ECG?

What direction is the mean QRS axis?

Answer 7

• Signs of RV hypertrophy (revise year II problems)
  
  • V4, V5, V6
• However the expanded chest associated with COPD may reduce the ECG potentials.
• Increased amplitude of QRS
• ​mean QRS: Right axis deviation

Question 8

A 68 year-old man who has been a life-long smoker has for some time
experienced dyspnoea with exertion. Recently, however, he has begun to feel
tired with very limited exercise. Physical examination reveals a blood pressure
of 120/75 mm Hg, a loud pulmonic component of the 2nd heart sound, neck
vein distension, hepatomegaly and peripheral oedema. Chest x-rays show right
ventricular and proximal pulmonary artery enlargement, but no sign of
pulmonary congestion. An echocardiogram shows normal left ventricular wall
thickness and cavity volume. However, the right ventricle is distended and
hypertrophied. The septum appears to be displaced to the left during diastole.

Explain why the interventricular septum is displaced leftward during diastole.

Answer 8

• Leftward displacement of the septum is seen in both chronic pulmonary
  hypertension and acute pulmonary hypertension (due for instance to
  pulmonary embolism).
• It can be explained by increased RV diastolic pressures and a pressure
  gradient across the interventricular septum during systole that pushes it
  into the LV cavity.

Question 9

What is the main cause of an irregularly irregular heartbeat?

Answer 9

Atrial fribrillation

Question 10

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced _shortness of
breath with exertio_n and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement a_nd evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial n_arrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Do you think the patient’s childhood rheumatic fever is related to her development of mitral stenosis?

Answer 10

• Absolutely Yes:
• Most cases of mitral stenosis are caused by chronic rheumatic heart disease, although more than 50% of these patients do not have a known history of rheumatic fever.
• Mitral stenosis often develops years after the initial streptococcal infection and symptoms may not develop until many years afterwards.
• This patient’s symptoms are consistent with very severe mitral stenosis.

Question 11

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced _shortness of
breath with exertio_n and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement a_nd evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial n_arrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

How does P wave shape and ventricular response in the patient’s ECG differ from normal, and what is the explanation for the differences?

Answer 11

• There are no P waves in this patient’s rhythm strip indicating there is no
  evidence of regular organised atrial electrical activity.
• Ventricular rhythm is irregularly irregular (as noted above).
• These observations indicate this patient has atrial fibrillation

Question 12

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Comment of the ventricular activity in the patient’s ECG.

Answer 12

• QRS complexes are irregula_r but are o_therwise normal (indicating that
ventricular activation is occurring via the specialised conduction system).
• In AF, a_trial excitation is disordered_ and occurs very rapidly (350 per minute).
• The ventricular rate is much less (90 to 160 per minute) due to the prolonged
refractory period of the AV node, the ventricles are activated by every second or
every third atrial ‘excitation’ only.
• This accounts for the irregularity of the ventricular response

Question 13

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

What is the pathological progress of the heart damage?

Answer 13

• The stenosis is due to the thickening of the valve leaflets with f_ibrous
obliteration._

• There may be _calcium deposition in the leaflet_s, chordae and the annulus with
commissural and chordal fusion.

• Eventually, a _funnel-shaped mitral valv_e with a fish-mouth orifice may occur.

Question 14

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Explain the shortness of breath and fatigue with exercise?

Answer 14

• The narrowed mitral orifice results in a build up of ‘back-pressure’ in the
pulmonary vasulature, leading to pulmonary vascular engorgement, _reduced lung
complianc_e and increased work of breathing.

• Also the lack of atrial contraction (atrial fibrillation) leads to reduced ventricular
preload.

• At rest, this may not be a problem, but during exercise, the heart is unable to
increase output sufficiently to meet the increased demand.

Question 15

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Why is the patient unable to increase her cardiac output with exercise?

Answer 15

• LV filling is impaired at rest as result of the increased resistance of mitral valve.
• The the loss of “the atrial primer pump” and the _reduced (and irregular) diastolic
interva_l also reduces LV function.

• The capacity to achieve a stable increased heart rate in exercise will be
compromised by the atrial fibrillation.
• The pulmonary veins are engorged at rest and this will become worse in
exercise.
• This is an example of left sided heart failure (as a result of impaired filling rather
than cardiomyopathy).
• Pulmonary vascular engorgement is leading to r_educed lung compliance_ and
increased work of breathing.

Question 16

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Explain the vocal-cord paralysis.

Answer 16

• (rare) Ortner’s syndrome
• Compression of left recurrent laryngeal nerve by enlarged LA or pulmonary
artery.

Question 17

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Explain the accentuated first heart
sound.

Answer 17

• A loud S1 is a hallmark of hemodynamically significant mitral stenosis.
• Mobile but stiff mitral leaflets produce a loud S1 unless the leaflets are heavily calcified.
• The loud S1 is due primarily to greater excursion of the leaflets during closure, since elevated LA pressure has kept the leaflets relatively wide apart.
• In addition, _stiff, noncompliant leaflet_s and chordae tendineae appear to resonate with increased amplitude.

Question 18

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Explain the opening snap

Answer 18

• The opening snap (of the mitral valve) occurs because, under a high pressure gradient the abnormal valves billow into the LV and are rapidly arrested by the chordae, causing sudden vibrations.
• If the valve is significantly calcified the opening snap may not be heard as the stiff valves do not move so freely and rapidly.

Question 19

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Explain the prolonged diastolic murmur.– Draw the Wiggers Diagram

Answer 19

• The prolonged diastolic murmur is associated with sustained turbulent flow through the narrowed valve (remember year II – turbulence…)
• This indicates that a high velocity of blood flow through the narrowed mitral valve is maintained over a large proportion of diastole.

Question 20

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Where on the precordium would this (prolonged diastolic murmur) sound be heard best, and would one use the bell or diapragm of the stethoscope to listen for it?

Answer 20

• Apex (mitral sound)
  
  • Low pitch, so use the bell.

Question 21

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced shortness of
breath with exertion and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement and evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial narrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Describe how and why the intracardiac pressures in this patient with mitral
stenosis will typically differ from those in a normal heart.

Answer 21

• Under normal conditions, there is a small pressure gradient between the LA and
LV in early diastole (rapid filling) and during atrial contraction when flow from
LA to LV is greatest.
• During the rest of diastole, flow through the mitral valve is much reduced and
the pressures in LA and LV are the same.

• In mitral stenosi_s there is an i_ncreased diastolic A-V pressure gradient reflecting
the resistance presented by the narrowed mitral valve.

• This is greatest in early filling when the rate of blood flow from atrium to ventricle is maximal.

• In severe mitral stenosis, LA and LV pressure do not equilibrate and LV filling
continues at a relatively uniform rate throughout diastole.
• LA volume and pressure remain elevated throughout the cardiac cycle

Question 22

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced _shortness of
breath with exertio_n and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement a_nd evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial n_arrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Describe how and why the intracardiac pressures in this patient with mitral
stenosis will typically differ from those in a normal heart.

Answer 22

• Because of the substantial reduction in the cross-sectional area of the mitral
valve orifice, the velocity of the blood flowing through the inlet valve is
increased and t_urbulence occurs as a result._

• No a-wave would be observed on the atrial pressure trace because the patient has atrial fibrillation.
• Ventricular peak pressure is reduced with respect to normal and LV end-diastolic pressure will be decreased also, due to the low LV filling as a result of the mitral stenosis. (note patient’s BP = 110/80)

Question 23

A 38 year-old woman suffered from rheumatic fever at the age of 11, which left her
with a heart murmur. Over the past four years she has experienced _shortness of
breath with exertio_n and more recently has noticed some irregularity of her heart
beat. She has also noticed that her voice has become somewhat hoarse.

On physical examination, the patient’s blood pressure was found to be 110/80 mmHg. Her heart rhythm was entirely irregular (irregularly irregular), with her heart rate varying between 90 and 160 per minute. She had an accentuated first heart sound with an opening snap shortly after the second heart sound and a prolonged diastolic murmur.

Examination of her larynx revealed paralysis of her left vocal-cord.

A chest X-ray showed an enlarged left atrium, pulmonary artery enlargement a_nd evidence of pulmonary vein congestion. Transthoracic ultrasound demonstrated substantial n_arrowing of the mitral valve orifice and reduced mobility of the mitral valve leaflets.

Describe the main difference between the left-sided heart pressures for this patient
compared to one with mitral stenosis but who does not have atrial fibrillation.

Answer 23

Question 24

What treatments are possible for this patient’s stenosed mitral valve?

Answer 24

The treatment options for mitral stenosis include:
_- percutaneous mitral valvuloplast_y (balloon)
- mitral valve replacement surgery

Question 25

Why are patients with mitral stenosis typically at risk of developing atrial arrhythmias such as atrial fibrillation?

Answer 25

• The patient has atrial fibrillation due to _structural remodelling of the left atrium._ • The remodelling is manifested by _LA distension and hypertroph_y as well as _extensive diffuse fibrosis._ • The LA enlargement increases _atrial electrical path lengths_ and the distension also increases the probability of _ectopic activation originating in the sleeves_ at the _base of the pulmonary veins_ where they enter the roof of the LA. • The i_nflammation and fibrosis_ further contributes to the _tortuous conduction and activation delays_that facilitate unstable electrical activity. • There is thought to be _regionally-varying ANS remodelling_, _changing the excitability of some regions of the atria._ • These (and other) changes markedly _increase the probability of reentrant arrhythmia_ in the atria and in extreme cases leads to _atrial fibrillation_ • The incidence of AF increases in the elderly and in patients with heart failure for similar reasons.

Question 26

What is the ‘natural course/[PROGRESSION’ of atrial fibrillation?

Answer 26

* Progression * Paroxysmal AF * Persistent AF * Permanent AF * (AF as result of MS – more aggressive -\> permanent) * AF begets AF

Question 27

What treatments are possible for the atrial fibrillation? What other drugs are important in atrial fibrillation, and why?

Answer 27

* _AF: Rate control_ * Ca channel blocker * Beta-blocker * digoxin * _AF: Rhythm control (once in permanent AF)_ * amiodarone * sotalol - non specific b-blocker (II) & III) * dc conversion * ablation therapy… * _What other drugs are important in atrial fibrillation, and why?_ * Anticoagulant (risk of stroke)

Question 28

A blood sample is taken and cardiac natriuretic peptide levels are assayed. The plasma concentration of the inactive N-terminal fragment of proBNP is found to be 30 pM/L (normal 5-50 pM/L). An echocardiogram shows no evidence of the left ventricular wall wall thickening, but the left atrium is grossly enlarged. Left ventricular cavity dimensions are reduced with respect to normal and the left ventricular ejection fraction is 70 percent. **Given these finding explain the patient’s dyspnoea.**

Answer 28

* This patient has _left sided heart failure_ * as a result of _impaired filling_ rather than cardiomyopathy.

Question 29

What are the risk factors for Aortic Stenosis?

Answer 29

Risk factors include: * hypertension, * smoking, * male sex, * age, * increased LDL, * diabetes.

Question 30

Describe the progression of aortic stenosis.

Answer 30

* _Age-related progressive calcification_ occurs in many patients with normal trileaflet aortic valve. * Begins with _endothelial damage_ from increased mechanical stress. * _Inflammation_ occurs then _deposition of LDL cholesterol and Lipoprotein_(a). * When _AS develops in younger people_ – often the cause is a bicuspid aortic valve (1-2% of US population). * _LV must generate higher pressure to eject blood._ * Leads to the _development of LV hypertrophy_ (concentric), _impaired diastolic function_ (HFpEF). * Over time this can _progresses to LV dilatatio_n, _wall thinning & systolic failure_ (HFrEF). * The _calcification_ process that occurs in _aortic stenosis_ can progress to extend beyond the aortic valve and into the electrical conduction system of the heart. Evidence of this phenomenon may rarely include * ECG patterns characteristic of certain types of heart block such as LBBB.

Question 31

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ _Explain the systolic murmur_

Answer 31

Increased velocity through narrowed aortic valve during ejection - leads to turbulence (remember Reynold’s number) - heard as a murmur

Question 32

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ Where would you expect this murmur to be heard best, and what characteristics would you expect to hear?

Answer 32

A _systolic_, _crescendo-decrescendo (i.e., 'ejection’) murmur i_s heard l_oudest at the upper right sternal border_ and _radiates into the neck bilaterally._

Question 33

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and **_a single second heart sound_ (no splitting of S2).** _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ **_Explain the lack of splitting of the second heart sound (S2). (only 1 2nd heart sound)_**

Answer 33

The _aortic componen_t of the second heart sound tends to become _decreased_ and _softer_ as the aortic stenosis becomes more severe. This is a result of the _increasing calcification_ of the valve _preventing it from "snapping" shut_ and producing a sharp, loud sound. = only closure of the pulmonary valve is heard

Question 34

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ Draw a Wiggers diagram of the cardiac cycle for a normal person and for this patient (include LV pressure, aortic pressure, LA pressure, ECG, and heart sounds).

Answer 34

Question 35

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ Explain why the patient feels dizzy or faint when exercising.

Answer 35

Exercising muscles need extra blood, hence _vasodilatation_ occurs within the skeletal muscles. However the _heart cannot deliver the extra blood flow rate_ because of stenotic (narrowed) aortic valve. Remember: **Flow ≈ MAP/resistance -\> MAP = Flow x resistance.** If r_esistance drops_ (vasodilatation), but _flow rate does not change_ - then MAP will fall. This can lead to fainting due to reduced brain perfusion.

Question 36

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ What would you expect to find on examination of his ECG, and why?

Answer 36

ECG= larger QRS (because of Left ventricle hypertrophy) ECG manifestations of left ventricular hypertrophy are common in aortic stenosis and arise as a result of the stenosis having placed a chronically high pressure load (afterload) on the LV.

Question 37

What would you see in an ECG for LV hypertrophy?

Answer 37

* Enlarged R waves (LVH) * Left axis deviation (tendency) * LV strain pattern (Lateral: I, aVL, V5, V6) * ie: ST segment and T wave changes (lateral leads) * Perhaps notched M-shaped P wave (from subsequent LA hypertrophy). * R-wave peak time \> 50 ms in V5-6 with associated QRS broadening.

Question 38

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ **Speculate on the possible cause of the the mild chest discomfort during exercise.**

Answer 38

* _Angina_ * _Increased LV muscle mass,_ without concomitant increase in vasculature, reduces coronary reserve. * _Increased heart rate_ and _ventricular wall tension_ during exercise, (_demand_) _cannot be met by increased coronary perfusion (supply)_ because of the aortic stenosis. * (coronary ostia are outside the aortic valve where pressure is low - increased flow rate here will also reduce pressure - remember Bernoulli's law from last year).

Question 39

A 70-year-old man presents to his GP reporting that breathlessness_, moderate chest discomfort_ and the experience of a _fainting feeling_ prevent him from exercising at any more than a gentle walk. He is a _smoker_ and is on treatment for _hypertension_. Physical examination reveals a _systolic murmur_ and _a single second heart sound_ (no splitting of S2). _Aortic stenosis_ is suspected and an echocardiogram is performed showing _left ventricular hypertrophy_ and a _heavily calcified aortic valve._ **The exercise intolerance suggests the patient has some degree of heart failure. Explain the possible basis of the heart failure.**

Answer 39

Initially the patient will develop _thickened LV myocardium_ because of _chronically increased afterload_, this will lead to _impaired filling_ (diastolic dysfunction - HFpEF) and _elevated filling pressure._ Subsequently this can _progress to LV wall thinning and chamber dilatation_ and subsequent _systolic dysfunction (_HFrEF).

Question 40

Speculate on treatment possibilities for Aortic Stenosis

Answer 40

* Medical therapies do not prevent progression of the disease, though are used for symptomatic treatment. * Definitive treatment is aortic valve replacement (at appropriate timing) * Decision on when to treat is based on severity: * Primarily based on transaortic pressure gradient and blood flow velocity across the aortic valve. * Development of angina, syncope or dyspnoea indicate valve replacement is required promptly. * _Doppler echocardiography provides:_ - blood flow velocity (N = 1 m/sec) - pressure gradient across the valve (calculated from a modified Bernoulli equation N\<5 mm Hg) - valve area (calculated from continuity equation and velocity time integral N = 2.5 - 4.5 cm2).

Question 41

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Estimate the patient’s ejection fraction. Is this normal?**

Answer 41

* Estimate the patient’s ejection fraction. Is this normal? * EF is the % of ventricular end diastolic volume that is ejected during systole. * EF = 100\*(SV/EDV) = 100\*(EDV-ESV)/EDV * SV is stroke volume, EDV is end-diastolic volume, ESV is end-systolic volume. * In this case, EDV = 150 mL, ESV = 100 mL, * EF = 100\*50/150 = 33% A normal ejection fraction at rest is \> 50%

Question 42

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Explain why plasma levels of the N-terminal fragment of proBNP are elevated in this patient.**

Answer 42

• Increased levels of cardiac natriuretic peptides are released into the blood when the heart chambers are distended. • ANP is predominantly stored in and released from the atria while most BNP is stored in and released from the ventricles. • Stretch triggers the secretion of the 108 amino acid residue precursor molecule proBNP from ventricular myocytes. • ProBNP is rapidly cleaved to BNP (32 AA), containing the central 17 amino acid ring that characterizes all of the natriuretic peptides, and an inactive N-terminal fragment, NT-proBNP (76AA) .

Question 43

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Why is this inactive component assayed instead of BNP?**

Answer 43

• BNP has a short half life (2-4 minutes), but the inactive N-terminal fragment is cleared much more slowly. • therefore plasma concentrations of the N-terminal fragment of proBNP rise to higher levels than those of BNP when proBNP is secreted and the N-terminal fragment is thus a more sensitive index of congestive heart failure than BNP. • Current evidence demonstrates that, for more than 90% of symptomatic patients with heart failure, plasma levels of the N-terminal fragment of proBNP are \> 150 pM/L, more than 3 times greater than the normal range (5 - 50 pM/L).

Question 44

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Construct an approximate LV pressure-volume loop for the patient at rest and indicate how it differs from normal.**

Answer 44

Question 45

Construct an approximate LV pressure-volume loop for the patient at rest and indicate how it differs from normal.

Answer 45

Question 46

Draw the Ventricular Pressure-volume loops in normal, systeolic and diastolic dysfunction.

Answer 46

Question 47

What is the - Ejection fraction - Relative wall tickness - End diastolic pressure for Diastolic vs Systolic Heart failure

Answer 47

**_Diastolic Heart Failure_** * Ejection fraction * Normal * Relative wall tickness * Increased * End diastolic pressure * ​Normal **_Systolic Heart Failure_** * Ejection fraction * Decreased * Relative wall tickness * Decreased * End diastolic pressure * Increased

Question 48

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Explain the patient's shortness of breath with exercise.**

Answer 48

• Assuming this is LV failure then there is a _mismatch between the pumping capacities of left and right hearts._ • The autonomic stimulation triggered by exercise causes the right heart to transfer blood into the pulmonary circulation which is not cleared by the left heart as would normally be the case. • The increased pulmonary pressures increase the afterload seen by the RV and reduce its output to match the decreased output of the LV. • The breathlessness is due to pulmonary congestion, the consequent reduction in pulmonary compliance and the perception of increased work associated with breathing. • These factors are exacerbated by increased demands by the heart and rest of the body during exercise, resulting in increased heart rate, contractility and cardiac output.

Question 49

A 56 year-old man who had a myocardial infarction 2 years previously attends a cardiology outpatient clinic, having complained to his GP _of fatigue and shortness of breath (dyspnoea_) with moderate exercise. His heart rate _is 85 beats per minute_ and his blood pressure when supine is 125/80 mm Hg. A blood sample is taken and cardiac _natriuretic peptide levels are assayed._ The plasma concentration of the inactive Nterminal fragment of proBNP is found to be 300 pM/L (normal 5-50 pM/L). An ultrasound scan reveals some _enlargement of his heart._ His LV end-diastolic and endsystolic volumes are estimated to be 150 mL and 100 mL, respectively. **Why is the patient's exercise capacity impaired?**

Answer 49

• In this patient _LV function is depressed at rest_ and the _extent to which LV pumping capacity can be enhanced in exercise will be reduced also._ • This will l_imit the maximum cardiac output_ which can be achieved in exercise.