structural heart disease

Question 1

what are the basic phases of systole?

Answer 1

systole:
contraction
3 parts
1/3 of total beat

phase2 - isovolumetric contraction:
heart depolarisation, ventricles contract (QRS complex)
mitral valve closes - first heart sound
pressure increases in left ventricle, but volume doesnt change (it is at end diastolic volume)

phase3 - rapid ejection:
pressure in LV continues to rise until it is above that of the aorta
the aortic semilunar valve opens
pressure in LV and aorta continues to rise
volume in LV decreases

phase4 - reduced ejection:
repolarisation gives T wave on ECG
pressure in LV and aorta starts to decrease
the aortic valve closes - gives second heart sound
ventricular muscle relaxes

Question 2

what are the basic phases of diastole?

Answer 2

diastole:
relaxation
4 parts
2/3 of beat

phase5 - isovolumetric relaxation:
pressure in LV decreases
mitral valve is still closed, so volume in LV stays the same (end systolic volume)

phase6 - rapid passive filling:
pressure in LV is lower than LA, so mitral valve opens
volume in LV starts to increase passively
but pressure in LV remains the same pretty much

phase7 - reduced passive filling:
ventricular volume increases more slowly

phase1 - atrial systole:
atria almost full from passive filling
they contract to top up volume in them 
P wave on ECG
contributes more to filling during exercise

Question 3

what is the equation stroke volume?

Answer 3

end diastolic volume - end systolic volume

Question 4

what are structural heart disease?

Answer 4

covers a number of defects which affect the valves and chambers of the heart and aorta

can be congenital
or develop later in life (eg. due to infection)

congenital - eg. atrial septal defect, ventricular septal defect, coarctation of the aorta, patent foramen ovale, patent ductus arteriosus, tetralogy of fallot

develop later in life - eg. can be due to valvular dysfunctions ( atrial stenosis/regurgitation or muscular (cardiomyopathies))

Question 5

what is ventricular septal defect?

Answer 5

VSD
congential

hole in wall between ventricles

leads to mixing of oxygenated and deoxygenated blood

presents in children with:
poor weight gain
poor feeding
palpitations

sometimes small enough to close on its own
if too big, requires surgery

Question 6

what is tetralogy of fallot?

Answer 6

TOF
congenital

involves 4 defects

1. Ventricular septal defect
2. pulmonary stenosis (pulmonary trunk)
3. widening of the aortic valve- so wide it opens into both ventricles (also due to the VSD) and oxygenated and deoxygenated blood mix
4. right ventricular hypertrophy

need to undergo many surgeries to correct these defects

Question 7

what is atrial septal defect?

Answer 7

ASD
congenital

hole in wall between two atria

Question 8

what is coarctation of the aorta?

Answer 8

congenital

narrowing in wall of descending aorta

ventricle must work much harder to force blood through this narrowing to allow enough blood to be ejected in each stroke

can lead to thickening of the ventricles or heart failure

requires urgent repair

Question 9

what are valvular defects?

Answer 9

most common:

aortic stenosis (narrowing of aortic valve)
aortic regurgitation (incompetence of the aortic valve, leads to backflow)

mitral stenosis (narrowing)
mitral regurgitation (incompetence, leading to backflow)

Question 10

what is the epidemiology of valvular heart disease?

Answer 10

rheumatic heart disease:
biggest cause of problems that can lead to valvular heart disease in developing countries
25-49 Yrs are most commonly effected
higher prevalence in females

calcific aortic valve disease:
highest prevalence above 70 years
equal distribution between men and women

degenerative mitral valve disease:
seen most from 70 onwards
more in females than males

Question 11

what is the aetiology of aortic stenosis?

Answer 11

most common valvular disease in the US and Europe requiring treatment

second most frequent cause for heart surgery

largely a disease of older people (70+)

preceded by aortic sclerosis (aortic valve thickening without flow limitation)

often suspected by the presence of an early peaking, systolic ejection murmur, and confirmed by Echocardiography

Question 12

what are risk factors and causes for aortic stenosis?

Answer 12

hypertension
LDL levels
smoking
elevated CRP
congenital bicuspid valves (more prone to wear and tear and infections)
chronic kidney disease (more prone to infection)
radiotherapy 
older age

causes:
most common is rheumatic heart disease (in developing countries)
congenital heart disease
calcium build up
infective endocarditis

Question 13

what is the pathophysiology of aortic stenosis?

Answer 13

the valvular endocardium is damaged - as the result of abnormal blood flow across the valve (in the case of a bicuspid valve - abnormal) or by an unknown trigger

endocardial injury initiates an inflammatory process - similar to atherosclerosis and ultimately leads to leaflet fibrosis and deposition of calcium on the valve

progressive calcium deposition and fibrosis - limit aortic leaflet mobility and eventually produce stenosis

In aortic valve stenosis,
there is narrowing which prevents the valve from completely opening and facilitating the
flow of blood into systemic circulation through the aorta.

in the case of rheumatic disease - an autoimmune inflammatory reaction is triggered by prior streptococcus infection that targets the valvular endothelium, leading to inflammation and eventually calcification

Question 14

what is the result of aortic stenosis?

Answer 14

leads to long standing pressure overload -> left ventricular hypertrophy

concentric left ventricular hypertrophy (Sarcomeres are added in parallel to
existing ones). This pathophysiological response is to support a greater contractile force
to open the valve.

ventricle tries to maintain a normal wall stress (pressure increases but it tries to reduce radius. this effects edv capacity) despite the pressure overload produced by stenosis ->
as the stenosis worsens, the adaptive mechanism fails and left ventricular wall stress increases

systolic function declines as wall stress increases
resultant systolic heart failure

Question 15

what is the history and presentation of aortic stenosis?

Answer 15

presentation:
exertional dyspnoea and fatigue
chest pain
ejection systolic murmur (>3/6 is present with crescendo-decrescendo pattern that peaks mid systole and radiates to the carotid)

history:
rheumatic fever
high lipoprotein
high LDL
chronic kidney disease
age over 65

Question 16

what investigations are done for aortic stenosis?

Answer 16

transthoracic echocardiography (can see the structure of the walls and any problems, very helpful)
ECG 
chest X-ray (LVH)
cardiac catheterisation
cardiac MRI

Question 17

how is aortic stenosis managed?

Answer 17

usually aortic valve replacement (AVR):

first line in patients who are symptomatic
or in asymptomatic patients with an ejection fraction <50%, or who are undergoing other cardiac surgery
AVR may be considered in asymptomatic patients with rapid progression, an abnormal exercise test, or elevated serum B natriuretic peptide (BNP)

balloon aortic valvuloplasty

antihypertensives

ACE inhibitors

Statins

Question 18

what is the aetiology of aortic regurgitation?

Answer 18

the diastolic leakage of blood from the aorta back into the left ventricle

occurs due to incompetence of valve leaflets resulting from either intrinsic valve disease or dilation of the aortic root

it is not as common as aortic stenosis or mitral regurgitation

chronic -> culminate into congestive heart failure

acute -> medical emergency, presenting with sudden onset of pulmonary oedema and hypotension or cardiogenic shock

Question 19

what are the causes of aortic regurgitation?

Answer 19

congenital and acquired:
rheumatic heart disease
infective endocarditis
aortic valve stenosis
congenital heart defects
congenital bicuspid valves

from aortic root dilation:
marfans syndrome
connective tissue disease/ collagen vascular disease
idiopathic
ankylosing spondylitis
traumatic

Question 20

what is the pathophysiology of acute aortic regurgitation?

Answer 20

infective endocarditis can lead to rupture of leaflets or even paravalvular leaks.

Vegetations on the valvular cusps can also cause inadequate closure of leaflets, resulting in leakage of blood.

Chest trauma can cause tear in ascending aorta leading to AR

Question 21

what is the pathophysiology of chronic aortic regurgitation?

Answer 21

Bicuspid aortic valve

Rheumatic fever -> fibrotic changes causing thickening and retraction of leaflets

Question 22

what happens as a result of acute aortic regurgitation?

Answer 22

Increase blood volume in LV during systole ->

LV end diastolic pressure increases->

increase in pulmonary venous pressure->

dyspnea and pulmonary oedema->

heart failure->

cardiogenic shock

Question 23

what happens as a result of chronic aortic regurgitation?

Answer 23

gradually increase in LV volume->

LV enlargement and eccentric hypertrophy
Early stages->

Ejection fraction normal or slightly increase->

after some time, Ejection fraction falls and LV end systolic volume rises

Eventually LV dyspnoea ->

lower coronary perfusion ->

ischemia, necrosis and apoptosis

Question 24

how does aortic regurgitation present?

Answer 24

Acute AR:

Cardiogenic shock
Tachycardia
Cyanosis
Pulmonary oedem

Chronic AR:

Wide pulse pressure
Pistol shot pulse (Traube sign)

Question 25

what investigations are done for aortic regurgitation?

Answer 25

Transthoracic echocardiography Chest X ray Cardiac catheterisation Cardiac MRI/CT Scan

Question 26

how is aortic regurgitation managed?

Answer 26

acute: Ionotropes/vasodilators valve replacement & repair chronic: asymptomatic - If LV function is normal can be managed by drugs or reassurance symptomatic - First line is valve replacement with adjunct vasodilator therapy prevention: Treat Rheumatic fever and infective endocarditis. (eg. antibiotics)

Question 27

what is the aetiology of mitral stenosis?

Answer 27

Obstruction to left ventricular inflow at the level of mitral valve due to structural abnormality of the mitral valve Rheumatic fever is the main cause ( in developing countries) As disease progresses it leads to pulmonary hypertension and right heart failure occurs

Question 28

what are the causes of mitral stenosis?

Answer 28

``` rheumatic fever carcinoid syndrome use of ergo/serotonergic drugs SLE mitral annular calcification due to ageing amyloidosis rheumatoid arthritis whipple disease congenital deformity of the valve ```

Question 29

what is the pathophysiology of mitral stenosis?

Answer 29

Stenosis of the valve typically occurs decades after the episode of acute rheumatic fever Acute insult leads to formation of multiple foci and infiltrates in the endo and myocardium and along the walls of the vales With passage of time it gets thickened , calcified and contracted resulting in stenosis

Question 30

what happens as a result of mitral stenosis?

Answer 30

Initially moderate exercise or tachycardia result in exertional dyspnoea due to increased left atrial pressure Severe mitral stenosis leads to increase in left atrial pressure , transudation of fluid into the lung interstitium leading to dyspnoea at rest or exertion due to back pressure increase in the pulmonary circulation Pulmonary hypertension may develop as the result of it The restricted orifice limits filling of left ventricle limiting cardiac output Hemoptysis if bronchial vein rupture

Question 31

how does mitral stenosis present?

Answer 31

``` H/0 of Rheumatic fever Dyspnoea orthopnoea Diastolic murmur Loud P2 Neck vein distention Hemoptysis 40-50 years age ```

Question 32

what investigations are done for mitral stenosis?

Answer 32

``` ECG Transthoracic echocardiography (can be bedside) Chest X ray Cardiac catheterisation Cardiac MRI/CT Scan ```

Question 33

how is mitral stenosis managed?

Answer 33

Progressive asymptomatic: No therapy required Severe asymptomatic: no therapy generally required adjuvant balloon valvotomy Severe symptomatic: diuretic, balloon valvotomy, valve replacement & repair adjunct beta blockers

Question 34

what is the aetiology of mitral regurgitation?

Answer 34

Abnormal reversal of blood flow from the left ventricle to the left atrium. It is the most frequent valvular heart disease It is caused by the disruption in any part of the mitral valve apparatus

Question 35

wha are the causes of mitral regurgitation?

Answer 35

``` acute: mitral calve prolapse rheumatic heart disease infective endocarditis following valvular surgery prosthetic mitral valve dysfunction ``` ``` chronic: rheumatic heart disease SLE scleroderma hypertrophic cardiomyopathy drug related ```

Question 36

what is the pathophysiology of mitral regurgitation?

Answer 36

MI causing damage to the papillary muscles, thus the chordae tendinea cannot effectively hold the valve closed. Infective endocarditis, Rheumatic fever: Inflammatory condition which initiates leaflet fibrosis. Infectious endocarditis: Abscess formation, vegetations, rupture of chordae tendineae and leaflet perforation

Question 37

what happens as a result of mitral regurgitation?

Answer 37

Chronic MR: progression leads to eccentric hypertrophy leading to elongation of myocardial fibres and increased left end diastolic volume Increase in preload & a decrease in afterload -> increase in end- diastolic volume -> and a decrease in end-systolic volume Eventually prolonged volume overload leads to left ventricular dysfunction and increased left ventricular end-systolic diameter this all leads to heart failure later on in life

Question 38

how does mitral regurgitation present?

Answer 38

``` Dyspnea diminished S1, murmur high Fatigue pitched, blowing xx Orthopnea Chest pain Atrial fibrillation ```

Question 39

what investigation are done for mitral regurgitation?

Answer 39

``` ECG Transthoracic echocardiography Chest X ray Cardiac catheterisation Cardiac MRI/CT Scan ```

Question 40

how is mitral regurgitation managed?

Answer 40

Acute MR: Emergency Surgery adjunct preoperative diuretics adjunct intra-aortic balloon counterpulsation Chronic asymptomatic: 1st ACE inhibitors Beta blockers if left ventricular ejection fraction is less than 60%, 1st line is surgery Chronic symptomatic: 1st surgery plus medical treatment If left ventricular ejection fraction is less than 30% 1st line is Intra-aortic balloon counterpulsation

Question 41

what is cardiomyopathy?

Answer 41

Cardiomyopathy is a disease of the heart muscle that makes it harder for heart to pump blood to rest of your body It can lead to heart failure Main types are: Dilated Hypertrophic Restrictive

Question 42

what is the aetiology of dilated cardiomyopathy?

Answer 42

The estimated prevalence of dilated cardiomyopathy is 1:2500. This condition is among the most common causes of heart failure. Dilated cardiomyopathy may manifest clinically at a wide range of ages, but this condition most commonly occurs in the third or fourth decade of life. Dilated cardiomyopathy is a progressive, usually irreversible, disease causing global systolic (contractile) dysfunction with heart failure.

Question 43

what are the causes of dilated cardiomyopaty?

Answer 43

familial (25%) idiopathic ``` secondary: heart valve disease after child birth thyroid disease myocarditis alcoholism autoimmune disorders drugs mitochondrial disorders ```

Question 44

what is the pathophysiology of dilated cardiomyopathy?

Answer 44

Dilated cardiomyopathy is characterized by left ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness. the hallmark gross finding at autopsy is left ventricular dilatation, usually more than 4 cm.  Familial DCM is a genetic condition. In rare autosomal dominant inheritance patterns (at least two family member have idiopathic DCM), first degree relatives (parents, siblings, children) have a 50 percent chance of inheriting the condition

Question 45

what happens as as a result of dilated cardiomyopathy?

Answer 45

Enlargement of the left ventricle lower ejection fraction and increase in the ventricular wall stress and end systolic volumes. Early compensatory mechanisms include an increase in heart rate and tone of the peripheral vascular system. neurohormonal activation of the renin-angiotensin aldosterone system and an increase in circulating levels of catecholamines. levels of natriuretic peptides are also increased. helps heart to contract more often to eject the blood in the ventricles Eventually these compensatory mechanisms become overwhelmed and the heart fails.

Question 46

how does dilated cardiomyopathy present?

Answer 46

``` Dyspnoea, displaced apex beat due to enlargement of LV, S3 or systolic murmur fatigue, angina, pulmonary congestion low cardiac output ```

Question 47

what are the investigation for dilated cardiomyopathy?

Answer 47

``` Genetic Testing Viral serology ECG Chest X ray Cardiac catheterisation Cardiac MRI/CT Scan Exercise stress test Echocardiography ```

Question 48

how is dilated cardiomyopathy managed?

Answer 48

counselling, life long condition, chances of familial inheritance diet modification, fluid and sodium restriction treat any underlying conditions if heart failure: ACE inhibitors, beta blockers, diuretics last line is heart transplant

Question 49

what is the aetiology of hypertrophic cardiomyopathy?

Answer 49

Hypertrophic cardiomyopathy (HCM) is a genetic cardiovascular disease. It is defined by an increase in left ventricular wall thickness that is not solely explained by abnormal loading conditions. HCM is the leading cause of sudden cardiac death in preadolescent and adolescent children. Familial HCM occurs as an autosomal dominant Mendelian-inherited disease in approximately 50% of cases. Most patients with HCM are asymptomatic. Unfortunately, the first clinical manifestation of the disease in such individuals may be sudden death, likely from ventricular tachycardia or fibrillation.

Question 50

what is the pathophysiology of hypertrophic cardiomyopathy?

Answer 50

The hallmark of the disorder is myocardial hypertrophy that is inappropriate, often asymmetrical, and occurs in the absence of an obvious hypertrophy stimulus. This hypertrophy can occur in any region of the left ventricle but frequently involves the interventricular septum, which results in an obstruction of flow through the left ventricular (LV) outflow tract.

Question 51

what happens as a result of hypertrophic cardiomyopathy?

Answer 51

Most patients with HCM have abnormal diastolic function, which impairs ventricular filling and increases filling pressure, despite a normal or small ventricular cavity. These patients have abnormal calcium kinetics and subendocardial ischemia, which are related to the profound hypertrophy and myopathic process. cant keep up with required cardiac output

Question 52

how does hypertrophic cardiomyopathy present?

Answer 52

``` Sudden cardiac death Double carotid artery impulse, S3 gallop, Syncope ejection systolic murmur Presyncope Congestive heart failure Dizziness Palpitations Angina ```

Question 53

what investigations are sone for hypertrophic cardiomyopathy?

Answer 53

Hemoglobin level: Anemia exacerbates chest pain and dyspnea Brain natriuretic peptide (BNP), troponin T levels: Elevated BNP, NT-proBNP, and troponin T levels are associated with a higher risk of cardiovascular events, heart failure, and death Echocardiography Chest Xray Cardiac MRI

Question 54

how is hypertrophic cardiomyopathy managed?

Answer 54

beta blockers, if side effects, switch to verapamil and calcium channel blockers more medications can be added if patient is not responding if all else fails, mechanical therapy is needed ( eg. pacemaker) or surgery, to remove excess septal muscle

Question 55

what is the aetiology of restrictive cardiomyopathy?

Answer 55

It is a  less well-defined cardiomyopathy as its diagnosis is based on establishing the presence of a restrictive ventricular filling pattern. It is characterized by diastolic dysfunction with restrictive ventricular physiology, whereas systolic function often remains normal. Atrial enlargement occurs due to impaired ventricular filling during diastole, but the volume and wall thickness of the ventricles are usually normal. the ventricular walls are abnormally stiff RCM accounts for approximately 5% of all cases of diagnosed cardiomyopathies It may be idiopathic, familial (has been related to troponin I or desmin mutations, the latter often in association with a skeletal myopathy), or associated with various systemic disorders, such as haemochromatosis, amyloidosis, sarcoidosis, Fabry's disease, carcinoid syndrome, scleroderma, anthracycline toxicity, or previous radiation. 

Question 56

what is the pathophysiology of restrictive cardiomyopathy?

Answer 56

Increased stiffness of the myocardium due to familial or other secondary causes e.g amyloidosis Infiltrative cardiomyopathies are characterized by deposition of abnormal substances (ie, amyloid proteins, noncaseating granulomas, iron) within the heart tissue. Infiltration causes the ventricular walls to stiffen, leading to diastolic dysfunction. Restrictive physiology predominates in the early stages, causing conduction abnormalities and diastolic heart failure. Adverse remodelling may lead to systolic dysfunction and ventricular arrhythmias in advanced cases.

Question 57

what happens as a result of restrictive hypertrophy?

Answer 57

 Increased stiffness of the myocardium causes ventricular pressures to rise precipitously with small increases in volume. Thus, accentuated filling occurs in early diastole and terminates abruptly at the end of the rapid filling phase. Patients typically have reduced compliance (increased diastolic stiffness), and the left ventricle cannot fill adequately at normal filling pressures Reduced left ventricular filling volume leads to a reduced cardiac output.

Question 58

how does restrictive cardiomyopathy present?

Answer 58

comfortable in the sitting position because of fluid in the abdomen or lungs, and they frequently have ascites and pitting edema of the lower extremities. The liver is usually enlarged and full of fluid, which may be painful. Weight loss and cardiac cachexia are not uncommon. Easy bruising, periorbital purpura, macroglossia, and other systemic findings, such as carpal tunnel syndrome, should be an indication for the clinician to consider amyloidosis. Increased jugular venous pressure is present. The pulse volume is decreased, consistent with decreased stroke volume and cardiac output.

Question 59

what investigations are done for restrictive cardiomyopathy?

Answer 59

``` CBC Serology Amylodosis check Chest Xray ECG Echocardiography, Catheterisation MRI/Biopsy ```

Question 60

how is restrictive cardiomyopathy managed?

Answer 60

Heart failure medication: Guideline-directed medical therapy for heart failure, including angiotensin-converting enzyme inhibitors or angiotensin receptor II blockers, diuretics and aldosterone inhibitors should be initiated in patients with reduced LV Antiarrhythmic Therapy Immunosuppression- Steroids (eg. for amyloidosis) Pacemaker Cardiac transplantation, last choice