Cardiovascular Pathology Flashcards
What is CVD?
CVD is an umbrella term used to describe all conditions of the heart and blood vessels. Includes congenital
diseases and acquired conditions like IHD, AF, Heart Failure and Stroke.
Affect heart & blood vessels; includes congenital & acquired.
How many people are affected by CVD in the UK?
435 people with lose their lives to CVD today & 530 will go to hospital due to a heart attack
42,000 of these deaths every year occur in those under 75 years of age
7 million people living with CVD (3.5 each male & female), 530 will go to hospital for IHD, 190 die from IHD
What is Ischaemic heart disease?
Definition: generic designation for a group of syndromes resulting from MI
CVD includes IHD
(Ischaemia- imbalance between demand & supply of oxygenated blood to heart)
Aetiology: almost always caused by coronary artery atherosclerosis, sometimes due to hypertrophy
(demand)
What are the 4 IHD syndromes?
- MI- duration and severity of ischaemia causes myocardial death
- Angina Pectoris- ischaemia is less severe and does not cause myocardial death
o Stable angina- typical angina
o Prinzmetal angina- variant form of angina due to vasospasm of artreies NOT due to atherosclerosis
o Unstable angina- crescendo angina - Chronic IHD with heart failure
- Sudden cardiac death
MI, Unstable angina, sudden cardia death= acute coronary syndrome
DUNNO
Cancer taking it over
Coronary heart disease is the UKs single biggesst killer
Prevalence of IHD is highest in Northern England and Scotland.
What are the medical risk factors for IHD?
High blood pressure
Lipid profile abnormalities
High blood cholesterol- now evidence; looking at total LDL not going to give estimate, need to look at
alpha & B lipid subunits (but we can’t do this atm), so we look at ratio of total cholesterol: HDL (higher
ratio- more at risk of developing IHD) or high HDL (better indicator of CVD risk)
Diabetes doubles the risk of developing CVD
What are the lifestyle risk factors for IHD?
(Alcohol cardio protective in small amounts)
Modifiable risk factors (e.g. smoking, physical inactivity & poor diet)
20,000 cardiovasc deaths per year due to smoking in UK
27% adults in UK obese
20,000 cardiovasc deaths per year due to smoking in
What are the therapeutic advances for IHD and why are they effective?
Therapeutic advances have allowed earlier, more effective and safer treatments
People now living with rather than just dying from it
Statins- 2ndry prevention (debate about being a primary preventative drug)
Surgeries- coronary artery bypass grafts, percutaneous coronary intervention
What is the pathogenesis of IHD?
MI is a consequence of reduced blood flow in coronary arteries due to a combination offixed vessel
narrowingandabnormal vascular toneas a result ofatherosclerosisandendothelial dysfunction. This
leads to an imbalance between myocardial oxygen supply and demand
In coronary arteries
o 3 parts (media, intima, adventitia)
o Inflammation to coronary artery- is the trigger
o Cholesterol tries to act as a plaster
o Form an atherosclerotic plaque fibrous cap
o Get typical angina- at rest occlusion of artery but mechanism for vessel to vasodilate to deliver
more blood, but in case where need more oxygen (e.g. climbing stairs) heart needs more O2
angina
o What can then happen;
1.Plaque can continue to grow- after 75% occlusion artery can no longer autoregulate with
vasodilation & heart will undergo changes
2. Erosion of atherosclerotic plaqueplatelet aggregation thrombus unstable angina
If thrombus continues to grow complete
occlusion full transmural occlusion
Acute coronary syndrome- Unstable angina
What is MI?
Death of cardiac muscle from prolonged ischaemia.
Transmural vs Subendocardial; full thickness vs inner one third of the wall (least well perfused)
Subendocardial- inner 1/3 of heart wall (most vulnerable part of endocardium to infarction)
What is the pathophysiology of MI’s?
- Stable atherosclerotic plaque
- Acute plaque changes
- Platelet aggregation
- Thrombus formation
- Coronary artery occlusion
How is coronary artery thrombus formed?
- Can have complete occlusion
- & bleeding into plaque
- Occlusion in 1st 24hrs can’t see changes to naked eye or microscope
- 1st see pale area in subendocardial region then after 2-3 days will be a transmurial infarct
- Then get a transmural infarction
What Myocardium changes are shown in MI ? (TIMELINE)
Myocardium changes
<24h Normal
1-2dy Pale, oedema, myocyte necrosis, neutrophils
3-4dy Yellow with haemorrhagic edge, myocyte necrosis, macrophages
1-3wk Pale, thin, granulation tissue then fibrosis
3-6wk Dense fibrous scar
• Area supplied by coronary artery oedematous
• Neutrophils (acute inflamm cells) – trying to respond to dead cells
• Macrophages then replace neutrophils- chronicity of condition
• Granulation tissue- remains in place for lifetime
Transverse section- yellow pale area with haemorrhagic edge (3-4 days)
What are the complications of MI’s?
- Arrhythmias (change in normal sinus rhythm of heart)- either directly or by limited perfusion to the conduction system structures (SA node, AV node etc)- ischemia’s to those critical strucs
- Congestive cardiac failure- contractility dysfunction (with smaller coronary artery branches- specifically ones that supply papillary muscles that control mitral valve affected) or by papillary muscle infarct/ severe MR (mitral regurg) congestive cardiac failure
- Thromboembolism- if have subendocardial region of infarction tissue now vulnerable & can break off- send fragments of tissue (if on R side of heart pulmonary emboli, if on Lstroke)
- Pericarditis- if inflamm intense enough neutrophils can go through endocardium to pericardium- pericarditis (complication of infarction)
- Ventricular aneurysm- wall weakening, rest of wall continues contracting at normal pace weakened area gets pushed aside & causes aneurysm to ventricle
- Cardiac tamponade- full thiockness of myocardium infacted, becomes so weak that blood rushes into pericardial sac & decompresses the heart (e.g. can have large haematoma encasing heart)
- Cardiogenic shock
Mural thrombus- thrombus formation can occur in heart- if no thrombus formation then that area gets pushed out ventricular aneurysm
What are the complications of MI’s
- Impaired contractility-Ventricular thrombus-Stroke(embolism)
- Impaired contractility-Hypo tension, decreased coronary perfusion, increased ischaemia-Cardiogenic shock
- Tissue Necrosis-papillary muscle infarction-mitral regurgitation-Congestive Heart failure.
- Tissue Necrosis-Ventricular Wall Rupture-Cardiac Tamponade
- Electrical Instabilitty-Arrhythmias
- Pericardial Inflammation-Pericarditis
What are the blood markers for IHD?
Blood Markers of IHD
• Troponins T & I
o Proteins released by damaged myocytes (any muscle damage not specific to heart)
o detectable 2 – 3h, peaks at 12h, detectable to 7 days
o raised post MI but also in pulmonary embolism, heart failure, & myocarditis.
• Creatinine kinase MB
o detectable 2 – 3h, peaks at 10-24h, detectable to 3 days
o Creatine kinase (or creatine phosphokinase)- enzyme mainly in brain, skel muscles & heart
o Elevated level of creatine kinase in heart attacks, heart muscle damage, or conditions that damage skeletal muscles or brain.
o 3 isoenzymes of creatine kinase (CK)-BB, -MM, and -MB
o MB subtype more concentrated in myocardium (also in skel muscle)
o Increased in Polymyositis, rhabdomyolysis, carbon monoxide poisoning, crush injuries, pulmonary embolism, hypothyroidism & muscular dystrophy.
• Myoglobin
o peak at 2h but also released from damaged skeletal muscle
• Lactate Dehydrogenase Isoenzyme I
o peaks at 3days, detectable to 14days
• Aspartate transaminase
o Also present in liver so less useful as a marker of myocardial damage
• All biomarkers detectable within 2-3 hrs
• But take into account that lactate dehdrog also in liver damage
What is hypertension?
• Primary (Idiopathic or Essential) and Secondary
• Definition:
o Blood pressure (BP)- a continuously distributed variable, essential hypertension is one extreme of this distribution rather than a distinct disease (at one end extreme of this distribution rather than an actual disease)
o Detrimental effects of raised BP increase continuously as pressure rises
o Hypertension- a sustained diastolic pressure greater than 90 mm Hg or sustained systolic pressure greater than 140 mm Hg.
Whats the aetiology of Primary Hypertension?
Aetiology of Primary Hypertension
• Majority of patients (90%) have primary essential hypertension of unknown cause
• Assume its; multifactorial, genetics & env
• Environmental;
o Obesity
o Alcohol
o Smoking
o Stress
o Na+ intake (increase salt intake)
• Genetic;
o insulin resistance (metabolic syndrome)
• Metabolic syndrome- combination of diabetes, high BP & obesity;
o Need 3 or more of the symptoms; a certain waist circumference, high triglyceride & low HDL levels in blood, high BP (consistently 140/90mmHg or higher), can’t control blood sugar level (insulin resistance), increased risk of developing blood clots (e.g. DVT), tendancy to develop infalmm
o Risk factors; age (older), race (Asian, African), other conditions (CVD, non-fatty liver disease, polycystic ovary syndrome)
Whats the epidemology of Hypertension?
- Hypertension prevalence in adults of 16 years or older was 31.5% in men and 29.0% in women (2010)
- WHO estimated over 1 billion people worldwide in 2008
- Vulnerability to complications increases with age
- Africans affected more.
How do Hypertrophied Arteries differ from normal?
- 3 layers in vessel; endothelial cells, middle bit- smooth muscle component, outside layer
- Abnormal if hypertension; more cigar shaped nuclei & more layers (smooth muscle hypertrophied) & lumen narrowed
How is BP regulated?
• Aetiology: determined by factors that affect cardiac output & peripheral resistance in BP regulation
What is the Renin-Angiotensin Aldosterone system?
- Role in regulating blood vol & systemic vasc resistance- both influence cardiac output & arterial pressure
- Renin- released by juxstoglomerular apparatus in kidneys-
- When renin is released into blood, it acts oncirculating angiotensinogen, that undergoes proteolytic cleavage to form the decapeptide angiotensin I.
- Angiotensin 1 ACE (from all endothelium cells especially lungs) converts it to ang 2
- Vascular endothelium, particularly in lungs, has an enzyme, angiotensin converting enzyme (ACE), that cleaves off 2 amino acids to form the octapeptide, angiotensin II (AII), although many other tissues in body (heart, brain, vascular) also can form AII.
- Ang 2; constricts blood vessels (has ang 2 receps), stims Na transport in kidneys (increases BP), stimulates aldosterone to be released from adrenal cortex
- Aldosterone- Na & fluid retention (increases BP) by releasing ADH
What is Angiotensin II?
- Constricts resistance vessels (via AII [AT1] receps)- increasing systemic vasc resistance & arterial pressure
- Stims sodium transport (reabsorption) at several renal tubular sites- increasing sodium & water retention
- Acts on adrenal cortex to release aldosterone, which acts on kidneys to increase sodium & fluid retention
- Stims release of vasopressin (antidiuretic hormone, ADH) from posterior pituitary- increases fluid retention by kidneys
- Stimulates thirst centers in brain
- Facilitates norepinephrine release from sympathetic nerve endings & inhibits norepinephrine re-uptake by nerve endings, thereby enhancing sympathetic adrenergic function
- Stims cardiac hypertrophy & vascular hypertrophy
- ACE (angiotensin converting enzyme)- benefit of using ACE Inhibitors in hypertension treatment!
What is Secondary Hypertension?
Affects 5% of those with hypertension
• Cushing’s – adrenal glands stim cortisol – stimulates the sympathetic nervous system and has an aldosterone like action on the kidneys
• Conn’s disease- adrenal gland directly releases aldosterone into blood (bypassing renin & angiotensin) Na+ and water retention = hypertension (increases BP)
• Pheocytochritoma (medical emergy)- vast amount of catecholamines released by adrenal gland (adrenaline & noradrenaline) sympathetic nervous system stim allowing BP to increase
• Aorta coarctation- congenital narrowing of aorta (BP to kidneys reduced- trigger cascade of events that will increase BP)
• Renal artery stenosis- (BP to kidneys reduced- trigger cascade of events that will increase BP) juxtaglomerular apparatus stimulated to produce renin
What is Malignant Hypertension?
• BP >180/120mmHg
• Clinically signs & symptoms of organ damage;
o acute hypertensive encephalopathy
o and/or nephropathy
o with retinal haemorrhages/papilloedema
• Needs urgent treatment to prevent organ damage & preserve organ function
What are the complications of Hypertension?
• Hypertensive Renal disease;
o Renal cortical scarring seen at autopsy- “Flea bitten” kidney
o Flea bitten kidney- petechial haemorrhages & microinfarctions on renal cortical surface (typical of malignant hypertension) which are caused by thromboses in certain arteries
• Hypertensive Cerebrovascular disease-subarachnoid haemorrhage 2ndry to berry aneurysm rupture, lacunar infarcts (stroke from occlusion of small penetrating arteries that provide blood to brain’s deep strucs)
What is Hypertensive heart disease?
• Systemic (left sided) hypertensive heart disease
• In hypertension, heart hypertrophy- adaptive response to pressure overload, can lead to myocardial dilation, congestive heart failure & sudden death.
• Criteria:
o Left ventricular concentric hypertrophy
o History or pathological evidence for hypertension (3 readings of high BP)
• Concentric hypertrophy of the left side & interventricular septum. Right side compressed.
• L ventricle so expanded reduces R ventricle to a slither
What is Cor Pulmonale?
- Pulmonary (right sided) hypertensive heart disease
- Disorders of lung & blood vessels of lung causes R heart failure
- Right ventricular hypertrophy, dilation & potentially heart failure secondary to pulmonary artery hypertension caused by disorders of the lung or pulmonary vasculature.
- Right ventricular hypertrophy secondary to diseases of left side & congenital causes are generally excluded in definition; but pulmonary venous hypertension that follows left sided diseases is quite common.
- Causes;
What are Aneurysms?
- Definition: localised abnormal dilation of a blood vessel or the wall of the heart
- True aneurysm- when bounded by arterial wall components or the attenuated wall of the heart (all layers involved)
- False (pseudoaneurysm) aneurysm- breach in vascular wall intravascular hematoma that freely communicates with the intravascular space (pulsating on outer aspect of arterial wall- ‘pulsating haematoma’)
What is Dissection?
• Arterial dissection arises when blood enters wall of an artery, as a hematoma dissecting between its layers.
• Dissections may, but do not always, arise in aneurysmal arteries.
• Aneurysms and dissections (most importantly when affecting the aorta) can rupture!
• A false aneurysm is diff to dissection as in a false aneurysm- haematoma outside wall (so diff to dissection)
• True aneurysm (affects all 3 components- intima, media & adventitia) (at top);
o Saccular- affects one side
o Fusiform- affects 360 degrees around artery
• False aneurysm- hematoma outside 3 components (intmia etc) that communicates with inside artery
• Dissection- hematoma makes it’s way THROUGH wall of artery (predominantly in media component of wall)
• Aortic dissections can be divided into type A & B;
o Type A- ascending aorta affected
o Type B- only descending aorta affected
• Double barrelled aorta- dissection starts at break in wall of vessel, continues down, can rebreak at bottom, so get another channel (2ndry passageway) on outer aspect of aorta forming (blood flowing down both of these channels)
What causes Aneurysms?
• Aetiology;
o Atherosclerosis
o Cystic medial degeneration- affects media (middle aspect) of artery, cystic degen there allows blood to go through length of vessel
o Trauma
o Congenital defects (can give rise to berry aneurysm in brain)
o Infections (mycotic aneurysms)
• Atherosclerosis and cystic medial degeneration most common cause of AAA.
• Cystic medial degeneration frequently accompanies Marfan syndrome.
• Mycotic aneurysm can be secondary to infective endocarditis
• The obliterative endarteritis characteristic of the tertiary stage of syphilis shows a predilection for small vessels with complications especially in the aorta and nervous system.
Look up:
AAA- localized abdominal aorta enlargement, usually 2cm but can swell to over 5.5cm, most common in men >65yrs, if ruptures internal bleeding (most common symptom of rupture- sudden & severe abdo pain)
Marfan syndrome- connective tissue disorder usually inherited (autosomal dominant)- abnormal fibrillin produc, characteristics; tall, abnormally long slender limbs & fingers & toes, heart defects, lens dislocation
Berry aneurysms- wall weakness causing bulge in blood vessel usually where it branches, usually in abdominal aorta & brain
Mycotic aneurysms (infected aneurysm)- from bacterial infec of arterial wall (common complication of hematogenous spread of bacterial infec classically from the heart), vessel wall can become digested false aneurysm forms
Syphilitic (Leutic) aneurysms- aorta inflamm associated with teritiary stage of syphilis infec (Treponema pallidum) , begins with inflamm of outermost layer of blood vessels aneurysm, coronary artery narrowing, aortic valve insufficiency. Ascending aorta most commonly involved.
What is a Abdominal Aortic Aneurysm?
• Need surgery when over 5 ½ cm • Atheroscelerosis most common cause • Risk factors; o Male o Smoking o Hypertension o Advanced age
What is Heart failure/congestive Cardiac failure?
• Heart can’t pump enough blood needed to meet tissue’s metabolic demands
• R & L ventricles failing
• Occurs insidiously or suddenly;
o Cumulative effects of chronic workload on ventricles (hypertension & valve diseases)- insidious
o Acute heamodynamic stress (fluid overload & large MI)- sudden
Pathogenesis of L sided Heart Failure
Pathogenesis of L Sided Heart Failure
• Cells stretch- try to compensate
• Cells increase their size to try to compensate
• If workload persistent ventricles start to fail, try to compensate by other mechanisms;
o Release norepinenphrine to increase heart rate & myocardial contractility
o Reduc in blood flow to kidneys- active RAAS to increase blood flow (as aadjusts fluid vol, but can be counterproductive pul oedema)
o Release natriuretic peptides from R atrium to decrease vol overload on heart (adjusts fluid vol)- reduce blood vol by excreting water & Na
Clinical effects of L sided failure due to;
• Low cardiac output & hypoperfusion of tissues
• Pulmonary congestion
L Heart Failure (Congestion)
• Heart doesn’t pump enough- back pressure in pulmonary system- causes pulmonary oedema
• Lungs; pulmonary congestion & oedema, heart failure cells
• Dyspnea
• Orthopnea (out of breath, relieved when up right)
• PND (paroxysmal Nocturnal Dyspnea)- feel like your drowning
• Blood tinged sputum- RBCs escape vasculature in alveoli
• Cyanosis
• Elevated pulmonary ‘WEDGE’ pressure (PCWP) (nl= 2-5mm Hg)
L Sided Failure (Low Cardiac Output)
• Reduced kidney perfusion
o Pre-renal azotemia- kidney’s can’t excrete waste products like urea & creatinine (pre-renal failure)
o Renin-angiotensin-aldosterone activation; salt & fluid retention (expansion of interstitial & intravascular fluid vol but can be counterproductive pulmonary oedema)
• Advanced cardiac failure can lead to cerebral hypoxia- irritability, restlessness, stupor & coma
What is R sided Heart Failure?
R Sided Heart Failure
Etiology
• L heart failure can cause R sided failure
• Cor pulmonale (R heart failure due to primary lung disease)
Symptoms & signs
• Fatigue
• Dependant oedema
• Distension of jugular veins
• Liver enlargement
• Ascites
• Anorexia & complaints of GI distress
• Cyanosis
• Elevation in peripheral venous pressure
Symptoms and signs due to
• (engorgement of systemic and portal venous systems)
• Liver and spleen (portal congestion)
o passive congestion (nutmeg liver)
o congestive splenomegaly
o ascites
o Congestion & oedema of bowel wall (can get malabsorption)
• Pleura/Pericardium (systemic venous congestion)
o pleural and pericardial effusions
o transudates
o Oedema of Peripheral and dependent parts of body
What are the cardiac changes in CHF?
- Cardiomegaly
- Chamber Dilatation
- Hypertrophy of myocardial fibers, BOXCAR nuclei
Valvular Abnormalities?
- Congenital
* Acquired
What is Valvular Heart disease?
Valvular Heart Disease (VHD)
Opening probs- STENOSIS
• Failure of valve to open completely impeding forward flow
• Leads to pressure overload of heart
• Almost alwayas due to chronic abnormality of valvular leaflet caused by relatively few disorders
• Acquired Aortic stenosis (AS)
o Calcification of a deformed valve (congenitally bicuspid- under more pressure), (50-70y age)
o “Senile” calcific AS- calcification of anatomically normal aortic valve (>70y age group)
o Rheum, Heart Dis.
• Acquired Mitral stenosis (MS)
o Rheumatic Heart Disease
• Both make 70% of all VHD
Closing probs- REGURGITATION or Incompentence or insufficiency
• Faliure of valve to close completely allowing revearse flow
• Leads to vol overload of heart
• Can result from intrinsic diseqase of valve cusps or damage to supporting strucs
• Has many causes & may appear acutely or chronically
What is Calcific Aortic Stenosis?
- Most common valvular abnormal (2% prevalence rising with increasing life expec)
- Usually consequence of age- related wear & tear of either normal valve or congenital bicuspid aortic valve (bicuspid AV undergoes more mechanical stress so becomes stenotic earlier)
- Role for hyperlipidaemia, hypertension & inflamm in pathogenesis (factors also implicated n atherosclerosis)
- Mitral valve generally normal but can be involved by extension of calcific deposits (calcification can extend to involve mitral valve)
What is Aortic stenosis?
- 2X gradient pressure
- LVH (but no hypertension), ischemia (can produce angina)
- Cardiac decompensation with persistent angina, CHF (congestive heart failure)
- 50% die in 5 years if angina present
- 50% die in 2 years if CHF present
What is RHD?
Rheumatic Heart Disease
• Follows a group A strep infection, a few weeks later
• Body responds, but some antibodies cross react with heart tissue causing damage e.g. myocardial inflammation, vegetation, pericarditis
• DECREASE in “developed” countries
• PANCARDITIS (inflammation of the 3 heart carditis layers):
1. Endocarditis
2. Myocarditis
3. Pericarditis
What is acute RHD?
- Inflammation
- Aschoff bodies
- Anitschkow cells
- Pancarditis
- Vegetations on chordae tendinae at leaflet junction
What is chronic RHD?
- THICKENED VALVES
- COMMISURAL FUSION
- THICK, SHORT, CHORDAE TENDINAE
Mitral valve always involved
MV affected alone in 70% cases, both MV & aortic valve in 25%
TV (tricuspid valve) infreq involved
PV only rarely
What are the clinical features of Acute RF?
Clinical Features of Acute Rheumatic Fever Jones Criteria • Evidence of preceding streptococcal infec • +2 major manifestations • Or 1 major + 2 minor Major manifestations • Migratory polyarthritis • Pancarditis- pericardial friction rub, weak heart sound, arrhythmias • Subcutaneous nodules • Erythema marginatum of skin • Sydenham chorea Minor manifestations • Fever • Arthralgia (pain in a joint) • Elevated acute phase proteins in blood
What are the Clinical features of chronic RHD?
- Appears years after initial rheumatic fever episode
- Depends on which cardiac valve involved
- Cardiac murmurs
- Cardiac hypertrophy & dilation
- Arrhythmias
- Cardiac failure
- Thromboembolic complications
- Infective endocarditis
What are Regurgitations (two types) ?
Regurgitations AR (Aortic Regurg) • Rheumatic • Infectious • Causes of aortic dilatations; o Syphilis o Rheumatoid Arthritis o Marfan MR (Mitral regurg) • MVP (mirtal valve prolapse) • Infectious • Fen-Phen (anti-obesity drug) • Papillary muscles, chordae tendinae (damage to MV strucs also causes MR) • Calcification of mitral ring (annulus)
What is Mitral Valve Prolapse?
• MYXOMATOUS degeneration of the mitral valve • Cause unknown in most cases, associated with connective tissue disorders (marfan syndrome) • “Floppy” valve • 3% incidence, F>>M • Easily seen on echocardiogram Clinical Features • Usually asymptomatic • Mid-systolic “click” • Holosystolic murmur if regurg. present • Occasional chest pain, dyspnea • 97% NO untoward effects (no problems) • 3% Infective endocarditis, mitral valve insufficiency, arrhythmias, sudden death
What is Mitral Annular calcification?
- Degenerative calcification of the mitral “skeleton” (annulus)
- F (>60y)»M
- Usually NO dysfunction
- Regurgitation usually, but Stenosis possible
- Arrhythmias & sudden death; deep penetration of calcium deposits impinging on atrioventricular conduction system
- Increased risk of infective endocarditis & embolic stroke from dislodged overlying thrombi
What is the meaning of congenital heart defects?
- Abnormalities of the heart & great vessels present from birth
- May not be evident until adult life (Coarctation, ASD)
- Faulty embryogenesis (week 3-8)
- Usually MONO-morphic (i.e., SINGLE lesion) (ASD, VSD, hypo-RV, hypo-LV)
- Overall incidence 1% of births
What are common malformations of congenital heart defects?
Highlighted D = LR shunt, T= R to L shunt (cyanosis, or “blue” babies) • Ventricaular septal Defect (42% per million live births) • Atrial Septal Defect (10%) • Pulmonary stenosis (8%) • Patent Ductus arteriosus (7%) • Tetralogy of fallot (5%) • Coarctation of aorta (5%) • Atrioventricular septal Defect (4%) • Aortic stenosis (4%) • Transposition of great arteries (4%) • Truncus arteriosus (1%) • Total anomaluous pulmonary venous connection (1%) • Tricuspid atresia
What are Sporadic Genetic Abnormalities in congenital heart diseases?
- Main known causes of congenital heart diseases
- Gene abnormalities in only 10% of CHD
- Trisomies 21 (Down), 13, 15, 18 & monosomy; XO (Turners syndrome)
- Mutations of genes which encode for transcription factors; TBX5= ASD, VSD, NKX2.5= ASD
- Deletion of Chr 22q11.2(chromosome 22 important in heart development)=conotruncus, abnormal development of thymus & parathyroid (DiGeorge syndrome)
What are environmental factors in congenital heart diseases?
- RUBELLA (congenital rubella syndrome) (in early preg)
- Gestational diabetes
- TERATOGENS
What is the stages in heart development?
- Heart formed by cells from lateral mesoderm
- Migrate in 2 waves
- By day 21 2nd wave of cells
- Heart properly formed by day 50
Atrial septal defect=
• Pressure moves from R to L
• Ventric septal defect L to R
• All increase pulmonary pressure= damage pulmonary arterioles
• When pul pressure high enough, blood moves from R to L – Eisenmenger syndrome
What are the 3 groups of Congenital Heart Disease?
- L to R SHUNTS: all “D’s” in their names
• NO cyanosis
• Pulmonary hypertension
• SIGNIFICANT pulmonary hypertension is IRREVERSIBLE
ASD, VSD, AVSD, PDA - R to L SHUNTS: all “T’s” in their names
• CYANOSIS (i.e., “blue” babies)- pressure on R exceeds pressure on L; deoxygenated blood in systemic circ
• VENOUS EMBOLI become SYSTEMIC “paradoxical” emboli
Tetralogy of fallot , Transposition of great arteries, Truncus arteriosus , Total anomalous pulmonary venous connection , Tricuspid atresia - OBSTRUCTIONS:
• Coarctation of aorta or aortic/ pulmonary valve stenosis
What is ASD?
• Abnormal fixed opening in atrial septum caused by incomplete tissue formation- allows communic of blood between L & R atria
• NOT patent foramen ovale (which is a flap like tissue that lets blood flow from R to L in foetus, closes after birth as pressure from R decreases & L increases when pulmonary circ starts working)
• Usually asymptomatic until adulthood
• 3 types of AD;
o SECUNDUM (90%): Defective fossa ovalis (not well formed), is near center of atrial septum
o PRIMUM (5%): Next to AV valves, mitral cleft
o SINUS VENOSUS (5%): Next to SVC entrance with anomalous pulmonary veins draining to SVC or RA
• Usually asymptomatic until adulthood
• Mortality low following repair
What is VSD?
• Most common CHD defect
• Only 30% are isolated
• Often with TETRALOGY of FALLOT
• Classified according to size & location;
o 90% involve the membranous septum (membranous VSD)
o 10% involve muscualr septum or lie below pulmonary valve (infundibular VSD)
• If muscular septum is involved, can have multiple holes (“swiss-cheese”septum)
• SMALL ones often close spontaneously
• LARGE ones progress to pulmonary hypertension
What is Tetralogy of Fallot ?
Most COMMON
1. VSD, large
2. OBSTRUCTION to RV outflow tract (subpulmonary stenosis)
3. Aorta OVERRIDES the VSD
4. RVH
• Due to anterosuperior displacement of infundibular septum during embryogenesis
• SURVIVAL DEPENDS on SEVERITY of SUBPULMONIC STENOSIS
• Classical TOF is a cyanotic congenital heart disease
• Can be a “PINK” (not cyanotic) tetralogy if subpulmonic obstruction is small, but the greater the obstruction, the greater is the R to L shunt
What is Obstructive CHD ?
Pulmonary stenosis/atresia
-Aortic stenosis/atresia
-COARCTATION of aorta*
• M>F (2:1)
• But females with Turner’s syndrome (XO) frequently have it
• 2 classical forms;
o INFANTILE FORM (proximal to PDA- patent ductus arteriosus) (SERIOUS)
Shunting of deoxygenated blood via PDA produces cyanosis in lower half of body
o ADULT FORM (CLOSED DUCTUS, i.e. NO PDA)
Typically hypertension in upper extremities & hypotension & weak pulses in lower extremities & features of atrial insufficiency (caludication & coldness)
Development of collateral circ between pre-coarctation arterial branches & post-coarctation arteries through enlarged intercostal & internal mammary arteries causing visible erosions (notching) of undersurface of ribs
• Bicuspid aortic valve 50% of the time
