Cardiology Flashcards
Define Thrombosis
- Exaggeration of normal haemostatic mechanisms that lead to
- formation of a solid mass within
- the circulating vascular system during life
- made from the blood constituents
Predisposing factors for thrombosis (3)
NB stasis -> turbulence
Mechanism of thrombus formation
- Stasis -> turbulence -> vessel wall damage
- Platelets recruited -> adhere, aggregate+ secrete factors to -> coagulation
- Vascular endothelium controls platelets + coagulation (protect blood)
Features of arterial/cardiac thrombi
- Mainly platelets = pale
- Mural or occlusive depending on vessel size
- Lines of Zahn
Features of venous thrombi
- Mainly blood clot = red
- Usually occlusive
- Lines of Zahn
Lines of Zahn
Light lamination layers - platelet + fibrin
Dark layers - blood
3 locations for cardiac thrombi and precipitating factors
- Atria - appendanges
a) HF = stasis
b) AF = stasis - Valves -> vegetation
a) Rheumatic fever
b) Infective endocarditis
c) Thrombotic endocarditis (Nonbac eg malignancy, SLE) - Ventricles -> mural
a) MI = stasis
b) Cardiomyopathy = stasis
3 precipitating causes of ARTERIAL thrombi
- atherosclerosis -> ruptutre -> mural thrombus = wall
- aneurysms = stasis
- inflammation, vasculitis
Precipitating causes of VENOUS thrombosis
- trauma
- post op (muscle relax, breath pain)
- immobility
- MI
- HF
- pelvic mass inc pregnancy
- thrombophlebitis(rare)
Natural clot resolution sequence
- Resolution = fibrinolysis within clot
- Organisation = ingrowth of granulation tissue (fibroblasts->collagen, phagocytes, capillaries)
- Recanalisation = restore lumen, organised thrombus
- Fibrosis to reconstruct
Main complication of arterial thrombus
ischaemia/infarction
Main complication of venous thrombosis
Embolism
Define embolism
- Passage of an insoluble mass
- within the blood stream
- impaction at a site distant from origin
Commonest places of emboli impaction and origin
- Pulmonary arteries when thrombus is R side of heart
- Systemic arteries when thrombus is from Lheart/aorta
Define ischaemia
- reduced blood supply to tissue/organ
- leading to harm effects due to hypoxia
3 mechanisms of ischaemia. think pipe
- Internal vessel disease
- Occlusion bc thrombus/emboli
- External compression of vessel
Define infarction
- Tissue death due to ischaemia
- usually caused by arterial occlusion
Clinical complications of PE
- Sudden death
- Pulmonary infarction
- Pulmonary hypertension
- Asmptomatic
Coronary artery network
LAD = apex, ant LV, ant IVS
LC = lat LV
RA = post inf LV, post IVS, RV
2 main types of MI
1.Transmural (majority)
- full wall thickness infarct
- usually bc main CA for that area occluded (atherosclerosis)
- sometimes caused by vasopasm/emboli
- see ST elevation + Q waves (STEMI)
2.Subendocondrial
- involves diffuse infarction, least perfused region
- usually due to critical stenosis, without plaque change event (eg triple vessle atheroma)
- see ST depression (NSTEMI)
What is haemopericardium and when does it usually develop
Rupture of LV wall post MI
4-10 days
consider in MI pxs who are having HF symptoms
NB myocardial rupture on free wall -> tamponade
septum -> shunt
pap muscle -> acute severe MR
What is a late >3 month complication of MI due to fibrosis of wall
Cardiac aneurysm
Define Gangrene
Necrosis
w bacterial infection
Rare things that can be emboli
- Fat
- Air/gas
- Tumour
- Amniotic fluid
- Infective material
Layers of arterial wall
Intima - thin, where atherosclerotic plaque lesions occur
Media- full of smooth muscle or elastic
Adventitia - blood supply to artery itself
Constituents of atherosclerotic plaque
Fibrous cap
Lipid core
CT, ECM
smooth muscle and inflamm cells
clinical consequences of atherosclerosis
- stroke
- Mi, CHD, sudden death
- AAA
- Gut ischaemia
- Gangrene of leg
Modifiable and non modifiable RF for atherosclerosis
Non modifiable:
- Age
- male
- FH
- Genetics
Modifiable:
- Hyperlipidaemia
- Hypertension
- Smoking
- Diabetes
NOT exercise
Response to injury hypothesis
Continuous endothelial damage -> inflammation -> plaque formation
Precipitating factors of ischaemic heart disease
- Atherosclerosis (majority)
- Hypertrophy, inc demand
- Inc HR, inc demand
- Hypotension, dec supply
- Hypoxoemia
MI vs Angina
Angina = episodic ischaemia -> pain
MI = prolonged ischaemia -> myocyte necrosis
= raised CrK, Trop
both rise within 4-8 hours of MI
Crk stays for 3 days
trop 10
Define critical stensosis
Atleast 75% cross sectional area of vessel occluded
compensatory vasodilation is insufficient to meet demand
NB less than this w unstable plaque, don’t produce angina but dangerous bc no pre-conditioning
Explain the terms:
- Reperfusion Injury
- Stunned myocardium
- Pre-conditioning
in the context of MI
- Ischaemic tissue gets ox for 1st time = free radical release = 2nd hit
- Saved ischaemic myocytes takes days to recover function
- Rep’d ischaemic hits may prepare tissue to protect from infarction eg via bv formation
Complications post-MI
- Cardiogenic shock (pump failure)
- Arrhythmias -> sudden death
- Late heart failure
4. post infarct unstable angina
- Cardiac rupture (MR, tamponade)
- Pericarditis
- Mural thrombus over scarred infarct
- Ventricular aneurysm
Body’s natural compensatory mechanisms for HF
- Hypertrophy SIZE.
- Dilation to inc preload
- Fluid retention -> inc BP + HR -> CO
NB hypertensive hypertrophy -> AF bc inc stiffness -> atrial load inc
LHF
- organ ischaemia
- pulmonary oedema
RHF
- Peripheral oedema
- congestion of organs
- ascites/ PE
usually secondary to LHF
Cor pulmonale is RHF due to pulmonary hypertension
Cor pulmonale can be acute - straight dilation eg due to PE (LHF cant)
or chronic = hypertrophy -> dilation
Define Valve Stenosis
Failure of valve to open comletely
impedes forward blood flow
Define Valve Regurg/Incompetence + functional regurg
Failure of valve to close completely
due to valve OR environmental abnormality
leads to backward flow
functional regurg - due to ventricle dilation
can be acute OR chronic
Which valve is normally bicuspid
Mitral
Causes and consequences of mitral stenosis
- RHEUMATIC FEVER (99%)
minority congenital
Consequences:
- Inc atrial pressure -> dilatation -> AF -> thromboemboli
- inc atrial pressure -> pul hypertension -> oedema
- Pul hypertension -> RH dilation + failure
What is rheumatic fever and relevance in cardio
Systemic inflammatory disease caused by group A strep infection
usually few weeks after throat infection
multiple infections = cumulative damage = chronic rheumatic heart disease :
- Mitral stenosis (fish mouth, button hole sten)
- Pancarditis
*
symptoms of mitral stenosis
- Exertional dyspnoea
- Fatigue
- Haemoptysis
- Emboli - stroke, PE, cyanosed face
Signs of mitral stenosis
AF
Raised JVP
Malar flush (low CO)
Others - palpable + loud S1 (snap)
RV heave + loud P2 bc pul hypertension
rumbling diastolic
Malar Flush
Indicitave of mitral stenosis because of Co2 retention
NB more commonly because of rosacea, SLE, COPD
Mitral Stenosis
Mid diastolic murmur
Rumbling
slight click after s2 (opening) before wooshing sound
NB can have presystolic murmur if sinus rhythm
Mitral Stenosis
Descending, ascending
Mid diastolic murmur, rumbling
loud S1, open snap
ACCENTUATE IT
Causes of Mitral Regurg (4,4)
PRIMARY (degen) : 1. Valve prolapse ( may be congenital)
- Rheumatic heart disease
- Infective endocarditis
- Collagen diseases
SECONDARY(func): IHD or cardiomyopathy
- Papillary/chordae rupture
- Papillary muscle dysfunction (post MI)
- functional = LV dilation due to HF
- Dilated cardiomyopathy
ACUTE MR presentation
No time for LV dilation to compensate so LA pressure inc -> pulmonary hypertension + oedema
SOB
Fatigue
RHF signs
CHRONIC MR presentation
Same as acute (SOB, fatigue)
+ palpitatons (dilation)
LHF
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MR
Pan systolic
soft S1
Loudest at apex, radiates to axilla
accentuate by expiration, NOT move
may hear S3 w bell, lower pitch than S2
Signs of MR
Displaced apex beat, thrusting
if get LVF -> S3 sound
if get pul hypertension -> RV heave and loud S2
INV for MR
Transthoracic echo
ECG
Medical + surgical management of MR
IF LVF -> diuretics and ACEI
IF AF -> anti-coag + digoxin
treat any systemic hypertension and prophylaxis for infective endocarditis. Observe
Surgical
- valve replacement prosthetic or bioprosthesis (donate or animal)
- valve repair/ring
- mitraclip
- issue: emboli (anticoag), deterioration, infective endocarditis
Causes of AS
- Calcification (most common, elderly > 70)
- Calcification of congenital bicuspid valve (middle age)
- Rheumatic heart disease
Presentation of AS
- Angina
- Breathlessness/HF (LVH on ecg)
- Collapse/syncope
- Death
ABCD
Signs of AS
- Slow rising carotid pulse
- Thrusting apex beat
- Soft/absent S2
- May have LVF (S3), LVHeave
- PP small
AS
Ejection Systolic murmur
loud S1
soft/absent S2
Early AS
Ejection systolic
soft S2
Causes of aortic regurgitation
ACUTE:
- Infective endocarditis
- Aortic dissection (usually due to aortic root dilation)
CHRONIC:
- Rheumatic fever
- Congenital bicuspid aortic valve
- Other eg syphylis, hypertension, CT disorder (lead to dilation of aortic root)
Presentation of AR
- SOB (sudden if acute cause)
- LVF signs
- Fatigue, chronic
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AR
End diastolic murmur
flat woosh after S2