Diseases of the Cardiovascular System (29) Flashcards
What’s the most common cause of death in women in UK?
CVD
Cancer
Resp disease
What’s the most common cause of death in men in UK?
Cancer
CVD
CHD
Resp
Ischaemic heart disease
Inadequate blood supply to the myocardium
IHD is due to
Reduced coronary blood flow, almost always due to atheroma +/- thrombus, myocardial hypertrophy - systemic hypertension
Pathogenesis
Auto-regulation of coronary blood flow breaks down if >75% occlusion, low diastolic flow (subendocardial), active aerobic metabolism of cardiac muscle, myocyte dysfunction, recovery possible if rapid reperfusion (15-20min)
Typical/stable angina
Fixed obstruction, predictable relationship to exertion
Crescendo/unstable angina
Often due to plaque disruption, red flag symptom
Variant/prinzmetal angina
Coronary artery spasm (Ca channel blockers)
Acute coronary syndrome
Acute MI (+/- ST elevation), crescendo/unstable angina
IHD syndromes
- Angina pectoris
- Acute coronary syndrome
- Sudden cardiac death
- Chronic ischaemic heart disease
Acute ischaemia
Atheroma + acute thrombosis/haemorrhage, lipid rich plaques, transmural MI, thrombolysis, myocardial stunning (contractile abnormality)
Diagnosis of acute ischaemia
Clinical, ECG, blood cardiac proteins
Subendocardial MIs
Poorly perfused, can infarct without any acute coronary occlusion if acute hypotensive episode/stable athermanous occlusion of coronary artery, non-elevation, involves innermost layer of myocardium doesn’t extend to epicardium
MI morphology
Normal
MI morphology 1-2 days
Pale, oedema, yellow infarct, myocyte necrosis, neutrophils
MI morphology 3-7 days
Yellow with haemorrhagic edge, myocyte necrosis, macrophages
MI morphology 1-3 weeks
Pale, thin, red/gray granulation tissue then fibrosis
MI morphology 3-6 weeks
Dense fibrous scar (collagen)
Blood markers of cardiac myocyte damage
- Troponins T & I
- Creatine kinase MB
- Myoglobin
- Lactate dehydrogenase isoenzyme 1
- Aspartate transaminase
Troponins T & I
- Detectable 2-3hrs-7 days, peaks 12 hours
- Raised post MI, P.E, heart failure and myocarditis
Creatine kinase MB
- Detectable 2-3hrs-3 days, peaks 10-24 hours
- Not very specific - skeletal muscle damage
Myoglobin
- Peaks at 2hr
- Released from damaged skeletal muscles
Lactate dehydrogenase isoenzyme 1
Peaks at 3 days, detectable until 14 days
Aspartate transaminase
Present in liver - not v.useful
Which is most useful marker of cardiac myocyte damage?
Troponins T & I
Prognosis of MI
20% 1-2hr mortality - sudden cardiac death
Complications of MI (80-90%)
Arrhythmias, ventricular fibrillation, sudden death, ischaemic pain, LV failure, shock, pericarditis, cardiac mural thrombus and emboli, DVT, P.E, myocardial rupture (tamponade, ventricular septal perforation, papillary muscle rupture), ventricular aneurysm, autoimmune pericarditis (Dressler’s) +/- pleurisy 2 weeks-months post, haemopericardium
Common MI complications
Ventricular fibrillation, LV failure, DVT and PE
Chronic IHD
Coronary artery atheroma produces relative myocardial ischaemia and angina pectoris on exertion, risk of sudden death/MI, possible previous MIs, crescendo/unstable angina (evolving plaque), variant angina (spasm)
Familial hypercholesterolaemia
Mutations in LDL receptor gene/apolipoprotein B
Familial hypercholesterolaemia heterozygotes
Xanthomas (yellow nodules) in tendons, perioccular, corneal arcus and early atherosclerosis
Familial hypercholesterolaemia heterozygotes treatment
Statins (hydroxymethyglutaryl CoA reductase inhibitors)
Familial hypercholesterolaemia homozygotes treatment
More complex and less effective
Blood pressure is physiologically regulated to
Ensure perfusion of organs sufficient to maintain function, prevents higher flow (that exceeds metabolic demands and increases damage to blood vessels and organs)
Hypertension
140/90 mmHg
What controls BP
Cardiac baroreceptors, RAAS, Kinin-kallikrein system, Naturetic peptides, Adrenergic receptor system, Autocrine factors produced by blood vessels, Autonomic NS, Na balance
Renin
Synthesised, stored in, released from juxtaglomerular apparatus in wall of afferent arterioles of the kidney, cleaves angiotensinogen > angiotensin I
Angiotensin 2
Vasoconstrictor, short half-life, stimulates adrenal cortex to produce aldosterone
Alodsterone
Mineralcorticoid, causes sodium and water retention, circulating blood vol increase
Renal artery stenosis
Reduced bp in kidneys and afferent arterioles, juxtaglomerular apparatus stimulates renin, RAAS stimulates adrenal cortex zone glomerulosa cells > aldosterone
Coarctation of aorta
Congenital narrowing, distal to original of left subclavian artery, RAAS activated, asymptomatic, difference in bp between arms and legs, chest x-ray
Treatment of coarctation of aorta
Surgery
Conn’s syndrome
Excess aldosterone secretion
Conn’s syndrome due to
Adrenocortical adenoma, micronodular hyperplasia
Conn’s syndrome causes
Renal sodium and water retention (hypertension), elevated aldosterone, low renin, potassium loss
Low potassium
Muscular weakness, cardiac arrhythmias, paraesthesia, metabolic alkalosis
Diagnosis of Conn’s syndrome
CT scan of adrenal glands and metabolic abnormalities
Phaeochromocytoma
Catecholamine secreting tumour of adrenal medulla (Vasoconstrictors - adrenaline and noradrenaline)
Phaeochromocytoma symptoms
Pallor, headaches, sweating, nervousness, hypertension
Phaeochromocytoma diagnosis
24hr urine collection for adrenaline metabolites
Cushing’s syndrome
Any steroid, caused by any source
Cushing’s disease cause
- Adrenocortical neoplasm (adenoma)
- Pituitary adenoma
- Paraneoplastic effect of other neoplasms producing adrenocorticotrophic hormone stimulates zona fasciculata cells on adrenal cortex
Cushing’s disease
Overproduction of cortisol by adrenal cortex
Cortisol’s effect
Increases sympathetic NS, aldosterone-like action on kidney > hypertension
Hypertensive effect on heart
Hypertensive heart disease, LV hypertrophy without dilataion > sudden death
Hypertensive effect on kidney
Renal failure (arterial intimal fibroelastosis, hyaline arteriolosclerosis)
Hypertensive effect on cerebrovascular
Hypertensive encephalopathy, increased risk of rupture abnormal arteries (atheromatous > intracerebral haemorrhage/berry aneuyrm > SAH)
Hypertensive crisis
BP >180/120 mmHg
Acute hypertensive encephalopathy, renal failure, retinal haemorrhages
Acute hypertensive encephalopathy presentation
Confusion, vomiting, convulsions, raised ICP coma and death
Pulmonary hypertension
Higher than normal pressure in pulmonary artery
Pulmonary hypertension caused by
- Loss of pulmonary vasculature
- Secondary LV failure
- Systemic to pulmonary artery shunting
- Primary/idiopathic
(Not high bp)
Pulmonary hypertension leads to
- Increased RV work
- RV hypertrophy without dilatation
- Dilatation and systemic venous congestion
- RV failure
Loss of pulmonary vasculature caused by
- Chronic obstructive lung disease
- Pulmonary interstitial fibrosis
- Pulmonary emboli/thrombosis
- Under ventilated alveoli
CVD risk factors
Gender, hypertension, smoking, high blood cholesterol, low blood high density lipoproteins, diabetes, sedentary lifestyle, obesity, alcohol, ethnicity - S.Asian
The Framingham Heart Study
Identifying risk factors for CVD (longitudinal population study)
Other risk assessments
- SCORE
- QRISK2
- Joint British Societies risk prediction charts
Thomas Royle Dawber
First director of Framingham Heart Study
Richard Doll
Link between smoking and lung cancer
Austin Bradford Hill
Link between smoking and lung cancer
James Black
Discovered B-blockers
Akira Endo
Discovered statins in fungi
Left sided failure leads to ….output
low
LHF and kidneys
Pre-renal azotemia (N2), salt and fluid retention (RAAS and natriuretic peptides)
Natriuretic peptides
Induces discharge of sodium through urine
LHF and brain
Irritability, decreased attention, stupor > coma
LHF and lungs (congestion)
Pulmonary congestion and oedema, heart failure cells, dyspnea, orthopnoea, Paroxysmal Nocturnal Dyspnea, Blood tinged sputum, Cyanosis, Elevated pulmonary ‘WEDGE’ pressure (normal 2-15 mm Hg)
RHF causes
Left heart failure or cor pulmonale (enlarged RHS)
RHF and liver and spleen
Passive congestion (nutmeg liver), congestive splenomegaly, ascites
RHF and kidneys
Not enough blood - congested
RHF and pleura/pericardium
Pleural and pericardial effusions and transudates
RHF and peripheral tissues
Oedema
CHF autopsy
Cardiomegaly, chamber dilatation, hypertrophy of myocardial fibres (boxcar nuclei)
Opening valvular HD
Stenosis
Closing valvular HD
Regurgitation (incomplete/insufficiency)
Aortic stenosis
Calcification of a deformed valve/Rheumatic heart disease, 2x gradient pressure, LVH (no hypertension), ischaemia, cardiac decompensation, angina, CHF
Mitral stenosis
Rheumatic HD
Rheumatic HD
Follows group A strep infection, decrease in ‘developed’ countries, pancarditis (endocarditis, myocarditis, pericarditis)
Acute Rheumatic HD
Inflammation, Aschoff bodies, Anitschkow cells, pancarditis, vegetations on chordae tendinae at leaflet junction
Chronic Rheumatic HD
Thickened valves, commisural fusion, thick, short chordae tendinae
Mitral annular (ring) calcification
No dysfunction, or regurgitation (stenosis), more common in females
Aortic regurgitation cause
Rheumatic, infectious, aortic dilatations (syphilis, RA, marfan)
Mitral regurgitation cause
Mitral valve prolapse, infectious, fen-phen, papillary muscles, chordae tendinae, calcification of mitral ring
Mitral Valve Prolapse (MVP)
Connective tissue weakening, ‘floppy’ valve
MVP epidemiology
3% incidence, F>M
MVP diagnosis
Echocardiogram
MVP clinical
Asymptomatic, mid-systolic ‘click’, holosystolic murmur (regurgitation), chest pain, dyspnea
MVP complications
(3%) Infective endocarditis, mitral insufficiency, arrythmias, sudden death
Congenital heart defects
Faulty embryogenesis (week 3-8), mono-morphic, not evident until adult life (coarctation, ASD), 1% incidence
Incidence of malformations
- VSD
- ASD
- Pulmonary stenosis
- PDA
- Tetralogy of Fallot
- Coarctation of aorta
- ASD
- Aortic stenosis
- Transposition of GA
- Truncus arteriosus
- Total anomalous pulmonary venous connection
- Tricuspid atresia
Genetics of Congenital heart defects
10%, trisomies 21, 13, 15, 18, XO, mutations of genes which encode for transcription factors TBX5 (ASD, VSD), NKX2.5 (ASD), region of chromosome 22 important in heart development
22q11.2 deletion
Conotruncus, brachial arch, face
Environmental factors
Rubella and teratogens
L > R shunt
No cyanosis, pulmonary hypertension (irreversible)
Examples of L > R shunt
ASD, VSD, PDA, AVSD
R > L shunt
Cyanosis, venous emboli become systemic (paradoxical)
Obstructions
Coarctation of aorta, pulmonary stenosis/atresia, aortic stenosis/atresia
Examples of R > L shunt
Tetralogy of Fallot, TGA, Truncus arteriosis, Tricuspid atresia, TAPVC
ASD
Defective fossa ovalis (secundum 90%), next to AV valves, mitral cleft (primum 5%), sinus venosus - next to SVC (5%)
VSD
Only 30% isolated (teralogy of fallot), 90% membranous septum, muscular septum multiple holes - small close spontaneously, large > pulmonary hypertension
Patent Ductal Arteriosus (PDA)
90% isolated, associated with VSD, coarctation of aorta, pulmonary or aortic stenosis, continuous harsh, machinery-like murmur
Atrial ventricular septal defect (AVSD)
Defective, inadequate AV valves, partial/complete (all chambers), more than 1/3rd with complete - down’s
Tetralogy of Fallot
- VSD
- RVH
- Overriding aorta
- Obstruction to RV outflow
Transposition of great arteries (TGA)
Abnormal formation of truncal and aortopulmonary septa, needs shunt for survival, fatal in first few months, surgical ‘switching’
TGA shunt needed
- PDA/PFO (65%)
- VSD (35%)
- RV>LV
Truncus arteriosus
Pulmonary artery and aorta don’t separate, associated with VSD, cyanosis, increased pulmonary blood flow
Tricuspid atresia
Hypoplastic RV, need shunt (ASD, VSD, PDA), high mortality
Total anomalous pulmonary venous connection (TAPVC)
Pulmonary veins go into LV/coronary sinus, need PFO/VSD, hypoplastic LA
Coarctation of aorta
M>F, common in XO’s, infant - proximal to PDA (serious), adult - no PDA, bbicuspid aortic valve 50% of time
Pulmonary stenosis/atresia
Hypoplastic RV with ASD
Aortic stenosis/atresia valvular
Severe, hypoplastic LV > fatal
Aortic stenosis/atresia sub-valvular (subaortic)
Aortic wall thick below cusps
Aortic stenosis/atresia supra-valvular
Aortical wall thick above cusps in ascending aorta