Cardiology Flashcards
what is atherosclerosis
- degenerative
- fibrous and lipid rich plaque with variable inflammation, calcification and a tendency to thrombosis
risk factors for atherosclerosis
Age Tobacco smoking High serum cholesterol Obesity Diabetes Hypertension Family history
distribution of atherosclerosis
- peripheral and coronary arteries
- focal distribution along length
- changes in blood flow/ turbulence cause artery to develop neointima (new growth)
what does a complex atherosclerotic plaque consist of
Lipid
Necrotic core
Connective tissue
Fibrous cap
what are the main cells involved in atherogenesis
endothelium, macrophages, smooth muscle cells and platelets
mechanism of development of an atherosclerotic plaque
- fatty streaks (<10y, lipid laden macrophage and T cells in intimal layer)
- intermediate lesions (smooth muscle, Tcells, platelets in vessel wall)
- fibrous plaques ( impedes flow, can rupture, more foam cells)
- plaque rupture (fibrous cap has to be resorbed and redeposited, shift in balance will cause rupture)
what makes a complicated plaque
calcification, mural thrombus, vulnerable plaque
what causes atherosclerosis to develop
- endothelial dysfunction and injury = lipid accumulation
- local cellular proliferation and lipid oxidisation
- mural thrombi, vessel healing and cycle repeats
adaptation of atherosclerotic plaques
- plaque becomes>50% of lumen so vessel can’t compensate by remodelling
- narrowing drives cell turnover in plaque
- new matrix
- may progress to unstable plaque
clinical manifestations of atherosclerosis
- Coronary arteries – chest pain/ pressure (angina)
- Brain arteries – transient ischaemic attack (TIA)
- Peripheral arteries – peripheral artery disease
- Renal arteries – high blood pressure or kidney failure
management of atherosclerosis
- PCI (percutaneous coronary intervention), stop restenosis by using drug eluting stents (anti-proliferative and inhibits healing)
- aspirin
- clopidogrel/ ticagrelor (inhibits P2Y12 ADP receptor on platelets)
- statins (reduce cholesterol synthesis)
investigations for heart disease - CXR
- snapshot of heart in little detail
- enlarged heart = congestive heart failure
- Signs of pulmonary oedema = decompensated heart failure
- globular heart = pericardial effusion
- Metal wires and valves show up
investigations for heart disease - echocardiography
- US can give real time images of moving heart
- used at rest, during exercise or after use of pharmacological stressor
investigations for heart disease - cardiac CT
- detailed
- CT angiography = contrast used = view coronary arteries = single breath hold and low radiation dose
investigations for heart disease - cardiac MR
- radiation free
- first choice to look at diseases directly affecting myocardium
- pacemakers are safe with MR
investigations for heart disease - nuclear imaging
- at rest or stress test
- assesses whether myocardium distal to blockage is viable ( hypoperfusion is reversed at rest)
if an impulse travels towards an electrode in an ECG which way will it deflect
- upwards deflection
what does each section/ wave show in an ECG
- P wave – atrial depolarisation
- PR interval – atrial depolarisation and delay in AV junction
- QRS – ventricular depolarisation
- T wave – ventricular repolarisation
standard calibration of an ECG
25mm/s
0.1mV/mm
common p-wave abnormalities
- Right atrial enlargement – tall >2.5mm – P pulmonale
- Left atrial enlargement – notched (M-shaped) – P mitrale
- long PR interval = first degree heart block
common QRS complex abnormalities
-Depth of the S wave should not excess 30mm
-Pathological Q wave:
>2mm deep and >1mm wide
>25% amplitude of the subsequent R wave
what does abnormalities in the QRS axis suggest
- ventricular enlargement or conduction blocks
common abnormalities of the ST segment
ST segment is usually flat (isoelectric), elevation or depression of ST segment by 1mm or more can be pathological
abnormalities in T wave
- Should be at least 1/8 but less than 2/3 of the amplitude of R
- Abnormal T waves are symmetrical, tall, peaked, biphasic or inverted
- T wave amplitude rarely exceeds 10mm
abnormalities in QT interval
- decreases when HR increases
- should be 0.35 - 0.45 seconds
abnormalities in U waves
- small, round, symmetrical and positive in lead II, with amplitude <2mm (regular)
- U wave should be same direction as T wave
what can cause ST elevation
Normal variant, acute MI, Prinzmetal’s angina, acute pericarditis, left ventricular aneurysm
what can cause ST depression
Normal variant, digitoxin toxicity, ischaemic, angina, NSTEMI, acute posterior MI
what may myocardial infarction look like on ECG
- T wave may become peaked and ST segments may begin to rise
- Within 24h, the T wave inverts. ST elevation rarely persists, unless a left ventricular aneurysm develops
what may a pulmonary embolism look like on ECG
sinus tachycardia, RBBB, right ventricular strain pattern
what is hypertension
- Chronic elevation of blood pressure in the arteries.
- WHO classification: >140/90mmHg.
- Malignant hypertension: >160/110mmHg (rapid rise causing fibrinoid necrosis of vessels)
- causes 50% of all vascular deaths
pathology of hypertension
- altered RAAS elevated BP, impaires sympathetic output, causes vasoconstriction
- normally balanced by atrial natriuretic factor
- hypertension alters vessel walls by increasing the wall thickness
causes of hypertension
- 90% primary with unknown aetiology
- secondary hypertension
causes of secondary hypertension
- Endocrine disease = overproduction of aldosterone (Conn’s syndrome), Chronic vascular disease
- renal disease (most common) = intrinsic renal disease, renovascular disease
- drugs = NSAIDS, COC, corticosteroids, ciclosporin, cold cures, antidepressants, recreational
- lifestyle = obesity, high salt and alcohol
signs and symptoms of hypertension
- asymptomatic
- Malignant hypertension = Bilateral renal haemorrhages, Papilledema, Headache and visual disturbance
- look for causes and end organ damage
tests for hypertension
- 24 hour ambulatory BP monitoring
- fasting glucose, cholesterol
- ECG or echo (look for organ damage)
- special tests (renal US, 24h urinary meta-adrenaline, urinary free cortisol)
complications of hypertension
- cor pulmonale:
- Right ventricular hypertrophy and dilatation due to pulmonary hypertension
- Can also be caused by emboli, cystic fibrosis or chronic bronchitis
management of hypertension
- treatment goal <140/90 mmHg - reduce slowly
- lifestyle changes
- drugs
calcium antagonists
dihydropidines - inhibit the opening of voltage-gated calcium channels in vascular smooth muscle (decrease vasoconstriction)
ACE inhibitors
Ramipril and captopril – prevent generation of angiotensin II from angiotensin I.
angiotensin receptor blockers
aliskiren (inhibits renin) – block the action of angiotensin II at peripheral angiotensin II receptors
thiazide diuretic
Bendroflumethiazide – inhibit sodium reabsorption by the DCT, reducing the ECF volume
drug treatment of hypertension in patients <55 or with T2DM
- ACEi (angiotensin blocker if not tolerated)
- ACEi + CCB or thiazide diuretic
- all 3
drug treatment of hypertension in patients >55 or of black African/Caribbean descent
- CCB
- CCB + ACEi (angiotensin blocker if black) or thiazide diuretic
- all 3
what is angina pectoris
Recurrent transient episodes of chest pain due to myocardial ischaemia
what are the 4 types of angina
- Stable angina: induced by effort, relieved by rest.
- Unstable angina (crescendo): angina of increasing frequency or severity – occurs on minimal exertion or at rest. high risk of MI.
- Decubitus angina: precipitated by lying flat.
- Prinzmetal angina: caused by coronary artery spasm (rare)
pathology of angina
- myocardial ischaemia occurs when myocardial O2 demand outweighs supply
- artery stenosis increases resistance to flow
- myocardial ischaemia = pain
causes of angina
- Atheroma
- Rarer = Anaemia, Coronary artery spas, Tachyarrhythmias
modifiable risk factors for angina
smoking, diabetes, hypertension, hypercholesterolaemia, sedentary lifestyle, stress
precipitants of angina
> affects supply = anaemia, hypoxemia, hypothermia, hypovolaemia, hypervolemia
affects demand = hypertension, hyperthyroidism, valvular heart disease, tachyarrhythmia, cold weather
3 angina history features
- Constricting/heavy discomfort to the chest, jaw, neck, shoulders or arms
- Symptoms brought on by exertion
- Symptoms relieved within 5min by rest or GTN spray
- 3/3 = typical angina, 2/3 atypical, 0/3 not anginal pain
symptoms of angina
Dyspnoea Nausea Sweatiness Faintness Crushing chest pain
investigations for angina
- ECG (often normal, Twave inversion, BBB)
- bloods = FBC, U&E, TFTs, lipids, HbA1c
- echo = normal or signs of previous infarcts
- CXR
- stress echo, exercise stress treadmill, perfusion MRI
management of angina
- address exacerbating factors (anaemia, tachycardia, hyperthyroid)
- GTN (glyceryl trinitrate) spray
- ambulance if pain doesn’t go 5mins after second dose
primary prevention of angina
- reduce risk of CAD and complications
- risk factor modification
secondary prevention of angina
- lifestyle changes
- 75mg aspirin daily
- ACEi if diabetic
- PCI or surgery (CABG)
what is coronary artery bypass graft surgery (CABG)
- deals with complex disease
- open heart surgery
- risk of stroke/bleeding
- one-time treatment
- can’t do if frail
what are acute coronary syndromes
- unstable angina, MI
- pathology = plaque rupture, thrombosis, inflammation
what is myocardial infarction
- myocardial cell death, releasing troponin.
- full thickness necrosis
- Non-ST-elevation myocardial infarction (NSTEMI)
- ST-elevation myocardial infarction (STEMI)
modifiable risk factors for acute coronary syndromes
- smoking, diabetes, hypertension, hyperlipidaemia, sedentary lifestyle, cocaine use
diagnosis of acute coronary syndromes
- An increase in cardiac biomarkers (e.g. troponin)
- Symptoms of ischaemia
- ECG changes of new ischaemia
- Development of pathological Q waves
- New loss of myocardium
symptoms of acute coronary syndromes
- Acute central chest pain lasting >20min
- Nausea
- Sweatiness
- Dyspnoea
- Palpitations
- silent ACS = in elderly = syncope, pulmonary oedema, epigastric pain
signs of ACS
Distress Anxiety Pallor Sweatiness 4th heart sound Possibly signs of heart failure Low grade fever
management of ACS
- GTN and opiates for chest pain
- modify risk factors
- cardioprotective meds = aspirin, clopidogrel, anticoagulants, beta blocker, ACEi, high dose statin
unstable angina
- severe acute myocardial ischaemia without necrosis
- at rest or minimal exertion
- no significant rise in troponin
different types of MI
- Subendocardial/ patchy infarction – involves the innermost layer and some middle parts of the myocardium, but not the epicardium. NSTEMI
- Transmural infarction – full thickness of the myocardium
initial management of STEMI
- 12-lead ECG
- IV access. Bloods for FBC, U&E, glucose, lipids, troponin
- History
- Aspirin 300mg and ticagrelor 180mg
- Morphine 5-10mg IV +anti-emetic
- STEMI on ECG = primary PCI
treatment of MI
- Aspirin – inhibits platelet function
- LMW heparin
- Thrombolytic therapy
what is cardiac failure
- heart can’t pump enough = cardiac output is inadequate for the body’s requirements
- severe cardiac failure causes cardiogenic shock
what happens if the stretch capability of sarcomeres in the myocardium is exceeded
- cardiac contraction force diminishes
- hypertrophic response triggered by angiotensin 2, ET-1, I-LGF1, TGF-beta
systolic failure
- inability of the ventricle to contract normally, resulting in low cardiac output.
- Ejection fraction <40%.
- Causes: IHD, MI, Cardiomyopathy
diastolic failure
- inability of the ventricle to relax and fill normally, causing increased filling pressures
- stiff heart
- Ventricular hypertrophy, Constrictive pericarditis, Tamponade , Restrictive cardiomyopathy, Obesity
L and R ventricular failure
- L = causes pulmonary congestion then overload of R side
- R = venous hypertension and congestion (leg veins)
acute HF
new-onset acute or decompensation of chronic heart failure characterised by pulmonary and/or peripheral oedema with/without signs of peripheral hypoperfusion
chronic HF
develops or progresses slowly. Venous congestion is common but arterial pressure is well maintained until very late
diagnosis of HF
- symptoms of failure
- FBC, U&E, CXR, ECG (cause), echo
signs of HF
Cyanosis Decreased BP Narrow pulse pressure Displaced apex (LV dilatation) Pulmonary hypertension Pink frothy sputum Signs of valve diseases
differential diagnoses for HF
COPD Emphysema Myocardial infarction Pulmonary embolism Pneumonia
management to acute HF - emergency
- sit upright
- high flow O2
- treat arrhythmias
- investigations
- Diamorphine 1.25-5mg IV slowly
- Furosemide 40-80mg IV slowly
- GTN spray 2 SL puffs
- If systolic BP 100mmHg, start a nitrate transfusion
management of chronic HF
- manage risk factors
- treat cause and exacerbating factors (anaemia, infection)
- flu vaccine
- pharmacological = diuretics, ACEi, beta-blocker (carvedilol), mineralocorticoid receptor antagonist (spironolactone), digoxin ( helps symptoms), vasodilators (hydralazine and isosorbide nitrate)
2 congenital valvular heart diseases
Congenital aortic stenosis
Congenital bicuspid valve
2 acquired valvular heart diseases
Degenerative calcification
Rheumatic heart disease
what is mitral regurgitation
- Backflow through the mitral valve during systole.
- Acute – back up into the lungs
- Chronic – dilation as it has had time to adjust
- volume overload
- compensated by LA enlargement, LVH and increased contractility
causes of mitral valve regurgitation
Rheumatic fever Infective endocarditis Mitral valve prolapse Ruptured chordae tendinea Papillary muscle dysfunction Cardiomyopathy
signs and symptoms of mitral regurgitation
- Dyspnoea (exertion), Pulmonary oedema, Fatigue, Palpitations
- AF, pansystolic murmur, large LV
tests for mitral regurgitation
- ECG = AF, Pmitrale, LA enlargement and LV hypertrophy
- CXR = mitral valve calcification
- echo
management of mitral regurgitation
- Beta blocker if fast rate
- anticoagulant
- vasodilators - CCB (hydralazine)
- diuretics improve symptoms
- replace/ repair valve
what is mitral valve prolapse
- most common valvular abnormality
- two valve flaps of the mitral valve do not close smoothly or evenly, but instead bulge upwards into the left atrium
- atypical chest pain, palpitations, and autonomic dysfunction symptoms
- Mid-systolic click and/or late systolic murmur
complications of mitral valve prolapse
Mitral Regurgitation (MR)
Cerebral emboli
Arrhythmias
Sudden death
tests for mitral valve prolapse
- echo = diagnostic