Cardiology Flashcards
3 divisions of ACS
STEMI
- ST elevation of 1mm in 2 or more continguous leads
- ST elevation of 2mm in 2 or more chest leads
- ST depression in 2 or more leads V1-V4 (posterior stemi)
- new onset LBBB
NSTMI
- raised cardiac biomarkers
- ECG may show non-specific ischaemic changes like ST depression or T wave inversion
unstable angina
- non-specific ischaemic changes butbiomarkers normal
aetiology of atheromas qlaque
- Fatty streaks start in childhood
- Atheromatous plaques develop slowly throughout life
o Endothelial damage means more permeable
o LDLs become deposited in tunica intima and become oxidised
o Migration of monocytes into tunica intima to become macrophages
o Release cytokines that attract more monocytes and further damage endothelium
o Take up oxidised LDLs and become foamy macrophages which release lipid contents -> plaque growth
o Smooth muscle proliferation and hardening of plaque
classification of angina
class I-IV
I - no angina with ordinary physical activity. strenuous activity may cause symptoms
II - angina causes slight limitation on ordinary activity
III - angina causes marked limitaiton on ordinary activity
IV - angina occurs with any physical activity and may be present at rest
causes of stable angina
usually by coronary artery disease
less commonly by valve disease, hypertrophic obstructive cardiomyopathy or hypertensive heart disease
symptoms of stable angina
chest pressure or squeezing lasting several mins, which may radiate to one or both arms, neck or teeth
provoked by exercise or emtional stress
how does stable angina differ from unstable
pain from exertion lasts less than 10 minutes and is usually less
normal/unchanged ECG
angina is considered unstable if it occurs at rest, is new in onset and is severe (occurs with walking 1 flight of stairs, or similarly low level of exertion)
diamond classification for chest pain
1 sub-sternal discomfort of characteristic quality
2 provoked by exertion or stress
3 relieved by rest +/- nitrates within minutes
typical angina = all 3
atypical angina = 2/3
non-angina pain = none
INITIAL investigations for stable angina
take a history - age, male, presence of CV risk factors, history of CAD (e.g. previous MI) makes diagnosis more liekly
ECG - looking for changes that inficate ishcaemia or previous MI (i.e. that they already have CAD) such as pathological Q waves, LBBB, ST or T wave changes
then look at blood for things that could worsen workload of the heart e.g. FBC (anaemia), lipid profile (increased risk of CVD)
do U+E prior to starting meds and LFTs prior to starting statins
when to FURTHER investigate stable angina
after the inital clincal examination, must decide whether the probability of ischaemia is sufficient to warrent further testing
is done via age and sex and whether or not the pain is typical (via the Diamond criteria) - e..g increased age and a man is more likely angina
FURTHER investigations for stable angina depending on the CAD likliehood percentage
- > 90% treat as known CAD – i.e. as known stable angina
- 61–90% invasive angiography, or functional imaging if inappropriate (SPECT, stress echo, stree MIR)
- 30–60% functional imaging (SPECT, stress echo, stress MRI)
• 10–29% CT calcium scoring (coronary artery calcification scanning)
If CT calcium score is 0 then angina is unlikely
1-400 then proceed to CT angiography
If >400 then invasive coronary angiography or functional imaging
• <10% reconsider diagnosis.
when is a stress exercise ECG useful for stable angina investigations
NICE – only done when there is diagnostic uncertainty in people with KNOWN CAD (e.g. previous MI or angioplasty) and NOT TO MAKE A PRIMARY DIAGNOSIS of CAD/stable angina
conservative management for stable angina
patient education
- explain the factors that can provoke angina like exertion, emotional stress, exposure to cold or eating a large meal
- advise to seek medical help if there is sudden worsening in the severity of their angina
conservative
- physical activity, smoking, alcohol, weight, stress, diet
medical management for stable angina
GTN spray for symptomatic relief - advise the person that if they experience chest pain they should stop what they are doing and rest. take the spray. then take a 2nd dose after 5 mins if still pain. call 999 if pain has not eased after 5 mins after the 2nd dose or earlier if pain is intensifying
a beta blocker or a CCB - If they cannot tolerate one or the other, then switch to the other one
low dose aspirin 75mg for secondary prevention
consider ACEi for people with stable angina and DM
offer a statin or HTN if needed
if a person with stable angina cannot tolerate or are contraindicated to beta blockers and CCBs then what should you consider monotherapy with
Long-acting nitrate (e.g. isosorbide mononitrate)
Nicorandil
Ivabradine
Ranolazine (consider seeking specialist advice when initiating ivabradine or ranolazine)
driving with angina
- For those driving cars, driving must cease when symptoms occur at rest, with emotion or whilst driving
- Driving may recommence when symptom control is achieved – do not need to inform DVLA
complications of stable angina
- Stroke
- MI
- Unstable angina
- Sudden cardiac death
- Anxiety, depression, reduced QoL
prognosis of stable angina
With guideline-directed management, 58% of patients can expect to be free of angina within 1 year
when to offer a stain with stable angina
if cholesterol is >4mmol/L
3 different presentations of unstable angina
o exertional angina of new onset – even if relieved with rest and requiring a consistent amount of exertion to produce symptoms, angina is considered unstable when it first occurs
o exertional angina that was previously stable and now occurs with less physical exertion (occurs with walking 1 flight of stairs, or similarly low level of exertion)
o anginal symptoms at rest with no exertion
pathophysiology of unstable angina
- the initiating lesion in CAD is a fissure in the vessel endothelial lining over an underlying cholesterol plaque
- this results in a loss in the integrity of the plaque cap
- leads to exposure of subendothelial matrix elements like collagen
- this stimulates platelet activation and thrombus formation
- release of TF directly activates the coagulation cascade and promotes formation of fibrin
o If an occlusive thrombus forms, the patient may develop an acute ST segment elevation myocardial infarction - unless the affected myocardium is richly collateralised
- If the thrombus formation is not occlusive, the patient may develop UA or non-specific ST changes on the ECG (ST depression or T-wave changes)
- Myocardial supply and demand mismatch may cause ischaemia without significant CAD. These include:
o Increased myocardial oxygen requirements such as fever, tachycardia, thyrotoxicosis
o Reduced coronary blood flow: for example, hypotension
o Reduced myocardial oxygen delivery such as anaemia or hypoxaemia
investigations for unstable angina
examination
ECG to rule out STEMI - may be normal or have T wave inversion or ST segment depression
troponins to rule out MI - measured at presentaiton then 3 hours after presentation
lipid profile, blood glucose, FBC
CXR - may show complications of ischaemia e.g. pulmonary oedema or explore alteraive diagnoses (pneumothorax or aortic aneursym)
echo - provides information about precipitating causes like AS or hypertrophic cardiomyopathy
coronary angiography = gold standard for assessing presence + severity of CAD
when to perform angiography on someone with CAD (unstable angina or NSTEMI)
work out risk of MI via TIMI score or GRACE score
o Urgent (<120 mins after presentation) if ongoing angina despite treatment and evolving ST changes, signs of cardiogenic shock or life-threatening arrythmias
(with follow-on PCI if indicated)
• PCI vs CABG depends on coronary angiographic findings and comorbidities – discuss with interventional cardiologist if unsure
o High-risk patients for progression to MI or death require urgent coronary angiography (<24 hours)
(with follow-on PCI if indicated)
o Patients with intermediate score should be referred to coronary angiography within <72 hours
(with follow-on PCI if indicated)
conservative management of unstable angina / NSTEMI
patient education
admit to CCU and monitor closely
medical treatment of unstable angina/ NSTEMI
aspirin 300mg oxygen if <90% or breathless nitrates morphine 5-10mg IV metoclompramide 10mg IV
perform a risk assessment to calculate a 6-month mortality rate (age, previous MI, BP, HR, ECG, bloods)
clopidogrel 300mg if >1.5% risk (continue the dual antiplatelet therapy for 12 months)
beta blocker if tachycardic or hyeprtension or LV function <40%
ACEi
statin
check serial ECGs and troponins
coronary angiography
what to do before discharge for unstable angina/NSTEMI
o assess Lv function - Assessment is recommended in all patients who have had an MI. Should be considered in all patients with unstable angina
o Continue fondaparinux (or LMWH or heparin) until discharge
o Offer information about cardiac rehabilitation
o Management of CV risk factors and lifestyle changes
o Arrangements for follow up
NSTEMI / unstable angina symptoms in men vs women
- male
o chest pressure/discomfort lasting at least several minutes - women
o more commonly with middle/upper back pain
o or may have upper abdominal pain (atypical presentation) - both can present with
o sweating
o dyspnoea
o nausea
o anxiety
troponins in NSTEMI
o >99th percentile of normal
o troponins rise 4-6 hours after onset of infarction, peak at 18-24 hours and may persist for 14 days or longer
o infarct size can be estimated from the troponin value measured at 72 hours
posterior MI on ECG
V1, V2, V3 : ST depression + wide R wave and high T wave in V2
lateral MI ECG
circumflex
I, aVL, V5, V6