Ischaemic Heart Disease Flashcards
what is the definition of ischaemic heart disease
reduced blood supply to cardiac muscle
causes angina pectoris
what are the different presentations of IHD
-stable angina ACS: -unstable angina -NSTEMI -STEMI
what is the definition of myocardial infarction
cardiac muscle necrosis due to ischaemia
what is the aetiology of IHD
O2 demand>O2 supply (angina) BY: -atherosclerosis (most common) -spasms e.g. cocaine -arteritis -emboli
what is the aetiology of MI in IHD
sudden occlusion of coronary artery due to rupture of arthomatous plaque and thrombus formation
what is the pathophysiology of atherosclerosis
endothelial injury
migration of monocytes into subendoethlial space
differentiation into macrophages
accumulation of LDLs in macrophages in subendothelium forming foam cells
release of GFs
stimulates SM proliferation, production of collagen and proteoglycans
formation of atheromatous plaque
what are the risk factors associated with IHD
male DM family history HTN hyperlipidaemia smoking previous history
what is the epidemiology of IHD
> 2% of population
more males than females
incidence is 5 per 1000 PA
what history is associated with stable angina
brought on by exertion
relieved by rest
what history is associated with ACS
acute onset chest pain
central heavy tight ‘gripping’ pain
radiation to L arm, neck, jaw, epigastrium
occurs at rest
increasing severity and frequency of previously stable angina
what would be the examination findings in stable angina
none
BUT observe for signs of risk factors
what would be the examination findings in ACS
may be no clinical signs
pale/sweating/low-grade pyrexia
radio-radial delay
arrhythmias
disturbances of BP
new heart murmurs (pansystolic murmur of mitral regurg)
indications of complications (acute HF/cardiogenic shock)
what would you find in cardiogenic shock
hypotension
cold peripheries
oliguria
what investigations would be performed in suspected IHD
1. bloods 2 ECG 3 CXR 4 exercise ECG 5 radionuclide myocardial perfusion imaging 6 echo 7 pharmacologic stress testing 8 cardiac catheterisation/angiography 9 coronary calcium scoring
what bloods would you test in suspected IHD
FBC/UEs/CRP/glucose/lipids cardiac enzymes amylase/TFTs AST LDH
what cardiac enzymes would you investigate in suspected IHD
CK-MB
troponin T/I
what is CK-MB
creatine kinase of the myocardium
released in response to myocardial damage
what is troponin T/I
very sensitive & specific markers of myocardial damage
increased 12H post myocardial damage
what are the other reasons for raised troponin T/I
sepsis tachycardia PE cardiac failure stroke
why is it important to measure amylase in IHD
pancreatitis may mimic MI
what is AST
aspartate aminotransferase
increased (peaks) 24H post myocardial damage
what is LDH
lactate dehydrogenase
increased (peaks) 48H post myocardial damage
what would be the expected findings on an ECG in unstable angina/NSTEMI
ST depression
T wave inversion
Q waves can indicate old MI
what would be the expected findings on an ECG in a STEMI
early -hyperacute T waves -ST elevation (>1mm in limb leads & >2mm in chest leads) -new onset LBBB late -T inversion (hours) -Q waves (days)
what leads correspond to the inferior wall of the heart
II, III, aVF
what leads correspond to the anterior wall of the heart
septum V1-2
apex V3-4
anterolateral V5-6
what leads correspond to the lateral wall of the heart
I, aVL, V5-6
what would a posterior infarct show on an ECG
tall R wave and ST depression in V1-3
what would be the expected findings on a CXR in suspected IHD
signs of HF
- alveolar oedema
- kerley B-lines
- cardiomegaly
- diversion and dilation of upper lobe vessels
- pleural effusion
what is the use of an exercise ECG test in IHD
determines prognosis and management
what are the indications for an exercise ECG test in suspected IHD
troponin negative ACS/stable angina
probable CAD
why is it important to know if a patient is on digoxin before completing an exercise ECG test
produces a false positive result
what is a positive test result in an exercise ECG
> 1mm horizontal/downward sloping ST depression
measured at 80ms after end of QRS
what is a failed test in an exercise ECG
failure to reach 85% of predicted maximal HR (220-age)
no chest pain/ECG findings
why should beta blockers be stopped prior to an exercise ECG test
reduces maximal HR
what is radionuclide myocardial perfusion imaging
uses Tc-99m sestamini/tetrofosmin
performed under stress(exercise/psychological)/at rest
-stress testing: shows low uptake into ischaemic myocardium
-rest testing: used in patients with ACS with no previous MI
what would an echo investigate in suspected IHD
LVEF
exercise/dobutamine stress echo may detect wall motion abnormalities
what is pharmacologic stress testing
for patients who can’t exercise/exercise ECG inconclusive
imaging detects ischaemic myocardium
what would be used to induce tachycardia in pharmacologic stress testing
dipyradamole
adenosine
dobutamine
when is cardiac catheterisation/angiography used in suspected IHD
ACS with positive troponin
TIMI score of 5-7
high risk with stress testing
what is coronary calcium scoring and when is it used in suspected IHD
a specialised CT
for presentation of atypical chest pain
for presentation of acute chest pain not clearly due to ischaemia
what would be the management for stable angina
minimise cardiac risk factors
-control BP/hyperlipidaemia/diabetes
-stop smoking/more exercise/weight loss/healthier diet
-aspirin 75mg
immediate symptom relief
-GTN spray
long-term treatment
-beta-blockers(atenolol)/CCBs(verapamil)/nitrates
-dual therapy if monotherapy ineffective
PCI
-for localised stenosis in uncontrollable angina
-restenosis rate is 25% at 6 months
-drug eluting coronary stents reduce restenosis rates
CABP
-in severe cases (3-vessel disease)
-rates of MI & survival are similar to PCI
what are the contraindications of beta-blockers in long-term treatment of IHD
acute HF cardiogenic shock bradycardia heart block asthma
what would be the management for unstable angina/NSTEMI
CCU( O2, IV access, monitor vital signs, serial ECG)
analgesia (GTN, morphine sulphate/diamorphine)
aspirin (300mg loading, 75mg maintenance indefinitely)
clopidogrel (300mg loading, 75mg maintenance for minimum 1yr in troponin positive)
LMWH (dalteparin)
beta-blockers (metoprolol)
glucose-insuline infusion if blood glucose>11mmol/L
consider GPIIb/IIIa inhibitors if patient:
-undergoing PCI
-at high risk of cardiac events (troponin positive)
what is the mneumonic for treatment of heart attack
Morphine
Oxygen
Nitrates
Aspirin
what would be the management for a STEMI
CCU
-O2, IV access, monitor vital signs, serial ECG
analgesia
-GTN, morphine sulphate/diamorphine
aspirin
-300mg loading, 75mg maintenance indefinitely
clopidogrel
-600mg loading with PCI, 300mg loading with thrombolysis+.75yrs, otherwise 75mg maintenance for minimum 1yr
-beta blocker
what would be the management for a STEMI if undergoing primary PCI
IV heparin (+GPIIb/IIIa inhibitor)/antithrombin bivalirudin
what is bivalirudin
reversible direct thrombin inhibitor
what would be the management for a STEMI if undergoing thrombolysis
recombinant tissue plasminogen activator
IV heparin
when would you use a glucose-insulin infusion in a STEMI
blood glucose>11mmol/L
what is the secondary prevention for IHD
antiplatelet agents -aspirin -clopidogrel ACE inhibitors beta-blockers statins control HTN, smoking, diabetes
what advice would be given to someone with IHD
lifestyle changes
cannot drive for 1 month post MI
when would a CABG be used in IHD patients
patients with left main stem/three vessel disease
what are the complications associated with IHD
increased risk of MI/stroke/peripheral vascular disease
cardiac injury secondary to HF/+arrhythmias
what are the early complications (24-72h) associated with MI
death cardiogenic shock HF ventricular arrhythmias HB pericarditis thromboembolism
what are the late complications associated with MI
ventricular wall/septum rupture valvular regurgitation ventricular aneurysms tamponande dressler's syndrome (pericarditis) thromboembolism
what does the TIMI score estimate
estimates mortality in patients with unstable angina/NSTEMI
what is the TIMI score
1 >65yrs 2 known CAD (stenosis>50%) 3 aspirin use in past 7 days 4 severe angina (past 24h) 5 ST deviation >1mm 6 elevated troponin levels 7 >3 CAD risk factors -HTN -hyperlipidaemia -family history -diabetes -smoking
what is the killip classification of acute MI
class I no evidence of HF class II mild/moderate evidence of HF (HS3, crepitations
