IHD Flashcards
cause of angina
mostly atheroma
mismatch of o2 demand and supply
environmental exacerbating factors
cold weather, heavy meals, emotional stress
supply/demand exacerbating factors for angina
impairment of blood flow e.g. arterial stenosis
increased distal resistance e.g. LV hypertrophy
reduced o2-carrying capacity: anaemia
typical angina presenting patient
older male, FH, smoker
stable angina definition
induced by effort, relieved by rest
angina ECG
mainly normal
may show ST depression, flat or inverted T waves, signs of past MI
what Ix to show how much plaque someone with angina has?
CT calcium scoring
CT coronary angiography
surgical options for angina
percutaneous coronary intervention (PCI)
coronary artery bypass graft (CABG)
why are cold fingers a side effect of beta blockers?
they dilate coronary arteries but constrict skin and muscle ones –> cold fingers
what does negatively chronotropic mean?
decrease in heart rate
what does negatively inotropic mean?
decrease in LV contractility (force of contraction)
Side effects of beta blockers
erectile dysfunction, cold hands + feet, bradycardia
How do nitrates work?
they are ventilators
increase venous capacity –> reduction in preload
how does aspirin work?
cyclo-oxygenase inhibitor
reduces prostaglandin synthesis, results in decreased platelet aggregation.
Is antipyretic, anti-inflammatory, analgesic
what do statins do?
reduce the amount of cholesterol produced by the liver
what does angiotensin II do?
increased sympathetic activity
release of aldosterone
vasoconstriction
what do ACE inhibitors block?
the conversion of angiotensin I to angiotensin II
underlying pathology of unstable angina and evolving MI?
plaque rupture, thrombosis and inflammation
what do we call acute MI?
STEMI - diagnosed by ECG on presentation
How is a N-STEMI diagnosed?
Its retrospective
Made after troponin/other results
modifiable risk factors?
age, male, family history
presentation of acute coronary syndrome?
acute central chest pain lasting >20 mins
often associated with nausea, sweatiness, dyspnoea
what would you look for on a CXR for acute coronary syndrome
cardiomegaly
pulmonary oedema
widened mediastinum?
what are the most sensitive + specific markers of MI?
cardiac troponin levels (T and I)
what is troponin?
protein complex that regulates actin:myosin contraction
helps level with risk stratification
what is CK-MB
one of 3 isosomes of creatine kinase.
CK-MB is mainly in the heart
Why use opiates with caution for ACS?
they can delay absorption of PY12 inhibitors
1st line management for ACS (pre-hospital)
MONA
morphine, oxygen, nitrate, aspirin
What is clopidogrel and its metabolism?
a P2Y12 inhibitor. has to be metabolised to its active form by 2 steps in the liver
great target due to its amplification role
Side effects of anti platelet drugs
increased risk of bleeding, rash, GI disturbance
what do anticoagulants target?
formation and/or activity of thrombin
Complications of MI
cardiac arrest
cariogenic shock
unstable angina
bradycardia, tachyarrhythmias or heart block
pathology of NSTEMI
occluding thrombus causes myocardial damage –> elevation of myocardial damage markers: troponin & creatinine kinase
STEMI
complete occlusion of artery by thrombus
more severe symptoms
ST elevation on ECG
elevated troponin & creatinine kinase
what would normal serum troponin at 12 hrs suggest?
unstable angina (instead of NSTEMI/STEMI)
Medical treatment after MI
primary angioplasty/thrombolysis BBs (atenolol) ACE-i (lisinopril) or ARB (candesartan) Statin Dual anti platelet therapy: aspirin and a P2Y12 inhibitor (clopidogrel)
What is cardiac tamponade?
pericardial effusion: fluid accumulation in pericardium –> reduced ventricular filling –> haemodynamic compromise
LT rx angina
CCB/B-blocker/long acting nitrate e.g. amlodipine, atenolol, nicorandil
Post MI what should pts do
What is contraindicated
Attend cardiac rehab – advice on activity etc.
Lifestyle changes
NSAIDS absolute CI for 2/12 post STEMI
