Cardiovascular Disease Flashcards
Outline lipid metabolism pathways.
EXOGENOUS:
fat ingestion –> triglycerides and cholesterol esters incorporated into chylomicrons –> lymphatics –> thoracic duct –> systemic circulation –> lipoprotein lipase on adipocytes takes FFAs into cells –> chylomicron remnants to liver.
ENDOGENOUS:
1. Liver releases VLDL –> lipoprotein lipase on adipocytes takes FFAs into cells –> produces IDL and then LDL –> LDL returns to liver, binds to LDL receptor on hepatocytes –> invaginates into the cell and fuses with lysosomes –> LDL receptor is recycled back to the surface of the hepatocyte (recycling inhibited by PCSK9).
2. Liver releases HDL –> takes up cholesterol via ABC-A1 –> returns to liver.
MOA of STATINS.
UE?
Statins inhibit HMG-CoA-reductase.
Decreased intrahepatic cholesterol synthesis –> upregulation of LDL receptor –> increased LDL uptake by hepatocytes –> decreased serum LDL.
UE:
MUSCLE: myalgia, myopathy, myositis, rhabdomyolysis.
HEPATIC: raised LFTs
GIT UPSET: diarrhoea, constipation, flatulence
MOA of FIBRATES
USE?
Unwanted Effects?
Fibrates –> activate PPAR-alpha –> increased activity of lipoprotein lipase.
Primary use is to decrease triglyceride level.
UE:
Myalgia
Raised LFTs
Cholelithiasis (contraindicated in gallbladder disease)
MOA of PCSK9 inhibitors e.g. evolocumab.
UE?
Monoclonal antibodies to PCSK9 –> increased recycling of LDL receptor to surface of hepatocyte –> increased LDL uptake into liver –> decreased serum LDL.
UE:
Myalgia
MOA of EZETIMIBE
UE
Ezetimibe --> inhibition of cholesterol transporter in GIT UE: GIT UPSET: diarrhoea Raised LFTs Myalgia
MOA of CHOLESTYRAMINE
UE
Cholestyramine --> binds to bile acids in intestine --> inhibition of enterohepatic circulation of bile acids --> increased bile acid excretion UE: GIT: nausea, bloating, abdominal pain Myalgia Raised LFTs
What is your approach to management of dyslipidemia?
1. Calculate absolute cardiovascular risk in next 5 years. LOW RISK = < 10%. - provide healthy lifestyle advice - repeat lipids every 5 years MODERATE RISK = 10-15% - provide healthy lifestyle advice - consider pharmacotherapy if target not reached after 6 mo of lifestyle change. HIGH RISK = >15% - provide healthy lifestyle advice - pharmacotherapy: statin
What are your cholesterol target levels?
Total cholesterol < 4
LDL < 2
Triglycerides < 2
HDL > 1
How is STEMI diagnosed on ECG?
ST elevation in 2 contiguous leads or new LBBB.
What ECG leads correspond with:
- Lateral MI?
- Anterior MI?
- Inferior MI?
Lateral: lead I, AVL, V5, V6
Anterior: V1, V2, V3
Inferior: II, III and AVF
Give contraindications to fibrinolysis for STEMI.
ABSOLUTE: Previous intracranial haemorrhage Cerebral AVM Ischemic stroke in last 3 months Intracranial malignancy Uncontrolled active bleeding Bleeding diathesis Suspected aortic dissection Severe uncontrolled hypertension RELATIVE: Recent major surgery Recent internal bleeding
Outline the options for reperfusion of STEMI.
For STEMI, PCI is preferred over fibrinolysis.
The goal is PCI within 90 minutes of arrival.
When PCI will be delayed by more than 120 min, fibrinolytic therapy should be given ASAP in the ED (unless contraindicated).
After fibrinolysis, the patient should be transferred to a PCI-capable hospital. PCI should be performed as early as feasible after fibrinolysis and is still beneficial.
How would you manage a STEMI?
Admit the patient. Continuous monitoring. Bedrest. NBM until stable. Serial troponins. IV access. Oxygen as needed to maintain sat > 90%. Analgesia - morphine, GTN Definitive treatment: reperfusion - PCI preferred if available within 90 min; otherwise fibrinolysis and transfer to PCI-capable facility for fibrinolysis ASAP (as long as not contraindicated). Begin medications: IMMEDIATELY: Dual antiplatelet: Aspirin PO 325mg immediately, then 100 mg daily. P2Y12 inhibitor - ticagrelor or clopidogrel IV heparin. Metoprolol (if not contraindicated) BEFORE DISCHARGE: Statin ACE-Inhibitor
How would you manage a NSTEMI?
When DX is made, perform risk assessment - e.g. using TIMI score
If high risk - manage as per STEMI
If low risk - may manage conservatively: as per STEMI with delayed or w/o revascularisation.
How would you manage stable angina?
LIFESTYLE: - Exercise - Healthy diet - Weight loss: BMI < 25 - Cease smoking - Healthy alcohol intake CONTROL RISK FACTORS: - Statin - ACE-Inhibitor if HTN - DM: ensure good control CONTROL SYMPTOM: - GTN or B-blocker (use cardioselective: atenolol or metoprolol) PREVENT ACS: - Low dose aspirin PO 100-150 mg daily
What are the features of rheumatic fever?
Sydenham chorea Migratory polyarthritis Subcutaneous nodules Erythema marginatum Carditis
How would you treat strep throat?
- Confirm it is a GAS infection.
- Serology (antistreptolysin O or antistreptococcal DNAse B titers increased) OR throat swab + culture OR rapid antigen detection test.
- Assess for complications: ECG and echo - Prompt treatment of pharyngitis - penicillin
- Secondary prevention if rheumatic heart disease:
IM penicillin G every 4 weeks for 10 years or until 21 years (whichever is longer).
How would you manage AF?
For persistent AF, you need to:
CONTROL SYMPTOMS - using RATE control or RHYTHM control.
CONTROL VTE RISK - using anticoagulant.
Usually the preference is:
Symptomatic from AF, heart failure or younger pt –> rhythm control.
Asymptomatic, older pt –> rate control.
RHYTHM CONTROL:
- Pharmacological or electrical cardioversion.
Pharmacological cardioversion use: (1) FLECAINIDE if no structural heart disease or IHD; (2) amiodarone if structural heart disease or IHD present. Likely continue the drug used long term to prevent recurrence of AF.
For safe cardioversion, consider length of time pt has been in AF:
If < 48 hours –> may cardiovert immediately. If 48+ hours –> anticoagulate for 4 weeks before cardioversion attempt.
RATE CONTROL:
Can use: (1) B blocker - atenolol or metoprolol, or (2) ca channel blocker - verapamil or diltiazem.
ANTICOAGULATION:
For VALVULAR AF –> warfarin
For NONVALVULAR AF –> calculate risk of stroke using CHADs VASC - use NOAC if score 2+ in men and 3+ in women.
How would you treat AV node re-entrant or AV re-entrant tachycardias?
If STABLE –>
- Vagal manoeuvre: carotid sinus massage, Valsalva
- Adenosine
Both of these (1) decrease rate of SA depolarisation; (2) decrease rate of conduction esp through AV node.
If UNSTABLE or above does not work –>
- Electrical DC cardioversion
Explain Wolff-Parkinson-White syndrome.
Why does it occur?
What does it look like on ECG?
WPW is a type of AV reentrant tachycardia.
It is caused by an accessory pathway between the atria and ventricle.
On ECG:
- Slurred upstroke of QRS known as delta wave
- Short PR interval
- Wide QRS