acute coronary syndromes

Question 1

what triad is used to group patients with cardiac chest pain?

Answer 1

• presting symptoms
• ECG
• hs- Tnl level (high sensitivity troponin 1 released from cardiac myocytes due to necrosis)

Question 2

how do patients with ST elevation MI present (STEMI)?

Answer 2

cardiac sounding chest pain

persistent ST segment elevation in 2 or more leads in the same zone, or new Left bundle branch block on their ECG

ST elevation should be >1mm in limb leads and 2mm in chest leads.

hs-Tnl will be >100ng/L and CK >400.

Question 3

how do patients with non ST elevation MI present (NSTEMI)?

Answer 3

present with cardiac sounding chest pain

ECG may show ST segment depression, T wave inversion or may be normal

hs-Tnl will be >100ng/L

ECG changes may occur

Question 4

how do patients with angina present?

Answer 4

present with cardiac sounding chest pain

ECG may have ST segment depression, T wave inversion or may be nermal

hs-Tnl will be normal

Question 5

how do Tnl levels rise with myocardial damage and how should you measure it on admission?

Answer 5

rise 3-4 hours after myocardial damage and stay elevated for up to 2 weeks.

for quick diagnosis, take on admission then again in 1 hour. if event has occurred 3 or more hours before, you only need 1. if uncertain, a second one can be taken 2 hours later (3hrs after the first). a second hs-Tnl is good for comparison to see if its rising or falling.

(CK should also be measured in STEMI patients)

Question 6

what do Tnl levels suggest?

Answer 6

males = >34ng/L suggests myocardial necrosis

females = >16 ng/L suggests myocardial necrosis

Question 7

what is a type 1 myocardial infarction and how can hs- Tnl levels suggest the type of MI?

Answer 7

MI is caused by an acute atherothrombotic coronary event

if hs- Tnl levels are 5x the upper limit, its a high predictive value for type 1 MI’s.

Question 8

how can an ACS be differentiated from chronic cardiomyocyte damage from troponin levels?

Answer 8

a rise greater than 5 ng/L may indicate ACS

Question 9

when can you get a false positive elevation of hs- Tnl?

Answer 9

in patients with

• advanced renal failure
• large PE

Question 10

what other cases, other than NSTEMI/STEMI can hs-tnl be raised?

Answer 10

• aortic dissection
• aortic stenosis
• hypertrophic cardiomyopathy
• malignancy
• stroke
• severe sepsis

Question 11

what does ST depression in leads V1-V4 suggest?

Answer 11

posterior myocardial infarction

it should be treated in the same manner as a STEMI

Question 12

why is it important to do a posterior (v7-v9) and right ventricular lead on or soon after admission?

Answer 12

as diagnostic changes may be transient

Question 13

what conditions may mimic a STEMI on ECG?

Answer 13

• early depolarisation causes up sloping of ST elevation, especially in V1 and V2, seen in younger, athletic patients, and some afro-caribbeans
• concave ST elevation in pericarditis and the ST changes my be very widespread
• brugada syndrome may be misdiagnosed as anterior STEMI.
• Takotsubo cardiomyopathy ( stress reaction affecting middle aged females) can mimic STEMI and NSTEMI.

Question 14

how do you manage a STEMI?

Answer 14

don’t delay transfer to cath lab, only preform further ECG if doubt to diagnosis.

1) IV access
2) pain relief, (morphine and antiemetic)
3) Oxygenation (if hypoxic, aim for sats 94%)
4) Asprin (300mg loading and 75mg od for life)
5) Prasugrel (inhibits ADP receptors) for patients under 75, over 60kg with no prior TIA or stroke, undergoing a PPCI.
6) clopidogrel (inhibits ADP receptors) 600mg loading and 75mg od for 12 months if patient won’t receive prasugrel.
7) Ticagrelor if can’t have prasugrel
8) PPCI - primary angioplasty
9) biochemistry screen, lipid profile, glucose and HbA1C assay, FBC
10) medications - bisoprolol, ACE inhibitors e.g ramipril or Angiotensin receptor blockers e.g losartan. statin. Ezetemibe if statins cause ADRs.
11) control diabetes e.g via insulin infusions. introduce metformin with caution.
12) control hypertension.
13) smoking cessation.
14) triple therapy - be careful if they’re taking anticoagulants, lots can increase risk of bleeding so stop and give PPI.
15) be aware of complications.

Question 15

how is an NSTEMI/unstable angina managed?

Answer 15

1) pain relief
2) aspirin 300mg loading and 75mg od
3) LMWH, enoxaparin for 48hrs based on weight and creatinine
4) repeat ECG
5) risk assessment of patient with elevated hs-Tnl using grace score.
6) Tricagrelor if risk >3% (medium) 180mg loading and 90mg BD.
7) whilst waiting for inpatient angiography consider anti-anginals: nitrates, ranolazine, calcium channel blockers.