Cardiac causes of cardiac arrest

Question 1

What leads constitute the following areas and which vessel are they associated with…

i) lateral?
ii) inferior?
iii) anterior?

Answer 1

i) I, aVL, V5+V6 = circumflex artery
ii) II, III, aVF = right coronary artery
iii) V1–4 = left anterior descending artery

Question 2

What are the classical features on an ECG of a massive PE?

Answer 2

• S1Q3T3
• S wave in lead I, deep Q wave in lead III, T wave inversion in lead III

Question 3

What is the initial management of ACS?

Answer 3

• Aspirin 300mg PO
• GTN sublingual if not hypotensive
• Oxygen if hypoxic
• IV morphine titrate to effect with anti-emetic

Question 4

What is the treatment of a STEMI?
In what time frame?
Which is preferred?

Answer 4

• Mechanical (PPCI) or pharmacological (fibrinolytic) reperfusion within 12h symptom onset
• PPCI
• PPCI “call-to-balloon” = 2 hours

Question 5

What other medications are used in PPCI?

Answer 5

• Loading with a paltelet ADP receptor blocker prior e.g. clopi 600mg, ticagrelor 180mg or prasugrel 60mg (not if >75, <60kg or Hx bleeding or stroke)
• Anticoagulation with unfractionated or LMWH or bivalirudin (direct thrombin inhibitor)
• High risk cases, glycoprotein IIb/IIIa may be given

Question 6

What other medications are used in fibrinolytic therapy?

Answer 6

• Aspirin 300mg and ticagrelor 180mg loading doses (or clopidogrel 300mg if high bleeding risk)
• Anti-thrombin therapy = LMWH (IV bolus then SC), unfractionated heparin or fondaparinux

Question 7

How do you determine failed fibrinolytic therapy?
How is this managed?

Answer 7

• Repeat ECG 60–90m and failure of ST-segment elevation to resolve by >50% indicates failure
• Rescue PCI (angioplasty)

Question 8

What is the management of NSTEMI in relation to preventing further thrombus formation?

Answer 8

• Fondaparinux 2.5mg OD
• Aspirin 75mg OD (after 300mg STAT)
• Prasugrel 60mg STAT then 10mg OD, ticagrelor 180mg STAT then 90mg BD or clopidogrel 300mg then 75mg OD if elevated trop or planned for angiography ±revascularisation

Question 9

What is the management of NSTEMI in relation to reducing myocardial oxygen demand?

Answer 9

• Beta-blocker (or diltiazem if C/I)
• ?IV nitrate infusion if angina persists or recurs after sublingual
• Early ACEi (esp if LVSD)

Question 10

What rhythm may occur after reperfusion therapy?

Answer 10

• Idioventricular rhythm = no P waves, broad QRS, ventricular origin