Module 2C - Cardiology Flashcards
Name some post-MI complications (ACT RAPID)
What does ST depression in leads V1- V3?
Posterior MI
How should you treat a Pt with LBBB and symptoms of MI?
As if they’re having an MI because their LBBB will hide the ST elevation on the ECG
What is troponin?
Regulatory protein that controls interactions between Actin and Myosin
Acute chest pain differentials
- Pericarditis –> sharp pain, worse on breathing in and lying down due to the myocardium stretching. Presents as wide spread ST elevation
- Aortic Dissection –> sudden and very severe pain (compared to gradual in ACS), pain radiates to the back , can also cause ST elevation
- Respiratory causes –> e.g. Pulmonary embolism, Pneumonia, pneumothorax, Oesophageal rupture
Where does the RCA originate + what node does the RCA supply?
- RCA originates in the right aortic sinus
Where does the LCA originate, how does it divide?
- LCA originates in the left aortic sinus
- LCA then divides into 2 main branches which are the left anterior descending (LAD) artery and the left circumflex artery
Supplies of RCA and LCA
Dominance of coronary arterial system
- Dominance depends on whether right or left coronary artery gives off posterior interventricular branch (PIB)
- 67-85% –> RCA gives off the PIB, this is known as RIGHT dominance –> in this case the RCA and LCA each supply about 50% of the heart supply
- 8-15% –> LCA is dominant and the PIB comes off the left circumflex artery
- 7-18% –> there is codominance, where both the RCA and left circumflex artery give off branches that form the PIB
Collateral circulation of heart
Collateral circulation can occur in all hearts too, typically at the terminal ends of the RCA and LCA in the coronary sulcus
On anterior side of heart, what vein drains areas supplied by the LCA into the coronary sinus?
Great cardiac vein
(heart veins drain into the coronary sinus which then drains into right atrium, some small veins drain directly into the right atrium)
On posterior side of heart, what vein drains areas supplied by the RCA into the coronary sinus?
small cardiac vein (drains from right marginal artery of RCA) and the middle cardiac vein (drains from PIB), these two arteries drain most of the areas supplied by the RCA
Which arteries is coronary angiography usually done via
via radial or femoral artery
- 7 = Right coronary artery
- 8 = right acute marginal artery
- 9 = posterior descending artery
- 1 = Left main coronary artery
- 2 = Left circumflex artery
- 3 = First diagonal artery
- 4 = First septal artery
- 5 = Left aneterior descending (LAD)
- 6 = Left first marginal artery
- 7 = Right coronary artery
- 8 = right acute marginal artery
- 9 = Posterior descending artery
- 10 = Posterior left ventricular artery
Right coronary artery
(looks like the letter ‘C’)
Pathophysiology of acute coronary syndrome
- ACS is usually the result of a thrombus from an atherosclerotic plaque blocking a coronary artery
- When a thrombus forms in a fast-flowing artery, it is formed mainly of platelets
Anatomy of coronary arteries
how long should symptoms continue at rest for?
Presentation of acute coronary syndrome
- typically central, constricting chest pain with…
- Pain radiating to the jaw or arms
- Nausea and vomiting
- Sweating and clamminess
- A feeling of impending doom
- Shortness of breath
- Palpitations
(symptoms should continue at rest for > 15 mins)
ECG changes in ACS
–> STEMi
–> NSTEMI
STEMI:
- ST-segment elevation
- New left bundle branch block
NSTEMI:
- ST segment depression
- T wave inversion
What is PCI (Percutaneous coronary intervention)?
- involves putting a catheter into the patient’s radial or femoral artery (radial is preferred), feeding it up to the coronary arteries under x-ray guidance and injecting contrast to identify the area of blockage (angiography)
- Blockages can be treated using balloons to widen the lumen (angioplasty) or devices to remove or aspirate the blockage
- Usually, a stent is inserted to keep the artery open