Acute myocardial infarction 1B Flashcards
What is acute coronary syndrome?
a spectrum of Ischaemic conditions ranging from stable angina, unstable angina and MI
What is the pathophysiology of acute coronary syndrome?
it involves a rupture of atheromatous plaque in the coronary artery leading to thrombus formation which results in vessel occlusion locally or elsewhere in the heart
What are the 3 types of ACS?
ST elevation myocardial infarction (STEMI), Non-STEMI and Unstable angina
What is characteristic of STEMI?
ST elevation on ECG and ↑troponin
What is characteristic of NSTEMI?
↑troponin and Ischaemia symptoms and ecg changes
What is characteristic of unstable angina?
it is prolonged severe angina usually at rest, possible ECG changes and normal troponin after 12hrs
What are the 5 types of MI?
- Type 1 (Due to atherosclerotic plaque rupture);
- Type 2 (Due to imbalance in myocardial oxygen supply and demand e.g. anaemia, ↑HR, ↓BP, arterial spasm, embolism or arrhythmia. May also happen due to surgery or illness. ;
- Type 3 (Due to sudden cardiac death.) ;
- Type 4( due to PCI)
- Type 5 (Due to CABG)
What is typical of the chest pain in MI?
usually a sudden, central, a tight crushing but not sharp pain
Where does the pain in MI radiate to and why?
to the left arm, neck and jaw.
This is because of presence of heart on the left of chest, so pain radiates along left sided cervical nerve roots.
What is angor animi?
it is a symptom some patients feel when having an MI which is an impending sense of doom
What ECG changes are seen in the acute stages of a STEMI?
peaked T waves (<5mins), then ST elevation (<20 mins)
Where does ST elevation occur on the ECG and what is the criterion for diagnosis of STEMI from an ECG?
Occurs at the J point (end of the QRS) and it must be ≥ 2 consecutive leads
what is the minimum height of ST elevation in V2 and V3 occurring in a 40 year old man and woman respectively?
≥2mm and ≥1.5mm
What happens within days in STEMI?
Q waves then T wave inversion. Q wave indicating the net direction of early ventricular depolarization (QRS) electrical forces projects towards the negative pole of the lead axis in question.
Which coronary artery is implicated in an inferior MI and which leads can these be seen on?
Right coronary artery (RCA), with STE in lead II,III and AVF
What are other causes of inferior MI due to?
Due to LCX infarction in 10% of inferior MI known as inferolateral MI
What coronary artery is is implicated in anterior MI?
Left anterior descending, STE is seen in leads V1-4
Which leads are referred to as the septal leads in an anterior MI?
V1 and V2
What is seen in leads III and aVF in an anterior MI?
reciprocal ST depression
What coronary artery is implicated in a lateral MI and what leads show ST elevation?
the left circumflex artery and in leads I, aVL, V5 and V6
What is seen in a posterior MI?
peaked R and horizontal ST depression in V1-3, upright T waves
