MI Flashcards
MI What is it?
Myocardial - relating to the heart
Infarction - obstruction of the blood supply to an organ or region of tissue, typically by a thrombus or embolus, causing local death of the tissue
An MI is a sudden reduction of blood flow to the heart, usually caused by a rupture of an atherosclerotic plaque within the wall of a coronary artery, and may cause the formation of a blood clot
Pathophysiology of an MI
Blood flow to the heart is fully or partially obstructed by plaque. Lack of blood flow causes ischaemia to the area the blood supplies causing the tissue to die and start necrosis.
Depending on what area it affected, conduction and cardiac function can be compromised.
If the infarcted area heals, the heart can be remodelled with scarring, segmental hypertrophy and general cardiac dysfunction
Causes of MI
- Coronary heart disease- Cholesterol/plaque build up is the cause. These deposits narrow your arteries, decreasing blood flow.
- Hypoxia is a less common cause
- Thrombus due to break off of plaque
- Coronary artery embolism due to a clot from eg AF, congestive HF
Signs and Symptoms of MI
- Chest pain
- Nausea/vomiting
- Dizziness/light-headedness
- Referred pain in jaw, neck, back
- Clamminess/sweating
- SOB
Potential Primary Survey of an MI
- Sweaty
- Obvious pain/distress
- Levines signs
- Altered LOC
- Signs of hypotension
- Pallor
- SOB
Secondary Survey of MI
- Use SOCRATES for pain
PMH - Previous MIs, angina, HTN
Dhx - cardiac meds
FH - any ?
SH - drugs, alcohol, cocaine, lifestyle, long haul flights
Risk Factors for MI
- Diabetes
- Obesity
- Smoking
- HTM
- High cholesterol lvls
- Family history
- Ethnicity
- Male
- Advancing age
ECG Changes in STEMI
- ST Elevation usually with reciprocal changes in opposite leads
- Pathological Q waves
- Inverted T waves could indicate ischaemia
Which Leads Correspond to Which Type of STEMI?
V1-V4 = anterior stemi
I, avL, V5, V6 = Lateral
II, III, aVF = inferior stem
LBBB In MIs
- The presences of a LBBB on its own is not diagnostic of an MI
- But a new, symptomatic LBBB could indicate that the patient is having an MI
- ST elevation may not be seen due to the type of MI and the limited view of the heart the ECG provides
General Managment for STEMI
- Transmit to PPCI and call them
- If unsure call CCD
- Use the carry chair for extrication
- Convey immediately
- All drugs ect done on route
- Follow-up call with PPCI for ETA ect
- Pads on? (not meant to routinely apply other than bring defib in with you)
What does GTN do for STEMI Treatment
GTN is a potent vasodilator that will open up the arteries and veins in the entire cardiovascular system as well as the artery that is causing the infarction, this is in hopes of restoring some blood flow to the now ischaemic area
Oxygen in MI Treatment
No need to given oxygen unless showing signs of hypoxia. Some evidence shows it could be harmful.
Pain Releif in MI Management
- Make sure to get pain scores before and after
- IVP and morphine are routinely given in MI’s especially if pain is severe
- Pain relief is important to combat the sympathetic nervous response pain produces. As any increased CO could further clotting
Ondansetron in MI Manamgement
Can consider ondansetron to combat any nausea and vomiting
