myocardial infarction Flashcards
(28 cards)
define myocardial infarction
Necrosis of cardiac tissue due to prolonged myocardial ischaemia due to COMPLETE occlusion of an artery by thrombus.
pathology of MI
- plaque rupture
- development of thrombosis
- total occlusion of coronary arterY
- myocardial cell death
ECG of STEMI
ST elevation
Tall T waves
Might present as a new LBBB (WilliaM)
Pathological Q waves
ECG OF NSTEMI
ST depression and/or T wave inversion
what do both STEMI and NSTEMI have
increased troponin
risk factors for MI
Age
Male
History of premature coronary heart disease
Diabetes mellitus
Hypertension
Hyperlipidaemia
Family history
symptoms of MI
- Crushing central chest pain similar to that occurring in angina – described as “elephant sitting on chest
- Sweating
- SOB/Dyspnoea
- Fatigue
- Nausea
- Vomiting
can MI occur at rest
yes
how long does MI last
anywhere from few mins to several hours
can MI be relived by GTN spray
no
where can MI pain radiate to
to left arm, neck and/or jaw
are pulse and bp high or low in MI
may vary between being up or down
how does a patient with MI appear
pale, sweaty and grey
what can you hear in MI
4th heart sound – due to forceful contraction of the atria to overcome a stiff or dysfunctional ventricle
Pansystolic murmur – due to papillary muscle dysfunction or rupture
who is at highest risk of silent infarction
elderly patients, diabetics or those with hypertension.
what symptoms occur in silent infarction
either nothing
or
hypotension, arrhythmias or pulmonary oedema
differential diagnosis for MI
Stable/unstable angina
Pericarditis
Aortic aneurysm
Endocarditis
Pulmonary Embolism
Pneumothorax
investigations for mI
- clinical history
- ECG
- cardiac enzymes
- CT angiography
- CXR
- FBC
- U&E
- Blood glucose and lipids
what is the acute (initial) managment for MI
- Get to hospital immediately
- MONA
Morphine
Oxygen (if sats are <94%)
Nitrates – typically fondaparinux in Sheffield
Aspirin 300mg – chewed in order to increase absorption - 12 lead ECG and cardiac monitor
- Beta blocker IV – contraindicated in hypotension, HF, bradycardia and asthma
- Refer for PCI, thrombolysis (IV alteplase) or CABG ASAP as long as it’s not contraindicated
what is the subsequent secondary prevention for MI
- modification of risk factors
- aspirin 75 mg daily
- Clopidogrel/ticagrelor (for dual antiplatelet therapy)
- Statins
- Beta blocker – if contraindicated give ACE-I
- ACE inhibitors – use angiotensin receptor blocker if intolerant e.g. valsartan
- Advice
what advice to give someone whose had an MI
Return to work after 2 months – not all professions e.g. airline pilots,
divers, air traffic controllers
No air travel for 2 months
No sex for 1 month
complications from MI
- Myocardial rupture
- Arrhythmias
- Pericarditis
- Dressler’s syndrome
- Death
- Mitral incompetence
3 types of myocardial rupture
Rupture of ventricular septum 🡪 right HF
LV wall 🡪 cardiac tamponade
Papillary muscle rupture 🡪 mitral regurgitation/prolapse
2 types of arrhythmias
Tachycardia – Sinus, VF, AF
Brachycardia – Sinus, AV block
