Myocardial infarction Flashcards
define an MI
blockage of blood flow to the heart muscle leading to ischaemia and infarction
presentation of an MI
- central, crushing chest pain that can radiate to the neck, arm or jaw
- not relieved by GTN, onset at rest or activity
- nausea, sweating and vomiting
- sense of impending doom
diagnosis
- ECG
- troponin (I and T)
- creatinine kinase (CK)
inferior STEMI ECG
II, III and aVF
which coronary artery is an inferior STEMI
right coronary artery
anterior STEMI ECG
V2-V5
which coronary artery is an anterior STEMI
left main stem
anteroseptal STEMI ECG
V1-V3
which coronary artery is an anteroseptal STEMI
left anterior descending (LAD)
anterolateral STEMI ECG
I, aVL, V4-V6
which coronary artery is an anterolateral STEMI
left circumflex
acute management of STEMI (initially on scene)
MONA + C morphine oxygen GTN aspirin clopidogrel
management of MI
- PCI
2. if PCI unavailable then thrombolysis (reteplase, alteplase or tenecteplase)
when is thrombolysis contradicted
aortic dissection GI bleeding e.g. active peptic ulcer recent trauma neuro hypertension
management for signs of heart failure
beta blockers
management for signs of cardiogenic shock and pulmonary oedema
MOA
no nitrates because hypotension
long-term management
lifestyle aspiring beta blockers ACEI statin
diagnosis of an NSTEMI
ECG is normal
troponin raised
not relieved by a trial of GTN
Complete diagnosis of MI
troponin + ST elevation + symptoms
who can have reduced chest pain?
diabetics
why do people die from an MI?
VF
other causes of ST elevation?
high take off
what does T wave inversion indicate?
LVH
what to consider as causation in someone with STEMI and AF?
thrombus as cause
what do straight lines prior to depolarisation on an ECG indicate?
pacemaker is present, can be dual or single chamber
what may appear on an ECG within a few hours following an MI?
pathological Q waves (deep and wide)
how to calculate QTc?
QTc = QT / square root of R-R interval
normal QTc
0.38-0.42s
what can long QT lead to?
VT
what is a J wave seen in?
hypothermia
SAH
hypercalcaemia
what is the normal heart axis?
-30 to +90 degrees
what is sick sinus syndrome?
damage to SAN so it can no longer generate normal sinus rhythm
