PBL 1 Flashcards
what is ischaemic heart disease?
heart problems caused by narrowed coronary arteries
what are the types of ischaemic heart disease?
stable angina
unstable angina
NSTEMi
STEMI
what are the risk factors for ischaemic heart disease?
hypertension hypercholesterolinemia diabetes mellitus smoking obese not enough physical activity FHx older age
what is a myocardial infarction?
myocardial necrosis due to ischaemic often caused by ischaemic heart disease of the coronary circulation
what are the 3 most commonly blocked coronary arteries in an MI?
LAD
right coronary
left circumflex
what does the left anterior descending artery supply?
blood to the anterior wall and septum of left ventricles
what does the right coronary artery supply?
right ventricle and atrium
SA and AV nodes
what does the left circumflex artery supply?
lateral wall of left ventricle
outline the structure of the heart wall?
endocardium lines inside, myocardium and epucardium
what is a subendocardial infarct?
when only the inner 1/3rd of the myocardium is affected - this is also known as an NSTEMI as we dont see ST elevation
what is a transmural infarct?
after about 3-6 hours the zone of necrosis extends across endocardium, myocardium and epicardium - also known as a STEMI as we see ST elevation
what is the earliest ECG change you can see in an MI?
tall T waves
how many myocardiocytes do you lose per second during an MI?
500
what are symptoms of an MI?
severe central crushing chest pain that may radiate to left arm, neck, jaw, ear tachycardia diaphoresis nausea fatigue dyspnoea anxiety
what is a silent MI?
an MI with no/mild symptoms
how do we diagnose an MI?
ECG
blood - tropinin I, T and CK-MB
why does troponin increase in an MI?
cardiomyocytes are damaged and eventually membranes break down due to a build up of toxins = leaking troponin
how long does it take for troponin levels to return to normal after an MI?
up to 14 days
how long does it take for CK-MB
48 hours (useful to diagnosing reinfarctuon)
what are complications of an MI?
arrhythmias cardiogenic shock pericarditis myocardial ruture heart failure
what are some non-pharmacological interventions for an MI?
primary percuatenous coronary intervtnitoon
angioplasty
adressing underlying risk factors e.g. improving diet and managing stress
what is reperfusion injury?
a complication of establishing re-perfusion after an MI. the blood flowing back brings an influx of Ca2+ which can cause irreversibly damaged cells to contract and get stuck like this, a lot of O2 is also suddenly brought back which can form free radicals
outline the Vaughan-Williams classification of antiarrhythmic drugs?
class 1 - Na+ channel blockers class 2 - beta blockers class 3 - K+ channel blockers class 4 - Ca2+ channel blockers
what are examples of Na+ channel blockers for anti arrhythmia?
wuinidine
procainamide
lidocaine
phenytoin
propafenone
what are examples of beta blockers used for arrhythmias?
propanolol
metoprolol
what are examples of K+ channel blockers used for arrhythmias?
amiodarone and sotalol
what are examples of Ca2+ channel blockers used for arrhythmias?
verapamil and dibiazem
what do class 1a Na+ channel blockers do?
lengthen the action potential
what do class 1b Na+ channel blockers do?
shortens the action potential
what do class 1c Na+ channel blockers do?
has no significant efect on action potential butcauses a huge reduction in phase 0 slope
what branches does the left coronary artery give?
left anteror descending - gives rise to diagonal branches
left circumflex - this gives rise to the left marginal artery
what does the right coronary artery branch into?
right marginal artery and posterior interventricular artery
