Myocardial Infarction Flashcards by Anna Parker

chain of events leading to an MI

atherosclerosis 
plaque rupture 
platlet aggregation
thrombus formation 
vessel occlusion 
vasospasm 
distal ischemia 
ischemic complications

How well did you know this?

Not at all

Perfectly

classic symptoms of an MI

intense opressive chest pain/pressure radiating to left arm

How well did you know this?

Not at all

Perfectly

other symptoms of MI

increased chest heaviness 
nausea 
dyspona
ligthheadness
sweating 
confusion

How well did you know this?

Not at all

Perfectly

characteristics of a stable angina

transient (<30mins) episodic chest discomfort
predictable, reproducible
often follows physical excertion or emotional stress

How well did you know this?

Not at all

Perfectly

ECG of stable angina

normal,
t wave changes
st depression

How well did you know this?

Not at all

Perfectly

unstable angina

new onset
rest angina
angine worseing in severity or occuring with PA

How well did you know this?

Not at all

Perfectly

ischemic ECG

assocaited with inverted t wave or st segment depression

How well did you know this?

Not at all

Perfectly

Non-STEMI ECG

partial or intermittent blockage of the artery, may show ST depression

How well did you know this?

Not at all

Perfectly

STEMI ECG

St segment elevation and t wave inversion

casued by complete and perishing blockage of the artery

How well did you know this?

Not at all

Perfectly

how does ischemia reduce ATP availibilty

K+ channels open if Low ATP, thus K+ quickly leak out of cell = trigger deploarization
Ca and Na flood inwards
reduced K:Na pump activity
K builds up outisde, reducing gradient
cell stays positve for longer before repolarzing

How well did you know this?

Not at all

Perfectly

effect MI on ST

depression
depolarises, ischemic region generates electrical current
pocket of +ive signal elevates baseline volatge
when ventricles become depolarized, all the muscle depolarises so 0 voltage is recorded
ST segment appears depresssed relative to baseline

How well did you know this?

Not at all

Perfectly

potential charactersitics of ST depression

downsloping 
upsloping 
horizontal 
need to be >1mm below baseline 
seen in at least 2 leads

How well did you know this?

Not at all

Perfectly

effect of MI Q wave

damage to left ventricle

dead area so no signal

How well did you know this?

Not at all

Perfectly

non pathological q wave

q wave less than 2mm are normal

How well did you know this?

Not at all

Perfectly

pathological q wave

q wave greater than 2mm

How well did you know this?

Not at all

Perfectly

marker of historic heart attcak

deeper q wave

due to damage in the tissue

How well did you know this?

Not at all

Perfectly

surivival of MI

60min golden window

irreversible injury typically requires 30 mins of ischemia

How well did you know this?

Not at all

Perfectly

use of cardiac enzymes

allow clincians to document when hearrt attack started as each spike at different times
released when myocardial tissue dies causing cells to collapse and spill contents into blood

How well did you know this?

Not at all

Perfectly

CPK peak and time

12-36 hours

raise 3-4 d

tropoin peak

peak 12-24

approx 8

anti- ischemics

oxygen
beta-blockers - slow HR, reduced O2 requirement
nitrates - vasodilator
morphine - pain relief

anti thrombotics

anti platelet agents

- tissue plasminogen activator

Post myocardial infarction

first 4-6 hours

poor contraction

loses systolic power

Post myocardial infarction

7 days

infarct dilation and remodling
inflammation
bruising
thinning of ventricles and enlargement of infarct site

Post myocardial infarction | 6-12 weeks

necrosis may develop congestive heart failure scarring - scar tissue leads to increased stiffness - partially resolves with time

types of blood thinners

asprin plus another antiplatelet therapy (warfrin) | novel oral anti-coagulents

effect of ACE Inhibitors

decrease peripheral resistance = reduce BP and less heart work aids fibrin disolving

effect of Beta blockers

reduce heart work | adrenaline, epinephrin blocker

effect of statins

cholestrol lowering

effect of calcium channel blockers

decrease peripheral resistance = less heart work

effects of diruetics

reduce blood volume = reduces BP & heart work

aspects of a comprehensive cardiac rehab programme

``` exercise training psychological and stress counselling dietary advice advice on meds and treatment risk factor modification facilitating social reintegration ```

benefits of exercise based cardiac rehab

``` 13-26% decrease in all cause mortality 10-36% decrease in cardiac mortality 20-50% decrease in reinfarction 10% risk decrease cardiac mortality 23-56% decrease in hopital readmission cost effective increase QoL ```

starting rehab

normally met in hospital Post MI/PTCA rehab starts 2-4 weeks later Post CABG - rehab starts 4-6 weeks

rehab stage 1

before discharge from hospital - assessment - lifestyle advice - medication - informative

rehab stage 2

early post discharge - comperhensive assesment - education

rehab stage 3

strucural exercise | maintain access to advice and support

rehab phase 4

long term maintenance - long term advice - referal onto other groups - outside exercise

what is the best single measure of an individuals Cadio respiratory fitness

peak oxygen uptake

VO2 equation

VO2 = Q xA - VO2 Diff

peak vo2 of aerobically fit vs unfit

unfit is lower

peak vo2 of cardiac patient

CAD patients may have 50% lower peak VO2

stroke volume cardiac patients

increases with exercise levels off at 50% peak vo2 dictated by venous return, TPR and myocardial contractility

why does SV decrease

``` scarring and ischemia - increases wall stiffness - hypokinectic myocardium decrease EDV decrease contractility - increase afterload decrease SV ```

why does Q decrease

coronary vasoconstriction - exercise can cause locailised vasocon reduces blood supply to myocardium making it hypokinetic - subnormal production of endotheliam NO - localised overproduction of endothelium

redistrubution in cardiac patients

``` do not redistrubute as effectively viseral blood flow as % resting value - normal 20% - cardiac 50% therefore less delivered to the muscles ```