interpreting ECGs Flashcards
what questions do we ask ourself whe looking at an ECG?
- regular?
- rate?
- P waves? are they upwards?
- is PR interval normal ?
- is every P wasve followed by QRS?
- is every QRS followed by P?
- is QRS normal width?
- is QT interval normal?
what are atrioventricular conduction blocks?
what are the 3 types?
what are causes of heart block?
delay or failure to conduct impulses from atria to ventricles via AV node and bundle of his
first degree, second degree (mobitz type 1 and 2), third degree
degeneration of electrical conducting system e.g. age, sclerosis, fibrosis, myocardial ischaemia, medication, valvular heart disases
what is first degree heart block?
how to reognise on ECG?
when all P waves are followed by QRS but the PR interval is prolonged (more than 0.2 seconds), regular HR, no skipped beats, conduction slowed.
looks normal aprt from prolonged PR interval
what is second degree AV block type 1?
what does it look like on ECG?
mobitz/wenkebach heart block
it is when there are sucessively longer PR intervals until 1 QRS is dropped and no conduction through ventricles for that beat - this repeats
PR intervals increasing with each beat until one QRS is skipped - p wave then a long pause and another p wave followed by QRS
what is a second degree heart block type 2?
what does it look like on ECG?
what is the risk?
what tretment is needed?
mobitz type 2
when PR intervals do not lengthen but there is a sudden drop and no QRS complex
P waves are regular but ventricular is irregular
normal heart beats but then no QRS sometimes
can progress to complete heart block
needs pacemaker
what is a third degree AV block ?
why is it dangerous?
what does it look like on ECG?
what is needed?
when the atria nd ventricles are depolarising independently of eachother - no AV node activity - the ventricular myocye pace maker takes over which is only 20-40 bmp
heart rate is too slow to mainatin blood pressure
regular P(atria rate normal) , widened QRS and not frequent
pacemaker (ventricular rate is slow)
what is a bundle branch block ?
what does an ECG look like?
what classical charateristic is seen on ECGs?
when there is a delayed conduction in the bundle branches (can be right or left BB)
P and PR normal
wide QRS as it takes longer to depolarise ventricles
notches - W notch on V1 and M notch on V6
wat is the difference between supraventricular and ventricular arythmias?
supraventricular is above the ventricles so can be arythmias in AV node, atrium or sinus node - normal QRS
ventriuclar arythmia is just arythmia in the ventricles - bizzare QRS
example of supraventricular arythmia: atrial fibrillation
what is it?
what does it look like on ECG?
can AF cause tachycardia?
what is coarse and fine fibrilation ?
- lots of atrial foci creating a depolarisation making a rapid chaotic pulse - not all depolariations from SA node
not all foci depolariation sare conducted
- no clear P waves - just wavey line
irregular RR intervals
normal QRS when the depolarisations are conducted
- yes it can cuase tachy and bradycardia - depends hoe many atrial impuses are conducted
- coarse is when the wavey bottom line impulses are more than 0.5mm in height (can be mistaken for true P waves) fine is vice versa
what can AF cause?
how?
blood clots leading to strokes
loss of organised and powerful atrial contraction = blood stasis = small clots
HR is irregular
what is premature ventricular ectopic beats?
(PVCs)
do people get symptoms?
why is diagnosing PVC important?
premature ontactions genterated outside noraml conduction pathway
ectopic focus is in ventricle mass and does not spead fast as it doesnt spread via His purkinje complex = wider QRS
it is premature as it pops up on ECG earlier than the expected next sinus beat
lot of people have no symptoms, some have heat palpatations
can be a sign of a damaged heart
what is ventricular tachycardia? (VTACH)
what does it look like on ECG?
is it dangerous?
3 or more PVCs consecutively
it is broard complex tachycardia
just up and down lots - no clear PQRST
yes - can lead to VF
what is ventricular fibrilation? (VF)
why is it bad?
abnormal fast choatic depolarisation of the ventricles
impulses from many ectopic sites in ventricle
no coordination in contraction
quivering ventricles
no proper contraction = poor CO and cardiac arrest if sustained
what is the difference between ischaemia and MI?
both have lack of perfusion but MI has necrosis as well and wil test posittive for troponin
what is STEMI?
why does it happen?
what is seen on ECG?
ST segment Elevation Myocardial Infarction
complete block of coronary artery
full wall thickness of heart effected
ST elevations, T waver inversion
