ecg+arrhythmias Flashcards
which leads are involved in the frontal plane
limb leads and augmented vector leads
horizontal plane has which leads
V leads
what does the P wave represent
- atrial depolarization
- ATRIAL CONTRACTION occurs during ST segment
- must have pause after P wave to allow atria to contract & eject contents into ventricle (PR interval)
PR interval time should be less than
200ms
what happens during the PR interval
covers beginning of P wave to just before QRS complex. Atrial depolarization and contraction.
what happens during PR segment
atria contract, while signal is sitting at AV node and bundle of his
whats the purpose of the AV node?
AV node and bundle of his slows the conduction speed which allows atria to contract and fill ventricles. . After the atria contract, the signal moves to right and left bundle branches and on to ventricles
what does the QRS complex represent?
ventricular depolarization
what is the conduction combination during the QRS complex
- bundle branches, purkinje fibres and ventricular muscle cells
how many fascicles does the left bundle branch have and how many does the right have?
- left anterior and left posterior
- right only has one
QRS duration?
<120ms
if the signal is blocked, what happens to the QRS?
gets wider
which bundle branch looks like rabit ears
right
what is the QRS influenced by?
- muscle thickness
- body habitus
- pericardium
what does the ST segment represent?
- gap between ventricular depolarization & repolarization.
- ventricles START to contract
if patient has myocardial ischemia, what happens to the ST segment?
it will be depressed
if the patient has myocardial infarction, what will the ST segment look like?
elevated
wat does the T wave represent?
- ventricular depolarization
- mechanically coincides with ventricular systole
whats normal sinus rhythm
60-90bpm
50-60 & 90-100 borderline
what is the five steps in diagnosing rhythms?
- HR
- rhythm (R-R should be same)
- are P waves identical?
- is the PR interval long or short?
- is the QRS wide or narrow?
sinus bradycardia
<50-60bpm
sinus tachy
> 90-100bpm
if PR interval is >200 and the only thing wrong with ECG, what does this indicate?
First degree AV block
describe what happens during atrial flutter?
- atrial contraction is semi organized so P waves look similar to normal P waves. There’s an electrical re-entry loop through the atrial tissue that allow it to depolarize repeatedly. 2-4 P waves for every QRS.
