Conduction disorders Part 1 Bradycardias and AV blocks Flashcards
What does the P wave represent?
atrium contracting
What does the QRS respresent?
ventricular contracting
If the beat is coming from the atrium (sinus node) what leads will have upright P waves?
I, II, III, aVF–this is a “sinus rhythm”
If the rhythm is junctional what will the p waves look like?
none
What causes junctional bradycardia rhythms?
could be normal, or myocarditis, CAD or dig toxicity
What does a ventricular bradycardia (ventricular escape) look like?
wide QRS, slow rate
What causes a ventricular bradycardia (ventricular escape)?
usually pathologic–cardiomyopathy, ischemic heart disease, hypothermia, electrolyte disorder, medication toxcity
What does a 1st degree AV block look like?
1 P wave for every QRS, prolonged PR (>.2 sec) but constant
Do you need to treat a 1st degree block?
NO
What does a type 1 (Wenkebach) 2nd degree AV block look like?
PR interval gradually increases until there is a dropped QRS complex
Do you treat a type 1, 2nd degree block?
NO
What does a type 2, 2nd degree AV block look like?
PR intervals are constant and then there is a dropped QRS complex
Why is type 2, 2nd degree block more serious than type 1?
it more often progress to 3rd degree block and is associated with anterior MI
What does 3rd degree AV block look like?
atrium and ventricle are not talking to each other–PR intervals vary in length–QRS constant and P wave constant but not together
Why is 3rd degree block so serious?
associated with inferior and anterior MIs (anterior are worse)
