Heart Blocks Flashcards
First degree heart block
consistent delay of conduction at the AV node. Not a true block. Characteristicly long R from P
If your R is far from P
it is first degree
First degree heart block ECG characteristics
prolonged PR interval, >.2
First degree heart block causes
can occur in healthy person for no reason. or could be from cardiac disease like inferior acute MI. Could also be causes by increased vagal tone, Beta blockers, Digoxin or other antidysrhythmics. could also be caused by hypothyroidism.
first degree heart block treatment
non indicated, CO is unaffected.
first degree heart block precautions
can progress to a higher degree block, especially if prompted by an MI
Second degree heart block type I
intermittent block at the AV node
Longer longer longer, drop, now you have a Wenckebach
Second degree heart block type I
Second degree heart block type I causes
can be in a healthy person, but can also be from an inferior wall MI, or acute myocarditis. can also be caused by drugs like BB, digoxin, etc, increased vagal tone and hyperkalemia.
Second degree heart block type I effects
usually transient and reversible. If ventricular beat is dropped frequently can show signs of decreased CO–> chest pain and hypotension.
Second degree heart block type I treatment
if showing symptoms, give O2 and start IV line. If HR is slow, can give atropine and transcutaneous pacing.
Second degree heart block type I prognosis
may progress to more serious blocks, especially in presence of inferior MI
Second degree heart block type I ECG characteristics
patterned irregularity rhythm, PR interval gets progressively longer and then cycle will drop and repeat.
Second degree heart block type II
intermittent block at bundle of His or the bundle branches. Results in atrial pulses that are not conducted to the ventricles, so there are more P waves than QRS complexes. This is serious.
Second degree heart block type II causes
anterior wall MI, degenerative disease of the AV node or severe CAD. like other blocks can also be caused by BB and medications.
If your P’s don’t go through
you have a mobitz type II, Second degree heart block type II
Second degree heart block type II effects
decreased CO and hypoperfusion- fatigue, syncope, hypotension, AMS.
Second degree heart block type II treatment
Give O2, start IV line and do transcutaneous pacing. If there is a new, wide QRS complex then give atropine while setting up transq pacing.
Second degree heart block type II ECG characteristics
atrial rate is not normal, but ventricular rate may be. PR interval is constant, where beats are actually conducted.
Second degree heart block type II prognosis
may progress to more severe bloc and ventricular asystole
Third degree heart block
complete block of conduction at or below the AV node, so the impulse from the atria cannot reach the ventricles.
Third degree heart block causes
usually congenital, but can also be caused from degenerative diseases, anterior or inferior wall MI, etc.
Third degree heart block effects
well tolerated, as long as the escape rhythm is fast enough to generate sufficient CO. May see decreased CO and have fatigue, syncope, etc.
Third degree heart block treatment
if symptomatic, give O2, start IV line and do transcutateous pacing. If there is a new, wide QRS can give atropine while setting up transq pacing.
intrinsic atrial rate
60-100 bpm, by SA node
AV junction rate
40-60 bpm. If signaled from here, will have narrow QRS
Ventricular rate
20-40 bpm. If signaled from here, will have wide QRS.
If your q’s and p’s do not agree
its a Third degree heart block
Third degree heart block ECG characteristics
slower ventricular rate (RR), atrial and ventricular rhythms are normal but not related. P wave is normal, but will march through the QRS.
First degree heart block ECG
second degree heart block type I ECG
Second degree heart block type II ECG
Third degree heart block ECG
