arrhythmia intro Flashcards
how to pacemakers control HR
spont depolarization, fine tuned by sympa/para
effect of sympathy on HR
increase phase 4 depil rate> tachy
effect of parpasympa on HR
decrease phase 4 deploy rate>brady
arrhythmia def
abnormal heart rhythm
bradycardia
<69, sinus or AV node disfunction
tachycardia
> 100, supra ventricular, ventricular, or systole
how to tell if pacemaker is it above or below av node?
is QRS WIDE or narrow? narrow must be above!
syncope def
loss of conciousness and postural tone, spont resolves
syncope differential
arrhythmia, vasocavag, aortic valve, tampaonde, shock , seizure
which arrhythmia’s can cause syncope and how?
BOTH! decrease CO (by changing HR or HR and SV), decrease cerebral perfusion
vasovagal syncope
simple fainting, increase in vagus activity (vascular and HR), no increase in HR and vasodilation… decrease SV
cardiac arrest
syncope with severe cardiac arrythmia, no spontaneous return to circulation
mech for arrhythmia (3)
reentry, enhanced automaticity, triggered activity
reentry
most common, 90%, excitable gap/refractory tissue, continuous depot,
enhanced automaticity
sinus tachy, premature atrial contraction, premature ventricular contraction
