Brady Cardia= tom brady is slow, below normal HR
Tacacardia= above normal HR
Third Degree block= conduction b/t atria and ventricles through AV node isn't happening (extra p-waves)
Atrial fibrillation= electrical chaos, depol. everywhere, no coord. contraction of atria (no p-waves)
Ventricular fibrilation= electrical chaos in ventricles, heart quivers, cardiac arrest, treated with defib (shocks heart, stops electrical chaos)
2:1 ratio of conduction between atria and ventricles
1/2 of atrial beats conducted to ventricle
Av node= frequency filter, many of atrial impulses reach AV node during its refractory period.
This protects the ventricles from dangerously high rates that compromise CO