Basic Cardiac Rhythm analysis

conductivity

the ability to conduct nerve impulse from cell to cell due to electrolytes

-calcium, sodium, potassium, and magnesium

Excitability

ability to respond to stimulants

-fight or flight

automaticity

ability to conduct impulse without outside stimulation

Contractility

mechanical movement of the heart

action potential

movement of ions across cell membrane causes electrical impulse that stimulates muscle contraction

depolarization

when cell stimulated by an electrical impulse, sodium rushes into the cell and potassium leaks out cause cell to become positively charged

repolarization

during cell recovery, ions shift back to their original places and return the cell to negative

sinoatrial (SA) node

-pacemaker of heart

-all electrical activity starts here

60-100bpm

atrioventricular node

-gatekeeper

-slows things down to allow ventricles to fully fill; filter out extra impulses

-backup pacemaker if needed

40-60bpm

ventricles

can run the show for a short period of time

20-40bpm