Ventricular Action Potential

SA Node Action Potential

45

46

40

23

95

40

O2

CO2

V

A

T I(S) M I(S)

T S(D) M S(D)

P I(D) A I(D)

P S(S) A S(S)

Systole: TMC PAO (S1)

Diastole: TMO PAC (S2)

TM AV valve

AP SL valve

S3 end of rapid ventricular filling

S4 high atrial pressure

40

45

V

A

A/V = 104

To Lungs

Systole:

MIASTIPS

O2 from lungs

CARDIAC CYCLE

Isometric relaxation: PAC

Rapid filling: TMO

Diastasis: Slowing of outflow from atria to ventricles

Atrial systole: onset of atrial contraction

Isometric contraction: onset of ventricular contraction

Maximum ejection: PAO

Reduced ejection: peak intraventricular pressure

Proto diastole: onset ventricular relaxation

Out (+) In (-)

0 Na

1 K

2 Ca

3 K

4 K Na

-85 to -95 mV Normal Action Potential

CO = SV x HR

Chest Leads:

V1 4th ICS Right

V2 4th ICS Left

V3 b/w V2 & V3

V4 5th ICS Left midclav

V5 5th ICS ant axillary

V6 5th ICS mid axillary

Small square: 0.04 sec

Big square: 0.20 sec

time

mV

Na

Ca

K