5 precordial axis

12-Lead Electrocardiography

a comprehensive course

Adam Thompson, EMT-P, A.S.

The

Precordial

Axis

Frontal Axis

Precordial Axis

• Sometimes called Z axis• Clockwise or Counterclockwise rotation

Precordial AxisFrontal Plane Axis Precordial Axis

ERAD-90 to 180

Right Axis Deviation90 to 180

Pathological Left Axis Deviation

-30 to -90

Early TransitionCounterclockwise

Rotation

Late TransitionClockwise Rotation

• Ventricular Rhythm• Paced Rhythm• Dextrocardia• Electrolyte derangement

• May be normal• LPFB• Pulmonary disease• RVH• RBBB• WPW• Dextrocardia•Venrticular Rhythm

• Pregnancy• LAFB• WPW• Pulmonary disease• LBBB• Hyperkalemia• Q-waves, MI

• Posterior wall infarction• RVH• RBBB• WPW

• Sometimes Normal, especially in women• Anterior MI• LVH• LAFB• LBBB• Lung Disease

Precordial Axis

Precordial Leads = V Leads

Sometimes called Chest Leads

Precordial Axis

• The main impulse travels down then to the left.

1

3

22

3

4

Mean vector

Cardiac vector

Precordial Axis

1

3

22

3

4

Mean vector

Cardiac vector

V1 V2

V3V4 V5

V6

Precordial Axis

• The normal transition zone is between V3 and V4.

• V1 should be predominately negative.• V6 should be mostly positive.

Precordial Axis

Lets take a look at a 12-lead

Precordial Axis

Is V1 mostly negative?

Precordial Axis

Is V6 mostly positive?

Precordial Axis

Where is the transition?

Precordial Axis

The Precordial Axis is Normal

Precordial Axis

Now picture the precordial leads in this pattern.

V1

V2

V3

V4

V5V6

Precordial Axis

V1

V2

V3

V4

V5V6

Normal transition

Precordial Axis

V1

V2

V3

V4

V5V6

Early transition = Counterclockwise Rotation

Precordial Axis

V1

V2

V3

V4

V5V6

Late transition = Clockwise Rotation

Precordial Axis

Precordial Axis

Early Transition - Counterclockwise Rotation

Precordial Axis

Early Transition - Counterclockwise Rotation

Precordial Axis

Another Example

Precordial Axis

Late Transition - Clockwise Rotation

Precordial AxisFrontal Plane Axis Precordial Axis

ERAD-90 to 180

Right Axis Deviation90 to 180

Pathological Left Axis Deviation

-30 to -90

Early TransitionCounterclockwise

Rotation

Late TransitionClockwise Rotation

• Ventricular Rhythm• Paced Rhythm• Dextrocardia• Electrolyte derangement

• May be normal• LPFB• Pulmonary disease• RVH• RBBB• WPW• Dextrocardia•Venrticular Rhythm

• Pregnancy• LAFB• WPW• Pulmonary disease• LBBB• Hyperkalemia• Q-waves, MI

• Posterior wall infarction• RVH• RBBB• WPW

• Sometimes Normal, especially in women• Anterior MI• LVH• LAFB• LBBB• Lung Disease

Precordial AxisNormal R-wave progression

Precordial AxisEarly R-wave progression

Precordial AxisLate R-wave progression

Bundle Branch Blocks

1

2

3

Left Bundle Branch Block

V1

Bundle Branch Blocks

1

2

3

Right Bundle Branch Block

V1

Bundle Branch Blocks

V1

V1

Bundle Branch Blocks

= RBBB

= LBBB

V1

V1

GT

RBBB Morphologies

LBBB Morphologies

Bundle Branch BlocksFrontal Plane Axis Precordial Axis

ERAD-90 to 180

Right Axis Deviation90 to 180

Pathological Left Axis Deviation

-30 to -90

Early TransitionCounterclockwise

Rotation

Late TransitionClockwise Rotation

• Ventricular Rhythm• Paced Rhythm• Dextrocardia• Electrolyte derangement

• May be normal• LPFB• Pulmonary disease• RVH• RBBB• WPW• Dextrocardia•Venrticular Rhythm

• Pregnancy• LAFB• WPW• Pulmonary disease• LBBB• Hyperkalemia• Q-waves, MI

• Posterior wall infarction• RVH• RBBB• WPW

• Sometimes Normal, especially in women• Anterior MI• LVH• LAFB• LBBB• Lung Disease

Bundle Branch Blocks

Bundle Branch Blocks

The End

“Its finally over”

…Well almost.

More to come in lesson three.