AXIS

The

average

direction of electrical forces in the frontal plane (limb leads)

measured from the zero reference point (lead 1)

+/-180degrees Lead 1 0degrees

http://www.ecgteacher.com/index.php/axis-a-chambers/the-cardiac-axis

Normal QRS/Cardiac Axis

QRS: -30 to 90 degrees

Recognising Axis Deviation

http://www.ecgteacher.com/index.php/axis-a-chambers/axis-deviation-recognition

Quick Look Test 1 & aVF

Lead I is a left-sided

lead, and as aVF is perpendicular to lead I, it can be considered a right-sided lead.

Quick Look Test Limb Leads

Limb leads

Lead 1 = zero

All about the…

QRS-30 to 90 degrees = Normal

Greater than 90 degrees = Right Axis Deviation

Less than -30 degrees = Left Axis Deviation

Right Axis Deviation…RAD

Right Ventricular Hypertrophy (RVH) — most common

Lateral and apical MI

Acute Right Heart Strain, e.g. acute lung disease such as pulmonary embolus

Chronic lung disease, e.g. COPD

Dextrocardia – rare +++

Normal in infants and children

Left Posterior Fascicular Block (LPFB) — diagnosis of exclusion

Hyperkalemia

Left Axis Deviation…LAD

Left Ventricular Hypertrophy (LVH) — most common

Left Anterior Fascicular Block (LAFB) — diagnosis of exclusion

LBBB

Inferior MI

paced beats

Ventricular pre-excitation (WPW)

Primum ASD — rSR’ pattern

Extreme Axis Deviation

180 to -90 degrees

rare

Right Ventricular Hypertrophy (RVH)

Apical MI

VT

Hyperkalemia

Rule of thumb: the heart axis

(QRS) rotates towards hypertropy and away from infarction

For more info and with thanks…

http://lifeinthefastlane.com/ecg-library/basics/axis/

http://www.ecgteacher.com/