## How do I calculate axis deviation?

Right Axis Deviation = QRS axis greater than +90°….

- Step 1: Find the isoelectric lead. The isoelectric (equiphasic) lead is the frontal lead with zero net amplitude.
- Step 2: Find the positive leads. Look for the leads with the tallest R waves (or largest R/S ratios)
- Step 3: Calculate the QRS axis.

## What does axis deviation mean on ECG?

Right axis deviation (RAD) involves the direction of depolarisation being distorted to the right (between +90º and +180º). The most common cause of RAD is right ventricular hypertrophy. Extra right ventricular tissue results in a stronger electrical signal being generated by the right side of the heart.

**What is normal calculated R axis?**

In other words, 0 degrees to +90 degrees is a normal axis, +90 degrees to 180 degrees is RAD, 0 degrees to -90 degrees is LAD, and -90 degrees to 180 degrees is an extreme axis.

### What is the deviation of the QRS axis?

Right Axis Deviation = QRS axis greater than +90°. Normal Axis = QRS axis between -30° and +90°. Left Axis Deviation = QRS axis less than -30°.

### What does a deviation on the right axis mean?

Right Axis Deviation = QRS axis greater than +90°. Normal Axis = QRS axis between -30° and +90°. Left Axis Deviation = QRS axis less than -30°. Extreme Axis Deviation = QRS axis between -90° and 180° (AKA “Northwest Axis”)

**Which is the correct axis for lead I and aVF?**

Combining both coloured areas – the quadrant of overlap determines the axis. So If Lead I and aVF are both positive, the axis is between 0° and +90° (i.e. normal axis). Note: **Possible LAD can be further evaluated using Lead II as detailed in method 2 below… A positive QRS in Lead I puts the axis in roughly the same direction as lead I.

#### How are the quadrants of the abdomen determined?

Determining these regions can be done by putting a vertical line crossing the navel and a horizontal line also crossing the navel. After putting these two lines, you’ll have intersecting lines with four areas on upper right, upper left, lower left and lower right which are the abdominal quadrants.