How do you use the hexaxial reference system?

To use the hexaxial reference system, locate the most isoelectric (or equiphasic) lead (I, II, III, aVR, aVL, or aVF) on a diagnostic quality ECG with proper lead placement. Then find the corresponding spoke on the hexaxial reference system. The perpendicular spoke will point to the heart’s electrical axis.

What are the Hexaxial leads?

The hexaxial reference system, better known as the Cabrera system, is a convention to present the extremity leads of the 12 lead electrocardiogram, that provides an illustrative logical sequence that helps interpretation of the ECG, especially to determine the heart’s electrical axis in the frontal plane.

What does Equiphasic mean in ECG?

If the QRS is ISOELECTRIC (equiphasic) in any given lead (positive deflection = negative deflection), the axis is at 90° to this lead.

What is the normal QRS axis?

The normal adult QRS axis is between -30 degrees and +90 degrees, which is directed downward and to the left. This adult range is sometimes extended from -30 degrees to +100 degrees.

How does the hexaxial reference system relate to the lead views of the heart?

The hexaxial diagram shows each lead’s view of the heart in the vertical plane. The direction of current flow is towards leads with a positive deflection, away from leads with a negative deflection, and at 90° to a lead with an equiphasic QRS complex.

Why do we use lead 2 in ECG?

Lead II is the most common, most popular, and generally the best view because the placement of the positive electrode in Lead II views the wavefront of the impulse from the inferior aspect of the heart, as it travels from the right shoulder (RA) towards the left leg (LL).

Where are leads I II and III placed?

Leads I, II, III, aVF, aVL and aVR are all derived using three electrodes, which are placed on the right arm, the left arm and the left leg. Given the electrode placements, in relation to the heart, these leads primarily detect electrical activity in the frontal plane.

How does the Hexaxial reference system relate to the lead views of the heart?

How do you find the Equiphasic lead?

Locate a lead that has the smallest total QRS complex and/or is equiphasic. The QRS axis should be at 90 degrees to this lead. Now look at the lead that (on the vector diagram) is 90 degrees from the equiphasic lead. If this lead’s QRS complex is positive, the QRS axis is in the direction of that lead.

What does the QRS axis tell you about the heart?

Answer. The QRS axis represents the major vector of ventricular activation, which is the overall direction of electrical activity.

Where is lead1 placed?

Apply lead 1 to the left arm. We suggest the front of the left shoulder in a place where there is little muscle or muscle movement, to avoid any EMG signal disturbance. Next, apply lead 2 to the right arm. Again, the front of the shoulder is suggested here, in a place with little or no muscle or movement.

What are leads I II and III?

What do the aVR AVL and aVF leads look at?

The information from the limb electrodes is combined to produce the six limb leads (I, II, III, aVR, aVL, and aVF), which view the heart in the vertical plane. The information from these 12 leads is combined to form a standard electrocardiogram.

What is a good T axis?

The frontal plane T-wave axis was estimated from 12-lead electrocardiograms obtained on admission and categorized as normal (15 degrees to 75 degrees ), borderline (75 degrees to 105 degrees or 15 degrees to -15 degrees ), and abnormal (>105 degrees or < -15 degrees ).

What is the hexaxial reference system?

In the hexaxial reference system, each lead is assigned an axis for its positive pole. The negative pole will be diametrically opposite to it. Mean QRS amplitude in each lead is checked to see if there is a lead in which it is equiphasic.

What are the methods of ECG axis interpretation?

ECG Axis Interpretation Methods of ECG Axis Interpretation. Method 1 – The Quadrant Method. The most efficient way to estimate axis is to look at LEAD I and LEAD aVF. A positive… Method 2: Three Lead analysis – (Lead I, Lead II and aVF). Next we add in Lead II to the analysis of Lead I and aVF

How do you find the QRS axis in hexaxial reference system?

In the hexaxial reference system, each lead is assigned an axis for its positive pole. The negative pole will be diametrically opposite to it. Mean QRS amplitude in each lead is checked to see if there is a lead in which it is equiphasic. If so, the QRS axis is taken as perpendicular to it.

What is the normal electrical axis of the heart on ECG?

For example, if the most isoelectric (or equiphasic) lead is aVL, the perpendicular lead on the hexaxial reference system is lead II. If lead II is positively deflected on the ECG, the heart’s electrical axis in the frontal plane will be approximately +60°. Normal axis: -30° to +90°.