Nov 17, 2024 · Cardiac axis represents the sum of depolarisation vectors generated by individual cardiac myocytes. Clinically is is reflected by the ventricular axis, and interpretation relies on determining the relationship between the QRS axis and limb leads of the ECG (below diagram)

Mar 17, 2025 · If you want to know the exact location of the cardiac axis (for example: "The axis is located at exactly 63º"), you should measure the QRS in leads I and III, translate the measurements to the hexaxial reference system and manually calculate the heart axis angle.

If the mean QRS axis is more to the right – approaching or even beyond +90°, in adults we should suspect a strain on the right heart caused by an acute pulmonary embolus or pulmonary emphysema with depression of the diaphragm.

The frontal plane QRS axis represents only the average direction of ventricular activation in the frontal plane. As such this measure can inform the ECG reader of changes in the sequence of ventricular activation (e.g., left anterior fascicular block), or it can be an indicator of myocardial damage (e.g., inferior myocardial infarction).

A tool for learning cardiac axis / QRS axis interpretation in an ecg.

The axis is calculated (to the nearest degree) by the ECG machine. The axis can also be approximated manually by judging the net direction of the QRS complex in leads I and II. The following rules apply: Normal axis: Net positive QRS complex in leads I and II. Right axis deviation: Net negative QRS complex in lead I but positive in lead II.

Dec 20, 2023 · Calculate the QRS axis. The QRS axis is at 90° to the isoelectric lead, pointing in the direction of the positive leads. Lead I and aVF are postive and so axis will be between 0 and 90 degrees. Lead aVL is the most isoelectric. Lead II is perpendicular to lead aVL. As lead II is positive axis will be around +60 degrees.

Jan 14, 2021 · A change of the heart axis or an extreme deviation can be an indication of pathology. To determine the heart axis you look at the extremity leads only (not V1-V6). If you focus especially on leads I, II, and AVF you can make a good estimate of the heart axis.

The diagram below illustrates the relationship between QRS axis and the frontal leads of the ECG. -Normal Axis = QRS axis between -30° and +90°. -Left Axis Deviation = QRS axis less than -30°. -Right Axis Deviation = QRS axis greater than +90°. -Extreme Axis Deviation = QRS axis between -90° and 180° (AKA "Northwest Axis").

Normal QRS axis is from around -30 to +90 degrees. More negative than -30 is called left axis deviation. More positive than +90 is called right axis deviation. The average direction of electrical activity is the "QRS axis." See the diagram: if the axis …