Qrs axis determination

  During ECG interpretation, cardiac Axis, or direction of electrical impulses, may be normal (physiologic) or abnormal (pathologic), suggesting abnormal cardiac conductivity. Although every deflection obtained on the ECG will have an axis, we will focus on the ventricular axis.  When we think of our cardiac monitoring lead placement, we have to understand cardiac Vectors, which is the sum of all electrical impulses. These are recorded on each individual lead, because impulses travel underneath the electrodes in multiple directions, therefore, incorrect lead placement will give a false axis. Here, we will disuss Frontal Plane Leads (Limb Leads) form the Ethoven’s Triangle as follow:  Lead I is obtained from the Right Arm (-) and Left Arm (+) electrodes, looking towards the lateral (left) aspect of the Left Ventricle (LV).   Lead II is obtained from the Right Arm (-) and the Left Leg (+) electrodes, looking towards the inferior leftward portion of the LV., and follows the normal conductivity path (from the SA Node towards the ventricles), which explains why this leads is often used for rhythm monitoring.   Lead III is obtained from the Left Arm (-) and the Left Leg (+) electrodes, looking towards the inferior wall of the LV and Right Ventricle (RV), having the most rightward view. The Augmented leads are, as the name says, an augmented view obtained when we have the limb leads in place and are perpendicular to the angle obtained from the limb leads. ...
Source: EMS 12-Lead - Category: Cardiology Authors: Tags: 12 lead ecg axis determination hexaxial reference system vector Source Type: research