page_title: Right axis deviation
section_title: Diagnosis
hierarchical_section_title: Right axis deviation / Diagnosis
caption_attribution_description: The rhythm is not clear. It could be sinus with very flat P waves (there are prominent U waves that make it difficult to see P waves) or perhaps nodal rhythm, with most likely ventricular premature complexes. There is a right axis deviation of the QRS and tall R waves in V5 (&gt; 35mm) with wide spread ST changes. The EKG suggest left ventricular hypertrophy with possibly a left posterior fascicular block.
context_page_description: The electrical axis of the heart is the net direction in which the wave of depolarisation travels. It is measured using an electrocardiogram. Normally, this begins at the atrioventricular node; from here the wave of depolarisation travels down to the apex of the heart. The hexaxial reference system can be used to visualise the directions in which the depolarisation wave may travel.
  On a hexaxial diagram:
  If the electrical axis falls between the values of -30° to +90° this is considered normal.
  If the electrical axis is between -30° to -90° this is considered left axis deviation.
  If the electrical axis is between +90° to +180° this is considered right axis deviation.
  RAD is an ECG finding that arises either as an anatomically normal variant or an indicator of underlying pathology.
context_section_description: In general, a positive (upwards) deflection of an ECG trace demonstrates an electrical activity which moves towards the measuring electrode, whereas a negative (downwards) deflection of an ECG trace demonstrates an electrical activity which moves away from the measuring electrode. The electrical heart axis can be estimated from the ECG by using the quadrant method or degree method.
  Quadrant Method: Leads I and II are usually observed. If lead I is positive (translating to 0° on the hexaxial reference system) and lead II is positive (translating to 60°), the electrical heart axis is estimated to fall in the left lower quadrant within the normal range. On the other hand, as shown in Figure 2, if lead I is negative (translating to 180°) and lead II is positive, the electrical heart axis is estimated to fall in the right lower quadrant suggesting a right axis deviation. Similarly, leads I and aVF can be used.
  Degree method: First, identify the lead with the smallest QRS complex or isoelectric (flat) QRS complex (lead a). After locating the axis of the lead on the hexaxial reference system, identify the lead which is perpendicular to it (lead b). If lead b is positive, the electrical heart axis can be estimated to lie within the quadrant between axis of lead a and lead b.
  A simple tool to quickly identify axis deviation (Figure 3) is the popular mnemonic; Reaching for Right Axis Deviation and Leaving for Left Axis Deviation. This refers to the appearance of leads I and III. If the QRS complex is negative in lead I and positive in lead III, the QRS complexes appear to be "reaching" to touch each other. This signifies right axis deviation. Conversely, if the QRS complex is positive in lead I and negative in lead III. the leads have the appearance of "leaving" each other. If the QRS complex in lead II is also negative, this confirms a left axis deviation.
caption: ECG showing right axis deviation
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