Lewis lead for recognition of P wave during wide QRS tachycardia

Lewis lead for recognition of P wave during wide QRS tachycardia

Lewis lead is useful for recognition of P wave during wide QRS tachycardia when the P waves are usually obscured by the QRS complex or T wave. While recording the lead I configuration in the ECG machine, keep the right arm electrode (colour code red) at the right sternal edge in the second intercostal space and left arm electrode (colour code yellow) in the fourth intercostal space at the right sternal edge. The right foot (colour code black) and the left foot (colour code green) electrodes are placed as usual. A double voltage recording with a gain setting of 1 milli Volt = 20 millimeters may be used for the better delineation of the P waves.