Question

Which of the patient’s limbs serves as an electrical ground? A)left arm b) right

Arm c)right leg d)left leg

Answer 1

c)RIGHT LEG is used as electrical ground.let us have a brief review regard this-

Electrical activation of heart is required for mechanical activation of heart.The activation can be done by using skin electrodes placed on skin by following protocol.

Let us learn type of leads and where we have to keep electrical ground-

1)first set of leads are called as Standard limb leads/bipolar limb leads.in this type electrodes are placed on wrists and ankles of limb,where there is no muscle mass to generate action potentials and both arms and left leg were used as active leads,WHILE THE RIGHT LEG WAS USED AS GROUND.

2)Lead 1 is another type constructed by comparing left arm as positive and right arm as negative.Here in this type any current flowing through right produces negative deflection and through left produces postitive deflection ,WHILE THE RIGHT LEG WAS USED AS GROUND.

3)Lead 2 connects left leg as positive to the negative right arm WHILE RIGHT LEG AS GROUND and lead 3 connects left leg as positive to the negative left arm WITH RIGHT LEG USED AS GROUND.

We should always double check about placement of electrodes because inaccurate placement of leads may leads to in accurate wave forms and wrong ECG interpretation.ALWAYS USE RIGHT LEG AS GROUND ,WHICH DOESN'T CONTRIBUTE TO THE WAVE FORM for to attain standardized universal reading.

ADDITIONAL INFO- If we became expertise we can keep ground lead at any spot outside the triangle of other limb leads for example-keeping the right leg lead on the left leg just below the left led i.e.,that is outside the triangle.(BUT THIS SYSTEM USUALLY FOLLOWED AFTER ATTAINING GOOD KNOWLEDGE REGARDING APPLICATION OF LEADS)

RIGHT LEG WAS THE ANSWER-OPTION C