The ECG of a 40 year old male was recorded using standard bipolar limb leads. The sum of voltage of the three standard leads was found to be 5 millivolts. This indicates:

D i.e. Increased cardiac muscle massWhen the sum of voltages of all the QRS complexes of the three standard leads is greater than 4 millivolts, the ECG is considered as high voltage electrocardiogram. Most often due to increased cardiac muscle massQ.The voltage in the three standard leads is measured from the peak of R wave to the bottom of S wave = 0.5 - 2.0 millivoltsHighest voltage is in lead II, lowest in lead III.