Battery Powered ECG Holter Dielectric Test

Hello everyone.
We've developed a battery powered body-worn ECG Holter. It uses an internal single-cell LiPo battery which can be recharge when it is not connected to the patient's body. We sent the device for IEC60601-1 certification. The lab did this experiment for the dielectric insulation test (please check the attached image):
1- They opened the enclosure and disconnected the internal LiPo battery to it's PCB.
2- The negative (GND) and the positive pins of the battery on the circuit were shorted.
3- They give high voltage between this shorted pins and one of the ECG electrodes (the device is single lead and it has 2 electrodes)
4- They rise the high voltage to 1kV and it fails around 400V (the current rises suddenly more than allowed)


Is it mandatory for this device to pass such a test?