Hello n Welcome to HCM...
defibrillator means whenever our heart rate
increases due to VT/VF, it gives a shock
regarding test means, they want to see that whenever ur grandmother gets any VT/VF, that point of time defibrillator is giving SHOCK or not.
what they do, they increases the heart rate artificially by pacemaker or other machine and watch for the shock automatically by defibrillator.
in short, test means to see the defibrillator that weather it may give the shock when needed ??
so, good luck for ur grandma ....