Thank you for your reply.
Yes, I did research on ventricular fibrillation, and an implantable cardioverter-defibrillator is the only treatment.
I hope that it is not ventricular fibrillation.
Although the doctor seems to be stressing that the vasovagal sycnope is caused by postural hypotension because my mom rose from the chair to reach out to turn on the electric fan.
No, it's not likely that it may be ventricular fibrillation. This is similar to cardiac arrest and does not happen out of nothing, and if it happens, it will not stop without an electrical shock.
A vasovagal syncope can happen even with a normal blood pressure, and blood sugar has nothing to do with a vasovagal syncope.
Unfortunately, it's not possible for any of us (we are not doctors) to provide any differensial diagnosis. Fainting is not uncommon with sick sinus syndrome but the pacemaker should usually prevent that.
Since you asked: The only treatment against ventricular fibrillation is an ICD. Or, if there is any cause for it, it can be treated too, but most people that are resucitated from VF will get an ICD implanted.