Heating cables, Heating Coils, Roof Deicing Cables, and Heat Tape are terms you often hearing when referring to this ice damn prevention. The cables use electricity to generate heat to melt pathways through snow on the roof. The pathways allow water to escape from the roof instead of backing up into the home. Please note, the purpose of heating cables are only to create pathways rather than keep entire roofs / gutters snow free.
When a qualified professional like installs high quality heat cables they can provide some ice damn prevention, however we frequently run into homes in our inspections that still have ice damns issues. We believe the reason for this to be is our extreme climate in Ottawa. Vast amounts of snow in Ottawa can not melt with heat generated by heating cables, as they should not be hot enough to damage shingles.
In our opinion you are much better off topping up your insulation and/or adding vents. In a worst case scenario you may explore re roofing your roof with high quality Grace Ice & Water protector.