The trigemino-cardiac reflex is the sudden onset of dysrhythmia and hypotension during manipulation of any of the branches of the
trigeminal nerve and it may manifest as bradyarryhthmias, proceeding to asystole or asystole directly. In this case report we present a
patient of bilateral TMJ ankylosis who experienced bradyarryhthmias following insertion of Hister’s mouth gag to access the oral
cavity by dental surgeons.