Paroxysmal atrial tachycardia may be caused by several different things. The fast rate may be triggered by a premature atrial beat that sends an impulse along an abnormal electrical path to the ventricles. Other causes stem from anxiety, stimulants, overactive thyroid, and in some women, the onset of menstruation.
Sudden hearing loss is associated with vertigo in between 20 to 60% of patients (Rambold et al, 2005). The wide spread probably depends on what you define as vertigo -- a little bit of dizziness, or a profound sensation of rotation. Patients with vertigo also usually have worse hearing (Niu et al, 2015).
Some individuals may become totally deaf. The loss of hearing often happens suddenly and in stages. Sometimes, after a sudden decrease in hearing, a person's hearing will nearly return to its previous level. Almost all people with Pendred syndrome have bilateral hearing loss, or hearing loss in both ears. The hearing loss often is greater in one ear than in the other.