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).
Sensorineural hearing loss is hearing loss due to damage to the hair cells of the organ of Corti or to the auditory part of the vestibulocochlear nerve. Tinnitus is ringing or buzzing in the ears. Vertigo is the illusion of movement. Nystagmus is a to-and-fro movement of the eyes.