There is in fact very little evidence to suggest prednisolone
can set off premature ventricular contractions; but certainly can set off palpitations if the dose was higher than required. Some patients with adrenal insufficiency
who require steroids
for life also feel the same once they start and novice patients will feel more of the effect. You have not mentioned the dose you had, or whether you took it on an empty stomach or without PPI cover. Gastritis
is a problem when taken on an empty stomach, and that set off palpitations.
It should subside within 24 hours, but if you still feel unwell, I would suggest you get seen by a physician as soon as possible for an ECG and a thorough evaluation.