Does Propanolol Cause Arrhythmia?

Hi my name is Nestor. I am a male of 42 yrs of age. Currently, taking propanolol, lorazepam and methimazole. Lorazepam for anxiety and methimazole and propanolol for hyperthyroidism. My last blood work revealed that my thyroid levels were normal but was still feeling palpitations. Most recently some occacional arrhytmia which is what concerns me. I am feeling this way since I started on propanolol. Q's Isn't propanolol supposed to take care of heart palpitations and arrhythmia simultaneously? Can propanolol be causative of the arrhythmia? Thanks. -Nestor