My mom gets cardiac arrhythmia, so am I likely to get it later?

Possibly. Depending on how old she was when she first had her arrhythmia, and what kind, your risk varies. Some arrhytmias (atrial fibrillation) have less heritability risk; others (ventricular arrhythmias) have a higher risk.
Not necessarily . There are some genetics involved in some arrhythmias (e.g. Wpw, atrial fibrillation), but most people would agree that the arrhythmias in general are not inherited. It also depends on the kind of arrhythmia she has.