When would you be hospitalized for arrhythmia?

It depends. Many arrhythmias can be managed in the outpatient setting. A few arrhythmias are potentially dangerous such as ventricular tachycardia. Patients with low blood pressure, pulmonary congestion, chest pain or fainting are usually hospitalized.
Up to the doctor. Arrhythmias can range from being harmless abnormalities to life-threatening or fatal events. Only an expert in cardiac arrhythmias can determine whether you need to be hospitalized. Hospitalization is necessary for close monitoring of potentially fatal arrhythmias and often necessary for treatment of those rhythm disturbances.