There are many types of arrhythmia, some of which, like sinus tachycardia, sinus bradycardia, occasional premature atrial contractions, premature ventricular contractions, and premature junctional contractions, can also occur in healthy individuals and usually do not require treatment. Another category requires treatment, such as supraventricular tachycardia, including atrioventricular nodal reentrant tachycardia, which can be cured by radiofrequency ablation. Additionally, conditions like atrial fibrillation can be treated with radiofrequency ablation; many patients may be cured, but some may not respond to this treatment and require medication instead. There are also patients with intrinsic structural heart disease presenting various arrhythmias that can only be managed with medication, not cured.