Synchronized cardioversion is recommended for acute treatment in patients with hemodynamically unstable focal AT.94,208 See Online Data Supplement 6. Although minimum data are available on cardioversion of focal AT, synchronized cardioversion is a consideration in patients with drug- resistant arrhythmias associated with signs and symptoms of compromised hemodynamics. Termination of tachycardia is expected when a focal AT is of a microreentrant mechanism. Response of a triggered focal AT to cardioversion can be variable, whereas electrical cardioversion is not likely to be effective in focal AT with an automatic mechanism. In this latter case, antiarrhythmic drug therapy is usually required. Page et al 2015 ACC/AHA/HRS SVT Guideline e527 4.1.2. Ongoing Management: Recommendations IIa B-NR Adenosine can be useful in the acute setting to either restore sinus rhythm or diagnose the tachycardia mechanism in patients with suspected focal AT.123,200,207 See Online Data Supplement 6. Adenosine is usually effective in terminating focal AT of a triggered mechanism but is not expected to be effective in reentrant focal AT.207 Transient suppression can be observed in automatic focal AT. The observation of transient AV block with persistent AT can be helpful in making the diagnosis and differentiating focal AT from AVNRT and AVRT. IIb C-LD Intravenous amiodarone may be reasonable in the acute setting to either restore sinus rhythm or slow the ventricular rate in hemodynamically stable patients with focal AT.205,206 See Online Data Supplement 6. The therapeutic effect of intravenous amiodarone in the acute setting is likely mediated via blockade of the beta receptors or calcium channels. Amiodarone may be preferred in patients with reduced ventricular function or with a history of heart failure. IIb C-LD 2. Ibutilide may be reasonable in the acute setting to restore sinus rhythm in hemodynamically stable patients with focal AT.205,206 See Online Data Supplement 6. 