Internal Cardioversion in Two Patients with Atrial Fibrillation Refractory to External Cardioversion

2 male patients (ages 26 and 17) with sustained atrial fibrillation refractory to external cardioversion (failed four attempts with maximum delivered energy of 360 J). One patient had a history of congenital heart disease, presyncope, and wide complex tachycardia; the other had a history of sick sinus syndrome.

Low energy internal cardioversion using biphasic waveforms and internal transvenous defibrillation electrodes

Successful cardioversion