Self-terminated long-lasting ventricular fibrillation: What is the mechanism?

A 60-year-old woman with dilated cardiomyopathy was referred to our hospital due to recurrent syncope. The electrocardiogram recorded by an implantable loop recorder during a syncopal episode revealed an episode of ventricular fibrillation lasting almost 3 min that terminated spontaneously. A detailed analysis of the rhythm strip showed that the chaotic rhythm became an organized ventricular rhythm with a cycle length of 220 ms for the last 14 s before it terminated.