Multistage low-energy electrical pulses as described in Janardhan AH et al. JACC 2014 Jan7-14:63(1):40-8 will be delivered to a patient in atrial fibrillation. The responses to these stimuli will be recorded.

The parameters of the Multistage waveform will be altered and the response of the atria will be recorded.

Multistage low-energy pulses are delivered to the atria of patients while in atrial fibrillation. The atrial electrograms will be recorded and used to evaluate if there was a change in the atrial fibrillation cycle length, increased organization of the arrhythmia using frequency analysis or if the pulses were able to terminate the atrial fibrillation.