Patent ID: 6873873

Claim:
A system for treating a heart, comprising: an implantable housing; a first atrial catheter attached to the implantable housing of the system, where the first atrial catheter has a first atrial electrode and a first defibrillation electrode, and is positioned within the heart with the first atrial electrode and the first defibrillation electrode in a supraventricular region of the heart; a ventricular catheter attached to the implantable housing of the system, where the ventricular catheter has a first ventricular electrode, and is positioned within the heart with the first ventricular electrode in a right ventricular chamber of the heart; and electronic control circuitry within the implantable housing, connected to the first atrial electrode, the first defibrillation electrode, and the first ventricular electrode and where the electronic control circuitry receives cardiac signals through the first atrial electrode and the first ventricular electrode, and upon detecting atrial fibrillation, delivers a plurality of pacing pulses to convert the atrial fibrillation to a non-fibrillation atrial arrhythmia, analyzes the ventricular intervals for stability and delivers a first level atrial shock to the heart during a period of stable ventricular intervals.