A method for defibrillating a patient's atria with an implantable defibrillator having defibrillation synchronized to the atrial fibrillation waveform. The defibrillator is used to detect fibrillation in a patient's aria, monitor at least one atrial fibrillation signal across two electrodes,...http://www.google.de/patents/US5853426?utm_source=gb-gplus-sharePatent US5853426 - Method and apparatus for delivering atrial defibrillaton therapy with improved effectiveness 
