An implanted pacemaker senses intrinsic atrial events and generates corresponding pacing pulses. The atrial events are also monitored for a precursor of an atrial fibrillation episode. If such a precursor is detected, the pacemaker generates therapy designed to prevent the atrial fibrillation episode....http://www.google.co.uk/patents/US5951593?utm_source=gb-gplus-sharePatent US5951593 - Apparatus for preventing atrial fibrillation using precursors
