The invention provides a cardiac rhythm management system which includes a tachyarrhythmia detection and classification circuit programmed to detect and classify a tachyarrhythmia, a biologic therapy delivery device configured to deliver or regulate an expression cassette suitable for terminating or preventing atrial fibrillation (AF), and a control circuit coupled to the tachyarrhythmia detection and classification circuit and the biologic therapy delivery device. Also provided is an implantable medical device for use in a body having a cardiovascular system, which includes an implantable device body including at least a cardiovascular portion configured to be in the cardiovascular system, and an expression cassette incorporated into the cardiovascular portion of the implantable device body, the expression cassette selected to express a gene product that terminates or prevents AF. Further provided are methods which employ particular expression cassettes to prevent, inhibit or treat AF.
