An implantable cardiac stimulation device monitors the progression and/or regression of heart disease. The device comprises a sensing circuit that senses activity of a heart and provides an electrogram for each one of a plurality of cardiac cycles, an averaging circuit that averages a number of the plurality of electrograms at spaced apart intervals to provide averaged trend electrograms, and a data generator that provides a metric reflective of progression or regression of heart failure responsive to a difference between a current averaged trend electrogram and a previous averaged trend electrogram.