Structural changes that occur with HFpEF are often radically different from those associated with heart failure with reduced ejection fraction (HFrEF).[16] Many patients experience increased thickening of the ventricular wall in comparison to chamber size, termed concentric hypertrophy. This leads to increased left ventricular mass and is typically accompanied by a normal, or slightly reduced, end diastolic filling volume. Conversely, HFrEF is typically associated with eccentric hypertrophy, characterized by an increase in cardiac chamber size without an accompanying increase in wall thickness.