An implantable medical device has an impedance processor that determines impedance data reflective of the transvalvular impedance of a heart valve of a heart during a heart cycle. The determined impedance data are processed by a representation processor that estimates diastolic and systolic transvalvular impedance representations. A condition processor determines the presence of any heart valve malfunction, such as valve regurgitation andor stenosis, of the heart valve based on the estimated diastolic and systolic transvalvular impedance representations.