Heart failure with a normal ejection fraction (HFNEF) predominantly afflicts older, female individuals and is considered to be a consequence of diastolic dysfunction. Doppler echocardiography has become the standard method for identifying and characterizing diastolic function. However, the important distinction between Doppler measures of filling dynamics and true indexes of intrinsic ventricular diastolic chamber properties is not widely appreciated. Herein, we delineate physiologic measures of intrinsic ventricular diastolic function, as determined by pressure volume analysis, and compare and contrast these measures with those derived from Doppler echocardiography. Doppler-derived indexes of ventricular filling do not provide specific information on intrinsic passive diastolic properties, and thus, abnormal filling dynamics do not necessarily equate with intrinsic myocardial diastolic dysfunction. This raises a fundamental question as to whether delayed relaxation and/or stiffened passive properties are the unifying pathophysiologic mechanisms in all patients who present with HFNEF.