Concepts related to the study of diastolic function: a personal commentary.

The phasic character of the transmitral flow wave is determined by the AV pressure difference and the impedance of the mitral valve complex. The measured LV pressure is determined by the complex contributions from 4 sources: rate and extent of deactivation, passive myocardial properties, deformation due to shape change, and viscoelasticity. An understanding of the functional value of diastolic indices is helped by an understanding of the basic physiology. Many questions remain unanswered at both the macro level, which has been the focus of this commentary, and the micro level where the ultimate source of function arises. New modalities for the study of diastolic function at the macro level are constantly under development, and progress is being made at the micro level. It is unfortunate that the role of left atrial properties has not received the attention required, considering that it is more than 10 years since Ishida et al. demonstrated the importance of LA pressure in creating the early filling wave. I trust that the reader understands that this paper is not meant to be a comprehensive review, but rather a discussion of basic principles from the very personal, albeit limited, point of view of my years of collaboration with colleagues from Japan. I dedicate this paper to all my former Fellows included among the authors in References 1-14, whose contributions to the study of diastolic function deserve the highest praise.