Diastole is an essential part of the cardiac cycle, during which significant changes in myocardial function, ion and energy transfer, as well as coronary flow, occur. In contrast to systole, diastole consists of four phases, each of which has its distinguishing function and events. However, the four phases are inter-related with events in early diastole correlating with those in late diastole and those occurring during the isovolumic relaxation time predicting both. The complexity of diastolic phases is reflected in the ways by which diastolic function is assessed. While intra-cardiac flow velocities, into and out of the atria, are measured by pulsed-wave Doppler, those of wall motion are assessed by M-mode, myocardial Doppler velocities or, recently, speckle tracking technique. Optimum integration of various aspects of diastolic function should always be considered in order to obtain an accurate comprehensive assessment, bearing in mind factors that normally affect it, for example age.
Michael Y Henein - Departments of Public Health and Clinical Medicine and Surgery and Perioperative Sciences, Umea University, Umea, Sweden Canterbury Christ Church University, Kent, UK
Per Lindqvist - Departments of Public Health and Clinical Medicine and Surgery and Perioperative Sciences, Umea University, Umea, Sweden