In assessing cardiac function, much attention has been paid to systolic function such as ejection fraction (EF), and the importance of diastolic function has been underestimated. However, 30–40% of patients with heart failure (HF) have preserved EF; their prognosis is as poor as HF patients with reduced EF, and diastolic dysfunction plays a crucial role in the pathogenesis of this type of HF. In addition, diastolic function is an independent determinant of prognosis even in HF patients with reduced EF. Based on these clinical findings, there is emerging interest in the assessment of diastolic function. In patients with reduced EF, increased ratio of early to late filling velocities of the transmitral flow velocity curves (E/A) and shortened deceleration time of E wave (DT) represent an elevation of left ventricular (LV) filling pressures secondary to LV diastolic dysfunction, indicating that evaluation of transmitral flow velocity curves is useful in assessment of severity of diastolic dysfunction. However, E/A ratio or DT does not correlate with LV filling pressure in subjects with preserved EF, and it is impossible to assess diastolic function and LV filling pressures in subjects with preserved EF using only transmitral flow velocity curves. Although combined analysis of transmitral and pulmonary venous flow velocity curves provides a reliable index for estimating LV filling pressure independent of EF, recording pulmonary venous flow velocity curves is not as easy as recording transmitral flow velocity curves. Tissue Doppler imaging has been utilized recently in clinical practice. Tissue Doppler imaging of mitral annular movement consists of systolic, early diastolic (e0), and late diastolic velocity curves, and several studies have demonstrated that the ratio of E to e0 (E/e0) correlated with LV filling pressure independent of EF. As tissue Doppler imaging of mitral annular movement is as easy as recording transmitral flow velocity curves, E/e0 ratio is currently used as a first line in diagnosing HF patients with preserved EF. However, several critical issues have been reported regarding the reliability of E/e0 ratio in assessing LV filling pressures. In patients with hypertrophic cardiomyopathy, E/e0 ratio may overestimate LV filling pressures. In patients with reduced EF and advanced decompensated HF, E/e0 ratio did not correlate with LV filling pressures, and E/A ratio was likely to show better correlation. In addition, ultrasound imaging machines without tissue Doppler imaging capability are still widely used by primary physicians, who are likely to follow more than half of HF patients with preserved EF in Japan. There has been growing interest in a newly developed technique, called speckle tracking, to assess cardiac function, and several articles have been published about the utility of this new method. However, analysis systems differ and the results are not consistent among ultrasound apparatuses. In assessing LV diastolic function, attention has been paid to the indices derived from LV echocardiographic imaging or flow dynamics during the diastolic phase. Left atrial (LA) size has been assessable by conventional echocardiography for a long time, but it has not been fully utilized in clinical practice. We previously showed that left atrium is enlarged in HF patients with preserved EF as K. Yamamoto (&) The Center for Advanced Medical Engineering and Informatics, Osaka University, 2-2 Yamadaoka, Suita 565-0871, Japan e-mail: kazuhiro@medone.med.osaka-u.ac.jp