Background: Noninvasive assessment of left ventricular (LV) diastolic function is not established in patients with preserved ejection fraction. We investigated a relation between diastolic function and diastolic wall dynamics.
Methods and results: In the animal study, data were collected in hypertensive Dahl salt-sensitive rats, a diastolic heart failure (DHF) model (n = 35), and normotensive Dahl rats (n = 26). In the clinical study, echocardiography was conducted in 26 diabetic patients with normal ejection fraction and 10 age-matched controls. The diastolic index of color-encoded images (color kinesis diastolic index [CK-DI]) was calculated as the ratio of LV cavity area expansion during the first 30% of diastolic filling time to that during the whole diastolic filling period. In the DHF model, the E/A ratio of the transmitral flow velocity curves was pseudonormalized with the development of heart failure, but CK-DI was not. CK-DI, not E/A, was significantly and inversely correlated with the time constant of LV relaxation. Angiotensin receptor blocker improved LV relaxation in the DHF model and increased CK-DI, but not E/A. The diabetic patients showed lower CK-DI than the controls, although E/A was not different.
Conclusion: Color-encoded imaging is useful in evaluating LV diastolic function. The prevalence of LV diastolic dysfunction may have been clinically underestimated by the transmitral flow velocity curves.