Left ventricular (LV) relaxation is an energy-dependent process and susceptible to disruption by various disease statuses. For assessment of LV relaxation, not only invasive methods but also noninvasive methods have been developed, such as digitized M mode echocardiogram, RNA, RVG, DTI, and cardiac cine CT or MRI. Recently, new techniques were developed to measure myocardial rotational movement, such as 2-dimensional STI, VVI, and harmonic phase-tagged MRI.