Application of Quantitative Tissue Velocity Imaging to Evaluate Left Ventricular Early Diastolic Dysfunction in Dogs With Heart Failure Due to Rapid Ventricular Pacing

QTVI is a sensitive and specific quantitative method that can be used for the early detection of LVEDDY under tachycardic conditions. The novel indices described here, including time-R, time-E′, and S′/R, can serve as effective, noninvasive, possibly heart rate independent LVEDDY markers.