Abstract 14584: Noninvasive Estimation of Time Constant of Left Ventricular Pressure Decline as an Index of Relaxation by Speckle Tracking Echocardiography; Validation Study by Cardiac Catheterization
Background: There has been no established echo parameter to accurately assess left ventricular (LV) relaxation as diastolic function. LV relaxation assessed by time constant of LV pressure decline (Tau) using left heart catheterization is reported to be deteriorated even in the early stage of hypertension. Thus, it is important to noninvasively evaluate LV relaxation in various cardiac diseases. We sought to noninvasively estimate Tau (eTau) by speckle tracking echocardiography (STE) and to validate eTau by Tau measured by cardiac catheterization.
Methods: Isovolume relaxation time (IVRT) was reported to be measured as the time between end of LV outflow wave and beginning of inflow wave by Doppler echo. We reported that pulmonary capillary wedge pressure (ePCWP) was accurately estimated as 10.8 - 12.4 x Log (left atrial active emptying function / minimum left atrial volume) by STE. Thus, the eTau by echo was obtained using the formula: eTau = IVRT / (ln 0.9 x systolic blood pressure - ln ePCWP). Echo parameters including eTau, e’, E/e’ and E / longitudinal strain were measured during sinus rhythm just before catheterization in 92 patients with various cardiac diseases (age 71±8).
Results: The ePCWP had a good correlation with LV end diastolic pressure (r=0.61, p<0.001). There was a good correlation between eTau estimated by STE and Tau obtained by cardiac catheterization (r=0.75, p<0.001), whereas e’ and E/e’ had a poor correlation with Tau (r=-0.22, r=0.26, p<0.05, respectively). There was no correlation between tau and E / longitudinal strain. Bland-Altman analysis revealed a good agreement between the eTau and Tau without a fixed and proportional bias.
Conclusions: This study demonstrated that the eTau estimated by our noninvasive method using STE has a good correlation with Tau obtained by cardiac catheterization. LV relaxation represented by Tau obtained by invasive method may be noninvasively and accurately estimated by echocardiography in various cardiac diseases.
Author Disclosures: I. Kawamura: None. M. Kawasaki: None. R. Tanaka: None. T. Yoshizane: None. T. Kato: None. M. Saeki: None. M. Nagaya: None. K. Ono: None. M. Iwama: None. M. Arai: None. Y. Kawase: None. M. Okubo: None. A. Tsuchiya: None. S. Tomita: None. H. Matsuo: None. T. Noda: None. T. Suzuki: None. H. Ohashi: None. S. Watanabe: None. S. Minatoguchi: None.
- © 2016 by American Heart Association, Inc.