Abstract 15495: Ventricular Relaxation Assessment Using Early Diastolic Mitral Annular Velocity in Pediatric Patients
Background: Early diastolic mitral annular velocity (e') has been used for non-invasive assessment of ventricular relaxation. However, applicability of this Methods in pediatric population remains unclear. Recently, lengthening load and restoring force were reported to be independent determinants of e' as well as ventricular relaxation in normal experimental animal. We tested the hypothesis that time constant of ventricular relaxation (t) may be better estimated by e' with those factors taken into consideration in pediatric population.
Methods: We studied serial 36 pediatric patients (0.5–13 years) with various congenital heart disease. Left ventricular (LV) pressure was measured using high fidelity pressure guidewire and t was calculated by logistic fit. LV end-diastolic pressure (EDP) and maximum rate of LV pressure rise (dp/dt max) were calculated as surrogates of lengthening load and restoring force, respectively. We simultaneously measured e' using commercially available echo machine. Data acquisition was repeated after dobutamine administration (5μg/kg/min).
Results: The t was inversely correlated with e' (P=0.002) but the correlation were scattered (R=0.54). Thus, we assessed the determinants of t by using multiple stepwise linear regression analysis with e', EDP, dp/dt max, and HR included as independent variables. This yielded more accurate estimation of t (R=0.79, P<0.0001) with associations to t in e' (β=-0.34), EDP (β=0.22), dp/dt max (β=-0.21), and HR (β=-0.50). Especially, EDP positively correlated with slow relaxation rather than serving the lengthening load to fast relaxation.
Conclusion: This study validated for the first time that e' provides simple assessment of ventricular relaxation in pediatric heart disease patients. Nevertheless, caution should be taken that e' is not exclusive measure of relaxation because heart rate and restoring force affect the relation between the two.
- © 2010 by American Heart Association, Inc.