Measurement of global longitudinal cardiac strain and strain rate is possible in fetuses using VVI. Segmental measurements are not significantly different from global measurements; global measurements may be a useful tool to quantitate fetal cardiac function.

Clinical trials often rely on echocardiographic measures of left ventricular (LV) size and function as surrogate end-points. However, the quantitative impact of factors that affect reproducibility of these measures is unknown. To address this issue, the NHLBI-funded Pediatric Heart Network designed a longitudinal observational study of children with known or suspected dilated cardiomyopathy (DCM) aged 0–22 years from 8 pediatric clinical centers. Methods Clinical data were collected together with 150 echocardiographic indices of LV size and function. Separate observers performed duplicate echocardiographic imaging. Multiple observers performed measurements from three cardiac cycles to enable assessment of intra and interobserver variability. We studied the impact of beat averaging (BA), observer type (local vs. core) and variable type (areas, calculations, dimensions, slopes, time intervals and velocities) on measurement reproducibility. The outcome measure was %error (100 × difference/mean) Results Of 173 enrolled subjects, 131 met criteria for DCM. BA, variable type and observer type all impacted %error (p<0.0001). Core inter-observer %error (median 11.4, 10.2 and 9.3% for 1-, 2- and 3-BA, respectively) was approximately twice the intra-observer %error (median 6.3, 4.9 and 4.2% for 1-, 2- and 3-BA, respectively). Slopes and calculated variables exhibited high %error despite BA. Chamber dimensions, areas, velocities and time intervals exhibited low %error. Conclusions This comprehensive evaluation of quantitative echocardiographic methods will provide a valuable resource for design of future pediatric studies. BA and a single core lab observer improve reproducibility of echo measurements in children with DCM. Certain measurements are highly reproducible, while others, despite BA, are poorly reproducible.

Background-The purpose of this study was to examine the effects of cyclooxygenase (COX) deficiency on baseline functional characteristics and on recovery of left ventricular developed pressure (LVDP) after 20 minutes of global ischemia and 40 minutes of reperfusion in untreated and preconditioned hearts. Methods and Results-Compared with hearts from wild-type (WT) and COX-2 Ϫ/Ϫ mice, baseline cardiac prostaglandin (PG) E 2 and 6-keto-PGF 1␣ levels were significantly decreased in hearts from COX-1 Ϫ/Ϫ mice. After ischemia, cardiac PGE 2 levels increased in WT, COX-1 Ϫ/Ϫ , and COX-2 Ϫ/Ϫ mice (PϽ0.05). Recovery of function (LVDP) after global ischemia in hearts from COX-1 Ϫ/Ϫ and COX-2 Ϫ/Ϫ mice was significantly less than in WT hearts. Pretreatment of WT mice with indomethacin for 2 days before ischemia significantly decreased LVDP recovery; however, perfusion of WT hearts with indomethacin for 40 minutes before ischemia did not significantly alter LVDP recovery. Postischemic recovery of LVDP in COX-1 Ϫ/Ϫ and COX-2 Ϫ/Ϫ was unchanged by perfusion with 5 mol/L PGE 2 , PGD 2 , PGF 2␣ , or carboprostacyclin. Hearts from COX-2 Ϫ/Ϫ mice showed an increase in ischemic contracture compared with hearts from WT and COX-1 Ϫ/Ϫ mice; however, hearts did not differ in intracellular pH, ATP, or inorganic phosphate during ischemia. Ischemic preconditioning significantly improved postischemic LVDP recovery in COX-1 Ϫ/Ϫ , COX-2 Ϫ/Ϫ , and WT mice. Conclusions-Genetic disruption or 2-day chemical inhibition of COX-1 and COX-2 decreases recovery of LVDP after ischemia; however, acute perfusion with indomethacin is not detrimental. These data are consistent with protection due to the altered expression of some protein that is modulated by COX or its metabolites.