Normal Pediatric Data for Isovolumic Acceleration at the Lateral Tricuspid Valve Annulus—A Heart Rate – Dependent Measure of Right Ventricular Contractility

BACKGROUND: Quantitative assessment of right ventricular (RV) function is important for the management of patients with congenital heart disease. Tissue Doppler (TDI)-derived myocardial acceleration during isovolumic contraction (IVA) is an echocardiographic measure of contractility that is independent of loading conditions. The aim of this study was to establish normative data for IVA at the lateral tricuspid valve annulus (RV IVA). METHODS: This is a retrospective study of 340 children who had normal echocardiograms. We analyzed RV IVA in relation to age, body surface area (BSA), gender, heart rate (HR), tricuspid annular plane systolic excursion (TAPSE), and TDI-derived S' (RV S'). RESULTS: RV IVA showed a positive correlation with HR (r = 0.58, P<0.001) and a negative correlation with age and BSA (r = -0.44, P<0.001, for both). RV IVA ranged from 2.3 m/sec(2) (±2 SD: 1-3.7 m/sec(2) ) at a HR of <60 beats per minute (bpm) to 4.9 m/sec(2) (±2 SD: 3.5-6.4 m/sec(2) ) at a HR of >160 bpm. When RV IVA was corrected for HR (RV IVAc), it became independent of HR, age, BSA, and gender. The mean RV IVAc was 2.3 m/sec(1.5) (±2 SD: 1.1-3.6 m/sec(1.5) ). There was a correlation of normalized RV IVAc with normalized TAPSE and RV S'. CONCLUSION: RV IVA, a marker of RV contractility, shows a strong dependence on HR. HR corrected RV IVA (RV IVAc) is independent of age, BSA, gender, and HR. We suggest measuring RV IVAc routinely in patients at risk for RV dysfunction.