Right Ventricular Mechanical Dyssynchrony and Asymmetric Contraction in Hypoplastic Heart Syndrome are Associated with Tricuspid Regurgitation

Background Right ventricular (RV) dysfunction and tricuspid regurgitation (TR) are associated with adverse outcome in hypoplastic left heart syndrome (HLHS) but remain poorly understood. The aim of this study was to assess RV longitudinal strain and mechanical dyssynchrony in HLHS in relation to TR. The hypothesis was that inhomogeneous RV contraction and mechanical dyssynchrony around the tricuspid valve apparatus may be associated with TR in some patients with HLHS. Methods Echocardiograms of children aged 0 to 2 years with HLHS at all stages of surgical palliation were retrospectively reviewed for anatomic subtype and severity of TR. RV peak strain and dyssynchrony were assessed by vector velocity imaging. Results Sixty echocardiograms of patients with a median age of 0.54 years (interquartile range, 0.04–1.63 years) and a median weight 6.40 kg (interquartile range, 3.70–10.45 kg) demonstrated TR, which was absent or trivial in 25 (42%), mild in 20 (33%), moderate in five (8%), and severe in 10 (17%). The difference in peak longitudinal strain between the RV free wall and the septum or left-sided RV wall was significantly higher in patients with moderate or severe TR compared with no, trivial, or mild TR (2.93 ± 6.03% vs 0.16 ± 6.6%, P = .04). The difference in time to peak longitudinal strain between walls was significantly longer in moderate or severe TR compared with no, trivial, or mild TR (57.4 ± 145.1 vs 15.8 ± 75.9 msec, P = .04). There was a significant difference in anatomic subtype between patients with the most difference in peak strain compared with those with the least. Conclusions RV mechanical dyssynchrony and inhomogeneous contraction are worse in patients with clinically important TR and HLHS.