Biventricular impact of mild to moderate fetal pulmonary valve stenosis.

OBJECTIVES: To define the pattern of fetal echocardiographic changes associated with isolated pulmonary valve stenosis (PS) and to correlate the echocardiographic findings with neonatal outcome and the need for postnatal pulmonary valvuloplasty within the first 12 months postpartum. METHODS: This was a prospective cohort study between January 2009 and October 2015 of 16 fetuses with isolated PS and 48 controls matched by gestational age at ultrasound examination (± 2 weeks) evaluated at the Fetal Cardiology Unit at BCNatal (Barcelona). Standard fetal ultrasound and comprehensive echocardiography, which included cardiovascular morphometric parameters, and systolic and diastolic functional and timing measurements, were performed in all cases. Baseline characteristics and perinatal outcome were retrieved from clinical records. Cases were followed up until 12 months of age, and admission to intensive care unit, days of hospitalization, need for prostaglandins and requirement for postnatal surgery were reviewed. Fetal PS cases were analyzed according to the need for postnatal pulmonary valvuloplasty. RESULTS: The study groups were similar in terms of baseline, fetal ultrasound and perinatal characteristics. Median gestational age at diagnosis of PS was 33.4 (range, 20.0-36.5) weeks. Most cases corresponded to mild or moderate PS; only three fetuses had reversed flow in the ductus arteriosus before delivery. Six (37.5%) newborns, including all three with reversed flow in the ductus arteriosus prenatally, required postnatal pulmonary valvuloplasty. Fetuses with PS presented with larger and more globular hearts, with increased myocardial wall thickness in the third trimester. Despite preserved right ventricular (RV) ejection fraction and systolic longitudinal motion, PS cases showed increased right cardiac output and signs of diastolic dysfunction, with higher ductus venosus pulsatility index (0.72 ± 0.32 vs 0.53 ± 0.16, P = 0.004) and tricuspid E/E' ratio (7.52 ± 3.07 vs 5.76 ± 1.79, P = 0.022). In addition, fetuses with PS displayed a compensatory increase in left ventricular (LV) radial and longitudinal motion, as shown by a higher ejection fraction (79.3 ± 8.23% vs 67.6 ± 11.3%, P = 0.003) and mitral annular-plane systolic excursion (5.94 ± 1.38 vs 5.0 ± 1.22 mm, P = 0.035). Finally, fetuses requiring postnatal pulmonary valvuloplasty showed a different pattern of echocardiographic findings from those not requiring valvuloplasty, with a significantly smaller RV and pulmonary valve diameter, reduced tricuspid annular-plane systolic excursion (5.08 ± 1.59 vs 8.07 ± 1.93 mm, P = 0.028), increased LV cardiac output (340 ± 16 vs 176 ± 44 mL/min/kg, P = 0.003) and more pronounced signs of LV diastolic dysfunction (mitral E' velocity, 5.78 ± 0.90 vs 8.16 ± 1.58 cm/s, P = 0.008). CONCLUSIONS: Fetuses with PS present with more hypertrophic, larger and more globular hearts in the third trimester of pregnancy, associated with a higher right cardiac output and impaired biventricular relaxation. In addition, signs of increased LV contraction were observed. Our data suggest that RV and LV functional parameters could be useful for predicting the need for postnatal pulmonary valvuloplasty. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Right ventricular function during exercise in children after heart transplantation.

Aims: Right ventricular (RV) dysfunction is a common problem after heart transplant (HTx). In this study, we used semi-supine bicycle ergometry (SSBE) stress echocardiography to evaluate RV systolic and diastolic reserve in paediatric HTx recipients. Methods and results: Thirty-nine pediatric HTx recipients and 23 controls underwent stepwise SSBE stress echocardiography. Colour tissue doppler imaging (TDI) peak systolic (s') and peak diastolic (e') velocities, myocardial acceleration during isovolumic contraction (IVA), and RV free wall longitudinal strain were measured at incremental heart rates (HR). The relationship with increasing HR was evaluated for each parameter by plotting values at each stage of exercise versus HR using linear and non-linear regression models. At rest, HTx recipients had higher HR with lower TDI velocities (s': 5.4 ± 1.7 vs. 10.4 ± 1.8 cm/s, P < 0.001; e': 6.4 ± 2.2 vs.12 ± 2.4 cm/s, P < 0.001) and RV IVA values (IVA: 1.2 ± 0.4 vs. 1.6 ± 0.8 m/s2, P = 0.04), while RV free wall longitudinal strain was similar between groups. At peak exercise, HR was higher in controls and all measurements of RV function were significantly lower in HTx recipients, except for RV free wall longitudinal strain. When assessing the increase in each parameter vs. HR, the slopes were not significantly different between patients and controls except for IVA, which was lower in HTx recipients. Conclusion: In pediatric HTx recipients RV systolic and diastolic functional response to exercise is preserved with a normal increase in TDI velocities and strain values with increasing HR. The blunted IVA response possibly indicates a mildly decreased RV contractile response but it requires further investigation.

Impact of surgical pulmonary valve replacement on ventricular mechanics in children with repaired tetralogy of Fallot.

Impaired ventricular myocardial mechanics are observed in patients with repaired tetralogy of Fallot (rTOF). Effects of pulmonary valve replacement (PVR) on ventricular remodeling are controversial. The objective was to assess the impact of surgical PVR on ventricular mechanics in pediatric patients after rTOF. Speckle-tracking analysis was performed in 50 rTOF children, aged 12.6 ± 3.3 years, pre-operatively and 14.5 ± 2.2 months post-PVR. Early post-operative studies 2.2 ± 0.6 months post-PVR were performed in 28 patients. Cardiac magnetic resonance (CMR) pre- and post-PVR was collected. Mid-term post-PVR right ventricular (RV) longitudinal strain increased above pre-operative strain (-19.2 ± 2.7 to -22.0 ± 3.0%, p < 0.001) with increases observed in individual RV segments. Left ventricular (LV) strain did not differ at medium-term follow-up. LV and RV longitudinal strain was reduced early post-operatively, followed by recovery of biventricular systolic strain by mid-term follow-up. CMR RV end-diastolic indexed volumes correlated with RV strain pre-operatively (r = 0.432, p = 0.005) and at mid-term follow-up (r = 0.532, p = 0.001). Volume-loaded RVs had reduced early RV basal longitudinal strain compared to pressure-loading conditions. Reversed basal counterclockwise rotation was associated with lower mid-term global LV and basal RV strain compared to patients with normal rotation. An increase in mid-term global and regional RV strain beyond pre-operative values suggests positive RV remodeling and adaptation occurs in children post-PVR. Patients with larger pre-operative RV volumes had lower RV strain post-operatively. The impact of LV rotation on RV mechanics highlights the presence of ventriculo-ventricular interactions. These findings have important clinical implications in pediatric rTOF patients towards identifying pre-operative factors that predict RV post-operative remodeling.

Echocardiography and cardiac resynchronization therapy in children and patients with congenital heart disease.

Cardiac resynchronization therapy (CRT) has been shown to improve mortality and morbidity in adults with refractory heart failure and prolonged QRS-duration. Recent research data suggest that the therapeutic benefit is related to the effect of CRT on interventricular and intraventricular dyssynchrony associated with electrical dyssynchrony. However, around 30-40% of the patients do not respond to CRT when device implantation is based only on QRS-duration. It was hoped that improved description of mechanical dyssynchrony using imaging techniques, might result in improved identification of patients who could benefit from CRT. Different methods have been proposed but a recent multicenter prospective echocardiographic study (PROSPECT) was disappointing. Applying adult criteria for CRT treatment to children and adults with acquired and congenital heart disease is even more challenging due to the age-dependency of QRS-duration and the wide variety of underlying diseases including different ventricular morphology that can result in heart failure. In this review we will overview the adult and pediatric data of CRT treatment and propose a mechanistic approach that could potentially be helpful in trying to identify those patients who might benefit from the treatment.