Systemic venous diameters, collapsibility indices, and right atrial measurements in normal pediatric subjects.

BACKGROUND: Compromise of right heart function is an important feature of many forms of congenital heart disease, and right atrial (RA) pressure is clinically relevant. Inferior vena cava (IVC) diameter and inspiratory collapse are indices of RA pressure, but pediatric data are lacking. METHODS: RA measurements, systemic venous diameters, and Doppler filling fractions were prospectively investigated in healthy volunteer children and adolescents. The IVC was measured in its long axis just above the junction with the hepatic veins in the subxiphoid view and the superior vena cava at its junction with the right atrium in the right parasternal view. The changes in IVC diameter (IVCD) during quiet respiration and with a sniff were recorded. Hepatic venous systolic filling fraction was calculated from Doppler velocities in the first hepatic vein. RA major-axis length, area, and volume were measured from the apical four-chamber view. Three measurements of each parameter were averaged over at least three respiratory cycles. The IVC collapsibility index (IVCCI) was calculated as [(IVCDmax - IVCDmin)/IVCDmax] × 100. Substituting IVCDsniff for IVCDmin in the formula, the IVCCIsniff was calculated. RESULTS: Of 132 subjects enrolled, data in 120 (mean age, 8.3 ± 4.5 years) were analyzed. The maximal (expiratory) and minimal (inspiratory) diameters during free breathing were 12.1 ± 3.8 and 8.9 ± 3.8 mm for the IVC and 11.9 ± 3.4 and 7.9 ± 2.6 mm for the superior vena cava. IVCCImin and IVCCIsniff were 30 ± 13 and 47 ± 18, respectively. The RA major-axis length, area, and indexed maximal volume were 3.7 ± 0.7 cm, 10.3 ± 3.6 cm(2), and 22.3 ± 7.0 mL/m(2), respectively. Correlations of maximal superior vena cava and IVC dimensions with body surface area were slightly better than with age and much stronger than with RA volume. No significant correlation was found between IVCCIs and age, gender, or indexed RA volume. CONCLUSIONS: Measurement of systemic venous diameters, collapsibility indices, and RA volumes is feasible in healthy children and adolescents. Venous diameters increase predictably with growth and so must be interpreted in light of body surface area. IVCCIs and hepatic venous filling fraction compare closely with those reported in adults. Pediatric nomograms for these parameters are provided, and they should next be evaluated for relation to directly measured RA pressure in this age group.

Functional maturation of left and right atrial systolic and diastolic performance in infants, children, and adolescents.

BACKGROUND: Left atrial (LA) function is an important modulator of left ventricular filling and has a prognostic role in adult heart failure, but pediatric data are limited. The aim of this study was to characterize the normal LA and right atrial (RA) strain (ε) and strain rate (SR) in infants and children. METHODS: Atrial ε and SR were prospectively investigated in 153 subjects using two-dimensional speckle-tracking echocardiography. High-frame rate, three-beat captures of LA (15-segment model; two-chamber, three-chamber, and four-chamber views) and RA (six-segment model; four-chamber view) were analyzed (Vivid 7, EchoPAC BT11). LA and RA segmental and global peak positive ε (εPos) and negative ε (εNeg) and peak positive SR, early negative SR, and late negative SR were measured. Linear and nonlinear regressions of ε and SR were performed with age and heart rate. Relationships of ε and SR with ventricular inflow Doppler and myocardial tissue Doppler indices were explored. RESULTS: The age range was 3 days to 20 years, and body surface area range from 0.17 to 2.3 m(2) for the study cohort. Mean global LA εPos, LA εNeg, RA εPos, and RA εNeg were 28 ± 9%, -16 ± 6%, 23 ± 9%, and -15 ± 6%, respectively. Positive correlations were found for global atrial εPos and εNeg with age (P < .001). A marked rate of changes in ε and SR was seen in the first year of life, reaching normal adult values by adolescence. Peak positive SR had a strong negative correlation with age, and early negative SR had a strong positive correlation with age (P < .001), while late negative SR was correlated nonlinearly. Heart rate and age both influenced all LA and RA ε and SR indices. CONCLUSIONS: Maturational changes in LA and RA ε and SR occur in normal children and are especially profound in infancy. Consequently, LA and RA performance indices must be interpreted in light of heart rate and age. Normal values and percentiles for atrial ε and SR reported here will provide a foundation for the study of pediatric atrial physiology and function in disease states.

Reduced global longitudinal and radial strain with normal left ventricular ejection fraction late after effective repair of aortic coarctation: a CMR feature tracking study.

We sought to determine whether global and regional left ventricular (LV) strain parameters were altered in repaired coarctation of the aorta (COA) with normal LV ejection fraction (EF) when compared with healthy adult controls, and whether such alterations were related to LV hypertrophy (LVH). We identified 81 patients after COA repair (31 female, age 25 ± 8.5 years) with inclusion criteria at follow-up CMR of: age ≥13 years, time post-repair ≥10 years, no aortic valve disease, LV-EF >50%). LV deformation indices derived using CMR-feature tracking and volumetric EF were compared between COA patients and normal controls (n = 20, 10 female, age 37 ± 7 years), and between COA with versus without LVH. In repaired COA versus controls, LV-EF (%) was 62 ± 7.2 versus 58 ± 3.0 (p = 0.01), and LV mass (g/m(2)) 66 ± 16.8 versus 57.7 ± 6.0 (p = 0.0001). LV global longitudinal strain (GLS) was decreased to -17.0 ± 4.7% in COA (-20 ± 5% in controls, p = 0.02), and global radial strain (GRS) reduced to 40 ± 15% (50 ± 12.4% in controls, p = 0.003). The global circumferential strain (GCS) was preserved in COA at -23 ± 4.7% (-24.6 ± 2.4% in controls, p = 0.14). Regionally, LS decrease was marked in the basal segments (septal, p = 0.005, lateral, p = 0.013). In COA with LVH (n = 45, mass 76.3 ± 12.8 g/m(2)) versus without LVH (n = 36, mass 52.2 ± 10 g/m(2)), GLS was more markedly decreased (-15.7 ± 4.8 vs. -18.5 ± 4.2%, p = 0.016, but GRS and GCS were similar (p = 0.49 and 0.27). In post-repair COA with normal LV-EF, GLS and GRS are reduced whilst GCS is preserved. GLS reduction is more pronounced in the presence of LVH. GLS may qualify as indicator of early LV dysfunction.

Echocardiography and cardiac magnetic resonance-based feature tracking in the assessment of myocardial mechanics in tetralogy of Fallot: an intermodality comparison.

We investigated intermodality agreements of strains from two-dimensional echocardiography (2DE) and cardiac magnetic resonance (CMR) feature tracking (FT) in the assessment of right (RV) and left ventricular (LV) mechanics in tetralogy of Fallot (TOF). Patients were prospectively studied with 2DE and CMR performed contiguously. LV and RV strains were computed separately using 2DE and CMR-FT. Segmental and global longitudinal strains (GLS) for the LV and RV were measured from four-chamber views; LV radial (global radial strain [GRS]) and circumferential strains (GCS) measured from short-axis views. Intermodality and interobserver agreements were examined. In 40 patients (20 TOF, mean age 23 years and 20 adult controls), LV, GCS showed narrowest intermodality limits of agreement (mean percentage error 9.5%), followed by GLS (16.4%). RV GLS had mean intermodality difference of 25.7%. GLS and GCS had acceptable interobserver agreement for the LV and RV with both 2DE and CMR-FT, whereas GRS had high interobserver and intermodality variability. In conclusion, myocardial strains for the RV and LV derived using currently available 2DE and CMR-FT software are subject to considerable intermodality variability. For both modalities, LV GCS, LV GLS, and RV GLS are reproducible enough to warrant further investigation of incremental clinical merit.

Safety of cardiac magnetic resonance and contrast angiography for neonates and small infants: a 10-year single-institution experience.

BACKGROUND: With increasing applications of cardiac magnetic resonance (CMR) and magnetic resonance angiography (MRA) for evaluation of congenital heart disease (CHD), safety of this technology in the very young is of particular interest. OBJECTIVE: We report our 10-year experience with CMR in neonates and small infants with particular focus on the safety profile and incidence of adverse events (AEs). MATERIALS AND METHODS: We reviewed clinical, anesthesia and nursing records of all children ≤120 days of age who underwent CMR. We recorded variables including cardiac diagnosis, study duration, anesthesia type and agents, prostaglandin E1 (PGE1) dependence and gadolinium (Gd) use. Serially recorded temperature, systemic saturation (SpO(2)) and cardiac rhythm were analyzed. Primary outcome measure was any AE during or <24 h after the procedure, including minor AEs such as hypothermia (axillary temperature ≤95 °F), desaturation (SpO(2) drop ≥10% below baseline) and bradycardia (heart rate ≤100 bpm). Secondary outcome measure was unplanned overnight hospitalization of outpatients. RESULTS: Children (n = 143; 74 boys, 69 girls) had a median age of 6 days (1-117), and 98 were ≤30 days at the time of CMR. The median weight was 3.4 kg (1.4-6 kg) and body surface area 0.22 m(2) (0.13-0.32 m(2)). There were 118 (83%) inpatients (108 receiving intensive care) and 25 (17%) outpatients. Indications for CMR were assessment of aortic arch (n = 57), complex CHD (n = 41), pulmonary veins (n = 15), vascular ring (n = 8), intracardiac mass (n = 8), pulmonary artery (n = 7), ventricular volume (n = 4), and systemic veins (n = 3). CMR was performed using a 1.5-T scanner and a commercially available coil. CMR utilized general anesthesia (GA) in 86 children, deep sedation (DS) in 50 and comforting methods in seven. MRA was performed in 136 children. Fifty-nine children were PGE1-dependent and 39 had single-ventricle circulation. Among children on PGE1, 43 (73%) had GA and 10 (17%) had DS. Twelve children (9%) had adverse events (AEs)-one major and 11 minor. Of those 12, nine children had GA (10%) and three had DS (6%). The single major AE was respiratory arrest after DS in a neonate (resuscitated without sequelae). Minor AEs included desaturations (n = 2), hypothermia (n = 5), bradycardia (n = 2), and bradycardia with hypoxemia (n = 2). Incidence of minor AEs was 9% for inpatients (vs. 4% for outpatients), and 8% for neonates (vs. 9% for age ≥30 days). Incidence of minor AEs was similar between PGE1-dependent infants and the non-PGE1 group. There were no adverse events related to MRA. Of 25 outpatients, 5 (20%) were admitted for overnight observation due to desaturations. CONCLUSION: CMR and MRA can be accomplished safely in neonates and infants ≤120 days old for a wide range of pre-surgical cardiac indications. Adverse events were unrelated to patient age, complexity of heart disease, type of anesthesia or PGE1 dependence.