Larger Ventricular Dimensions 30 Days After Birth in Neonates With ASD

Larger right ventricular dimensions and larger atrial volumes are observable within the first 30 days after birth among neonates with atrial septal defect (ASD), according to study findings published in Pediatric Cardiology.

Investigators sought to determine if infants with ASD express a distinct cardiac morphology and function within the first month of birth. They conducted a case-control study using echocardiographic data from a cohort of 716 unselected neonates with ASD included in the Copenhagen Baby Heart Study (CBHS; ClinicalTrials.gov Identifier: NCT02753348), a population-based, multicenter study (N=27,595). CBHS inclusion was offered to all expectant parents from April 2016 through October 2018 in the Capital Region of Denmark. All but 5 neonates received transthoracic echocardiography within 60 days after birth.

Neonates from the CBHS study without ASD (control patients) were matched for sex (52% girls) and age in a 1:1 ratio with neonates with ASD at the time of echocardiographic examination (mean age 11 days). Additionally, neonates with ASD vs control patients were well-matched for median gestational age at birth (280 days vs 281 days), mean body surface area (Haycock formula, 0.23 vs 0.23), mean birth weight (3474 g vs 3488 g), and mean birth length (51.3 cm vs 51.6 cm).

A majority of neonates with ASD (90%) had left-to-right shunting while 10% had both left-to-right and right-to-left shunting. There were no neonates with only right-to-left shunting.

The investigators found that neonates with ASD vs the control patients had larger right ventricular (RV) dimensions (RV outflow tract diameter, 13.6 mm vs 12.4 mm; RV basal dimension end-diastole, 14.9 mm vs 13.8 mm; RV longitudinal dimension end-diastole, 27.7 mm vs 26.7 mm; all P <.001).

Neonates with ASD vs control patients had larger tricuspid annular plane systolic excursion (10.2 mm vs 9.6 mm) and larger atrial volumes (right atrial end-systolic volume, 2.9 mL vs 2.1 mL; left atrial end-systolic volume, 2.0 mL vs 1.8 mL; all P <.001). There was a slightly larger main pulmonary artery diameter in patients with ASD but it was not statistically significant.

There was no between-group differences in left ventricular dimensions and function.

Study limitations include echocardiographic interobserver variability and inclusion of neonates with asymptomatic and smaller ASD defects than typical in clinical settings.

“…ASDs were associated with altered cardiac dimensions already in the neonatal period, with larger right ventricular dimensions and larger atrial volumes at echocardiography within the first 30 days after birth,” the investigators wrote. “These findings indicate that the morphological cardiac changes typical for ASDs are found very early in life after only a few days of left-to-right shunting.”

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.