P6458The prevalence of left ventricular non-compaction in newborns
Authors: Borresen M F , Blixenkrone-Moeller E M , Tindholdt M , Vogg R O B , Pihl C , Sillesen A , Norsk J B , Vejlstrup N , Iversen K , Bundgaard H , Axelsson Raja A 
Published: October 2019

Abstract

Background
Pronounced trabeculation of the left ventricular myocardium, or non-compaction, may be accompanied by systolic dysfunction in ventricular non-compaction cardiomyopathy (LVNC). It is unclear whether non-compaction represents a fetal development defect or may develop later in life. Previous studies have estimated the prevalence of non-compaction to 0.01–0.31% in adults referred for echocardiography. The prevalences in unselected populations of adults or children are unknown.

Purpose
To determine the prevalence of non-compaction of the left ventricle in a large population-based cohort of newborns and to assess the relation to left ventricular systolic function.

Methods
Transthoracic echocardiography was performed according to a standardized protocol in all newborns included in a regional population-based cohort study in 2016–2018. For the present study, the extent of trabeculations were assessed by one of three primary reviewers in apical long-axis views (4-chamber, 5-chamber, and sinus coronarius views), parasternal short (SAX), and long axis (PLAX) views. Based on the presence of pronounced trabeculations, deep intertrabecular recesses and/or an impression of a ratio of >1 of non-compact:compact myocardium (NC:C), the exam was regarded as either possible or not possible non-compaction: In examinations classified as possible non-compaction, an expert reviewer would determine if diagnostic criteria were fulfilled. A ratio of NC:C myocardium ≥2 was considered as non-compaction in accordance with previously suggested criteria.

Results
As of January 11, 2019, 6,880 neonate echocardiograms (median age 10 days [IQR 5,14], 48.8% females) had been analyzed. In total, 127 (1.8%) were considered as possible non-compaction. Six newborns (median age 14 days [IQR 8,18], 33.3% females) had a ratio of NC:C myocardium ≥2 corresponding to a prevalence of non-compaction of 8.7 per 10,000 newborns (95% CI 0.04–0.19%) (Figure). One of six neonates had a ratio of NC:C myocardium≥2 in more than one segment. Median fractional shortening (FS %), left ventricular end-diastolic (LVIDd) and end-systolic diameter (LVIDs) were 29.5% (IQR 27.0, 31.0), 1.9 cm (IQR 1.8, 2.1) and 1.3 cm (IQR 1.3, 1.5) respectively in the six newborns with non-compaction. The corresponding mean z-scores (standard deviations away from the age-matched reference mean) according to The Boston Children's Hospital z-score Calculator were FS: r=−3.0 (IQR r=−3.8, r=−2.5), LVIDd: r=−1.3 (IQR r=−2.7, r=−0.2), LVIDs: 0.2 (IQR r=−0.1, 1.6).
10-days-old boy with LVNC (FS 22%)

Conclusion
Echocardiography of an unselected population-based cohort of 6,880 newborns revealed a prevalence of non-compaction of 8.7 per 10,000 newborns. The prevalence is in accordance with previously described prevalences in adults referred for echocardiography and corroborate the view that non-compaction may be a fetal developmental defect. Non-compaction was not associated with left ventricular dilatation but with systolic dysfunction.

Acknowledgement/Funding
Danish Heart Association, Danish Children's Heart Foundation, Candy's Found., Toyota Found., Herlev-Gentofte Hospital Research Found., Gangsted Found.