Possibility of postnatal left ventricular growth in selected infants with non-apex-forming left ventricles.

To evaluate postnatal left ventricular growth potential, we reviewed the echocardiograms of seven infants with left ventricles that did not form an apex. Prostaglandins were used to maintain patency of the ductus arteriosus in six infants. Associated abnormalities included aortic stenosis in five, coarctation in three, and left atrial isomerism in one. Initial echocardiographic measurements (7 +/- 9 days) were compared with measurements at 1 month (36 +/- 9 days). Weight (3.0 +/- 0.1 vs 3.0 +/- 0.5 kg) and body surface area (BSA) (0.2 +/- 0.01 vs 0.2 +/- 0.01 m2) did not change. Comparing initial measurements with measurements at 1 month, there were significant increases (p < 0.05) in aortic annulus diameter (4.5 +/- 0.5 vs 5.6 +/- 0.7 mm), aortic root diameter indexed to BSA (2.9 +/- 0.5 vs 3.7 +/- 0.7 cm/m2), ratio of the long axis of the left ventricle to the long axis of the heart (0.74 +/- 0.1 vs 0.86 +/- 0.1), left ventricular end-diastolic volume indexed to BSA (10 +/- 2 vs 24 +/- 9 ml/m2), left ventricular mass indexed to BSA (27 +/- 13 vs 47 +/- 28 gm/m2), mitral valve area indexed to BSA (2.3 +/- 0.5 vs 3.2 +/- 0.7 cm2/m2), left ventricular area (2.1 +/- 0.5 vs 3.6 +/- 1.1 cm2), and Rhodes score (-2.7 +/- 0.5 vs -1.1 +/- 0.9). Tricuspid valve area indexed to BSA (5.8 +/- 1.5 vs 6.1 +/- 1.1 cm2/m2) and long axis of the heart indexed to BSA (13.0 +/- 2.8 vs 13.6 +/- 2.9 cm/m2) did not change. The increase in measurements appeared adequate for biventricular physiology in five infants (four are alive [3.9 +/- 2.6 years] and one died after not being able to wean from the ventilator). These data suggest that a non-apex-forming left ventricle may have postnatal growth potential.