Table 2:

Echocardiographic data of term and preterm infants at 1 month of age and 1 year of age

Variables	First Echocardiogram (1 month of age)				Second Echocardiogram (1 year of age)
	Term (n=50)	All Preterm (n=80)	Preterm w/out bronchopulmonary dysplasia (n=32)	Preterm with bronchopulmonary dysplasia (n=48)	Term (n=50)	All Preterm (n=80)	Preterm w/out bronchopulmonary dysplasia (n=32)	Preterm with bronchopulmonary dysplasia (n=48)
Age at echocardiogram (days)	32 (31, 35)	38 (33, 45)	33 (28, 41)	39 (36, 49)	371 (365, 380)	494 (452, 521)**	494 (450, 525)**	500 (468, 535)**
Weight at echocardiogram (kg)	4.6 (4.3, 4.9)	1.4 (1.2, 1.6)*	1.4 (1.3, 1.7)*	1.4 (1.1, 1.6)*	9.5 (8.7, 10.5)+	10.1 (9.4, 11.1)+	9.7 (9.1, 10.7)+	10.1 (9.4, 11.2)+
Body surface area (m2)	0.27 (0.26, 0.28)	0.26 (0.24, 0.29)	0.26 (0.25, 0.30)	0.26 (0.24, 0.28)	0.46 (0.42, 0.48)+	0.45 (0.44, 0.47)+	0.45 (0.43, 0.47)+	0.45 (0.44, 0.48)+
Heart rate (beats/minutes)	155 (129, 166)	157 (147, 169)	162 (145, 170)	156 (147, 168)	127 (120-136)+	129 (118, 141)+	130 (121, 139)+	127 (115, 143)+
Right ventricle function
Fractional area of change (%)	36 (31, 39)	32 (28, 36)*	36 (32-43)	30 (26, 33)*§	44 (40, 48)+	34 (32, 36)+*	39 (36, 43)+*	33 (31, 34)+*§
Tricuspid annular plane systolic excursion (mm)	10 (9, 10)	8 (7, 9)*	9 (8, 10)*	8 (7, 9)*§	18 (17, 19)+	16 (15, 18)+*	18 (16, 19)+	16 (15, 17)+*§
Free wall longitudinal strain (%)	−26 (−25, −29)	−19 (−17, −21)*	−22 (−20, −23)*	−18 (−17, −19)*§	−34 (−33, −37)+	−27 (−26, −29)+*	−30 (−29, −31)+*	−27 (−26,−28)+*§
Segmental longitudinal strain (%)
Basal	−30 (−34, −28)	−24 (−22, −25)*	−26 (−24, −27)*	−23 (−22, −24)*§	−38 (−35, −44)+	−30 (−28, −31)+*	−30 (−28, −30)+*	−29 (−28, −30)+*§
Mid-ventricular	−27 (−25, −30)	−22 (−21, −23)*	−23 (−22, −24)*	−21 (−20, −22)*§	−36 (−34, −39)+	−28 (−27, −29)+*	−29 (−28, −30)+*	−27 (−26, −28)+*§
Apical	−20 (−16, −24)	−19 (−17, −21)*	−21 (−20, −22)	−18 (−17, −19)*§	−28 (−21, −36)+	−25 (−24, −27)+*	−26 (−27, −28)+*	−24 (−23, −25)+*§
Free wall longitudinal strain rate (1/sec)	−2.7 (−2.4, −3.0)	−1.9 (−1.7, −2.3)*	−2.2 (−1.9, −2.4)*	−1.8 (−1.6, −2.1)*§	−2.9 (−2.7, −3.4)+	−1.8 (−1.6, −2.3)*	−2.3 (−1.8, −2.7)+*	−1.6 (−1.5, −1.9)+*§
Right ventricle Morphology
Basal length (cm)	1.7 (1.5, 1.8)	1.3 (1.2, 1.4)*	1.2 (1.1, 1.3)*	1.3 (1.2, 1.5)*	2.1 (2.0, 2.3)+	2.4 (2.2, 2.6)+*	2.4 (2.1, 2.5)+*	2.5 (2.3, 2.7)+*§
Mid-cavity length (cm)	1.2 (1.0, 1.2)	1.1 (1.0, 1.2)*	1.0 (0.9, 1.2)	1.2 (1.0, 1.3)	1.5 (1.4, 1.6)+	2.0 (1.9, 2.2)+*	1.9 (1.6, 2.0)+*	2.1 (1.9, 2.3)+*§
Major length (cm)	3.5 (3.3, 3.6)	2.0 (1.9, 2.2)*	2.0 (1.8, 2.2)*	2 (1.9, 2.2)*	4.0 (3.7, 4.2)+	3.9 (3.7, 4.2)+	3.9 (3.6, 4.2)+	3.9 (3.8, 4.2)+
Systolic area (cm2)	2.5 (2.3, 2.8)	1.7 (1.6, 1.9)*	1.6 (1.5, 1.8)*	1.8 (1.6, 2.0)*§	3.6 (3.3, 4.0)+	4.5 (4.1, 4.7)+*	4.1 (3.9, 4.2)+*	4.6 (4.5, 4.8)+*§
Diastolic area (cm2)	3.8 (3.4, 4.3)	2.6 (2.3, 2.8)*	2.6 (2.4, 2.8)*	2.6 (2.3, 3.0)*§	6.4 (6.1, 6.8)+	6.7 (6.1, 7.1)+*	6.7 (6.4, 7.0)+*	6.9 (6.8, 7.2)+*§
RV Afterload
Pulmonary artery acceleration time (mseconds)	74 (67, 81)	52 (39 - 60)*	56 (45, 66)*	43 (35, 53)*§	96 (92, 100)+	73 (65, 78)+*	79 (69, 82)+*	65 (60, 69)+*§
Pulmonary artery acceleration time / Right ventricle ejection time	0.34 (0.31, 0.38)	0.26 (0.21, 0.31)*	0.31 (0.23, 0.36)*	0.23 (0.20, 0.27)*§	0.36 (0.33, 0.38)+	0.31(0.26, 0.34)+*	0.31 (0.30, 0.36)+*	0.27 (0.25, 0.29)+*§

All data presented as median (interquartile range

^*P < 0.01 vs. Term;

^§P<0.01 vs. Preterm without bronchopulmonary dysplasia;

⁺P < 0.001 vs. first echocardiogram,

Note: right ventricle strain rate significantly decreased from the 1^st echocardiogram to the 2^nd echocardiogram for Preterm infants with bronchopulmonary dysplasia (P< 0.001)

^**These numbers reflect actual days of age, but corrected age (days) for all preterm infants was 381 (355,424), and for preterm without bronchopulmonary dysplasia was 381(357, 428) and preterm infants with bronchopulmonary dysplasia was 398 (377, 428).