Table 2. Main Study Outcomes at Fontan 1 and Fontan 3^*.

Characteristic††	N	Fontan 1	Fontan 3	Change	P Value††
Age at enrollment, years	373	11.7 ± 3.4	21.2 ± 3.5	9.5	------
Exercise Outcomes
Percent predicted VO2 at anaerobic threshold	196	80 ± 25	72 ± 25	−7.9	<0.001
Percent predicted maximum VO2 †	95	69 ± 14	61 ± 16	−7.1	<0.001
Percent predicted maximum work rate†	95	69 ± 15	56 ± 16	−13.1	<0.001
Percent predicted maximum oxygen pulse†	95	91 ± 23	80 ± 21	−11.3	<0.001
Chronotropic index‡	79	0.7 ± 0.1	0.7 ± 0.2	−0.1	0.64
Oxygen saturation (%)	267	92 ± 5	93 ± 5	1.1	0.23
Echo outcomes
Total echo end diastolic volume z score	259	−0.7 ± 1.7	−0.3 ± 2.2	0.4	<0.001
Total echo end systolic volume z score	259	0.2 ± 2.2	1.0 ± 3.7	0.8	<0.001
Total echo ventricular mass z score	257	0.9 ± 2.0	1.0 ± 2.6	0.1	0.42
Total echo stroke volume z score	259	−1.1 ± 1.7	−1.0 ± 1.6	0.1	0.31
Total echo ejection fraction z score	259	−1.0 ± 2.0	−1.5 ± 1.9	−0.5	0.001
Total ejection fraction	259	58 ± 11	55 ± 10	−2.5	<0.001
Echo mass:volume ratio z score	257	2.6 ± 3.2	2.4 ± 3.0	−0.2	0.45
BNP, pg/mL median (IQR)	340	13(7,25)	18(9,36)	3.9	<0.001
Log BNP	340	2.6 ± 0.9	2.9 ± 1.1	0.3	<0.001
Sinus rhythm (%)	355	67	70	3	0.30
Paced rhythm (%)	355	7	14	7	<0.001

^*Subjects were included if the outcome was measured at both Fontan 1 and 3. Values are mean±SD, %, or median (interquartile range). BNP= B-type natriuretic peptide; VO₂=oxygen uptake.

^†Limited to those subjects with maximal effort at both time points.

^‡Limited to non-paced subjects with maximal effort at both time points.

^††Paired T-test for means. Wilcoxon signed rank test for BNP. Mcnemar’s test for rhythm.