Stress increases intracardiac 4D flow cardiovascular magnetic resonance -derived energetics and vorticity and relates to VO2max in Fontan patients

Table 2 Quantitative analysis of energetics and vorticity at rest and stress

	Rest	Dobutamine stress	Difference(%)	P-value
	Mean ± SD or Median [IQR]	Mean ± SD	(Stress-rest)/rest x 100% Mean ± SD or Median [IQR]
Non-normalized
KE_{avg systole} (mJ)	2.4 ± 1.1	5.1 ± 1.8	99 [72-195]	< 0.001
KE_{avg diastole} (mJ)	1.4 ± 0.3	2.2 ± 0.7	61 ± 57	0.007
KE_{avg cycle} (mJ)	1.8 ± 0.5	3.3 ± 0.9	88 ± 52	< 0.001
EL_{avg systole} (mW)	1.2 [0.6-1.5]	3.1 ± 1.8	155 ± 61	0.005
EL_{avg diastole} (mW)	0.7 ± 0.2	1.2 ± 0.5	71 ± 66	0.007
EL_{avg cycle} (mW)	0.9 ± 0.4	1.9 ± 0.9	108 ± 49	< 0.001
Vorticity_vol_{avg systole} (mL/s)	3592 ± 1148	4928 ± 1626	37 ± 17	< 0.001
Vorticity_vol_{avg diastole} (mL/s)	3371 ± 770	4086 ± 1216	21 ± 25	0.02
Vorticity_vol_{avg cycle} (mL/s)	3441 ± 899	4394 ± 1322	27 ± 19	0.002
Normalized by stroke volume
KE_{avg cycle}/SV (mJ/mL)	0.023 ± 0.005	0.037 ± 0.009	64 ± 40	< 0.001
EL_{avg cycle}/SV (mW/mL)	0.012 ± 0.004	0.021 ± 0.009	81 ± 36	< 0.001
Vorticity_vol_{avg cycle}/SV (1/s)	44.1 ± 9.7	49.1 ± 11.1	11 ± 11	0.006

SD standard deviation, KE kinetic energy, SV stroke volume, EL viscous energy loss IQR interquartile range

ISSN: 1532-429X