TABLE 4.

Electrical heart axes in the frontal plane of zebrafish vs. humans.

Vector axis (o)	Mean ± SD; Range (95% CI)	Dominant quadrant (% subjects)
Zebrafish P axis
Total (n = 30)	−70 ± 49; (−156,142) [−89,−51]	IV (80%)
M (n = 15)	−86 ± 31; (−156,−46) [−103,−69]	IV (73%)
F (n = 15)	−54 ± 60; (−140,142) [−87,−21]	IV (87%)
Zebrafish QRS axis (main heart axis)
Total (n = 30)	−69 ± 25; (−167,−40) [−78,−60]	IV (93%)
M (n = 15)	−72 ± 28; (−167,−45) [−88,−56]	IV (93%)
F (n = 15)	−66 ± 21; (−130,−40) [−78,−55]	IV (93%)
Zebrafish T axis
Total (n = 30)	−51 ± 49; (−136,150) [−71,−33]	IV (83%)
M (n = 15)	−55 ± 34; (−136,−9) [−74,−36]	IV (87%)
F (n = 15)	−47 ± 62; (−122,150) [−82,−13]	IV (80%)
Human P axis
Total (n = 24)	+46 ± 24; (−4,84) [35,56]	I (92%)
M (n = 12)	+49 ± 25; (−4,73) [32,65]	I (92%)
F (n = 12)	+43 ± 24; (−1,84) [27,58]	I (92%)
Human QRS axis (main heart axis)
Total (n = 24)	+51 ± 27; (5,91) [40,62]	I (100%)
M (n = 12)	+56 ± 26; (5,91) [39,72]	I (100%)
F (n = 12)	+46 ± 28; (8,90) [29,64]	I (100%)
Human T axis
Total (n = 24)	+39 ± 24; (−30,71) [29,49]	I (92%)
M (n = 12)	+46 ± 12; (25,75) [39,54]	I (100%)
F (n = 12)	+32 ± 30; (−30,71) [13,52]	I (83%)
	P-value	[95% CI]
Zebrafish M vs. F P axis	0.06	[−1,47]
Zebrafish M vs. F QRS axis	0.4	[−8,16]
Zebrafish M vs. F T axis	0.9	[−28,24]
Human M vs. F P axis	0.3	[−26,10]
Human M vs. F QRS axis	0.5	[−35,14]
Human M vs. F T axis	0.3	[−30,6]
Fish vs. Human P axis	<0.0001	[107,304]
Fish vs. Human QRS axis	<0.0001	[104,133]
Fish vs. Human T axis	<0.0001	[81,109]

We compared differences between species and sexes using the Mann-Whitney-Wilcoxon test. P-values are shown in italics; statistically significant P-values and 95% confidence intervals [95% CI] in bold font.