Table 1 Overview of databases used in various works I

Nielsen et al. 1988 [28]

N/A

intra.

I.

30

N/A

Yes

No

No

obj.

50

Chung et al. 1995 [29]

FECG

intra.

N/A

N/A

N/A

Yes

Yes

Yes

obj.

73

Keith et al. 1995 [30]

N/A

intra.

N/A

> 120

Until del.

Yes

No

Yes

comb.

50

Bernardes et al. 1998 [31]

US, FECG

ante., intra.

I.,II.

–

Until del.

Yes

No

Yes

obj.

85

Maeda et al. 1998 [32]

N/A

intra.

N/A

50

N/A

No

No

No

subj.

49

Lee et al. 1999 [33]

FECG

intra.

N/A

–

N/A

Yes

No

No

subj.

53

Chung et al. 2001 [34]

US

ante., intra.

I.,II.

N/A

120

No

No

Yes

comb.

76

Strachan et al. 2001 [35]

FECG

intra.

I.,II.

> 30

Until del.

Yes

No

Yes

obj.

679

Siira et al. 2005 [36]

FECG

intra.

I.,II.

60

95% bellow 9

Yes

Yes

Yes

obj.

334

Cao et al. 2006 [37]

US, FECG

intra.

N/A

30

N/A

Yes

No

No

subj.

148

Salamalekis et al. 2006 [38]

US

intra.

I.,II.

N/A

Until del.

No

Yes

Yes

comb.

74

Georgoulas et al. 2006 [39]

FECG

intra.

I.,II.

20–60

Until del.

No

No

No

obj.

80

Gonçalves et al. 2006 [40]

US, FECG

intra.

I.,II.

32–60

Until del.

No

Yes

Yes

obj.

68

Costa et al. 2009 [41]

FECG

intra.

I.,II.

–

Until del.

Yes

Yes

Yes

obj.

148

Elliott et al. 2010 [42]

N/A

intra.

I.,II.

> 180

Until del.

Yes

Yes

Yes

subj.

2192

Warrick et al. 2010 [43]

US, FECG

intra.

I.,II.

> 180

Until del.

Yes

Yes

No

obj.

213

Jezewski et al. 2010 [25]

US

ante., intra.

N/A

–

N/A

Yes

Yes

Yes

obj.

749

Helgason et al. 2011 [44]

FECG

intra.

I.,II.

> 30

Until del.

Yes

No

No

comb.

47

Chudacek et al. 2011 [22]

US, FECG

intra.

I.,II.

20

Until del.

No

Yes

Yes

comb.

552

Spilka et al. 2012 [23]

US, FECG

intra.

I.,II.

20

Until del.

No

Yes

No

obj.

217

Georgieva et al. 2013 [45]

N/A

intra.

I.,II.

–

Until del.

No

Yes

Yes

obj.

7568

Czabanski et al. 2013 [46]

N/A

ante., intra.

N/A

60

N/A

No

Yes

Yes

subj.

2124 ^‡