Table 3

Accuracies and Predictive Values of Pooled Conventional versus A-ECG Criteria in the Test Set

Disease

(N = 208)

Healthy

(N = 107)

TP

FN

TN

FP

Sensitivity(CLs)

Specificity(CLs)

Accuracy(CLs)

Conventional ECG status

Abnormal (optimized pooled criteria)

163

45

91

16

78%(72-84%)

85%(77-91%)

81%(76-85%)

Best individual parameter status*

Abnormal QTVI in lead II (>-1.64 units)

161

47

87

20

77%(71-83%)

81%(73-88%)

79%(74-83%)

Best 1° A-ECG scores status*

"Full Disclosure" (5-min) A-ECG:

Abnormal 9-parameter score

185

23

98

9

89%(84-93%)‡

92%(85-96%)

90%(86-93%)†

Abnormal 7-parameter score

194

16

101

6

92%(88-96%)‡

94%(88-98%)†

93%(90-96%)†

"Snapshot" (10-sec) A-ECG:

Abnormal 7-parameter score

192

16

92

15

92%(88-96%)‡

86%(78-92%)

90%(86-93%)†

Disease

+LVSD

(N = 41)

Disease

no LVSD

(N = 44)

TP

FN

TN

FP

PPV (CLs)

NPV (CLs)

+LR

-LR

Conventional ECG status

Abnormal (optimized pooled criteria)

39

2

10

34

53%(41-65%)

83%(51-98%)

1.23

0.21

Best individual parameter status*

Abnormal Z integral (>12.4 mV*ms)

28

13

31

13

68%(52-82%)

70%(55-83%)

2.31

0.45

Best 2° A-ECG scores status*

Abnormal 5-parameter score

34

7

41

3

92%(78-98%)‡

85%(72-94%)

12.16

0.18

A-ECG, advanced ECG; LVSD, left ventricular systolic dysfunction; TP and FP, true and false positives; TN and FN, true and false negatives; CLs, exact 95% binomial confidence limits; PPV and NPV, positive and negative predictive values; +LR and -LR, positive and negative likelihood ratios; QTVI, the QT interval variability index; Z integral, the total integral of the Z-lead QRS complex above 5 Hz.

*The best individual parameters and their cut-off values and the best A-ECG scores are all carried over from the training set and are not necessarily fully optimized with respect to the test set.

†P < 0.05 and ‡P < 0.0001 versus the optimized pooled conventional ECG criteria.

Schlegel et al. BMC Cardiovascular Disorders 2010 10:28   doi:10.1186/1471-2261-10-28