J Endocrinol Metab

Journal of Endocrinology and Metabolism, ISSN 1923-2861 print, 1923-287X online, Open Access

Article copyright, the authors; Journal compilation copyright, J Endocrinol Metab and Elmer Press Inc

Journal website http://www.jofem.org

Original Article

Volume 2, Number 1, February 2012, pages 32-38

T Wave and QRS Complex Alternans During Stress ECG Testing According to the Presence or Absence of Diabetes Mellitus

Figure 1. Methods for the interval selection for the detection of TWA: Global (entire record) and Local (a set of windows).

**Table 1.** Demographic Characteristics and Risk Factor Distribution for the Whole Group of Patients
Clinical variable	Distribution n = 107
SD: standard deviation; BMI: body mass index; AH: arterial hypertension; MI: myocardial infarction; PCI: percutaneous coronary intervention; n: number.
Age - mean ± SD	62.8 ± 10.3
Male - n (%)	45 (42%)
BMI - mean ± SD	27.9 ± 4.4
AH - n (%)	96 (90%)
DM - n (%)	39 (36%)
Dyslipidemia - n (%)	87 (81%)
Family history of CAD - n (%)	11 (10%)
Present smokers - n (%)	16 (15%)
Ex-smokers - n (%)	25 (23%)
Angina pectoris - n (%)	86 (80%)
History of MI - n (%)	18 (17%)
Positive stress ECG test - n (%)	34 (32%)
AS-CAD - n (%)	48 (45%)
PCI - n (%)	40 (37%)
Coronary artery bypass grafting - n (%)	10 (9%)

Table 1. Demographic Characteristics and Risk Factor Distribution for the Whole Group of Patients

Clinical variable

Distribution
n = 107

SD: standard deviation; BMI: body mass index; AH: arterial hypertension; MI: myocardial infarction; PCI: percutaneous coronary intervention; n: number.

Age - mean ± SD

62.8 ± 10.3

Male - n (%)

45 (42%)

BMI - mean ± SD

27.9 ± 4.4

AH - n (%)

96 (90%)

DM - n (%)

39 (36%)

Dyslipidemia - n (%)

87 (81%)

Family history of CAD - n (%)

11 (10%)

Present smokers - n (%)

16 (15%)

Ex-smokers - n (%)

25 (23%)

Angina pectoris - n (%)

86 (80%)

History of MI - n (%)

18 (17%)

Positive stress ECG test - n (%)

34 (32%)

AS-CAD - n (%)

48 (45%)

PCI - n (%)

40 (37%)

Coronary artery bypass grafting - n (%)

10 (9%)

**Table 2.** Differences in TWA and QRSA Values Measured With 60 and 128 RR Interval Window
Parameter	60 RR	128 RR	Stat. sign (P)
TWA	1.8 ± 0.77	1.48 ± 0.82	P < 0.001
QRSA	1.43 ± 0.74	1.16 ± 0.68	P < 0.001

Table 2. Differences in TWA and QRSA Values Measured With 60 and 128 RR Interval Window

Parameter

60 RR

128 RR

Stat. sign (P)

TWA

1.8 ± 0.77

1.48 ± 0.82

P < 0.001

QRSA

1.43 ± 0.74

1.16 ± 0.68

P < 0.001

**Table 3.** Comparison TWA and QRSA (Measured With 60 and 128 RR Interval Window) Between Patients With Positive or Negative Stress ECG Test in the Whole Group Of Patients and in the Subgroups With or Without DM
Whole group n = 107	Stress pos	Stress neg	Stat. sign (P)
TWA-60	2.32 ± 0.68	1.22 ± 0.59	< 0.001
QRSA-60	1.79 ± 0.91	1.26 ± 0.71	0.003
TWA-128	2.03 ± 0.58	1.22 ± 0.79	< 0.001
QRSA-128	1.62 ± 0.85	0.95 ± 0.76	< 0.001
Subgroup DM n = 39
TWA-60	2.43 ± 0.65	1.24 ± 0.72	< 0.001
QRSA-60	2.29 ± 0.73	1.56 ± 0.82	0.02
TWA-128	2.07 ± 0.27	1.04 ± 0.69	0.001
QRSA-128	1.93 ± 0.88	1.04 ± 0.69	0.006
Subgroup no DM n =68
TWA-60	2.25 ± 0.72	1.73 ± 0.61	0.004
QRSA-60	1.45 ± 0.43	1.1 ± 0.39	0.04
TWA-128	2 ± 0.73	1.31 ±0.62	0.002
QRSA-128	1.4 ± 0.55	0.9 ± 0.25	0.013

Table 3. Comparison TWA and QRSA (Measured With 60 and 128 RR Interval Window) Between Patients With Positive or Negative Stress ECG Test in the Whole Group Of Patients and in the Subgroups With or Without DM

Whole group n = 107

Stress pos

Stress neg

Stat. sign (P)

TWA-60

2.32 ± 0.68

1.22 ± 0.59

< 0.001

QRSA-60

1.79 ± 0.91

1.26 ± 0.71

0.003

TWA-128

2.03 ± 0.58

1.22 ± 0.79

< 0.001

QRSA-128

1.62 ± 0.85

0.95 ± 0.76

< 0.001

Subgroup DM n = 39

TWA-60

2.43 ± 0.65

1.24 ± 0.72

< 0.001

QRSA-60

2.29 ± 0.73

1.56 ± 0.82

0.02

TWA-128

2.07 ± 0.27

1.04 ± 0.69

0.001

QRSA-128

1.93 ± 0.88

1.04 ± 0.69

0.006

Subgroup no DM n =68

TWA-60

2.25 ± 0.72

1.73 ± 0.61

0.004

QRSA-60

1.45 ± 0.43

1.1 ± 0.39

0.04

TWA-128

2 ± 0.73

1.31 ±0.62

0.002

QRSA-128

1.4 ± 0.55

0.9 ± 0.25

0.013

**Table 4.** Comparison TWA and QRSA (Measured With 60 and 128 RR Interval Window) Between Patients With or Without PCI in the Whole Group of Patients and in the Subgroups With or Without DM
Whole group n = 97	PCI	no PCI	Stat. sign (P)
TWA-60	2.18 ± 0.78	1.25 ± 0.69	< 0.001
QRSA-60	1.85 ± 0.8	1.18 ± 0.81	< 0.001
TWA-128	1.85 ± 0.74	1.25 ± 0.74	< 0.001
QRSA-128	1.55 ± 0.75	0.93 ± 0.46	< 0.001
Subgroup DM n = 34
TWA-60	2 ± 1.04	1.48 ± 0.77	ns
QRSA-60	2.07 ± 0.92	1.68 ± 1.07	ns
TWA-128	1.71 ± 0.83	1.26 ± 0.9	ns
QRSA-128	1.71 ± 0.91	1.16 ± 0.94	ns
Subgroup no DM n =63
TWA-60	2.27 ± 0.6	1.64 ± 0.62	< 0.001
QRSA-60	1.73 ± 0.62	0.99 ± 0.36	< 0.001
TWA-128	1.92 ± 0.69	1.26 ± 0.52	< 0.001
QRSA-128	1.46 ± 0.65	0.79 ± 0.21	< 0.001

Table 4. Comparison TWA and QRSA (Measured With 60 and 128 RR Interval Window) Between Patients With or Without PCI in the Whole Group of Patients and in the Subgroups With or Without DM

Whole group n = 97

PCI

no PCI

Stat. sign (P)

TWA-60

2.18 ± 0.78

1.25 ± 0.69

< 0.001

QRSA-60

1.85 ± 0.8

1.18 ± 0.81

< 0.001

TWA-128

1.85 ± 0.74

1.25 ± 0.74

< 0.001

QRSA-128

1.55 ± 0.75

0.93 ± 0.46

< 0.001

Subgroup DM n = 34

TWA-60

2 ± 1.04

1.48 ± 0.77

QRSA-60

2.07 ± 0.92

1.68 ± 1.07

TWA-128

1.71 ± 0.83

1.26 ± 0.9

QRSA-128

1.71 ± 0.91

1.16 ± 0.94

Subgroup no DM n =63

TWA-60

2.27 ± 0.6

1.64 ± 0.62

< 0.001

QRSA-60

1.73 ± 0.62

0.99 ± 0.36

< 0.001

TWA-128

1.92 ± 0.69

1.26 ± 0.52

< 0.001

QRSA-128

1.46 ± 0.65

0.79 ± 0.21

< 0.001