Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website https://www.cardiologyres.org

Original Article

Volume 9, Number 4, August 2018, pages 215-223

Association of Tp-Te/QT Ratio With Ventricular Tachycardia in Patients With Idiopathic Outflow Tract Ventricular Premature Contraction

Figure 1. EAD-induced trigger initiated long run of polymorphic VT in arterially perfused rabbit left ventricle pretreated with dl-sotalol 100 mmol/L [5].

**Table 1.** Basic Characteristics of the Idiopathic Outflow Tract VPC Subjects (N = 46)
Variables	Value (n = 46)
ECG: electrocardiogram; SD: standard deviation; SVT: supraventricular tachycardia.
Sex
Female; n (%)	32 (69.6%)
Male; n (%)	14 (30.4%)
Age mean ± SD (year)	44.59 ± 10.939
Comorbidities
Diabetes mellitus; n (%)	4 (8.7%)
Hypertension; n (%)	15 (32.6%)
Left ventricular hypertrophy; n (%)	5 (10.9%)
SVT; n (%)	0 (0%)
Ejection fraction (%)	63.6±6.099
Clinical complaints
Palpitation; n (%)	29 (63%)
Chest pain; n (%)	7 (15.2%)
Dizziness; n (%)	5 (10.9%)
Fatigue; n (%)	1 (2.2%)
Syncope; n (%)	2 (4.3%)
Hemodynamic disturbance; n (%)	2 (4.3%)
Antiarrhythmic drugs consumption during ECG recording
Bisoprolol; n (%)	5 (10.8%)
Metoprolol; n (%)	1 (2.1%)
Verapamil; n (%)	1 (2.1%)
Antihypertension drugs
Ramipril; n (%)	3 (6.3%)
Valsartan; n (%)	7 (15.2%)
Candesartan; n (%)	4 (8.6%)
Irbesartan; n (%)	1 (2.1%)
Tp-Te
Lead V4 ± SD (ms)	92.09 ± 16.52
Lead V5 ± SD (ms)	94.50 ± 14.84
Lead V6 ± SD (ms)	91.66 ± 17.23
QT
Lead V4 ± SD (ms)	408.93 ± 40.05
Lead V5 ± SD (ms)	413.32 ± 37.02
Lead V6 ± SD (ms)	409.55 ± 40.33
Tp-Te/QT
Lead V4 ± SD (ms)	0.225 ± 0.037
Lead V5 ± SD (ms)	0.228 ± 0.031
Lead V6 ± SD (ms)	0.223 ± 0.036

Table 1. Basic Characteristics of the Idiopathic Outflow Tract VPC Subjects (N = 46)

Variables

Value (n = 46)

ECG: electrocardiogram; SD: standard deviation; SVT: supraventricular tachycardia.

Sex

Female; n (%)

32 (69.6%)

Male; n (%)

14 (30.4%)

Age mean ± SD (year)

44.59 ± 10.939

Comorbidities

Diabetes mellitus; n (%)

4 (8.7%)

Hypertension; n (%)

15 (32.6%)

Left ventricular hypertrophy; n (%)

5 (10.9%)

SVT; n (%)

0 (0%)

Ejection fraction (%)

63.6±6.099

Clinical complaints

Palpitation; n (%)

29 (63%)

Chest pain; n (%)

7 (15.2%)

Dizziness; n (%)

5 (10.9%)

Fatigue; n (%)

1 (2.2%)

Syncope; n (%)

2 (4.3%)

Hemodynamic disturbance; n (%)

2 (4.3%)

Antiarrhythmic drugs consumption during ECG recording

Bisoprolol; n (%)

5 (10.8%)

Metoprolol; n (%)

1 (2.1%)

Verapamil; n (%)

1 (2.1%)

Antihypertension drugs

Ramipril; n (%)

3 (6.3%)

Valsartan; n (%)

7 (15.2%)

Candesartan; n (%)

4 (8.6%)

Irbesartan; n (%)

1 (2.1%)

Tp-Te

Lead V4 ± SD (ms)

92.09 ± 16.52

Lead V5 ± SD (ms)

94.50 ± 14.84

Lead V6 ± SD (ms)

91.66 ± 17.23

Lead V4 ± SD (ms)

408.93 ± 40.05

Lead V5 ± SD (ms)

413.32 ± 37.02

Lead V6 ± SD (ms)

409.55 ± 40.33

Tp-Te/QT

Lead V4 ± SD (ms)

0.225 ± 0.037

Lead V5 ± SD (ms)

0.228 ± 0.031

Lead V6 ± SD (ms)

0.223 ± 0.036

**Table 2.** Characteristics of Research Subjects Based on VT Incidence (N = 46)
Variables	Without VT (n = 18)	With VT (n = 28)	P
VT: ventricular tachycardia; ECG: electrocardiogram; RVOT: right ventricular outflow tract; LVOT: left ventricular outflow tract; SVT: supraventricular tachycardia; SD: standard deviation.*P < 0.05; 95% CI.
Sex
Female; n (%)	11 (69.6%)	21 (75%)	0.502
Male; n (%)	7 (30.4%)	7 (25%)
Age, mean ± s.d. (year)	40.5 ± 11.284	47.21 ± 10.049	0.41
Comorbidities
Diabetes mellitus; n (%)	1 (5.8%)	3 (10.7%)	0.944
Hypertension; n (%)	2 (11.1%)	13 (46.4%)	0.030*
Left ventricular hypertrophy; n (%)	2 (11.6%)	4 (14.3%)	0.634
SVT; n (%)	0 (0%)	0 (0%)	-
Ejection fraction	63.28 ± 2.824	63.68 ± 7.484	0.829
Drug consumption during ECG
Verapamil; n (%)	0 (0%)	1 (3.5%)	1
Bisoprolol; n (%)	2 (11.1%)	5 (17.8%)	1
Metoprolol; n (%)	1 (5.5%)	0 (0%)	0.391
Antihypertension therapy
Ramipril	1 (5.5%)	2 (7.1%)	1
Valsartan	1 (5.5%)	6 (21.4%)	0.297
Candesartan	0 (0%)	4 (14.3%)	0.891
Irbesartan	0 (0%)	1 (3.5%)	1
VT incidence
Spontaneous VT		21 (75%)
Induced VT		7 (25%)
Types of VT
Nonsustained VT	-	16 (57.1%)
Sustained VT	-	10 (35.7%)
Unstable VT	-	2 (7.2%)
Arrhythmia source
Septal RVOT	9 (50%)	7 (25%)	0.502
Anteroseptal RVOT	2 (11.1%)	3 (10.6%)	1
Posteroseptal RVOT	1 (5.6%)	2 (7.2%)	1
Basal septal RVOT	1 (5.6%)	1 (3.6%)	0.39
Anterior RVOT	1 (5.6%)	0 (0%)	0.39
Free wall RVOT	2 (11.1%)	1 (3.6%)	0.552
LVOT	1 (5.6%)	0 (0%)	0.391
Tp-Te
Lead V4 ± SD (ms)	75.83 ± 11.86	102.54 ± 8.76	< 0.001*
Lead V5 ± SD (ms)	80.50 ± 8.49	103.50 ± 10.34	< 0.001*
Lead V6 ± SD (ms)	74.76 ± 8.56	102.53 ± 11.67	< 0.001*
QT
Lead V4 ± SD (ms)	392.37 ± 39.33	419.58 ± 37.40	0.023*
Lead V5 ± SD (ms)	399.37 ± 35.96	422.30 ± 35.44	0.039*
Lead V6 ± SD (ms)	392.75 ± 33.99	420.35 ± 40.91	0.022*
Ratio Tp-Te/QT
Sandapan V4 ± SD (ms)	0.194 ± 0.033	0.245 ± 0.025	< 0.001*
Sandapan V5 ± SD (ms)	0.202 ± 0.021	0.245 ± 0.024	< 0.001*
Sandapan V6 ± SD (ms)	0.191 ± 0.022	0.245 ± 0.028	< 0.001*

Table 2. Characteristics of Research Subjects Based on VT Incidence (N = 46)

Variables

Without VT (n = 18)

With VT (n = 28)

VT: ventricular tachycardia; ECG: electrocardiogram; RVOT: right ventricular outflow tract; LVOT: left ventricular outflow tract; SVT: supraventricular tachycardia; SD: standard deviation.*P < 0.05; 95% CI.

Sex

Female; n (%)

11 (69.6%)

21 (75%)

0.502

Male; n (%)

7 (30.4%)

7 (25%)

Age, mean ± s.d. (year)

40.5 ± 11.284

47.21 ± 10.049

0.41

Comorbidities

Diabetes mellitus; n (%)

1 (5.8%)

3 (10.7%)

0.944

Hypertension; n (%)

2 (11.1%)

13 (46.4%)

0.030*

Left ventricular hypertrophy; n (%)

2 (11.6%)

4 (14.3%)

0.634

SVT; n (%)

0 (0%)

Ejection fraction

63.28 ± 2.824

63.68 ± 7.484

0.829

Drug consumption during ECG

Verapamil; n (%)

0 (0%)

1 (3.5%)

Bisoprolol; n (%)

2 (11.1%)

5 (17.8%)

Metoprolol; n (%)

1 (5.5%)

0 (0%)

0.391

Antihypertension therapy

Ramipril

1 (5.5%)

2 (7.1%)

Valsartan

1 (5.5%)

6 (21.4%)

0.297

Candesartan

0 (0%)

4 (14.3%)

0.891

Irbesartan

0 (0%)

1 (3.5%)

VT incidence

Spontaneous VT

21 (75%)

Induced VT

7 (25%)

Types of VT

Nonsustained VT

16 (57.1%)

Sustained VT

10 (35.7%)

Unstable VT

2 (7.2%)

Arrhythmia source

Septal RVOT

9 (50%)

7 (25%)

0.502

Anteroseptal RVOT

2 (11.1%)

3 (10.6%)

Posteroseptal RVOT

1 (5.6%)

2 (7.2%)

Basal septal RVOT

1 (5.6%)

1 (3.6%)

0.39

Anterior RVOT

1 (5.6%)

0 (0%)

0.39

Free wall RVOT

2 (11.1%)

1 (3.6%)

0.552

LVOT

1 (5.6%)

0 (0%)

0.391

Tp-Te

Lead V4 ± SD (ms)

75.83 ± 11.86

102.54 ± 8.76

< 0.001*

Lead V5 ± SD (ms)

80.50 ± 8.49

103.50 ± 10.34

< 0.001*

Lead V6 ± SD (ms)

74.76 ± 8.56

102.53 ± 11.67

< 0.001*

Lead V4 ± SD (ms)

392.37 ± 39.33

419.58 ± 37.40

0.023*

Lead V5 ± SD (ms)

399.37 ± 35.96

422.30 ± 35.44

0.039*

Lead V6 ± SD (ms)

392.75 ± 33.99

420.35 ± 40.91

0.022*

Ratio Tp-Te/QT

Sandapan V4 ± SD (ms)

0.194 ± 0.033

0.245 ± 0.025

< 0.001*

Sandapan V5 ± SD (ms)

0.202 ± 0.021

0.245 ± 0.024

< 0.001*

Sandapan V6 ± SD (ms)

0.191 ± 0.022

0.245 ± 0.028

< 0.001*

**Table 3.** Characteristics of Research Subjects Based on Tp-Te/QT Ratio Among Idiopathic Outflow Tract VPC Patients (N = 46)
Variable	Tp-Te/QT ratio in lead V4	Tp-Te/QT ratio in lead V5	Tp-Te/QT ratio in lead V6
ECG: electrocardiogram; RVOT: right ventricular outflow tract; LVOT: left ventricular outflow tract; SVT: supraventricular tachycardia; SD: standard deviation. *P < 0.05; 95% CI.
Sex
Female; n (%)	5 (45.5%)	27 (77.1%)	0.106	8 (61.5%)	24 (72.7%)	0.699	8 (61.5%)	24 (72.7%)	0.699
Male; n (%)	6 (54.5%)	8 (22.9%)		5 (38.5%)	9 (27.3%)		5 (38.5%)	9 (27.3%)
Age, mean ± SD (year)	42.82 ± 13.33	44.14 ± 10.23	0.545	43.31 ± 12.493	45.09 ± 10.432	0.624	43.85 ± 12.536	44.88 ± 10.443	0.777
Comorbidities
Diabetes mellitus; n (%)	1 (25%)	3 (75%)	1	1 (7.7%)	3 (9.1%)	1	1 (7.7%)	3 (9.1%)	1
Hypertension; n (%)	5 (45.5%)	10(28.6)	0.501	6 (46.2%)	9 (27.3%)	0.378	7 (53.8%)	8 (24.2%)	0.114
LV hypertrophy; n (%)	2 (18.2%)	4 (11.4%)	0.947	2 (15.4%)	4 (12.1%)	1	2 (15.4%)	4 (12.1%)	1
SVT; n (%)	0 (0%)	0 (0%)	-	0 (0%)	0 (0%)	-	0 (0%)	0 (0%)	-
Ejection fraction	64.0 ± 6.928	63.37 ± 5.857	0.768	64.0 ± 7.292	63.33 ± 5.611	0.741	64.31 ± 6.957	63.21 ± 5.749	0.586
Drug consumption during ECG
Verapamil; n (%)	1 (2.8%)	1 (2.8%)	1	1 (2.8%)	1 (2.8%)	1	1 (2.8%)	1 (2.8%)	1
Bisoprolol; n (%)	1 (9.0%)	3 (8.5%)	1	1 (9.0%)	3 (8.5%)	1	1 (9.0%)	3 (8.5%)	1
Metoprolol; n (%)	0 (0%)	1 (2.8%)	1	0 (0%)	1 (2.8%)	1	0 (0%)	1 (2.8%)	1
Arrhythmia source
Septal RVOT	1 (9.1%)	13 (37.1%)	0.165	2 (15.4%)	12 (36.4%)	0.3	3 (23.1%)	11 (33.0%)	0.745
Anteroseptal RVOT	0 (0%)	5 (14.3%)	0.44	1 (7.7%)	4 (12.2%)	1	0 (7.7%)	5 (15.2%)	0.337
Posteroseptal RVOT	2 (18.2%)	1 (2.9%)	0.273	2 (15.4%)	1 (3.0%)	0.387	2 (15.4%)	1 (3.0%)	0.387
Basal septal RVOT	0 (0%)	1 (2.9%)	1	0 (0%)	1 (3.0%)	1	0 (0%)	1 (3.0%)	1
Anterior RVOT	0 (0%)	1 (2.9%)	1	0 (0%)	1 (3.0%)	1	0 (0%)	1 (3.0%)	1
Free wall RVOT	1 (9.1%)	2 (5.7%)	1	1 (7.7%)	2 (6.1%)	1	1 (7.7%)	2 (6.1%)	1
LVOT	0 (0%)	1 (2.9%)	1	0 (0%)	1 (3.0%)	1	0 (0%)	1 (3.0%)	1

Table 3. Characteristics of Research Subjects Based on Tp-Te/QT Ratio Among Idiopathic Outflow Tract VPC Patients (N = 46)

Variable

Tp-Te/QT ratio in lead V4

Tp-Te/QT ratio in lead V5

Tp-Te/QT ratio in lead V6

Increased (n = 11)

Normal (n = 35)

Increased (n = 13)

Normal (n = 33)

Increased (n = 13)

Normal (n = 33)

ECG: electrocardiogram; RVOT: right ventricular outflow tract; LVOT: left ventricular outflow tract; SVT: supraventricular tachycardia; SD: standard deviation. *P < 0.05; 95% CI.

Sex

Female; n (%)

5 (45.5%)

27 (77.1%)

0.106

8 (61.5%)

24 (72.7%)

0.699

8 (61.5%)

24 (72.7%)

0.699

Male; n (%)

6 (54.5%)

8 (22.9%)

5 (38.5%)

9 (27.3%)

5 (38.5%)

9 (27.3%)

Age, mean ± SD (year)

42.82 ± 13.33

44.14 ± 10.23

0.545

43.31 ± 12.493

45.09 ± 10.432

0.624

43.85 ± 12.536

44.88 ± 10.443

0.777

Comorbidities

Diabetes mellitus; n (%)

1 (25%)

3 (75%)

1 (7.7%)

3 (9.1%)

1 (7.7%)

3 (9.1%)

Hypertension; n (%)

5 (45.5%)

10(28.6)

0.501

6 (46.2%)

9 (27.3%)

0.378

7 (53.8%)

8 (24.2%)

0.114

LV hypertrophy; n (%)

2 (18.2%)

4 (11.4%)

0.947

2 (15.4%)

4 (12.1%)

2 (15.4%)

4 (12.1%)

SVT; n (%)

0 (0%)

Ejection fraction

64.0 ± 6.928

63.37 ± 5.857

0.768

64.0 ± 7.292

63.33 ± 5.611

0.741

64.31 ± 6.957

63.21 ± 5.749

0.586

Drug consumption during ECG

Verapamil; n (%)

1 (2.8%)

Bisoprolol; n (%)

1 (9.0%)

3 (8.5%)

1 (9.0%)

3 (8.5%)

1 (9.0%)

3 (8.5%)

Metoprolol; n (%)

0 (0%)

1 (2.8%)

0 (0%)

1 (2.8%)

0 (0%)

1 (2.8%)

Arrhythmia source

Septal RVOT

1 (9.1%)

13 (37.1%)

0.165

2 (15.4%)

12 (36.4%)

0.3

3 (23.1%)

11 (33.0%)

0.745

Anteroseptal RVOT

0 (0%)

5 (14.3%)

0.44

1 (7.7%)

4 (12.2%)

0 (7.7%)

5 (15.2%)

0.337

Posteroseptal RVOT

2 (18.2%)

1 (2.9%)

0.273

2 (15.4%)

1 (3.0%)

0.387

2 (15.4%)

1 (3.0%)

0.387

Basal septal RVOT

0 (0%)

1 (2.9%)

0 (0%)

1 (3.0%)

0 (0%)

1 (3.0%)

Anterior RVOT

0 (0%)

1 (2.9%)

0 (0%)

1 (3.0%)

0 (0%)

1 (3.0%)

Free wall RVOT

1 (9.1%)

2 (5.7%)

1 (7.7%)

2 (6.1%)

1 (7.7%)

2 (6.1%)

LVOT

0 (0%)

1 (2.9%)

0 (0%)

1 (3.0%)

0 (0%)

1 (3.0%)

**Table 4.** Prevalence Ratio of Tp-Te/QT Ratio to VT Incidence Among Idiopathic Outflow Tract VPC Patients
Variable	PR	95% CI	P
Tp-Te: Tpeak-Tend interval; PR: prevalence ratio. *P < 0.05; 95% CI.
Tp-Te/QT ratio
Lead V4	2.059	1.464 - 2.895	0.007*
Lead V5	2.200	1.514 - 3.197	0.002*
Lead V6	2.200	1.514 - 3.197	0.002*

Table 4. Prevalence Ratio of Tp-Te/QT Ratio to VT Incidence Among Idiopathic Outflow Tract VPC Patients

Variable

95% CI

Tp-Te: Tpeak-Tend interval; PR: prevalence ratio. *P < 0.05; 95% CI.

Tp-Te/QT ratio

Lead V4

2.059

1.464 - 2.895

0.007*

Lead V5

2.200

1.514 - 3.197

0.002*

Lead V6

2.200

1.514 - 3.197

0.002*

**Table 5.** Comparison of Tp-Te/QT Ratio Measurements in Leads V4, V5 and V6
Lead	VT incidence	Mean Tp-Te/QT ± SD (ms)	P
Tp-Te: Tpeak-Tend interval; SD: standard deviation. *P < 0.05; 95% CI.
V4	Yes	0.245 ± 0.025	< 0.001*
	No	0.194 ± 0.033	< 0.001*
V5	Yes	0.245 ± 0.024	< 0.001*
	No	0.202 ± 0.021	< 0.001*
V6	Yes	0.245 ± 0.028	< 0.001*
	No	0.191 ± 0.022	< 0.001*

Table 5. Comparison of Tp-Te/QT Ratio Measurements in Leads V4, V5 and V6

Lead

VT incidence

Mean Tp-Te/QT ± SD (ms)

Tp-Te: Tpeak-Tend interval; SD: standard deviation. *P < 0.05; 95% CI.

Yes

0.245 ± 0.025

< 0.001*

0.194 ± 0.033

< 0.001*

Yes

0.245 ± 0.024

< 0.001*

0.202 ± 0.021

< 0.001*

Yes

0.245 ± 0.028

< 0.001*

0.191 ± 0.022

< 0.001*

**Table 6.** Multivariate Analysis of VT Incidence in Idiopathic Outflow Tract VPC Patients
Variable	Exp (B)	95% CI	P
Tp-Te: Tpeak-Tend interval; Exp (B): exponential beta. *P < 0.05; 95% CI.
Hypertension	0.685	0.230 - 2.043	0.497
Tp-Te/QT ratio (lead V6)	1.29	0.444 - 3.747	0.639

Table 6. Multivariate Analysis of VT Incidence in Idiopathic Outflow Tract VPC Patients

Variable

Exp (B)

95% CI

Tp-Te: Tpeak-Tend interval; Exp (B): exponential beta. *P < 0.05; 95% CI.

Hypertension

0.685

0.230 - 2.043

0.497

Tp-Te/QT ratio (lead V6)

1.29

0.444 - 3.747

0.639