Effect of reperfusion strategy on QT dispersion in patients with acute myocardial infarction: Impact on in-hospital arrhythmia

Table 1 Patient characteristics

Characteristic	Group I, n = 120 patients	Group II, n = 120 patients	P value
Age in yr	57.9 ± 9.6	59.1 ± 10.7	0.38
Male sex	96 (80)	93 (77.5)	0.64
Smoking	49 (40.8)	58 (48.3)	0.24
Hypertension	35 (29.2)	43 (35.8)	0.27
Diabetes mellitus	38 (31.7)	40 (33.3)	0.78
CKD	4 (3.3)	7 (5.8)	0.35
Family history of CAD	15 (12.5)	21 (17.5)	0.28
Dyslipidemia	61 (50.8)	49 (40.8)	0.12
Location of MI: Anterior MI non-anterior MI	72 (60) 48 (40)	61 (50.8) 59 (49.2)	0.15
Time from chest pain onset to reperfusion in hr	4.04 ± 1.96	4.39 ± 2.79	0.29

Data are expressed in form of mean ± SD or frequency (%). CAD: Coronary artery disease; CKD: Chronic kidney disease; MI: Myocardial infarction; SD: Standard deviation.

Table 2 Heart rate and QT interval before and after reperfusion, all patients

Parameter	Before reperfusion, n = 240 patients	After reperfusion, n = 240 patients	∆	P value
Heart rate in beat/min	78.6 ± 16.2	80.5 ± 15.7	-1.8 ± 16.9	0.09
Maximum QT in msec	407.1 ± 43.0	398.7 ± 45.2	8.5 ± 47.8	0.007
Minimum QT in msec	325.4 ± 41.7	341.3 ± 43.7	-15.9 ± 42.4	< 0.001
QTD in msec	81.8 ± 21.9	57.3 ± 18.9	24.4 ± 18.7	< 0.001
Maximum QTc in msec	461.2 ± 42.5	456.1 ± 38.9	5.1 ± 47.8	0.10
Minimum QTc in msec	368.5 ± 37.6	390.0 ± 36.4	-22.4 ± 44.5	< 0.001
QTcD in msec	92.7 ± 26.1	65.2 ± 22.6	27.5 ± 19.6	< 0.001

Data are expressed in form of mean ± SD. QTc: Corrected QT; QTD: QT dispersion; QTcD: Corrected QT dispersion; ∆: Delta is change in variables before and 24 hr after the reperfusion strategy.

Table 3 Heart rate and QT interval before and after reperfusion, group I vs group II

Parameter	Group I, n = 120 patients			Group II, n = 120 patients			P value
	Before	After	∆	Before	After	∆	P1	P2	P3	P4	P5
Heart rate in beat/min	81.0 ± 15.7	82.7 ± 16.4	-1.7 ± 18.9	76.2 ± 16.3	78.2 ± 14.8	-2.0 ± 14.9	0.34	0.14	0.02	0.02	0.87
Maximum QT in msec	411.7 ± 38.4	392.0 ± 44.1	19.7 ± 48.8	402.6 ± 46.9	405.3 ± 45.6	-2.8 ± 44.3	< 0.001	0.49	0.10	0.02	< 0.001
Minimum QT in msec	320.2 ± 34.6	338.1 ± 39.0	- 17.9 ± 34.4	330.6 ± 47.4	344.6 ± 48.0	-14.0 ± 41.3	< 0.001	0.001	0.06	0.25	0.48
QTD in msec	91.5 ± 20.6	53.9 ± 19.1	37.6 ± 17.1	72.0 ± 18.5	60.7 ± 18.1	11.3 ± 7.9	< 0.001	< 0.001	< 0.001	0.005	< 0.001
Maximum QTc in msec	474.3 ± 45.9	453.8 ± 38.1	20.6 ± 53.1	448.1 ± 34.1	458.4 ± 39.7	-10.4 ± 35.8	< 0.001	0.002	< 0.001	0.35	< 0.001
Minimum QTc in msec	369.9 ± 43.2	393.0 ± 32.1	- 23.1 ± 51.7	367.1 ± 31.1	388.9 ± 40.3	-21.8 ± 36.2	< 0.001	< 0.001	0.56	0.38	0.82
QTcD in msec	104.4 ± 22.1	60.8 ± 21.6	43.6 ± 13.6	80.9 ± 24.4	69.6 ± 22.8	11.4 ± 8.0	< 0.001	< 0.001	< 0.001	0.003	< 0.001

Data are expressed in form of mean ± SD. P1: P value comparing before and after PPCI in group I. P2: P value comparing before and after thrombolytic therapy in group II. P3: P value comparing group I and group II before reperfusion strategy. P4: P value comparing group I and group II after reperfusion strategy. P5: P value comparing group I and group II regarding delta change. QTc: Corrected QT; QTD: QT dispersion; QTcD: Corrected QT dispersion; ∆: Change in variables before and 24 hr after reperfusion; SD: Standard deviation.

Table 4 QT and corrected QT dispersion before and after reperfusion in patients with or without in-hospital arrhythmia

Parameter	In-hospital arrhythmia group, n = 33 patients			No in-hospital arrhythmia group, n = 207 patients			P value
	Before	After	∆	Before	After	∆	P1	P2	P3	P4	P5
QTD in msec	82.1 ± 19.3	67.3 ± 22.7	14.8 ± 18.9	81.7 ± 22.3	55.8 ± 17.7	25.9 ± 18.3	< 0.001	< 0.001	0.91	0.001	0.003
QTcD in msec	94.0 ± 25.3	74.2 ± 24.9	19.8 ± 14.5	92.5 ± 26.2	63.7 ± 21.9	28.7 ± 20.1	< 0.001	< 0.001	0.75	0.03	0.02

Data are expressed in form of mean ± SD. P1: P value comparing before and after reperfusion strategy in in-hospital arrhythmia group. P2: P value comparing before and after reperfusion strategy in no in-hospital arrhythmia group. P3: P value comparing in-hospital arrhythmia group and no in-hospital arrhythmia group before reperfusion strategy. P4: P value comparing in-hospital arrhythmia group and no in-hospital arrhythmia group after reperfusion strategy. P5: P value comparing in-hospital arrhythmia group and no in-hospital arrhythmia group regarding delta change. QTD: QT dispersion; QTcD: Corrected QT dispersion; ∆: Change in variables before and 24 hr after reperfusion; SD: Standard deviation.

Table 5 Studies addressing repolarization changes following reperfusion in ST-segment elevation myocardial infarction

Ref.	Study type	Study population	Time to evaluation	Reduction of QTD and QTcD	In-hospital arrhythmia	Remarks
Lopes et al[21], 2006	Retrospective	Thrombolytic (n = 154)	4 d	Sig. after 4 d	QTD not correlated with arrhythmia	CA after 48 h; Reduction in QTD is a predictor of coronary reperfusion
Ornek et al[22], 2014	Prospective	Thrombolytic (n = 20)	7 d	Sig. after 7 d	QTD correlated with arrhythmia	Use 24-h Holter monitor
Mulay et al[23], 2004	Prospective	STEMI (n = 100) Normal (n = 100)	24 hr On discharge	NA	Sig. high QTD in patients with ventricular arrhythmias compared to those without	Sig. higher QTD on admission, at 24 h, and at discharge than normal subjects
Pan et al[24], 2011	Prospective	PPCI (n = 81)	24 h	Sig. after 24 h	NA	QTcD change was an independent predictor of MACE at 1 yr
Hamza et al[25], 2014	Retrospective	PPCI (n = 54)	90 min 24 hr	Not sig after 90 min Sig. after 24 h	NA
Oni Heris et al[26], 2014	Prospective	Thrombolytic (n = 160)	1 hr 4 d	Not sig. after 1 hr Not sig. after 4 d	NA
Babapour et al[27], 2018	Retrospective	PPCI (n = 77)	24 h	Not sig. after 24 hr	NA
Cavusoglu et al[28], 2001	Prospective	PPCI (n = 21) Thrombolytic (n = 21)	24 h	Sig. in PPCI group Sig. in thrombolytic group Sig. in PPCI compared with thrombolytic	NA
George et al[29], 2015	Prospective	PPCI (n = 25) Thrombolytic (n = 25)	24 h	Sig. in PPCI group Not sig. in thrombolytic group Sig. in PPCI compared with thrombolytic	NA
Valizadeh et al[30], 2020	Prospective	PPCI (n = 70) Thrombolytic (n = 115)	24 h	Sig. in PPCI group Not sig. in thrombolytic group Not sig. in PPCI compared with thrombolytic	QTD mean in patients with arrhythmia was reduced before and after treatment with a significant reduction after PPCI as compared to thrombolysis

CA: Coronary angiogram; MACE: Major adverse cardiovascular event; NA: Not applicable; PPCI: Primary percutaneous coronary intervention; Ref.: Reference; Sig.: Significant; STEMI: ST-elevation myocardial infarction.