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Dahrab M, Gaddipati SP, Patel KB, Patel T, Gaddam AR, Jain M, Gudi TR, Meenashi Sundaram D, Mahfooz K, Vasavada AM. The Effect of Percutaneous Coronary Intervention on QT Dispersion and the Association Between Them: A Systematic Review. Cureus 2023; 15:e36226. [PMID: 37065409 PMCID: PMC10103800 DOI: 10.7759/cureus.36226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2023] [Indexed: 03/18/2023] Open
Abstract
Electrocardiography (ECG) parameters are significant in the prognosis of ischemia and other cardiovascular conditions. Reperfusion or revascularization techniques are essential in reestablishing blood flow to ischemic tissues. This study aims to demonstrate the association between percutaneous coronary intervention (PCI), a revascularization technique, and the electrocardiography (ECG) parameter, QT dispersion (QTd). We conducted a systematic review of the association between PCI and QTd through a literature search in three electronic databases, ScienceDirect, PubMed, and Google Scholar, for empirical studies published in English. Review Manager (RevMan) 5.4 (Cochrane Collaboration, Oxford, England) was used for statistical analysis. Of 3,626 studies, 12 articles met the inclusion criteria, enrolling a total of 1,239 patients. After a successful PCI procedure, QTd and corrected QT (QTc) tremendously reduced at various time intervals with statistical significance in most of the studies. There was a clear association between ECG parameters QTd, QTc, and corrected QT dispersion (QTcd), and PCI, in that there is a considerable reduction in these ECG parameters after PCI treatment.
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Helmy H, Abdel-Galeel A, Taha Kishk Y, Mohammed Sleem K. Correlation of corrected QT dispersion with the severity of coronary artery disease detected by SYNTAX score in non-diabetic patients with STEMI. Egypt Heart J 2017; 69:111-117. [PMID: 29622964 PMCID: PMC5839347 DOI: 10.1016/j.ehj.2016.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 12/24/2016] [Indexed: 10/31/2022] Open
Abstract
Introduction Determination of the QT interval dispersion by means of a standard ECG at rest has been widely used for cardiovascular risk assessment during the last 15 years as one of the recent explanations for the development of life threatening ventricular arrhythmias. However, little is known about the relation between QT dispersion and the severity of coronary artery atherosclerosis as defined by SYNTAX score. Aim of work The present study was done to assess the correlation between QTc dispersion and the severity of coronary artery disease in acute ST elevation myocardial infarction (STEMI) detected by SYNTAX score. Patients and methods It included 50 patients who were non-diabetic, non-hypertensive and diagnosed as acute STEMI within 6 months undergoing coronary angiography in the cath. lab. of Assiut University Hospital. QT dispersion was calculated as the difference between the longest (QT max) and the shortest QT (QTmin) interval recorded by standard 12 lead ECG. The QT interval was corrected by using Bazett's formula (QTc = QT/square root of R-R interval in seconds). Corrected QT dispersion (QTcd) was defined as the difference between the maximum and minimum QTc for a given heart rate. The SYNTAX score is calculated by syntax calculator, a new tool to grade the complexity of coronary artery disease. Results Out of 50 participating patients, there were 43 (86%) males with mean age 53.9 ± 12.1 years. The mean QTc dispersion was 83.1 ± 20.3 ms, while mean SYNTAX score was 11.6 ± 6.1. There is a strong positive correlation between QTc dispersion and SYNTAX score. This was not related to age, gender, risk factors or family history of ischemic heart disease. Of note, there was a relationship between QTc dispersion and serum creatinine. Conclusions Our study concluded that there is a significant positive correlation between corrected QT dispersion and severity of coronary artery disease as assessed by SYNTAX score.
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Affiliation(s)
- Hatem Helmy
- Department of Cardiology, Assiut University, Egypt
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Fukushima N, Tsurumi Y, Jujo K, Fukushima K, Sekiguchi H, Honda A, Yumino D, Kawana M, Hagiwara N. Impact of myocardial reperfusion status on QT dispersion after successful recanalization of the infarct-related artery in acute myocardial infarction. J Interv Cardiol 2014; 27:252-9. [PMID: 24450339 DOI: 10.1111/joic.12093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To determine whether adequate myocardial perfusion status after transluminal recanalization is associated with prompt improvement of QT dispersion (QTd). BACKGROUND Transluminal recanalization of the infarct-related coronary artery in acute myocardial infarction aims to promptly restore myocardial perfusion, to maximize electrical and mechanical recovery. QTd represents the heterogeneity of ventricular repolarization, which may affect electrical stability. METHODS Forty patients who underwent primary percutaneous coronary intervention for their first anterior acute ST-elevation myocardial infarction were prospectively enrolled. Myocardial reperfusion status was assessed by myocardial blush grade (MBG) on the final angiogram after successful recanalization (Thrombolysis In Myocardial Infarction Grade 3 flow). RESULTS Preprocedural QTd was similar in patients with final MBG 0-1, 2, and 3 (76 ± 24, 67 ± 13, and 69 ± 13 milliseconds, respectively; P = 0.661). After recanalization, QTd decreased in patients with MBG 3 (39 ± 16 milliseconds, P < 0.001) but not in patients with MBG 0-1 (74 ± 20 milliseconds) or MBG 2 (82 ± 16 milliseconds). Multivariate analysis showed that postprocedural MBG was an independent predictor of QTd after recanalization (standardized regression coefficient = -0.628, P < 0.001). CONCLUSIONS Adequate tissue perfusion may be crucial for electrical stability of the myocardium after reperfusion.
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Akcay A, Acar G, Sayarlioglu M, Sokmen A, Kaya H, Ispiroglu M, Koroglu S. QT dispersion and transmural dispersion of repolarization in patients with familial Mediterranean fever. Mod Rheumatol 2014. [DOI: 10.3109/s10165-009-0196-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Erdogan E, Akkaya M, Bacaksız A, Tasal A, Sönmez O, Asoglu E, Kul S, Sahın M, Turfan M, Vatankulu MA, Göktekin O. Short-term effect of percutaneous recanalization of chronic total occlusions on QT dispersion and heart rate variability parameters. Med Sci Monit 2013; 19:696-702. [PMID: 23969577 PMCID: PMC3762394 DOI: 10.12659/msm.889511] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background QT dispersion (QTd), which is a measure of inhomogeneity of myocardial repolarization, increases following impaired myocardial perfusion. Its prolongation may provide a suitable substrate for life-threatening ventricular arrhythmias. We investigated the changes in QTd and heart rate variability (HRV) parameters after successful coronary artery revascularization in a patient with chronic total occlusions (CTO). Material/Methods This study included 139 successfully revascularized CTO patients (118 men, 21 women, mean age 58.3±9.6 years). QTd was measured from a 12-lead electrocardiogram and was defined as the difference between maximum and minimum QT interval. HRV analyses of all subjects were obtained. Frequency domain (LF: HF) and time domain (SDNN, pNN50, and rMSSD) parameters were analyzed. QT intervals were also corrected for heart rate using Bazett’s formula, and the corrected QT interval dispersion (QTcd) was then calculated. All measurements were made before and after percutaneous coronary intervention (PCI). Results Both QTd and QTcd showed significant improvement following successful revascularization of CTO (55.83±14.79 to 38.87±11.69; p<0.001 and 61.02±16.28 to 42.92±13.41; p<0.001). The revascularization of LAD (n=38), Cx (n=28) and RCA (n=73) resulted in decrease in HRV indices, including SDDN, rMSSD, and pNN50, but none of the variables reached statistical significance. Conclusions Successful revascularization of CTO may result in improvement in regional heterogeneity of myocardial repolarization, evidenced as decreased QTcd after the PCI. The revascularization in CTO lesions does not seem to have a significant impact on HRV.
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Affiliation(s)
- Ercan Erdogan
- Department of Cardiology, Faculty of Medicine, Bezmialem Foundation University, Istanbul, Turkey
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Rezaian GR, Ghadicolay HS, Kazemi MBS, Zamirian M, Aghasadeghi K, Rezaian S. Earliest time of change in QT dispersion after stenting in patients with single vessel coronary artery disease. Int J Angiol 2012; 16:50-2. [PMID: 22477271 DOI: 10.1055/s-0031-1278247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Abstract
Dispersion of the QT interval (QTd) is a measure of inhomogeneity of ventricular repolarization, and its prolongation may provide a suitable substrate for life-threatening ventricular arrhythmias. The present study was performed to determine the onset time of change in the corrected QT (QTc) interval and QTd in patients with stable angina and single vessel coronary artery disease. Electrocardiograms of 60 patients with successful stenting, obtained 1 h before and 1 h, 6 h, 12 h and 24 h after the procedure were analyzed. The QTc interval, QTc maximum, QTc minimum and QTd were measured. All electrocardiograms were scanned, and then underwent computer-based analysis. There was a significant reduction in the mean QTc interval as early as 12 h after the procedure (from 474±41 ms to 460±31 ms; P<0.001), which persisted to the 24 h follow-up. This was associated with a significant reduction in mean QT maximum (from 496±31 ms to 418±66 ms; P<0.001) and a significant prolongation in mean QT minimum (from 403±21 ms to 444±12 ms; P<0.001) at the same time intervals. Therefore, successful stenting of coronary arteries in patients with single vessel coronary artery disease and stable angina decreases QTd as early as 12 h after the procedure. This phenomenon may be the result of improved regional myocardial circulation, and reduced ischemia. A persistently low QTd in the following months may therefore have prognostic significance, and can be used as a noninvasive marker of stent patency. Further studies are necessary to define the clinical applicability of QTd in the assessment of long-term stent patency in such patients.
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Affiliation(s)
- Gholam Reza Rezaian
- Department of Medicine (Cardiology), Shiraz University of Medical Sciences, Shiraz
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Takase B, Tujimoto T, Kitamura K, Hamabe A, Uehata A, Kazusige I, Satomura K, Ohsuzu F, Kurita A. Angioplasty decreases prolonged QT dispersion in patients with angina pectoris but not in patients with prior myocardial infarction. Clin Cardiol 2009; 24:127-31. [PMID: 11214742 PMCID: PMC6655102 DOI: 10.1002/clc.4960240206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND AND HYPOTHESIS Prolonged QT dispersion (QTd) is shortened by successful percutaneous transluminal coronary angioplasty (PTCA) in patients with ischemic heart disease. Particularly, QTd plays an important role in the prognostication in patients with prior myocardial infarction (MI). However, whether the effect of PTCA on QTd differs in patients with and without prior MI is not clear, and this study sought to clarify this question. METHODS In 41 consecutive patients with ischemic heart disease, we measured QTd from a routine 12-lead electrocardiogram taken at 72 h before and after successful PTCA. Patients were divided into two groups based on the presence or absence of prior MI: Group 1 consisted of 24 patients with angina (61 +/- 11 years old) without prior MI and Group 2 was comprised of 17 patients (69 +/- 10 years old) with prior MI. QTd was calculated as the difference between the maximum and minimum QT and QT corrected for heart rate (QTc), using Bazett's formula for calculating QTcd. All measurements were obtained manually and blindly. RESULTS In Group 1, 15 of 24 patients (63%) demonstrated multivessel disease and 16 of 24 (67%) patients had high QTd > 60 ms. Percutaneous transluminal coronary angioplasty decreased QTd and QTcd in Group 1 (QTd, from 83 +/- 35 to 57 +/- 19 ms, p < 0.05 ; QTcd, from 89 +/- 37 to 63 +/- 33 ms, p < 0.05), whereas no changes were observed in Group 2 (QTd, from 73 +/- 25 to 69 +/- 22 ms, NS; QTcd, from 80 +/- 30 to 79 +/- 28 ms, NS). QTd is more sensitive to decrease by successful PTCA in patients with angina than in patients with prior MI. CONCLUSIONS The effect of successful PTCA on inhomogeneity of ventricular repolarization reflected by QTd in patients with prior MI is different from that in patients without prior MI.
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Affiliation(s)
- B Takase
- National Defense Medical College, Internal Medicine-1, Tokorozawa, Saitama, Japan
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Akcay A, Acar G, Sayarlioglu M, Sokmen A, Kaya H, Ispiroglu M, Koroglu S. QT dispersion and transmural dispersion of repolarization in patients with familial Mediterranean fever. Mod Rheumatol 2009; 19:550-5. [PMID: 19578931 DOI: 10.1007/s10165-009-0196-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 06/12/2009] [Indexed: 11/30/2022]
Abstract
Familial Mediterranean fever (FMF) is a disease characterized by sporadic, paroxysmal attacks of fever and serosal inflammation. QT dispersion (QTd) and transmural dispersion of repolarization (TDR), simple noninvasive arrhythmogenic markers, that can be used to assess homogeneity of cardiac repolarization, have not been studied in FMF patients before. The aim of our study was to evaluate the QTd and TDR in FMF patients without overt cardiac involvement. A total of 50 patients with FMF (30 men, 20 women, 29.4 +/- 11.8 years) and 50 controls (30 men, 20 women; mean age 31.3 +/- 11.9 years) were included. QTd, corrected QTd (cQTd), maximum QT (QTmax), maximum corrected QT (cQTmax), minimum QT (QTmin), and minimum corrected QT intervals (cQTmin) and TDR were measured from standard 12-lead electrocardiography (ECG). We found that QTd, QTmax, and TDR were greater in FMF patients than in the control group (36.0 +/- 11.4 vs. 20 +/- 11.2, P < 0.001 and 354.8 +/- 30.9 vs. 342.8 +/- 18.0, P = 0.02; 62.0 +/- 16.0 vs. 49.0 +/- 9.5 P < 0.001, respectively), as were cQTd and cQTmax (40.4 +/- 13.5 vs. 21.9 +/- 12.4, P < 0.001 and 397.7 +/- 40.2 vs. 375.5 +/- 25.4 P = 0.001). A modest positive correlation was found between cQTd and C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) (r = 0.30, P < 0.001; r = 0.40, P < 0.001; respectively). QTd, which is an index of inhomogeneity of ventricular repolarization and an important predictor of cardiovascular mortality, and TDR, which is a better marker of cardiac repolarization, increased in FMF patients similarly as in other rheumatologic diseases.
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Affiliation(s)
- Ahmet Akcay
- Department of Cardiology, Faculty of Medicine, Kahramanmaras Sutcuimam University, Kahramanmaras, Turkey.
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Aytemir K, Bavafa V, Ozer N, Aksoyek S, Oto A, Ozmen F. Effect of balloon inflation-induced acute ischemia on QT dispersion during percutaneous transluminal coronary angioplasty. Clin Cardiol 2009; 22:21-4. [PMID: 9929750 PMCID: PMC6655594 DOI: 10.1002/clc.4960220109] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND QT dispersion (QTd = QTmax-QTmin) measured as interlead variability of QT interval reflects the spatial inhomogeneity of ventricular repolarization times, and increased QTd may provide a substrate for malignant ventricular arrhythmias. Ischemia is associated with regional abnormalities of conduction and repolarization. HYPOTHESIS This study aimed to investigate the effect of acute ischemia on QTd during successful percutaneous transluminal coronary angioplasty (PTCA). METHODS Forty-three patients (10 women, 33 men, mean age 56 years) were enrolled in the study. Electrocardiogram (ECG) recordings were taken before PTCA and during balloon inflation period. QT maximum (QTmax), QT minimum (QTmin), and QTd (QTmax-QTmin) values were calculated from the surface ECG. RESULTS There was no difference among QTmax values (p = 0.6). Mean QTmin during balloon inflation was lower than before PTCA (368 +/- 45 vs. 380 +/- 41 ms, p = 0.002). The difference between QTd values before and during balloon inflation was statistically important (65 +/- 9 vs. 76 +/- 10 ms, p = 0.001). This difference is caused by a decrease in QTmin during balloon inflation. CONCLUSION Acute reversible myocardial ischemia induced by balloon inflation causes an increase in QTd value, and this increment is the result of a decrease in QTmin interval. Therefore, QTd may be a marker of reversible myocardial ischemia.
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Affiliation(s)
- K Aytemir
- Hacettepe University, Faculty of Medicine, Department of Cardiology, Ankara, Turkey
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Hailer B, Van Leeuwen P, Sallner D, Lange S, Wehr M. Changes of QT dispersion in patients with coronary artery disease dependent on different methods of stress induction. Clin Cardiol 2009; 23:181-6. [PMID: 10761806 PMCID: PMC6654857 DOI: 10.1002/clc.4960230310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Episodes of stress-induced myocardial ischemia in patients with coronary artery disease (CAD) may cause increases of QT dispersion (QTd). HYPOTHESIS Aim of this study was to analyze the effect of increasing heart rates on QTd and to compare the effect of different methods of stress induction in patients with varying degrees of CAD when estimating QTd. METHODS We studied 58 patients, 22 with prior myocardial infarction (MI), 25 without MI or wall motion disturbances at rest, and 11 patients without evidence of CAD. Prior to coronary angiography, standard 12-lead ECGs were obtained at rest as well as during dynamic exercise and pharmacologic stress using arbutamine simultaneously with echocardiography. QTd was determined at each stress level by subtracting minimal from maximal QT interval duration. RESULTS QTd values at rest were not consistently higher in the patients with CAD. At maximal heart rate, QTd was statistically significantly higher in patients with CAD with a better discrimination between groups for pharmacologic stress (p < 0.005 for exercise, p < 0.0001 for arbutamine). Patients after MI had higher QTd values under all conditions than did the groups without MI. As in patients with CAD, the values of this group changed more radically as a result of pharmacologic stress. CONCLUSION Patients with CAD can be identified on the basis of QTd under stress. These changes were not as marked in patients with MI as their rest values were already increased. Overall, drug-induced stress produced greater differences than dynamic exercise, suggesting that the ischemic threshold might be lower in the former.
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Affiliation(s)
- B Hailer
- Department of Medicine, Philippusstift, Essen, Germany
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11
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Soliman EZ, Abdel-Salam M, Dardir MD. A simple ECG marker for the detection of coronary restenosis after successful coronary angioplasty. Intern Med 2009; 48:1793-8. [PMID: 19834270 DOI: 10.2169/internalmedicine.48.2463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The dynamic nature of QT dispersion (QTd) and the absence of an acceptable normal value suggest that the relative change not the absolute value of QTd would be a better predicator of coronary restenosis. We sought to examine the usefulness of the relative change in QTd, compared to the absolute value, as a predictor for coronary restenosis after previously successful percutaneous transluminal coronary angioplasty (PTCA). METHODS Ninety-two patients with a history of successful PTCA who were referred for coronary angiography (CA) for exclusion of coronary restenosis were included in this analysis. QTd was calculated as the difference in milliseconds between the maximum and minimum QT interval in the 12-lead ECG. Relative change in QTd was measured as [QTd at the time of angiography (current) - QTd after the successful PTCA (baseline)]/QTd (baseline) %. Receiver operating characteristics (ROC) analysis was used to detect the best cut-off point and also to compare the diagnostic accuracy of the relative change in QTd vs. the absolute QTd for prediction of coronary restenosis. RESULTS The relative change in QTd showed a significantly larger ROC area under curve (AUC) compared to the absolute QTd [AUC (95% CI): 0.79 (0.698, 0.872) and 0.61 (0.498, 0.703) respectively; p=0.011 for AUCs comparison]. The best cut-off point for the relative QTd was 40%, and for the absolute QTd this was 50 ms. The sensitivity and specificity of > or =40% increase in QTd to detect coronary restenosis was 71% and 83%, with positive and negative predictive values of 90% and 57%, respectively. The diagnostic accuracy of the absolute value of QTd was much less than this; the sensitivity and specificity of QTd > or =50 ms were 48% and 58%, with positive and negative predictive values of 71% and 34%, respectively. CONCLUSIONS Compared to the absolute value, the relative change in QTd is a better predictor of coronary restenosis after a previously successful PTCA. These findings may open the door for rethinking the use of QTd as a simple ECG predictor for cardiovascular outcomes.
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Affiliation(s)
- Elsayed Z Soliman
- Epidemiological Cardiology Research Center, Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
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Hansen S, Rasmussen V, Torp-Pedersen C, Jensen GB. QT intervals and QT dispersion determined from a 12-lead 24-hour Holter recording in patients with coronary artery disease and patients with heart failure. Ann Noninvasive Electrocardiol 2008; 13:22-30. [PMID: 18234003 DOI: 10.1111/j.1542-474x.2007.00197.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND QT dispersion is considered an index of spatial inhomogeneity of repolarization duration and increased dispersion of ventricular repolarization is supposed to increase the risk of ventricular arrhythmia. Circadian variation in QT dispersion was investigated. METHODS Three different modes of lead selection was used: all 12-leads (QTdisp 12), only precordial leads (QTdisp 6), and one pair of preselected leads (QTdisp 2) in a 24-hour Holter recording every fourth hour each comprising 10 consecutive measurements in 54 healthy subjects, 29 patients with coronary artery disease (CAD), and 29 patients with heart failure (HF). RESULTS A significant circadian variation was observed in healthy subjects when modes QTdisp 12 and QTdisp 6 were used (Mean +/- SD 35.58 +/- 16.48 ms; P < 0.0001; and 28.82 +/- 16.02 ms; P < 0.0001, respectively), and in patients with CAD (Mean +/- SD 37.86 +/- 17.87 ms; P < 0.01; and 28.72 +/- 17.06 ms; P < 0.0001, respectively), whereas no circadian variation was observed in QTdisp 2. No circadian variation was observed in patients with HF irrespectively of lead selection. Patients with CAD without myocardial infarction (MI) had a circadian variation in QTdisp 12 (Mean +/- SD 33.13 +/- 14.86 ms; P < 0.05), whereas no circadian variation was observed in patients with MI (Mean +/- SD 40.35 +/- 18.80 ms; P = NS). CONCLUSIONS Circadian variation of QT dispersion was detected in healthy subjects and in patients with uncomplicated CAD, but not in those who had suffered a previous MI and in patients with HF. The number of leads among which selection of the longest and shortest QT intervals took place was critical for the disclosure of circadian variation of QT dispersion.
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Affiliation(s)
- Stig Hansen
- Department of Cardiology, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
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Hansen S, Rasmussen V, Larsen K, Torp-Pedersen C, Jensen GB. Circadian variation in QT dispersion determined from a 12-lead Holter recording: a methodological study of an age- and sex-stratified group of healthy subjects. Ann Noninvasive Electrocardiol 2007; 12:185-96. [PMID: 17617062 PMCID: PMC6932468 DOI: 10.1111/j.1542-474x.2007.00160.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND QT dispersion is considered to reflect inhomogeneity of myocardial repolarization. METHOD The circadian variation of QT interval dispersion was examined in 95 healthy subjects using 24-hour Holter monitoring. Three different methods of lead selection were applied: all 12 leads (QTdisp 12), only precordial leads (QTdisp 6), and the pair of leads selected at 3 a.m. in which the longest and shortest QT intervals were found in each individual subject (QTdisp 2). RESULTS A preliminary methodological study including measurements from every minute in 10 subjects revealed no significant circadian variation using mean values of QTdisp 12, QTdisp 6, or QTdisp 2 obtained every hour, every 2, or every 4 hours, except in QTdisp 6, which demonstrated a significant circadian variation (P < 0.01) in 1-hour measurements. Analysis of all 95 subjects using measurements obtained every 4 hours revealed a significant circadian variation in QTdisp 12 and QTdisp 6 (P < 0.0001), whereas no circadian variation was seen in QTdisp 2. A subdivision into 10-year age groups revealed that subjects at age >50 years had a significant circadian variation in QTdisp 12 and QTdisp 6, but not in QTdisp 2. Only in males a significant circadian variation was seen in QTdisp 12 (P < 0.0001), whereas QTdisp 6 demonstrated a circadian variation both in females (P < 0.001) and in males (P < 0.0001). CONCLUSIONS Selection of leads is of crucial importance for repetitive measurements of QT dispersion. Circadian variation was detected in subjects over 50 years of age, when all 12 or only the 6 precordial leads were taken into account.
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Affiliation(s)
- Stig Hansen
- Department of Cardiology, Copenhagen University Hospital, Hvidovre, Denmark.
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Park JH, Kim DY, Kim BS, Lee HJ, Kim JH, Jang HS, Shin SM, Kang HJ, Lee BR, Jung BC. Characteristics of QT Interval and QT Dispersion in Exercise Electrocardiogram: Healthy Persons versus Stable Angina Patients. Korean Circ J 2007. [DOI: 10.4070/kcj.2007.37.11.543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Jin Hong Park
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Dae Young Kim
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Bong Soo Kim
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Hyun Jik Lee
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Jae Hoon Kim
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Hee Sang Jang
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Seung Min Shin
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Hyun Jae Kang
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Bong Ryeol Lee
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
| | - Byung Chun Jung
- Department of Cardiology, Fatima General Hospital, Daegu, Korea
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Lyras TG, Papapanagiotou VA, Foukarakis MG, Panou FK, Skampas ND, Lakoumentas JA, Priftis CV, Zacharoulis AA. Evaluation of serial QT dispersion in patients with first non-Q-wave myocardial infarction: relation to the severity of underlying coronary artery disease. Clin Cardiol 2006; 26:189-95. [PMID: 12708627 PMCID: PMC6654124 DOI: 10.1002/clc.4960260409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Increased QT dispersion (QTD) has been correlated with ventricular arrhythmias. Recent reports suggest that it may serve as a marker of the severity of underlying coronary artery disease (CAD). HYPOTHESIS The aim of this study was to examine in-hospital changes of QTD and their possible correlation with the severity of underlying CAD in patients with first non-Q-wave myocardial infarction. METHODS In 62 patients we estimated QTD, precordial QTD, as well as their values corrected for heart rate on Days 3 and 7 after admission. The severity of underlying ischemic burden was estimated by means of the number of diseased vessels as well as by the jeopardy score. RESULTS On Day 3, patients with jeopardy score > or = 6 exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p = 0.001, p = 0.003, p = 0.02, p = 0.036, respectively); patients with multivessel disease had greater QTD (p = 0.007). On Day 7, patients with jeopardy score > or = 6 and multivessel disease exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p < 0.001 for all). Multiple regression analysis revealed a jeopardy score of > or = 6 as the most significant independent predictor for QTD variables. From Days 3 to 7, only patients with none or one diseased vessel orjeopardy score < 6 had shortened QTD (p = 0.01 and p = 0.015, respectively) and corrected QTD (p < 0.001 for both). CONCLUSIONS In patients with first non-Q-wave myocardial infarction, QTD variables and their in-hospital changes reflect the severity of underlying CAD.
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Affiliation(s)
- T G Lyras
- Cardiology Department, Athens General Hospital G. Gennimatas, Athens, Greece.
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16
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Li VH, Dorbala S, Narula D, DePuey G, Steinberg JS. QT dispersion and viable myocardium in patients with prior myocardial infarction and severe left ventricular dysfunction. Ann Noninvasive Electrocardiol 2006; 7:53-9. [PMID: 11844292 PMCID: PMC7027710 DOI: 10.1111/j.1542-474x.2001.tb00139.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q-wave myocardial infarction and well-preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction. METHODS Thirty-four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc-99m sestamibi single photon emission cardiac tomography (SPECT) and F-18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable myocardium in the infarct area. RESULTS Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 +/- 22 ms, 61 +/- 23 ms, and 4.81 +/- 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 +/- 14 ms, QTcd = 70 +/- 16 ms and Qtcv = 5.06 +/- 1.20% [P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd. CONCLUSIONS This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction.
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Affiliation(s)
- Vuy Hun Li
- Division of Cardiology, St. Luke's-Roosevelt Hospital Center, 1111 Amsterdam Ave., New York, NY 10025, USA.
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17
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Yilmaz R, Demirbag R, Gur M. The association of QT dispersion and QT dispersion ratio with extent and severity of coronary artery disease. Ann Noninvasive Electrocardiol 2006; 11:43-51. [PMID: 16472282 PMCID: PMC6932384 DOI: 10.1111/j.1542-474x.2006.00081.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Although prolongation of the QT intervals in acute ischemic conditions, such as acute myocardial infarction, intracoronary balloon inflation, and exercise induced ischemia, has been shown, association of rest QT intervals with extent and severity of stable coronary artery disease (CAD) has not been assessed so far. The effects of extent and severity of stable CAD on rest QT interval were analyzed in this study. METHODS Rest 12-lead electrocardiograms (ECG) were recorded in 162 clinically stable subjects undergoing coronary angiography before the angiography for measurement of corrected QT dispersion (cQTd) and the QT dispersion ratio (QTdR) defined as QT dispersion divided by cycle length and expressed as a percentage. Angiographic "vessel score,""diffuse score," and "Gensini score" were used to evaluate the extent and severity of coronary atherosclerosis. Subjects were grouped as follows: those with normal angiogram (Group 1), those with insignificant (<50%) coronary stenosis (Group 2), and those with 1- (Group 3), 2- (Group 4), or 3-vessel disease (Group 5). RESULTS cQTd and QTdR were higher in Group 3 compared with Group 1 (P < 0.001 and P = 0.001, respectively), in Group 4 compared with Group 1 (P < 0.001 for both) and Group 2 (P = 0.001 and P = 0.003, respectively), and in Group 5 compared with Group 1 (P < 0.001 for both) and Group 2 (P < 0.001 and P = 0.003, respectively). cQTd and QTdR were positively correlated with the vessel score (r = 0.422, P < 0.001; r = 0.358, P < 0.001, respectively), diffuse score (r = 0.401, P < 0.001; r = 0.357, P < 0.001, respectively) and Gensini score (r = 0.378, P < 0.001; r = 0.373, P < 0.001, respectively). In multiple linear regression analyses, cQTd was found to be independently associated only with diffuse score (beta= 0.325, P = 0.038). Also, QTdR was independently associated with diffuse score (beta= 0.416, P = 0.006) and Gensini score (beta= 0.374, P = 0.011). CONCLUSIONS Rest cQTd and QTdR are increased, and related to the extent and severity of coronary atherosclerosis in patients with stable CAD.
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Affiliation(s)
- Remzi Yilmaz
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey.
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18
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Grygier M, Lesiak M, Podzerek T, Kowal J, Mitkowski P, Pyda M, Skorupski W, Grajek S, Cieśliński A. QT interval dispersion as a new marker of restenosis after percutaneous transluminal coronary angioplasty of isolated single-vessel coronary artery stenosis. Cardiology 2006; 106:89-97. [PMID: 16612075 DOI: 10.1159/000092637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 01/27/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND There are no reliable non-invasive markers of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The aim of our study was to measure changes in QT interval dispersion after PTCA and to determine whether restenosis subsequently affects QT interval dispersion. METHODS AND RESULTS Fifty-six consecutive patients - 41 men and 15 women (mean age: 56.2 +/-8.3 years) - with isolated stenosis of the left anterior descending artery who underwent successful PTCA were studied. A symptom-limited treadmill exercise test was performed within 7 days after PTCA and then again before repeated angiography. Repeated coronary angiography revealed restenosis in 15 patients (26.8%) and no signs of significant stenosis in 41 patients (73.2%). QT interval dispersion in the group of patients with restenosis measured before exercise increased from baseline 34 +/- 7 to 49 +/- 15 ms after 6 months (p < 0.01) and QT interval dispersion measured immediately after exercise increased from baseline 38 +/- 4 to 68 +/- 21 ms after 6 months (p < 0.001). In contrast, patients without restenosis showed no significant changes in QT interval dispersion measured before (baseline: 34 +/- 9 ms; after 6 months 33 +/- 12 ms; p = NS) and immediately after exercise (baseline: 34 +/- 12 ms; after 6 months: 33 +/- 10; p = NS). When QT interval dispersion > or =60 ms (measured 6 months after PTCA procedure) was considered as a potential marker of restenosis, this indicator had very high sensitivity and specificity when measured immediately after exercise (80 and 95% respectively). CONCLUSIONS QT interval dispersion significantly increases in the group of patients with documented restenosis and may be a simple, non-invasive marker of restenosis. However, further studies are needed to confirm this observation.
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Affiliation(s)
- M Grygier
- Chair and 1st Department of Cardiology, Poznan University of Medical Sciences, Poland.
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19
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Goodhart DM, Hubacek J, Anderson TJ, Duff H, Barbeau G, Ducas J, Carere RG, Lazzam C, Dzavik V, Buller CE, Traboulsi M. Effect of percutaneous coronary intervention of nonacute total coronary artery occlusions on QT dispersion. Am Heart J 2006; 151:529.e1-529.e6. [PMID: 16442926 DOI: 10.1016/j.ahj.2005.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Accepted: 08/11/2005] [Indexed: 11/29/2022]
Abstract
BACKGROUND Myocardial ischemia is one of several potential causes of increased QT dispersion (QTd) in patients with nonacute total coronary artery occlusions (TCOs). We sought to assess the effect of percutaneous revascularization (PCI) of TCO on QTd and the relationship between QTd and long-term vessel patency. METHODS Seventy patients enrolled in the TOSCA were analyzed. Patients were undergoing PCI of a TCO > 72 hours' duration. Two independent reviewers measured QTd from electrocardiograms done immediately before PCI (PRE), 12 to 18 hours after PCI (POST), and then at 6 months (6M). Follow-up angiography was performed at 6 months. RESULTS Mean QTd decreased from PRE (77 +/- 29 milliseconds) to POST (66 +/- 26 milliseconds, P < .001) and 6M (65 +/- 25 milliseconds, P < .001). Patients with the same or longer QTd at 6 months compared with POST (POST < or = 6M) had significantly higher risk of failed target-vessel patency (odds ratio 10.3, 95% CI 1.24-84.8) than patients with QTd reduction at 6M versus POST values. CONCLUSION Revascularization of TCO resulted in a decrease in QTd, which was sustained at 6M. This suggests that PCI to a TCO has a beneficial effect on stabilization of the underlying ischemic substrate. Furthermore, absence of QTd reduction at 6M versus POST was associated with increased risk of failed target-vessel patency.
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Affiliation(s)
- David M Goodhart
- Department of Medicine, University of Calgary, Calgary Health Region, Alberta, Canada.
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20
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Takase B, Kusama Y, Nishizaki M, Koide Y, Li S, Kawakubo K, Saito S, Tanabe T, Kodama K, Kishida H. Detecting Restenosis after Percutaneous Coronary Intervention Using Exercise-Stress Electrocardiogram Findings Including QT Dispersion. J Arrhythm 2006. [DOI: 10.1016/s1880-4276(06)80030-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Akutsu Y, Li HL, Shinozuka A, Kodama Y, Yamanaka H, Katagiri T. Change with exercise in QT dispersion in infarct-related myocardium after angioplasty. Int J Cardiol 2005; 99:105-10. [PMID: 15721507 DOI: 10.1016/j.ijcard.2003.12.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2003] [Revised: 12/05/2003] [Accepted: 12/25/2003] [Indexed: 11/17/2022]
Abstract
BACKGROUND The aim of this study was to evaluate the relationship between exercise-induced QT dispersion and condition of infarct-related myocardium including myocardial scar after angioplasty assessed with exercise perfusion single photon emission computed tomography (SPECT). METHODS Exercise thallium-201 SPECT was performed 6 months after successful direct angioplasty in 67 male patients (60.6 +/- 11.5 years), who had Q wave infarction resulting from single vessel disease, and the number of perfusion defect areas (DS) was measured at rest and exercise together with QT (QTc) dispersion. RESULTS In 52 patients with resting perfusion defects, the exercise-induced change in DS was correlated to the change in QT (or QTc) dispersion (r = -0.51 or r = -0.531, p < 0.0001). When the patients were grouped according to the patterns of transient perfusion defect, there were significant differences in DeltaQT dispersion and DeltaQTc dispersion among infarct-related three groups (reverse, fixed, and partial redistributions) and normal volunteers (DeltaQT dispersion; -5.7 +/- 12.7 ms in 13 patients with reverse redistribution, -16.3 +/- 13.1 ms in 30 patients with fixed redistribution, -28.9 +/- 29.5 ms in 9 patients with partial redistribution, and +3.4 +/- 20.9 ms in 12 normal volunteers, p = 0.0098; DeltaQTc dispersion; +18.2 +/- 20.8 ms, +1.4 +/- 16.7 ms, -15.4 +/- 30 ms, and +19 +/- 27.5 ms, p = 0.0017, respectively). DeltaQTc dispersion estimated the SPECT image patterns (p = 0.0002) with a sensitivity of 67.3%, a specificity of 83.7% and an accuracy of 78.2%. CONCLUSIONS The change with exercise in QT dispersion may help detect the condition of infarct-related myocardium after angioplasty.
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Affiliation(s)
- Yasushi Akutsu
- Third Department of Internal Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawaku, Tokyo 142-8666, Japan.
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22
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Ilkay E, Yavuzkir M, Karaca I, Akbulut M, Pekdemir M, Aslan N. The effect of ST resolution on QT dispersion after interventional treatment in acute myocardial infarction. Clin Cardiol 2004; 27:159-62. [PMID: 15049385 PMCID: PMC6654344 DOI: 10.1002/clc.4960270313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND It has been reported that reperfusion treatment reduces QT dispersion (QTD) in cases of acute myocardial infarction (AMI). Successful myocardial perfusion is not synonymous with Thrombolysis in Myocardial Infarction (TIMI) III flow. It has been demonstrated that in AMI, the grade of ST-resolution correlates strongly with left ventricular (LV) function, enzyme elevation, and mortality after primary angioplasty. HYPOTHESIS This study investigated the relation between ST-resolution grade and QTD and the feasibility of using QTD as a determinant of successful myocardial tissue perfusion in patients in whom TIMI III flow in the infarct-related artery (IRA) is restored by interventional treatment for AMI. METHODS The study included 57 patients (38 men, 19 women, average age 54.4 +/- 11.6 years), whose IRA was perfused by primary angioplasty after the diagnosis of anterior AMI with ST elevation. Electrocardiograms of patients were taken 45 +/- 12 min post procedure, and patients were divided into three groups depending on the grade of ST resolution: Group 1, full ST resolution; Group 2, partial ST resolution; and Group 3, unsuccessful ST resolution. RESULTS Full ST resolution was seen in 19 cases (33%), partial resolution in 26 cases (47%), and unsuccessful resolution in 12 cases (20%). There were no differences among groups in terms of risk factors, stent diameters, symptom onset-balloon time, LV function, and preprocedure corrected QTD (QTcD) (p = 0.274). After the procedure, a significant reduction in QTcD was found within the groups (p = 0.0001 in Group 1, p = 0.004 in Group 2, and p = 0.011 in Group 3). Reductions in QTcD post procedure were 24.21 +/- 14.27, 11.85 +/- 16.18, and 12.50 +/- 11.58 ms in Groups 1, 2, and 3, respectively. There was a statistically significant difference of p = 0.015 between Groups 1 and 2 and a difference of p = 0.028 between Groups 1 and 3. There was no statistically significant difference between Groups 2 and 3 (p = 0.916). CONCLUSION In acute MI, TIMI III flow led to a reduction in QTcD, and full myocardial perfusion made an additional contribution to the electrical stability of the myocardium.
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Affiliation(s)
- Erdoğan Ilkay
- Department of Cardiology, Firat University, School of Medicine, Elaziğ, Turkey.
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Papadopoulos CE, Karvounis HI, Parharidis GE, Louridas GE. Preconditioning reduces QTc value in patients with first non-ST-segment elevation myocardial infarction (NSTEMI). Ann Noninvasive Electrocardiol 2004; 8:275-83. [PMID: 14516282 PMCID: PMC7313237 DOI: 10.1046/j.1542-474x.2003.08403.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Preinfarction angina (PA) consists a strong clinical correlate to ischemic preconditioning (PC) and seems to occur in a bimodal time course. The aim of the study is to evaluate the impact of both forms of PC on QTc value representing myocardial electric stability, in patients with a first NSTEMI. METHODS Forty-eight patients, with first NSTEMI and poor or no collateral development were enrolled in the study. QTc at admission and discharge were recorded. All patients had comparable admission QTc values and were divided into three groups according to the absence or presence and exact timing of preinfarction angina. The first group consisted of 20 patients who did not report PA (PA-, representing no PC effect); the second group of 12 patients with reported PA within 12 hours prior to admission (12h PA+, representing the classic form of PC); and the third group of 16 patients reporting PA within 12 to 48 hours prior to admission (48-hour PA+, representing the delayed form of PC). The primary outcome was determined as the effect of PA on QTc value at discharge. RESULTS Discharge QTc values were significantly reduced in both (PA+) groups compared to (PA-) group (412 +/- 50 vs. 455 +/- 53 ms, p = 0.015 and 417 +/- 29 vs. 455 +/- 53 ms, P = 0.033, respectively). Both groups of (PA+) patients compared to (PA-) patients suffered no arrhythmic events during their hospitalization (0/12 vs. 6/20, P = 0.04 and 0/16 vs. 6/20, P = 0.02). CONCLUSIONS Both forms of preconditioning, similarly and significantly reduce QTc value at discharge in patients experiencing a first NSTEMI, suggesting possible protection from future arrhythmic events.
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Van Leeuwen P, Hailer B, Lange S, Grönemeyer D. Spatial distribution of repolarization times in patients with coronary artery disease. Pacing Clin Electrophysiol 2003; 26:1706-14. [PMID: 12877704 DOI: 10.1046/j.1460-9592.2003.t01-1-00256.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The potential clinical value of QT dispersion (QTd), a measure of the interlead range of QT interval duration in the surface 12-lead ECG, remains ambiguous. The aim of the study was the temporal and spatial analysis of the QT interval in healthy subjects and in patients with coronary artery disease (CAD) using magnetocardiography (MCG) and surface ECG. Standard 12-lead ECG and 37-channel MCG were performed in 20 healthy subjects, 23 patients with CAD without prior myocardial infarction (MI), 31 MI patients and 11 MI patients with ventricular tachycardia (VT). QTd was increased in CAD without MI compared to normals (ECG 46.1 +/- 6.0 vs 42.8 +/- 5.0, P < 0.05; MCG 66.8 +/- 20.3 vs 49.7 +/- 10.8, P < 0.01) and in VT compared to MI (ECG 66.8 +/- 16.5 vs 51.9 +/- 16.6, P < 0.05; MCG 93.6 +/- 29.6 vs 66.8 +/- 20.8, P < 0.005). In MCG, spatial distribution of QT intervals in patient groups differed from those in healthy subjects in three ways: (1) greater dispersion, (2) greater local variability, and (3) a change in overall pattern. This was quantified on the basis of smoothness indexes (SI). Normalized SI was higher in CAD without MI compared to normals (3.8 +/- 1.1 vs 2.7 +/- 0.6, P < 0.001) and in VT compared to MI (6.4 +/- 1.6 vs 4.2 +/- 1.4, P < 0.0005). For the normal-CAD comparison a sensitivity of 74% and a specificity of 80% was obtained, for MI-VT, 100% and 77%, respectively. The results suggest that examining the spatial interlead variability in multichannel MCG may aid in the initial identification of CAD patients with unimpaired left ventricular function and the identification of post-MI patients with augmented risk for VT.
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Affiliation(s)
- Peter Van Leeuwen
- Department of Biomagnetism, Research and Development Center for Microtherapy (EFMT), Bochum, Germany.
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25
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Atak R, Turhan H, Sezgin AT, Yetkin O, Senen K, Ileri M, Sahin O, Karabal O, Yetkin E, Kutuk E, Demirkan D. Effects of slow coronary artery flow on QT interval duration and dispersion. Ann Noninvasive Electrocardiol 2003; 8:107-11. [PMID: 12848790 PMCID: PMC6932652 DOI: 10.1046/j.1542-474x.2003.08203.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The coronary slow-flow phenomenon is an angiographic phenomenon characterized by delayed opacification of vessels in the absence of any evidence of obstructive epicardial coronary disease. Several studies have demonstrated myocardial ischemia in patients with slow coronary artery flow. In the present study, we aimed at evaluating the effects of slow coronary artery flow on QT interval duration and QT dispersion as a possible indicator of increased risk for ventricular arrhythmias and sudden cardiac death. METHODS The study population included 49 patients with angiographically proven normal coronary arteries and slow coronary flow in all three coronary vessels (group I, 33 males, 16 females, mean age = 48 +/- 9 years), and 71 patients with angiographically proven normal coronary arteries without associated slow coronary flow (group II, 47 males, 24 females, mean age = 50 +/- 8 years). Coronary flow rates of all subjects were documented by thrombolysis in myocardial infarction frame count (TIMI frame count). QT interval duration and QT dispersion of all subjects were measured on the standard 12-lead electrocardiogram. RESULTS There was no statistically significant difference between the two groups in respect to age, gender, presence of hypertension, and diabetes mellitus. There was a significant difference between the two groups in respect to the presence of cigarette smoking, typical angina, and positive exercise test results. TIMI frame counts of group I patients were significantly higher than those of group II patients for all three coronary arteries (P < 0.001). Maximum corrected QT interval (QTcmax) of group I did not differ from the QTcmax of group II (P > 0.05). However, minimum corrected QT interval (QTcmin) of group I was significantly lower than that for group II (P = 0.008). Consequently, corrected QT dispersion (QTcd) in group I was found to be significantly higher than in group II (P < 0.001). CONCLUSION QTcd, indicating increased risk for ventricular arrhythmias and cardiovascular mortality, was found to be significantly higher in patients with slow coronary artery flow. However, further long-term prospective studies should be carried out to establish the significance of QTcd as a risk factor for ventricular arrhythmias and subsequent sudden cardiac death in patients with slow coronary artery flow.
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Affiliation(s)
- Ramazan Atak
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Hasan Turhan
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Alpay T Sezgin
- Department of Cardiology, Inonu University Medical Faculty, Malatya
| | - Ozkan Yetkin
- Department of Chest Medicine, Ankara University Medical Faculty, Ankara, Turkey
| | - Kubilay Senen
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Mehmet Ileri
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Onur Sahin
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Orhan Karabal
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Ertan Yetkin
- Department of Cardiology, Inonu University Medical Faculty, Malatya
| | - Emine Kutuk
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
| | - Deniz Demirkan
- Department of Cardiology, Turkiye Yuksek Ihtisas Hospital, Ankara
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Kesek M, Englund A, Jernberg T, Lagerqvist B, Lindahl B. The relation of QT dispersion and localized QT difference to coronary pathology in a population with unstable coronary artery disease. Ann Noninvasive Electrocardiol 2003; 8:22-9. [PMID: 12848810 PMCID: PMC6932660 DOI: 10.1046/j.1542-474x.2003.08105.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND QT dispersion (QTd) contains prognostic information in several patient groups. The variable increases in several conditions with ischemia. Originally, it was thought to reflect the local repolarization inhomogeneity. Even though this explanation has been questioned lately, it continues to be put forward. In order to elucidate a possible local mechanism, we investigated the relation between QT dispersion, an ECG parameter reflecting the local dispersion, and angiographical measures in a population with unstable coronary artery disease. METHODS The 276 patients were recruited from the FRISC II trial. As the QTd parameter we used the mean value of automatically measured QTd during 27 hours after admission (QTdMean). As a local repolarization measure we used the maximal difference in QT between two adjacent ECG leads (QTdiffMean). The computations were performed on all available ECG leads and on a restricted set without the V1-V2 combination. Previously published angiographic scoring tools were adapted for rating and localizing the coronary pathology by two approaches and applied on 174 patients undergoing angiography. RESULTS QTdMean was significantly higher than that reported in previous material with unselected chest pain patients (55 vs 40 ms). QTdiffMean correlated strongly with QTdMean. No differences in QTdMean were detected between patients with different angiographical scores. No relation could be shown between the region with dominating coronary pathology as expressed by the scoring tools and the localization of QTdiffMean. CONCLUSIONS QTd in ischemia seems to be increased by a mechanism unrelated to localization and severity of coronary disease.
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Affiliation(s)
- Milos Kesek
- Department of Cardiology, Norrland University Hospital, 90185 Umea, Sweden.
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Poulsen PL. Blood pressure and cardiac autonomic function in relation to risk factors and treatment perspectives in Type 1 diabetes. J Renin Angiotensin Aldosterone Syst 2002; 3:222-42. [PMID: 12584666 DOI: 10.3317/jraas.2002.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The cumulative incidence of diabetic nephropathy in Type 1 diabetes mellitus is in the order of 25 30%. The recognition that elevated blood pressure (BP) is a major factor in the progression of these patients to end-stage renal failure has led to the widespread use of antihypertensive therapy in order to preserve glomerular filtration rate and ultimately to reduce mortality. The routine measurement of microalbuminuria allows early identification of the subgroup of patients at increased risk of developing clinical nephropathy. Microalbuminuric Type 1 diabetic patients show a number of characteristic pathological abnormalities. In addition to elevated BP and abnormal circadian rhythm, there are also associated abnormalities of vagal function, lipid profile and endothelial function, as well as an increased prevalence of retinopathy. The first section of this two-part review focusses on the early changes associated with renal involvement in Type 1 diabetes. It addresses the associations between urinary albumin excretion, glycaemic control, smoking, BP, circadian BP variation, QT interval abnormalities and autonomic function in three groups of patients; those with normoalbuminuria, those progressing towards microalbuminuria and those with established low-grade microalbuminuria.
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28
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Kesek M, Jernberg T, Lindahl B, Englund A. QT dispersion measured by an automatic continuous method early in patients admitted for chest pain. Int J Cardiol 2002; 85:217-24; discussion 225-7. [PMID: 12208586 DOI: 10.1016/s0167-5273(02)00158-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND There is a need for risk markers in patients with acute chest pain. QT dispersion (QTd) is a prognostic marker in several groups of patients. A problem with the manual measurement of QTd is operator dependency. This can be avoided by using an automatic method. We investigated QTd, derived from multiple automatic measurements, as a risk marker in a population with chest pain. METHODS In 548 patients admitted to the coronary care unit for chest pain and nondiagnostic ECG, 12-lead ECG recordings were collected each minute during the initial 17 h. From recordings with > or =10 valid leads, mean QTd (QTdMean), QTd in the first satisfactory recording and estimates of variability of QTd were computed and correlated to outcome. RESULTS In the group with QTdMean > or =40 ms (n=277), 10 patients died during the initial 30 days; one patient died in the group with QTdMean <40 ms (n=271) (P=0.07). During follow-up (median 6 months), 19 vs. five patients died in each group (P=0.03). The figures for the triple endpoint death/myocardial infarction/revascularisation were 52 vs. 27 events during the initial 30 days (P=0.018) and 76 vs. 41 events during follow-up (P=0.003). QTd in the first recording did not predict new cardiac events. CONCLUSIONS QTd measured as the mean value of multiple recordings was found to be a powerful marker for cardiac events during follow-up. It was superior to the analysis of QTd in a single ECG. It can be used for the selection of low-risk patients, but was not effective in identifying high-risk patients.
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Affiliation(s)
- Milos Kesek
- Department of Cardiology, Akademiska Hospital, 751 85 Uppsala, Sweden.
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Raj SR, Mitchell LB, Wyse DG, Duff HJ, Sheldon RS, Roach D, Gillis AM. Precordial QT dispersion does not predict inducibility of ventricular tachyarrhythmias at post-revascularization electrophysiologic study. J Interv Card Electrophysiol 2002; 6:25-33. [PMID: 11839880 DOI: 10.1023/a:1014120105686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVES We tested the hypothesis that revascularization would decrease QT interval dispersion and that QT interval dispersion would predict the outcome of the electrophysiologic study following revascularization. BACKGROUND QT interval dispersion may be a measure of the inhomogeneity of ventricular repolarization. The value of the QT interval dispersion for predicting inducibility of ventricular tachyarrhythmias (VT) during electrophysiologic studies after coronary artery revascularization in patients with hemodynamically significant VT is unknown. METHODS AND RESULTS QT interval dispersions were measured from electrocardiograms recorded before and after coronary artery revascularization, but before an electrophysiologic study during the same hospitalization. Fifty-six patients (93% male, 65.1 +/- 9.6 years) were studied. QT interval dispersion decreased significantly following revascularization from 69 +/- 31 ms to 53 +/- 23 ms (p=0.002). Inducibility of VT could not be predicted by the QT interval dispersion following revascularization (50 +/- 30 ms in patients with VT induced vs. 58 +/- 25 ms in patients without VT induced at electrophysiologic study; p=0.2). The change in QT interval dispersion with revascularization (-15 +/- 33 ms vs. -17 +/- 46 ms; p=0.9) could not predict VT inducibility. Actuarial survival after 80 months follow-up was similar in the patients in whom VT was induced (82%) and those patients in whom VT was not induced (83%; p=NS). CONCLUSIONS Coronary artery revascularization decreased QT interval dispersion in patients with hemodynamically significant VT, but QT interval dispersion was not predictive of inducibility of VT at follow-up electrophysiologic study. Actuarial survival was similar in patients in whom VT was induced and patients in whom VT was not induced.
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Affiliation(s)
- Satish R Raj
- Division of Cardiology, Foothills Medical Centre and the Cardiovascular Disease Research Group, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4N1
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Bodí V, Sanchis J, Navarro A, Plancha E, Chorro FJ, Berenguer A, Insa L, Escriche P, Cabadés F, Llácer A. QT dispersion within the first 6 months after an acute myocardial infarction: relationship with systolic function, left ventricular volumes, infarct related artery status and clinical outcome. Int J Cardiol 2001; 80:37-45. [PMID: 11532545 DOI: 10.1016/s0167-5273(01)00452-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION We analysed QT dispersion within the first 6 months postinfarction, its relationship with the main established risk stratifiers and its clinical value. METHODS AND RESULTS In 55 patients with a first Q-wave myocardial infarction the 12-lead electrocardiogram was scanned and digitised for analysis of QT dispersion (QT maximum-QT minimum) at first day (72 [61-96] ms), first week (69 [47-90] ms), first month (67 [46-88] ms) and sixth month (47 [40-74] ms; P<0.0001 vs. first day). Cardiac catheterization was performed at first week and at sixth month; QT dispersion was not related to ejection fraction, left ventricular volumes, infarct related artery status or contractile reserve (improvement of the infarcted area with low-dose dobutamine); no relation was found between QT dispersion decrease from first week to sixth month with regional systolic function improvement. Finally, during a mean follow-up period of 35+/-22 months QT dispersion was not independently related to clinical events. CONCLUSION QT dispersion decreases progressively during the first months after myocardial infarction. These changes should be taken into account to define cut-off values of clinical interest in this phase. This variable does not seem related to the classic prognosis predictors. In a nonselected postinfarction population it has a low clinical value.
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Affiliation(s)
- V Bodí
- Cardiology Unit, Internal Medicine Department, Hospital Comarcal. Avda. Gil de Atroncillo s/n. 12500, Vinaròs, Spain.
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Krishnamoorthy KM. QT dispersion after exercise as an indicator of coronary stenosis. Am J Cardiol 2001; 87:1234. [PMID: 11379600 DOI: 10.1016/s0002-9149(01)01665-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Poulsen PL, Ebbehøj E, Arildsen H, Knudsen ST, Hansen KW, Mølgaard H, Mogensen CE. Increased QTc dispersion is related to blunted circadian blood pressure variation in normoalbuminuric type 1 diabetic patients. Diabetes 2001; 50:837-42. [PMID: 11289050 DOI: 10.2337/diabetes.50.4.837] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A reduced nocturnal fall in blood pressure (BP) and increased QT dispersion both predict an increased risk of cardiovascular events in diabetic as well as nondiabetic subjects. The relationship between these two parameters remains unclear. The role of diabetic autonomic neuropathy in both QT dispersion and circadian BP variation has been proposed, but data have been conflicting. The aim of the present study was to describe associations between QT dispersion and circadian BP variation as well as autonomic function in type 1 diabetic patients. In 106 normoalbuminuric (urinary albumin excretion <20 microg/min) normotensive patients, we performed 24-h ambulatory BP (Spacelabs 90207) and short-term (three times in 5 min) power spectral analysis of RR interval oscillations, as well as cardiovascular reflex tests (deep breathing test, postural heart rate, and BP response). No patient had received (or had earlier received) antihypertensive or other medical treatment apart from insulin. In a resting 12-lead electrocardiogram, the QT interval was measured by the tangent method in all leads with well-defined T-waves. The measurement was made by one observer blinded to other data. The QT interval was corrected for heart rate using Bazett's formula. The QTc dispersion was defined as the difference between the maximum and the minimum QTc interval in any of the 12 leads. When comparing patients with QTc dispersion below and above the median (43 ms), the latter had significantly higher night BP (114/67 vs. 109/62 mmHg, P < 0.003/P < 0.001), whereas day BP was comparable (129/81 vs. 127/79 mmHg). Diurnal BP variation was blunted in the group with QTc dispersion >43 ms with significantly higher night/day ratio, both for systolic (88.8 vs. 86.2%, P < 0.01) and diastolic (83.1 vs. 79.5%, P < 0.01) BP. The association between QTc dispersion and diastolic night BP persisted after controlling for potential confounders such as sex, age, duration of diabetes, urinary albumin excretion, and HbA1c. Power spectral analysis suggested an altered sympathovagal balance in patients with QTc dispersion above the median (ratio of low-frequency/high-frequency power: 1.0 vs. 0.85, P < 0.01). In normoalbuminuric type 1 diabetic patients, increased QTc dispersion is associated with reduced nocturnal fall in BP and an altered sympathovagal balance. This coexistence may be operative in the ability of these parameters to predict cardiovascular events.
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Affiliation(s)
- P L Poulsen
- Medical Department M (Diabetes and Endocrinology), Aarhus Kommunehospital, Denmark.
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Chauhan VS, Tang AS. Dynamic changes of QT interval and QT dispersion in non-Q-wave and Q-wave myocardial infarction. J Electrocardiol 2001; 34:109-17. [PMID: 11320458 DOI: 10.1054/jelc.2001.23116] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
QT interval and QT dispersion both prolong early postinfarction. Non-Q wave (NQMI) and Q-wave myocardial infarction (QMI) differ in the extent of transmural necrosis, which may influence these measures of myocardial repolarization. This study compared dynamic changes in QT interval and QT dispersion early postinfarction between NQMI and QMI. In 40 patients with NQMI and 69 patients with QMI, maximum QTc (QTc(max)) and QT dispersion (QTD) were measured during the first 4 days postinfarction. Infarct size was assessed daily by using the Selvester QRS score. In both infarct types, QTc(max) and QTD were prolonged on day 1 of infarction, peaking over the next 2 days before returning toward baseline by day 4. NQMI patients had significantly longer QTc(max) and QTD by days 2 to 3 when compared with QMI patients. Multivariable linear regression identified "infarct type x QRS score" as the only independent predictor of QTc(max) (R(2) =.32, P <.0001) and QTD (R(2) =.19, P <.0001) on day 2. In conclusion, dynamic changes of QTc(max) and QTD occur in both infarct types. Large NQMI is associated with greater prolongation of QTc(max) and QTD, which may be due to greater M cell uncoupling and exposure when compared with QMI.
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Affiliation(s)
- V S Chauhan
- Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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Ali A, Malik FS, Dinshaw H, Jenkins JS, Collins T, White CJ, Ramee SR. Reduction in QT dispersion with rheolytic thrombectomy in acute myocardial infarction: evidence of electrial stability with reperfusion therapy. Catheter Cardiovasc Interv 2001; 52:56-8. [PMID: 11146524 DOI: 10.1002/1522-726x(200101)52:1<56::aid-ccd1014>3.0.co;2-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An increase in QT dispersion (QTd) is associated with myocardial ischemia and may serve as a marker of ischemia and ventricular arrhythmia. We studied the effect of early reperfusion with rheolytic thrombectomy using an angiojet catheter (Possis, Minneapolis, MN) on QTd in 12 patients who presented with acute myocardial infarction. QTd and QT dispersion, rate-corrected for RR interval, were significantly reduced from 57 +/- 16 and 68 +/- 13 msec before reperfusion to 34 +/- 16 and 44 +/- 19 msec after reperfusion respectively (mean +/- SD; P < 0.002 and P < 0.0008, respectively). Successful reperfusion with rheolytic thrombectomy reduces QTd and may confer electrical stability to vulnerable myocardium. Reduction in indexes of repolarization inhomogeneity with reperfusion may serve as a noninvasive marker of coronary patency.
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Affiliation(s)
- A Ali
- Department of Cardiology, St. John Hospital, and Ochsner Medical Institutions, New Orleans, Louisiana, USA.
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35
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Bonnemeier H, Hartmann F, Wiegand UK, Bode F, Katus HA, Richardt G. Course and prognostic implications of QT interval and QT interval variability after primary coronary angioplasty in acute myocardial infarction. J Am Coll Cardiol 2001; 37:44-50. [PMID: 11153771 DOI: 10.1016/s0735-1097(00)01061-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to determine the influence of early reperfusion on the course of QT interval and QT interval variability in patients undergoing primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) and its prognostic implications on major arrhythmic events during one-year follow-up. BACKGROUND Although early coronary artery recanalization by primary angioplasty is an established therapy in AMI, a substantial number of patients is still threatened by malignant arrhythmias even after early successful reperfusion, which may be caused by an inhomogeneity of ventricular repolarization despite reperfusion. METHOD Temporal fluctuations of ventricular repolarization were studied prospectively in 97 consecutive patients with a first AMI by measurements of QT interval and QT interval variability during and after successful PTCA (Thrombolysis in Myocardial Infarction flow grades 2 and 3). Continuous beat-to-beat QT interval measurement was performed from 24-h Holter monitoring, which was initiated at admission before PTCA. RESULTS Reperfusion caused a significant continuous increase of mean RR interval (738 +/- 98 to 808.5 +/- 121 ms; p < 0.001) and a significant decrease of parameters of QT interval (QTc: 440 +/- 32 to 416.5 +/- 37ms; p < 0.001) and QT interval variability (QTcSD: 27.5 +/- 3 to 24.9 +/- 6 ms; p < 0.001) in the majority of patients. However, in patients with major arrhythmic events at the one-year follow-up (sudden cardiac death, ventricular fibrillation or sustained ventricular tachycardia, n = 15), parameters of QT interval remained unaltered after successful reperfusion (QTc: 447.3 +/- 41 to 432.9 +/- 45 ms, p = NS; QTcSD: 35.1 +/- 13.4 to 29.0 +/- 9.1 ms, p = NS). CONCLUSIONS Reduction of QT interval and QT interval variability after timely reperfusion of the infarct-related artery may be a previously unreported beneficial mechanism of primary PTCA in AMI, indicating successful reperfusion.
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Affiliation(s)
- H Bonnemeier
- Medizinische Klinik II, Medizinische Universität zu Lübeck, Germany.
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36
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Aufderheide TP, Xue Q, Dhala AA, Reddy S, Kuhn EM. The added diagnostic value of automated QT-dispersion measurements and automated ST-segment deviations in the electrocardiographic diagnosis of acute cardiac ischemia. J Electrocardiol 2000; 33:329-39. [PMID: 11099358 DOI: 10.1054/jelc.2000.18358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to determine the added value of automated QT dispersion and ST-segment measurements to physician interpretation of 12-lead electrocardiograms (ECGs) in patients with chest pain. To date, poor reproducibility of manual measurements and lack of shown added value have limited the clinical use of QT dispersion. Twelve-lead ECGs (n = 1,161) from the Milwaukee Prehospital Chest Pain Database were independently classified by 2 physicians into 3 groups (acute myocardial infarction (AMI), acute cardiac ischemia (ACI), or nonischemic), and their consensus was obtained. QT-end and QT-peak dispersions were measured by a computerized system. The computer also identified ST-segment deviations. Sensitivity, specificity, and positive predictive values (PPVs) and negative predictive values (NPV) for AMI and ACI were evaluated independently and in combinations. For AMI, physicians' consensus classification was remarkably good (sensitivity, 48%, specificity, 99%). Independent classification by QT-end and QT-peak dispersions or ST deviations was not superior to the physicians' consensus. Optimal classification occurred by combining automated QT-end dispersion and ST deviations with physicians' consensus. This combination increased sensitivity for the diagnoses of AMI by 35% (65% vs 48%, P < .001) and ACI by 55% (62% vs 40%, P < .001) compared with physicians' consensus, while maintaining comparable specificity. This study supports a potential clinical role for automated QT dispersion when combined with other diagnostic methods for detecting AMI and ACI.
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Abstract
Abnormalities in the QT interval can be divided into 3 types, prolongation of the QT interval, increases in the dispersion of the QT interval, and abnormalities in the heart rate dependent behavior of the QT interval. Abnormalities may be found in short or long-term recordings. Prolongation of the QT interval may reflect factors associated with an adverse prognosis in coronary disease and may in itself be arrhythmogenic. The data to date suggest that there is an association between adverse prognosis and QT interval prolongation in coronary disease, both before and after acute myocardial infarctions. This relationship is weak, however, and is not clinically useful. The data as to whether increased QT dispersion postmyocardial infarction relates to adverse prognosis is weak because there is no convincing evidence yet. If there is a relationship it is weak. Abnormalities in the rate dependent behavior of the QT interval are widely found, but as no large scale prospective study with mortality as an endpoint has yet been undertaken the significance of rate dependent abnormalities is uncertain. The widespread introduction of beat-to-beat QT analysis of 24 hour Holter tapes may take QT intervalology into the realm of clinical practice.
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Affiliation(s)
- P Davey
- Nuffield Department of Medicine, John Radcliffe Hospital, Oxford, United Kingdom
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Kanaya S, Nishiyama Y, Maeda H, Tokuda K, Tanaka M, Hirano K, Koga Y. Improvement in corrected QT dispersion by physical training and percutaneous transluminal coronary angioplasty in patients with recent myocardial infarction. JAPANESE CIRCULATION JOURNAL 2000; 64:165-9. [PMID: 10732846 DOI: 10.1253/jcj.64.165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of the present study was to assess whether physical training and percutaneous transluminal coronary angioplasty (PTCA) improve the corrected QT (QTc) dispersion in patients with recent myocardial infarction (MI). Twenty-four patients with recent MI were allocated to one of 3 groups: training (n = 8), PTCA (n = 7) or controls (n = 9). Physical training as well as PTCA decreased QTc dispersion, whereas QTc dispersion increased in the control group. Changes in QTc dispersion after physical training or PTCA were inversely correlated with exercise-induced ST depression at the baseline test. These observations suggest that physical training, as well as PTCA, could improve QTc dispersion and electrical instability in patients with recent MI, possibly due to improvement of myocardial ischemia.
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Affiliation(s)
- S Kanaya
- Division of Cardiology, Kurume University Medical Center, Japan
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Abstract
Over the last 5 to 8 years, numerous clinical studies have been conducted evaluating the effects of coronary ischemia on disparity of ventricular repolarization (VR) as assessed by determination of QT dispersion from the surface electrocardiogram. From findings in patients with acute myocardial infarction, stable coronary disease, and vasospastic angina there is convincing evidence that acute coronary ischemia augments inhomogeneity in VR. In some studies, this was associated with the occurrence of ventricular arrhythmias. In general, therefore, these clinical observations confirm previous experimental work. One should keep in mind, however, various problems inherent to the current technology used to determine QT dispersion from the surface electrocardiogram. Whereas some of these technological limitations can be overcome in carefully designed and conducted clinical studies, these methodological shortcomings have so far precluded the routine use of QT dispersion in taking care of patients with acute coronary syndromes. It remains to be seen whether further refinements in technology will enable clinicians to incorporate assessment of disparity of VR in daily practice in an attempt to further improve care of patients with acute coronary syndromes.
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Affiliation(s)
- S H Hohnloser
- Department of Cardiology, J. W. Goethe University, Frankfurt, Germany
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Göldeli O, Kirimli O, Aslan O, Badak O, Güneri S. Value of QT dispersion in diagnosis of restenosis after intracoronary stent implantation. Int J Cardiol 1999; 72:13-7. [PMID: 10636628 DOI: 10.1016/s0167-5273(99)00126-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We studied the ECGs of patients with single vessel disease before and after (long term) coronary stent implantation. The interlead variability of the QT interval, known as QT dispersion (QTd), is believed to reflect the regional variations in ventricular repolarization and, thus, may provide an indirect marker of arrhythmogenicity. There are no reliable noninvasive markers of significant restenosis after stent implantation. The effect of coronary revascularization on QTd in patients who underwent coronary stenting has not been investigated extensively. The aim of this study was to evaluate the value of QTd in predicting restenosis after intracoronary stent implantation. QTd with 12 lead surface ECG was measured in 48 patients (21 with restenosis and 27 without restenosis; 33 male; mean age, 58+/-10.8 years) before the procedure and after long-term follow-up (mean, 6.8+/-3.2 months). All patients had coronary angiographic control at the end of the follow-up period. QTd (as the difference between the maximum and minimum QT interval measured from 12 lead ECG) and rate-corrected QT (QTcd) were evaluated at rest. In 27 patients without restenosis, QTd and QTcd decreased from 58+/-14.4 and 62.8+/-20.4 ms to 26.3+/-9.2 and 29.6+/-10.6 ms in the long term follow-up, respectively (P<0.001). However, in 21 patients with restenosis, there was no significant change in QTd and QTcd intervals and they were still increased at the end of the long-term follow-up (P>0.05). In conclusion, increased QT interval dispersion may be an inexpensive and simple marker of restenosis after intracoronary stent implantation.
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Affiliation(s)
- O Göldeli
- Department of Cardiology, Dokuz Eylül University Medical Faculty, Izmir, Turkey
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Arildsen H, May O, Christiansen EH, Damsgaard EM. Increased QT dispersion in patients with insulin-dependent diabetes mellitus. Int J Cardiol 1999; 71:235-42. [PMID: 10636529 DOI: 10.1016/s0167-5273(99)00140-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIM To compare the QT dispersion in unselected patients with insulin-dependent diabetes mellitus to non-diabetic control subjects and to assess the association between the QT dispersion and cardiac autonomic neuropathy, ischaemic heart disease, blood pressure level and nephropathy. METHODS 42 patients with insulin-dependent diabetes mellitus and 80 control subjects aged 40-57 years participated. The QT interval was measured in a resting 12-lead electrocardiogram (ECG) and the QT dispersion defined as the difference between the maximum and minimum QT interval. Bazett's formula was used to correct for heart rate (QTc). The degree of cardiac autonomic neuropathy was assessed by five function tests and ischaemic heart disease was defined by a previous myocardial infarction, ECG abnormalities or a positive exercise test. RESULTS Compared to control subjects, diabetic patients had a longer QTc interval (433 vs. 416 ms; P=0.002) and a higher QT dispersion (36 vs. 30 ms; P=0.02). In the diabetic group, the QTc interval was prolonged in patients with autonomic neuropathy (449 vs. 420 ms; P=0.007) and the QT dispersion was increased in patients with ischaemic heart disease (51 vs. 33 ms; P=0.004). No association was found to urinary albumin excretion rate or blood pressure. CONCLUSION The QT dispersion as well as the QTc interval is increased in patients with insulin-dependent diabetes mellitus. The association between QT dispersion and ischaemic heart disease indicates that abnormalities in cardiac repolarisation may be caused by complications to diabetes rather than diabetes in itself.
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Affiliation(s)
- H Arildsen
- Department of Cardiology (Research Unit), Skejby University Hospital, Aarhus N, Denmark.
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Tygesen H, Wettervik C, Claes G, Drott C, Emanuelsson H, Solem J, Lomsky M, Rådberg G, Wennerblom B. Long-term effect of endoscopic transthoracic sympathicotomy on heart rate variability and QT dispersion in severe angina pectoris. Int J Cardiol 1999; 70:283-92. [PMID: 10501343 DOI: 10.1016/s0167-5273(99)00101-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
UNLABELLED We evaluated short and long-term effects on QT dispersion and autonomic balance after endoscopic transthoracic sympathicotomy (ETS). Heart rate variability (HRV) reflects autonomic balance of the heart. QT dispersion is a marker of cardiac electrical instability in patients with ischemic heart disease. Holter recordings for 24 h and a twelve-lead ECG were made prior to, 1 month, 1 year and 2 years after ETS. HRV was analysed in time domain and spectral analysis was performed during controlled respiration in supine position and during head up tilt. Dispersion of QT time and QTc were calculated. Of 88 patients, 62 (60) were eligible for HRV (QT-dispersion) analysis after 1 month, 39 (38) patients after 1 year and 23 (24) patients after 2 years. The HRV analysis showed a significant change of indices reflecting sympatho-vagal balance indicating significantly reduced sympathetic (LF) and increased vagal (HF, rMSSD) tone. These changes still persisted after 2 years. Global HRV increased over time with significant elevation of SDANN after 2 years. QT dispersion was significantly reduced 1 month after surgery and the dispersion was further diminished 2 years later. CONCLUSION ETS changed HRV and QT dispersion which could imply reduced risk for malignant arrhythmias and death after ETS.
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Affiliation(s)
- H Tygesen
- Department of Medicine, Borås County Hospital, Sweden.
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Hailer B, Leeuwen PV, Lange S, Wehr M. Spatial distribution of QT dispersion measured by magnetocardiography under stress in coronary artery disease. J Electrocardiol 1999. [DOI: 10.1016/s0022-0736(99)90103-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Hailer B, Leeuwen P, Lange S, Pilath M, Wehr M. Coronary Artery Disease May Alter the Spatial Dispersion of the QT Interval at Rest. Ann Noninvasive Electrocardiol 1999. [DOI: 10.1111/j.1542-474x.1999.tb00210.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Tamura A, Nagase K, Mikuriya Y, Nasu M. Relation of QT dispersion to infarct size and left ventricular wall motion in anterior wall acute myocardial infarction. Am J Cardiol 1999; 83:1423-6. [PMID: 10335755 DOI: 10.1016/s0002-9149(99)00118-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previous studies have shown that QT dispersion increases during acute myocardial infarction (AMI). However, the relation of QT dispersion to infarct size and left ventricular (LV) function in AMI has not yet been fully clarified. Accordingly, this study was conducted to elucidate this relation at 1 month after anterior wall AMI. We examined 94 patients with first anterior wall AMI (< or = 6 hours) who underwent coronary arteriography at admission, 1 month, and 6 months after AMI, and left ventriculography at 1 and 6 months after AMI. Mean QT dispersion on the chronic phase (about 1 month after AMI) electrocardiogram was 79 +/- 33 ms. There were no significant correlations between QT dispersion and peak creatine phosphokinase levels, LV ejection fraction, and regional wall motion in the infarct region at 1 month after AMI (r = 0.06, p = 0.57; r = 0.11, p = 0.29; r = -0.05, p = 0.63, respectively). In conclusion, the findings of this study suggest that QT dispersion on the resting electrocardiogram at 1 month after anterior wall AMI is unrelated to infarct size estimated by the peak creatine phosphokinase level and the degree of LV dysfunction.
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Affiliation(s)
- A Tamura
- Second Department of Internal Medicine, Oita Medical University, Hasama, Japan
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Choi KJ, Lee CW, Kang DH, Song JK, Kim JJ, Park SW, Park SJ, Park CH, Kim YH. Change of QT Dispersion After PTCA in Angina Patients. Ann Noninvasive Electrocardiol 1999. [DOI: 10.1111/j.1542-474x.1999.tb00059.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Dispersión del intervalo QT en pacientes ingresados por insuficiencia cardíaca. Determinantes y valor pronóstico. Rev Esp Cardiol 1999. [DOI: 10.1016/s0300-8932(99)74972-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yu GL, Cheng IR, Zhao SP, Zhuang HP, Cai XY. Clinical significance of QT dispersion after exercise in patients with previous myocardial infarction. Int J Cardiol 1998; 65:255-60. [PMID: 9740482 DOI: 10.1016/s0167-5273(98)00120-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To evaluate the clinical significance of QT dispersion after exercise in patients with previous myocardial infarction, QT dispersion (QTd) and corrected QTd (QTcd) were assessed with standard 12 leads electrocardiogram in 90 patients with previous myocardial infarction and 30 healthy persons before and 3 min after a treadmill exercise test. In addition, 24 h ambulatory electrocardiogram and echo-cardiography were examined in all the subjects studied. Patients were followed up for 37.25 +/- 10.71 months. The results showed that there were no significant differences in the QTd and QTcd between the patients and the controls before exercise (36.11 +/- 13.42 ms versus 34.81 +/- 12.32 ms, P>0.05, 41.22 +/- 13.49 as versus 39.91 +/- 13.56 ms, P>0.05). Compared with those before exercise, QTd and QTcd were significantly increased in the patients 3 min after the exercise test (36.11 +/- 13.42 ms versus 47.20 +/- 14.41 ms, P<0.01, 41.22 +/- 13.49 ms versus 59.57 +/- 18.90 ms, P<0.01), but not in the controls (34.81 +/- 12.32 ms versus 38.76 +/- 12.09 ms, P>0.05, 39.91 +/- 13.56 ms versus 43.27 +/- 17.77 ms, P>0.05). The incidences of abnormal contraction of the left ventricular wall, aneurysms, NYHA III class, >III class of Lown's ventricular arrhythmia classification and cardiac sudden death were significantly higher in group A with QTcd >50 ms than that of group B with QTcd <50 ms (P<0.01). These findings indicate that the increased QT dispersion after exercise in 12 standard leads electrocardiogram might be associated with high incidences of sudden cardiac death and ventricular arrhythmia in the patients with previous myocardial infarction.
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Affiliation(s)
- G L Yu
- Department of Geriatric Cardiology, Xiang Ya Hospital, Hunan Medical University, Changsha, PR China
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