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Bunya N, Sawamoto K, Uemura S, Kyan R, Inoue H, Nishida J, Kouzu H, Kokubu N, Miura T, Narimatsu E. Cardiac arrest caused by sibutramine obtained over the Internet: a case of a young woman without pre-existing cardiovascular disease successfully resuscitated using extracorporeal membrane oxygenation. Acute Med Surg 2017; 4:334-337. [PMID: 29123885 PMCID: PMC5674461 DOI: 10.1002/ams2.275] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/30/2017] [Indexed: 01/13/2023] Open
Abstract
Case Sibutramine is a weight loss agent that was withdrawn from the market in the USA and European Union because it increases adverse events in patients with cardiovascular diseases. However, non‐prescription weight loss pills containing sibutramine can be still easily purchased over the Internet. A 21‐year‐old woman without history of cardiovascular diseases developed cardiac arrest. She was a user of a weight loss pills, containing sibutramine and hypokalemia‐inducing agents, imported from Thailand over the Internet. Outcome She was successfully resuscitated without any neurological deficits by using extracorporeal membrane oxygenation for refractory ventricular fibrillation. Conclusion This case indicates that sibutramine can cause cardiac arrest even in subjects without pre‐existing cardiovascular disease when combined with agents that promote QT prolongation.
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Affiliation(s)
- Naofumi Bunya
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
| | - Keigo Sawamoto
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
| | - Shuji Uemura
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
| | - Ryoko Kyan
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
| | - Hiroyuki Inoue
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
| | - Junichi Nishida
- Department of Cardiovascular, Renal and Metabolic Medicine Sapporo Medical University Hokkaido Japan
| | - Hidemichi Kouzu
- Department of Cardiovascular, Renal and Metabolic Medicine Sapporo Medical University Hokkaido Japan
| | - Nobuaki Kokubu
- Department of Cardiovascular, Renal and Metabolic Medicine Sapporo Medical University Hokkaido Japan
| | - Tetsuji Miura
- Department of Cardiovascular, Renal and Metabolic Medicine Sapporo Medical University Hokkaido Japan
| | - Eichi Narimatsu
- Department of Emergency Medicine Sapporo Medical University Hokkaido Japan
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Hurtado-de-Mendoza D, Corona-Villalobos CP, Pozios I, Gonzales J, Soleimanifard Y, Sivalokanathan S, Montoya-Cerrillo D, Vakrou S, Kamel I, Mormontoy-Laurel W, Dolores-Cerna K, Suarez J, Perez-Melo S, Bluemke DA, Abraham TP, Zimmerman SL, Abraham MR. Diffuse interstitial fibrosis assessed by cardiac magnetic resonance is associated with dispersion of ventricular repolarization in patients with hypertrophic cardiomyopathy. J Arrhythm 2016; 33:201-207. [PMID: 28607615 PMCID: PMC5459419 DOI: 10.1016/j.joa.2016.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 10/02/2016] [Accepted: 10/06/2016] [Indexed: 11/18/2022] Open
Abstract
Background Hypertrophic cardiomyopathy (HCM) is characterized by myocyte hypertrophy, disarray, fibrosis, and increased risk for ventricular arrhythmias. Increased QT dispersion has been reported in patients with HCM, but the underlying mechanisms have not been completely elucidated. In this study, we examined the relationship between diffuse interstitial fibrosis, replacement fibrosis, QTc dispersion and ventricular arrhythmias in patients with HCM. We hypothesized that fibrosis would slow impulse propagation and increase dispersion of ventricular repolarization, resulting in increased QTc dispersion on surface electrocardiogram (ECG) and ventricular arrhythmias. Methods ECG and cardiac magnetic resonance (CMR) image analyses were performed retrospectively in 112 patients with a clinical diagnosis of HCM. Replacement fibrosis was assessed by measuring late gadolinium (Gd) enhancement (LGE), using a semi-automated threshold technique. Diffuse interstitial fibrosis was assessed by measuring T1 relaxation times after Gd administration, using the Look–Locker sequence. QTc dispersion was measured digitally in the septal/anterior (V1–V4), inferior (II, III, and aVF), and lateral (I, aVL, V5, and V6) lead groups on surface ECG. Results All patients had evidence of asymmetric septal hypertrophy. LGE was evident in 70 (63%) patients; the median T1 relaxation time was 411±38 ms. An inverse correlation was observed between T1 relaxation time and QTc dispersion in leads V1–V4 (p<0.001). Patients with HCM who developed sustained ventricular tachycardia had slightly higher probability of increased QTc dispersion in leads V1–V4 (odds ratio, 1.011 [1.004–1.0178, p=0.003). We found no correlation between presence and percentage of LGE and QTc dispersion. Conclusion Diffuse interstitial fibrosis is associated with increased dispersion of ventricular repolarization in leads, reflecting electrical activity in the hypertrophied septum. Interstitial fibrosis combined with ion channel/gap junction remodeling in the septum could lead to inhomogeneity of ventricular refractoriness, resulting in increased QTc dispersion in leads V1–V4.
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Affiliation(s)
- David Hurtado-de-Mendoza
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA.,Cayetano Heredia University School of Medicine, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Celia P Corona-Villalobos
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, 600 North Wolfe Street, MRI 110B, Baltimore, MD 21287, USA
| | - Iraklis Pozios
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
| | - Jorge Gonzales
- Cayetano Heredia University School of Medicine, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Yalda Soleimanifard
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
| | - Sanjay Sivalokanathan
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
| | - Diego Montoya-Cerrillo
- Cayetano Heredia University School of Medicine, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Styliani Vakrou
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
| | - Ihab Kamel
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, 600 North Wolfe Street, MRI 110B, Baltimore, MD 21287, USA
| | - Wilfredo Mormontoy-Laurel
- Faculty of Sciences, Department of Statistics, Demography, Humanities and Social Sciences, Cayetano Heredia University, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Ketty Dolores-Cerna
- Faculty of Sciences, Department of Statistics, Demography, Humanities and Social Sciences, Cayetano Heredia University, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Jacsel Suarez
- Cayetano Heredia University School of Medicine, 430 Honorio Delgado Ave, Lima, LIMA 31, Peru
| | - Sergio Perez-Melo
- Department of Mathematics and Statistics, Florida International University, S.W. 8th Street, DM 430, Miami, FL 33199, USA
| | - David A Bluemke
- Department of Radiology and Imaging Sciences, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 10 Center Drive, Rm 10/1C355, Bethesda, MD 20892, USA
| | - Theodore P Abraham
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
| | - Stefan L Zimmerman
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, 600 North Wolfe Street, MRI 110B, Baltimore, MD 21287, USA
| | - M Roselle Abraham
- Hypertrophic Cardiomyopathy Center of Excellence, Department of Medicine, Johns Hopkins University School of Medicine, 720 Rutland Ave, Ross 871, Baltimore, MD 21205, USA
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3
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Öner T, Özdemir R, Hazan F, Karadeniz C, Doksoz Ö, Yilmazer MM, Meşe T, Tavli V. The association between brain natriuretic peptide and tissue Doppler parameters in children with hypertrophic cardiomyopathy. Bosn J Basic Med Sci 2016; 16:58-63. [PMID: 26773184 DOI: 10.17305/bjbms.2016.670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/20/2015] [Accepted: 09/21/2015] [Indexed: 01/20/2023] Open
Abstract
In this study, we investigated the association between brain natriuretic peptide (BNP) levels and tissue Doppler imaging measurements and also screening for deadly mutations in patients with hypertrophic cardiomyopathy (HCM). We enrolled 20 patients diagnosed with HCM (age:10.7±5 years (1-17), 85% male, weight:42.25±23.10 kg, height:141.80±32.45 cm) and 20 age, gender and body weight-matched control subjects. We performed electrocardiography, transthoracic echocardiography, and tissue Doppler echocardiography in each group, as well as genetic tests (for Arg403Gln, Arg453Cys, Arg719Trp and Arg719Gln mutations in MYH7 Exons 13, 14, 19) and BNP in the patients. The patients were divided into two groups according to the presence (Group 1) or absence (Group 2) of left ventricular (LV) outflow tract obstruction. QTc dispersion and the LV ejection fraction and left atrial (LA) volume index were increased in Group 1. The LA volume index and the mitral and septal E/Ea ratio and septum Z-score were increased while the mitral lateral annulus and septal annulus Ea wave velocities and the mitral and tricuspid E/A ratio were decreased in patients with high levels of BNP compared to those with normal BNP levels. There were no mutations that are associated with increased risk of sudden death found in patients included in this study. In the light of our data, we conclude that such parameters BNP levels above the 98 pg/mL, septal thickness Z-score ˃6, and higher mitral and septal E/Ea ratios can be used for management of patients with HCM according to life-threatening conditions.
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Affiliation(s)
- Taliha Öner
- Izmir Dr. Behçet Uz Children's Hopsital Department of Pediatric Cardiology, Izmir/Turkey.
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4
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Magrì D, Piccirillo G, Ricotta A, De Cecco CN, Mastromarino V, Serdoz A, Muscogiuri G, Gregori M, Casenghi M, Cauti FM, Oliviero G, Musumeci MB, Maruotti A, Autore C. Spatial QT Dispersion Predicts Nonsustained Ventricular Tachycardia and Correlates with Confined Systodiastolic Dysfunction in Hypertrophic Cardiomyopathy. Cardiology 2015; 131:122-9. [DOI: 10.1159/000377622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/28/2015] [Indexed: 11/19/2022]
Abstract
Objectives: An increased dispersion of myocardial repolarization represents one of the mechanisms underlying the arrhythmic risk in hypertrophic cardiomyopathy (HCM). We investigated spatial myocardial repolarization dispersion indices in HCM patients with nonsustained ventricular tachycardia (NSVT) and, contextually, their main clinical determinants. Methods: Fifty-two well-matched HCM outpatients were categorized into two groups according to the presence or the absence of NSVT at 24-hour Holter electrocardiogram (ECG) monitoring. Each patient underwent a clinical examination, including Doppler echocardiogram integrated with tissue Doppler imaging, cardiac magnetic resonance, and 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QTe), Q-Tpeak, Tpeak-Tend (TpTe), J-Tpeak, and J-Tend. Results: The NSVT group showed only QTe dispersion and TpTe dispersion values to be significantly higher than their counterparts. NSVT occurrence was independently predicted by late gadolinium enhancement presence (p = 0.021) and QTe Bazett dispersion (p = 0.030), the latter strongly associated with the myocardial performance index (MPI) obtained at the basal segment of the interventricular septum (p = 0.0004). Conclusion: Our data support QTe dispersion as an easy and noninvasive tool for identifying HCM patients with NSVT propensity. The strong relationship between QTe dispersion and MPI allows us to hypothesize an intriguing link between electrical instability and confined myocardial areas of systodiastolic dysfunction.
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Badran HM, Elnoamany MF, Soltan G, Ezat M, Elsedi M, Abdelfatah RA, Yacoub M. Relationship of mechanical dyssynchrony to QT interval prolongation in hypertrophic cardiomyopathy. Eur Heart J Cardiovasc Imaging 2011; 13:423-32. [DOI: 10.1093/ejechocard/jer290] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Kosar F, Ates F, Sahin I, Karincaoglu M, Yildirim B. QT interval analysis in patients with chronic liver disease: a prospective study. Angiology 2007; 58:218-24. [PMID: 17495272 DOI: 10.1177/0003319707300368] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In previous studies, it has been shown that QT interval prolongation is related to an increased mortality rate in chronic liver disease (CLD). But QT dispersion (QTd) and its clinical significance in CLD has not been well studied. The objectives of this study were to investigate the relation between QTd and severity of the disease and determine its prognostic value in cirrhotic patients. Thirty-three consecutive patients with cirrhosis and 35 sex- and age-matched healthy subjects were studied. QT intervals and QT dispersions were measured on admission, and all intervals were corrected for heart rate according to Bazett's formula. The authors analyzed the potential relationship between QT parameters and the disease severity according to Child-Pugh classification and compared these values between survivors and nonsurvivors after a 3-year follow-up. Child-Pugh classification is used to assess liver function in cirrhosis. Corrected QT (QTc) prolongations were found in 32% of patients with cirrhosis and 5.7% of the healthy controls (p <0.001). The prevalence of increased (>70 ms) corrected QT dispersion (QTcd) was 45% in patients with cirrhosis. According to Child-Pugh criteria: QTd, maximum QT interval (QTmax), corrected QTmax (QTcmax), and QTcd in class C were significantly higher than those of class A and B (p <0.05, for all comparison). But there was no significant difference between class A and B in QTmax, QTcmax, QTd, and QTcd. There were 10 (30%) deaths from all causes during 3-year follow-up in the study group. Cox regression analysis showed that QTd and QTcd were better mortality indicators than QTmax and QTcmax, and Child's classification was the best predictor for mortality among all variables. In conclusion, QT dispersion and corrected QT dispersion parameters were better mortality indicators than other QT interval parameters and also may give additional prognostic information in patients with chronic liver disease.
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Affiliation(s)
- Feridun Kosar
- Department of Cardiology, Inonu University, Faculty of Medicine, Malatya, Turkey.
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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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8
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Alonso JL, Martínez P, Vallverdú M, Cygankiewicz I, Pitzalis MV, Bayés Genís A, Cinca J, Rizzon P, Caminal P, Zareba W, Bayés de Luna A. Dynamics of ventricular repolarization in patients with dilated cardiomyopathy versus healthy subjects. Ann Noninvasive Electrocardiol 2005; 10:121-8. [PMID: 15842422 PMCID: PMC6932195 DOI: 10.1111/j.1542-474x.2005.05583.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Patients with impaired left ventricular function have a high risk of developing ventricular arrhythmias and sudden death. Among different markers of risk, the prolongation and regional heterogeneity of repolarization are of increasing interest. However, there are limited data regarding feasibility of analyzing repolarization parameters and their dynamics in 24-hour Holter ECG recordings. METHODS Dynamic behavior of repolarization parameters was studied with a new automatic algorithm in digital 24-hour Holter recordings of 60 healthy subjects and 55 patients with idiopathic dilated cardiomyopathy (IDC). Repolarization parameters included the mean value of QT and QTc durations, QT dispersion, and peaks of QT duration and QT dispersion above prespecified thresholds. RESULTS In comparison to healthy subjects, patients with IDC had lower heart rate variability, longer mean QT and QTc durations, higher content of QTc peaks >500 ms, longer QT dispersion and its standard deviation, and a higher content of peaks >100 ms of QT dispersion (P < 0.01 for all comparisons). These repolarization parameters were significantly higher in IDC patients after adjustment for age, sex, and heart rate variability. The parameters of repolarization dynamics correlated with SDNN in healthy subjects but not in dilated cardiomyopathy patients. CONCLUSIONS The automatic assessment of repolarization parameters in 24-hour digital ECG recordings is feasible and differentiates dilated cardiomyopathy patients from healthy subjects. Patients with dilated cardiomyopathy have increased QT duration, QT dispersion, and increased variability of QT dispersion reflecting variations in T-wave morphology, the factors which might predispose them to the development of arrhythmic events.
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9
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Sanbe A, James J, Tuzcu V, Nas S, Martin L, Gulick J, Osinska H, Sakthivel S, Klevitsky R, Ginsburg KS, Bers DM, Zinman B, Lakatta EG, Robbins J. Transgenic rabbit model for human troponin I-based hypertrophic cardiomyopathy. Circulation 2005; 111:2330-8. [PMID: 15867176 PMCID: PMC1314982 DOI: 10.1161/01.cir.0000164234.24957.75] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Transgenic and gene-targeted models have focused on the mouse. Fundamental differences between the mouse and human exist in Ca2+ handling during contraction/relaxation and in alterations in Ca2+ flux during heart failure, with the rabbit more accurately reflecting the human system. METHODS AND RESULTS Cardiac troponin I (cTnI) mutations can cause familial hypertrophic cardiomyopathy. An inhibitory domain mutation, arginine146-->glycine (cTnI(146Gly)), was modeled with the use of transgenic expression in the rabbit ventricle. cTnI(146Gly) levels >40% of total cTnI were perinatally lethal, whereas replacement levels of 15% to 25% were well tolerated. cTnI(146Gly) expression led to a leftward shift in the force-pCa2+ curves with cardiomyocyte disarray, fibrosis, and altered connexin43 organization. In isolated cTnI(146Gly) myocytes, twitch relaxation amplitudes were smaller than in normal cells, but [Ca]i transients and sarcoplasmic reticulum Ca2+ load were not different. Detrended fluctuation analysis of the QT(max) intervals was used to evaluate the cardiac repolarization phase and showed a significantly higher scaling exponent in the transgenic animals. CONCLUSIONS Expression of modest amounts of cTnI(146Gly) led to subtle defects without severely affecting cardiac function. Aberrant connexin organization, subtle morphological deficits, and an altered fractal pattern of the repolarization phase of transgenic rabbits, in the absence of entropy or other ECG abnormalities, may indicate an early developing pathology before the onset of more obvious repolarization abnormalities or major alterations in cardiac mechanics.
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MESH Headings
- Animals
- Animals, Genetically Modified
- Calcium/metabolism
- Cardiomegaly
- Cardiomyopathy, Hypertrophic, Familial/genetics
- Cardiomyopathy, Hypertrophic, Familial/pathology
- Cardiomyopathy, Hypertrophic, Familial/physiopathology
- Connexin 43/metabolism
- Disease Models, Animal
- Electrocardiography
- Fibrosis
- Heart Function Tests
- Heart Ventricles/metabolism
- Humans
- Mutation, Missense
- Myocytes, Cardiac/pathology
- Phenotype
- Rabbits
- Transgenes
- Troponin I/genetics
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Jeffrey Robbins
- Correspondence to: Jeffrey Robbins, Division of Molecular Cardiovascular Biology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039. Tel.: 513-636-8098; Fax: 513-636-3852;
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Voss F, Becker R, Bauer A, Kraft P, Senges-Becker JC, Katus HA, Schoels W. Are QT measurements on body surface ECG indicative of ventricular refractory patterns? Basic Res Cardiol 2004; 100:22-7. [PMID: 15490201 DOI: 10.1007/s00395-004-0493-9] [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] [Received: 06/07/2004] [Revised: 09/03/2004] [Accepted: 09/27/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Increased dispersion (DISP) of refractoriness (ERP) facilitates the induction of malignant ventricular arrhythmias. Accordingly, QT DISP on surface ECG, supposedly reflecting ERP DISP, has been proposed as a noninvasive marker for risk stratification. However, a comparative analysis of local ERPs and QT measurements is not available so far. METHODS AND RESULTS In 19 healthy dogs, standard 12 lead surface ECGs were recorded to measure QT and RR intervals. Based on these measurements, corrected QT intervals (QTc, Bazett formula) and DISP (maximum difference) of both QT and QTc intervals (QT-DISP and QTc-DISP, respectively) were calculated. Subsequently, 60 custom-made needle electrodes (12 mm long, 4 bipolar electrodes per needle, interelectrode distance 2.5 mm) were inserted into the left (LV) and right ventricle (RV). At each bipole of 14 randomly selected needle electrodes (8 LV, 6 RV) local ERPs were determined (extrastimulus technique, basic cycle length 1000 ms). Interventricular DISP of ERP (LV-RV-DISP) was defined as the difference between the longest and shortest ERP within both ventricles. Respective values were calculated for each ventricle (LV-DISP; RV-DISP). Scatter plots and correlation analysis did not reveal a significant correlation between QT, QTc, QT-DISP, QTc-DISP and any of the ERP measurements or calculations. Although not statistically significant, the closest correlation was found between QTc and mean ERP and between QTc-DISP and LV-RV-DISP. CONCLUSION QT measurements on surface ECG are poorly correlated with local ERPs. If anything, QT- or QTc-DISP might provide a rough estimate of interventricular, that is, global DISP of ERP. Local or even intraventricular DISP of ERP is definitely not reflected by these QT measurements.
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Affiliation(s)
- Frederik Voss
- Innere Medizin III, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
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11
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Sakata K, Shimizu M, Ino H, Yamaguchi M, Terai H, Hayashi K, Kiyama M, Hayashi T, Inoue M, Mabuchi H. QT dispersion and left ventricular morphology in patients with hypertrophic cardiomyopathy. Heart 2003; 89:882-6. [PMID: 12860864 PMCID: PMC1767760 DOI: 10.1136/heart.89.8.882] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE To evaluate the relation between QT variables and disproportion of left ventricular wall hypertrophy in patients with hypertrophic cardiomyopathy. DESIGN Retrospective analysis of the results of echocardiography and electrocardiography. SETTING University hospital (tertiary referral centre). PATIENTS 70 patients with hypertrophic cardiomyopathy were divided into four groups according to the distribution of left ventricular wall hypertrophy on cross sectional echocardiography: group A--hypertrophy confined to the interventricular septum; group B--hypertrophy confined to the interventricular septum and left ventricular anterior wall; group C--hypertrophy confined to the interventricular septum, left ventricular anterior wall, and lateral free wall; group D--hypertrophy involving all portions of the left ventricle. MAIN OUTCOME MEASURES QT intervals and QT dispersion in precordial six lead ECGs. RESULTS There were no significant differences in the maximum left ventricular wall thickness among the four groups, and maximum and minimum QTc intervals also did not differ. QTc dispersion was increased significantly in groups A and B compared with groups C and D. Dispersions of the interval from the J point to the end of the T wave (JTc dispersions) in groups A and B were also increased significantly compared with groups C and D. By linear regression analysis, QTc and JTc dispersions correlated with the ratio of the interventricular septal thickness to left ventricular posterior wall thickness (p = 0.0152 and p = 0.0075, respectively). CONCLUSIONS QT dispersion may be affected by not only electrical inhomogeneity but also by morphological inhomogeneity of the left ventricle in patients with hypertrophic cardiomyopathy.
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Affiliation(s)
- K Sakata
- Molecular Genetics of Cardiovascular Disorders, Division of Cardiovascular medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
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12
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Kawasaki T, Azuma A, Kuribayashi T, Shiraishi H, Sawada T, Sugihara H, Nakagawa M. Determinant of QT dispersion in patients with hypertrophic cardiomyopathy. Pacing Clin Electrophysiol 2003; 26:819-26. [PMID: 12715841 DOI: 10.1046/j.1460-9592.2003.t01-1-00145.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
QT dispersion is thought to reflect a regional difference in repolarization process although QT interval is composed of depolarization and repolarization. This study was designed to investigate the effect of depolarization and repolarization on QT dispersion in hypertrophic cardiomyopathy. Standard 12-lead ECG was recorded in 70 hypertrophic cardiomyopathy patients with anteroseptal wall hypertrophy (HC-As), 8 patients with lateral wall hypertrophy (HC-L), 8 patients with diffuse hypertrophy (HC-D), and 46 normal controls. QRS, JTc, maximum and minimum QTc, and QTc dispersion were compared. The maximum QTc was greater in HC-As and HC-L than in the control; the minimum QTc was similar in all 3 groups; consequently, QTc dispersion was greater in HC-As and HC-L. In HC-D, the maximum QTc and the minimum QTc were greater than the control, which produced QTc dispersion similar to that in the control. JTc did not differ among 4 groups. In hypertrophic cardiomyopathy, both QTc and QRS duration were increased in the leads coinciding with the left ventricular portion of localized hypertrophy. We conclude that QTc dispersion depended on the heterogeneity of QRS duration or depolarization rather than repolarization, which in fact may be ascribed to the regionally different hypertrophy of the left ventricle in hypertrophic cardiomyopathy.
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Affiliation(s)
- Tatsuya Kawasaki
- Second Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
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Jouven X, Hagege A, Charron P, Carrier L, Dubourg O, Langlard JM, Aliaga S, Bouhour JB, Schwartz K, Desnos M, Komajda M. Relation between QT duration and maximal wall thickness in familial hypertrophic cardiomyopathy. Heart 2002; 88:153-7. [PMID: 12117842 PMCID: PMC1767224 DOI: 10.1136/heart.88.2.153] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND QT abnormalities have been reported in left ventricular hypertrophy and hypertrophic cardiomyopathy. OBJECTIVE To determine the relation between left ventricular hypertrophy and increased QT interval in familial hypertrophic cardiomyopathy. METHODS The QT interval was measured in 206 genotyped adult subjects with familial hypertrophic cardiomyopathy from 15 unrelated families carrying mutations in the beta myosin heavy chain (beta-MHC) gene (five families, n = 68) or the cardiac myosin binding protein C (MyBPC) gene (10 families, n = 138). Subjects were classified as genetically unaffected (controls, n = 112), affected with left ventricular hypertrophy (penetrants, n = 58), or affected without left ventricular hypertrophy (non-penetrants, n = 36). RESULTS There was a significant increase in QTmax and QTmin from controls to non-penetrants and penetrants for both the MyBPC group (p < or = 0.001 and p < or = 0.001, respectively) and the beta-MHC group (p < or = 0.001 and p < or = 0.001, respectively). In the MyBPC group, the increase in the QT interval could be explained by increased left ventricular hypertrophy. In the beta-MHC group, non-penetrants had a significantly longer QTmax than controls despite the absence of left ventricular hypertrophy, and a similar QT interval to penetrants despite a lesser degree of left ventricular hypertrophy. CONCLUSIONS In familial hypertrophic cardiomyopathy, genetically affected subjects without left ventricular hypertrophy may have a prolonged QT duration, which depends not only on the degree of left ventricular hypertrophy, when present, but also on the causative mutation.
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Affiliation(s)
- X Jouven
- Service de Cardiologie, Hôpital Européen Georges Pompidou, Paris, France.
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14
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15
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Kajiyama A, Saito D, Murakami T, Shiraki T, Oka T, Doi M, Masaka T, Tanemoto K, Tsuji T. Relation of QT-interval variability to ventricular arrhythmias during percutaneous transluminal coronary angioplasty. JAPANESE CIRCULATION JOURNAL 2001; 65:779-82. [PMID: 11548875 DOI: 10.1253/jcj.65.779] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The present study investigated the role of the dispersion of QT interval in percutaneous transluminal coronary angioplasty (PTCA)-induced ventricular tachyarrhythmias. Patients with effort angina without a previous myocardial infarction (n = 22), who had single-vessel disease of the anterior descending coronary artery (LAD), underwent PTCA if the coronary lesion was 75% or more stenosed in segment 6 or 7 of the LAD. The standard 12-lead ECG was continuously recorded during the procedure. Averaged QTc and QTac intervals, where QTac was the interval from the beginning of QRS complex to the nadir of T wave corrected by Bazett's formula, did not change significantly during PTCA. Of the 22 patients, 7 showed ventricular arrhythmias during PTCA. The maximum difference (deltaQTc) and the standard deviation (QTcSD) of the corrected QT interval in the standard 12-lead ECG increased significantly during PTCA in the 7 patients with ventricular arrhythmias, whereas they decrreased in the 15 patients without ventricular arrhythmias. deltaQTac and QTacSD were not affected by PTCA regardless of ventricular arrhythmias, which shows that the increases in the variation of the ventricular repolarization process play a role in PTCA-induced ventricular arrhythmias.
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Affiliation(s)
- A Kajiyama
- Department of Cardiology, Iwakuni National Hospital, Japan
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16
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Shimizu M, Ino H, Okeie K, Yamaguchi M, Hayashi K, Nagata M, Itoh H, Iwaki T, Oe K, Konno T, Taki J, Nakajima K, Mabuchi H. Increased QT dispersion does not reflect the increased regional variation of cardiac sympathetic nervous activity in hypertrophic cardiomyopathy. Am Heart J 2001; 142:358-62. [PMID: 11479478 DOI: 10.1067/mhj.2001.116765] [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: 11/22/2022]
Abstract
BACKGROUND QT dispersion (QTD) reflects regional variation of ventricular repolarization. However, the relationship between QTD and the regional variation of cardiac sympathetic nerve activity in hypertrophic cardiomyopathy (HCM) is not yet elucidated. METHODS Cardiac sympathetic nerve activity was evaluated in 25 patients with HCM by iodine 123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy. With planar MIBG imaging, heart and mediastinum ratios (H/M) at early (20 minutes) and delayed (3 hours) acquisition and the washout rate (WR) were calculated. Polar maps of left ventricular myocardium were divided into 20 segments. The SD of early uptake (EU-SD), delayed uptake (DU-SD), and WR (WR-SD) in 20 segments as indices of regional variation were calculated. QT intervals were corrected by use of the Bazett formula. RESULTS Maximum QTc correlated positively with H/M early, WR, and left ventricular wall thickness (LVWT). Minimum QTc correlated positively with WR and LVWT. Corrected QTD (QTDc) correlated negatively with EU-SD, DU-SD, and WR-SD and positively with the interventricular septal thickness/posterior wall thickness ratio. Stepwise regression analysis revealed that the most powerful determinants for maximum QTc, minimum QTc, and QTDc were WR, LVWT, and EU-SD, respectively. CONCLUSIONS QTD correlated negatively rather than positively with the regional variability index of cardiac sympathetic nerve activity. These results suggest that increased QTD in patients with HCM may not reflect increased heterogeneity of cardiac sympathetic nerve activity.
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Affiliation(s)
- M Shimizu
- Second Department of Internal Medicine, Kanazawa University, Takara-machi 13-1, Kanazawa 920-8640, Japan.
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17
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Abstract
QT dispersion was originally proposed to measure spatial dispersion of ventricular recovery times. Later, it was shown that QT dispersion does not directly reflect the dispersion of recovery times and that it results mainly from variations in the T loop morphology and the error of QT measurement. The reliability of both automatic and manual measurement of QT dispersion is low and significantly lower than that of the QT interval. The measurement error is of the order of the differences between different patient groups. The agreement between automatic and manual measurement is poor. There is little to choose between various QT dispersion indices, as well as between different lead systems for their measurement. Reported values of QT dispersion vary widely, e.g., normal values from 10 to 71 ms. Although QT dispersion is increased in cardiac patients compared with healthy subjects and prognostic value of QT dispersion has been reported, values are largely overlapping, both between healthy subjects and cardiac patients and between patients with and without adverse outcome. In reality, QT dispersion is a crude and approximate measure of abnormality of the complete course of repolarization. Probably only grossly abnormal values (e.g. > or =100 ms), outside the range of measurement error may potentially have practical value by pointing to a grossly abnormal repolarization. Efforts should be directed toward established as well as new methods for assessment and quantification of repolarization abnormalities, such as principal component analysis of the T wave, T loop descriptors, and T wave morphology and wavefront direction descriptors.
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Affiliation(s)
- M Malik
- Department of Cardiological Sciences, St. George's Hospital Medical School, London, United Kingdom.
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18
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Costantini O, Drabek C, Rosenbaum DS. Can sudden cardiac death be predicted from the T wave of the ECG? A critical examination of T wave alternans and QT interval dispersion. Pacing Clin Electrophysiol 2000; 23:1407-16. [PMID: 11025899 DOI: 10.1111/j.1540-8159.2000.tb00971.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- O Costantini
- Heart and Vascular Research Center, Case Western Reserve University, Cleveland, Ohio 44109-1998, USA
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19
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20
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Gillis AM. Effects of antiarrhythmic drugs on QT interval dispersion--relationship to antiarrhythmic action and proarrhythmia. Prog Cardiovasc Dis 2000; 42:385-96. [PMID: 10768315 DOI: 10.1053/pcad.2000.0420385] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Class IA, IC, and III antiarrhythmic drugs prolong ventricular repolarization (VR) which is manifest as QT interval prolongation on the surface electrocardiogram. These drugs may prolong VR in a spatially heterogeneous manner which results in increased dispersion of VR. This may be manifest as increased QT interval dispersion. Antiarrhythmic drug-induced decreases in QT interval dispersion are associated with antiarrhythmic efficacy in patients with the long QT syndrome and in patients with sustained ventricular tachycardia. Antiarrhythmic drug-induced increases in QT interval dispersion are associated with ventricular proarrhythmia secondary to torsades de points ventricular tachycardia. A number of factors may modulate the effects of antiarrhythmic drugs on dispersion of VR, including the disease state, transient ischemia, electrolyte abnormalities, changes in autonomic tone, and hemodynamic stress.
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Affiliation(s)
- A M Gillis
- Division of Cardiology, Foothills Hospital, Calgary, Alberta, Canada
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21
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Jin GS, Morita N, Atarashi H, Endoh Y, Kobayashi Y, Saitoh H, Kishida H, Hayakawa H. [QT dispersion in premature beats produced by extrastimuli from the right atrium and right ventricle]. NIHON IKA DAIGAKU ZASSHI 1999; 66:388-94. [PMID: 10638188 DOI: 10.1272/jnms.66.388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The difference between the maximum and minimum QT interval measured from a 12-lead electrocardiogram was defined as an index of spatial inhomogeneous repolarization of the ventricular myocardium. The causal relationship between QT dispersion and incidence of ventricular arrhythmias has been pointed out in various heart diseases, but until now it was discussed mainly related to sinus rhythm. QT dispersion in extrasystole may be more important in the development of arrhythmias. We examined 5 cases (mean age 34 +/- 12 years) with a history of paroxysmal supraventricular tachycardia, who underwent electrophysiologic study. Both atrial and ventricular premature stimuli were given at a basic cycle length of 600 msec respectively. The QT interval and the ventricular activation time (VAT) (period from premature test stimulus to the summit of QRS) of the premature beats were measured in a simultaneously recorded 12-lead electrocardiogram. QT dispersion (the difference between the longest QT interval and the shortest QT interval) and VAT dispersion (the difference between the longest VAT and the shortest VAT) were measured. In atrial premature beats, there were no significant changes in the QT dispersion or VAT dispersion when the coupling interval of the premature beats was shortened. In the ventricular premature beats, however, both the QT dispersion and the VAT dispersion tended to increase with the shortening of the coupling interval. We concluded that only a short coupled ventricular premature beat induces greater QT and VAT dispersion. A ventricular couplet with short coupling interval may contribute to the development of ventricular tachyarrhythmias.
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Affiliation(s)
- G S Jin
- First Department of Internal Madicine, Nippon Medical School, Tokyo, Japan
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22
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Gölbaşi Z, Selçoki Y, Eraslan T, Kaya D, Aydoğdu S. QT dispersion. Is it an independent risk factor for in-hospital mortality in patients with intracerebral hemorrhage? JAPANESE HEART JOURNAL 1999; 40:405-11. [PMID: 10611905 DOI: 10.1536/jhj.40.405] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Electrocardiographic repolarization changes, comprising QT prolongation, are most commonly seen after intracerebral hemorrhage. In this study in patients with intracerebral hemorrhage (ICH), QT dispersion and its daily changes were examined and the relation between QT dispersion and in-hospital mortality assessed. In 28 patients with intracerebral hemorrhage, diagnosed by computerized tomographic scanning, an ECG was obtained on the day of admission to hospital and then serial ECGs were recorded on the following four consecutive days. Blood electrolytes (K, Ca, Mg) were also analysed. The patients with intracerebral hemorrhage were followed until discharge or death (mean 14 +/- 4 days). QT, QT peak, and QT-QT peak dispersion were measured on simultaneous twelve lead electrocardiograms. Also, in 29 healthy subjects as a control group, five consecutive day serial electrocardiograms were recorded. There were no statistically significant differences between the study and control groups in terms of gender and age. During the five days, QT, QT peak, and QT-QTpeak dispersion values were significantly higher in patients with intracerebral hemorrhage than in the control subjects (p < 0.001). There were no statistically significant differences in two patient groups with intracerebral hemorrhage who died and who were discharged in terms of mean QT, QTpeak, and QT-QTpeak dispersion values. In conclusion, QT, QT peak, and QT-QTpeak dispersion values were significantly greater in patients with intracerebral hemorrhage than in the control subjects, but QT, QT peak, and QT-QT peak dispersions were not independent risk factors for in-hospital mortality in patients with intracerebral hemorrhage.
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Affiliation(s)
- Z Gölbaşi
- Department of Cardiology, Ankara Numune Education and Research Hospital, Turkey
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23
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Bevilacqua LM, Maguire CT, Seidman JG, Seidman CE, Berul CI. QT dispersion in alpha-myosin heavy-chain familial hypertrophic cardiomyopathy mice. Pediatr Res 1999; 45:643-7. [PMID: 10231857 DOI: 10.1203/00006450-199905010-00005] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Patients with familial hypertrophic cardiomyopathy (FHC) are at risk for ventricular arrhythmias and sudden death. Regional variability in the QT interval [QT dispersion (QTd)] is significantly increased in humans with FHC and ventricular arrhythmias. A mouse model of FHC resulting from a mutation in the alpha-myosin heavy-chain (Arg403Gln) was used to study the electrophysiologic phenotype of this disease. Cardiac electrophysiology studies and surface ECGs were performed in FHC mice and wild-type controls to evaluate the feasibility and significance of QTd measurements in predicting the risk for ventricular arrhythmias. Atrial and ventricular pacing electrodes were placed by either a transvenous or epicardial approach. Standard pacing and extrastimulus protocols were followed. The QT interval was measured in six surface ECG leads. QTd was defined as the difference between the maximum and minimum measured QT intervals. Male FHC mice had greater QTd than wild-type controls (37.1 +/- 3.0 ms versus 23.9 +/- 1.9 ms, p = 0.001). There was also a significant gender difference in QTd within each genotype; female wild-type mice had greater QTd than male wild-type mice (37.4 +/- 5.3 ms versus 23.9 +/- 1.9 ms, p = 0.005), and male FHC mice had greater QTd than female FHC mice (37.1 +/- 3.0 ms versus 27.2 +/- 2.0 ms, p = 0.02). Twelve of 23 FHC mice had inducible ventricular arrhythmias, whereas only 2 of 32 wild-type mice were inducible (p = 0.004). Although a significantly increased number of FHC mice had arrhythmias compared with wild-type mice, QTd did not correlate with arrhythmia inducibility. The importance of this study is that it validates the mouse model for further investigation of arrhythmogenic risk and gender differences in the electrophysiologic phenotype in FHC. It also suggests that although gender- and genotype-specific QTd values are increased, they do not predict arrhythmia risk in FHC mice.
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Affiliation(s)
- L M Bevilacqua
- Department of Cardiology, Children's Hospital, Boston, Massachusetts 02115, USA
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24
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Teragawa H, Hirao H, Muraoka Y, Yamagata T, Matsuura H, Kajiyama G. Relation between QT dispersion and adenosine triphosphate stress thallium-201 single-photon emission computed tomographic imaging for detecting myocardial ischemia and scar. Am J Cardiol 1999; 83:1152-6. [PMID: 10215275 DOI: 10.1016/s0002-9149(99)00050-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It is not known if QT dispersion is useful for detecting coronary artery disease. We investigated whether QT dispersion at baseline and during adenosine triphosphate (ATP) infusion correlate with the imaging patterns obtained from ATP stress thallium-201 single-photon emission computed tomography (ATP-SPECT). QT dispersion was determined in 169 patients who underwent ATP-SPECT from 12-lead electrocardiograms obtained at baseline and 3 minutes after the beginning of ATP infusion. Based on the results of ATP-SPECT, patients were divided into 4 groups: normal (n = 55), ischemia (n = 38), ischemia and scar (n = 42), and scar (n = 34). Baseline QT dispersions (mean +/- SD) in the normal, ischemia, ischemia and scar, and scar groups were 48 +/- 15, 50 +/- 17, 69 +/- 25, and 70 +/- 24 ms, respectively. Baseline QT dispersion was significantly greater in the groups with myocardial scar. QT dispersions during ATP infusion were 43 +/- 16, 63 +/- 20, 76 +/- 20, and 62 +/- 25 ms in the normal, ischemia, ischemia and scar, and scar groups, respectively. QT dispersion increased with ATP infusion in patients with myocardial ischemia. QT dispersion at baseline and during ATP infusion correlated with the ATP-SPECT imaging pattern. These findings suggest that baseline QT dispersion and ATP-induced changes in QT dispersion may help detect the presence of myocardial ischemia and scar.
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Affiliation(s)
- H Teragawa
- The First Department of Internal Medicine, Hiroshima University School of Medicine, Japan.
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25
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Papandonakis E, Tsoukas A, Christakos S. QT Dispersion as a Noninvasive Arrhythmiogenic Marker in Acute Myocardial Infarction. Ann Noninvasive Electrocardiol 1999. [DOI: 10.1111/j.1542-474x.1999.tb00362.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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26
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Yetman AT, Hamilton RM, Benson LN, McCrindle BW. Long-term outcome and prognostic determinants in children with hypertrophic cardiomyopathy. J Am Coll Cardiol 1998; 32:1943-50. [PMID: 9857876 DOI: 10.1016/s0735-1097(98)00493-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES We sought to determine clinical, angiographic, and echocardiographic predictors of survival in children with isolated hypertrophic cardiomyopathy (HCM) in a large pediatric centre. BACKGROUND Sudden death is a catastrophic outcome of HCM in childhood but has been difficult to predict. Current therapies might provide for improved outcome if factors identifying high risk can be identified. METHODS Records of 99 patients diagnosed with HCM from 1958 to 1997 at <18 yr were reviewed for clinical, angiographic (n = 62) and echocardiographic (n = 83) predictors of survival outcome. The effects of clinical characteristics on sudden death (including resuscitated sudden death) were individually tested in Cox's proportionate hazard modeling. RESULTS Seventy-one subjects were male. Median age at diagnosis was 5.0 yr with a medical follow-up interval of 4.8 yr. Thirty-seven of 97 patients had a family history of HCM. Ambulatory electrocardiograms (ECG) in 78 patients demonstrated supraventricular tachycardia in 16 and ventricular tachycardia in 21. Death or resuscitated sudden death occurred in 18 patients. Sudden death rate was 2.7%/yr after age 8 yr. Cox's proportionate survival modeling revealed increased corrected QT interval (QTc) dispersion on ECG (relative risk [RR] 1.61 per 20 ms increment, p < 0.0003), ventricular tachycardia (VT) on ambulatory ECG (RR 3.75, p < 0.006) and myocardial bridging of the LAD coronary (RR 12.0, p < 0.003) to be associated with reduced time to death or resuscitated sudden death. CONCLUSIONS Detailed assessment of ECGs, ambulatory ECGs, and coronary angiography can assist in identifying which children with HCM are at risk for sudden death.
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Affiliation(s)
- A T Yetman
- Department of Pediatrics, The Hospital for Sick Children, Ontario, Toronto, Canada
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27
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Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R. Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death. N Engl J Med 1998; 339:1201-9. [PMID: 9780340 DOI: 10.1056/nejm199810223391704] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Myocardial bridging may cause compression of a coronary artery, and it has been suggested that myocardial ischemia may result. The clinical significance and prognostic value of myocardial bridging of the left anterior descending coronary artery in children with hypertrophic cardiomyopathy are unknown. We sought to determine the prevalence and clinical effects of myocardial bridging in children with hypertrophic cardiomyopathy who underwent cardiac catheterization. METHODS Angiograms from 36 children with hypertrophic cardiomyopathy were reviewed to determine whether myocardial bridging was present and, if so, to assess the characteristics of systolic narrowing of the left anterior descending coronary artery caused by myocardial bridging and the duration of residual diastolic compression. We also reviewed clinical data on these patients. RESULTS Myocardial bridging was present in 10 (28 percent) of the patients. Compression of the left anterior descending coronary artery persisted for a mean (+/-SD) of 50+/-17 percent of diastole. As compared with patients without bridging, patients with bridging had a greater incidence of chest pain (60 percent vs. 19 percent, P=0.04), cardiac arrest with subsequent resuscitation (50 percent vs. 4 percent, P=0.004), and ventricular tachycardia (80 percent vs. 8 percent, P<0.001). On average, the patients with bridging had a reduction in systolic blood pressure with exercise of 17+/-27 mm Hg, as compared with an elevation of 43+/-31 mm Hg in those without bridging (P<0.001). The patients with bridging also had greater ST-segment depression with exercise (median, 5 vs. 0 mm, P=0.004) and a shorter duration of exercise (mean, 6.6+/-2.4 vs. 9.1+/-1.4 minutes, P=0.008). The degree of dispersion of the QT interval corrected for heart rate on the electrocardiogram was greater in patients with bridging than in those without bridging (104+/-46 vs. 48+/-31 msec, P=0.002). Kaplan-Meier estimates of the proportions of patients who had not died or had cardiac arrest with subsequent resuscitation five years after the diagnosis of hypertrophic cardiomyopathy were 67 percent among patients with bridging and 94 percent among those without bridging (P=0.004). CONCLUSIONS Myocardial bridging is associated with a poor outcome in children with hypertrophic cardiomyopathy. Our observations suggest that bridging is associated with myocardial ischemia
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Affiliation(s)
- A T Yetman
- Department of Pediatrics, Hospital for Sick Children, University of Toronto Faculty of Medicine, Canada
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28
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Kazmierczak J, Kornacewicz-Jach Z, Kisly M, Gil R, Wojtarowicz A. Electrocardiographic changes after alcohol septal ablation in hypertrophic obstructive cardiomyopathy. Heart 1998; 80:257-62. [PMID: 9875085 PMCID: PMC1761105 DOI: 10.1136/hrt.80.3.257] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To report acute and mid-term electrocardiographic changes in patients with hypertrophic obstructive cardiomyopathy (HOCM) after alcohol ablation of the first large septal branch of the left anterior descending coronary artery; and to relate electrocardiographic data with the left ventricular outflow tract pressure gradients. PATIENTS Nine consecutive symptomatic patients with HOCM (mean (SD) age 45 (12) years). METHODS Analysis of baseline and post-procedure ECGs and 24 hour ambulatory monitoring (up to six months). ECG data were related to left ventricular outflow tract pressure gradients. RESULTS One patient developed complete atrioventricular block requiring permanent pacing. The PR interval was significantly prolonged up to third month after ablation. Immediately after the procedure all patients developed right bundle branch block. At the sixth month of follow up, right bundle branch block was present in four patients. New anterior ST elevation developed immediately after ablation in five of the nine patients, and new Q waves in four. The QRS duration was significantly prolonged immediately after ablation and during follow up. There was significant but transient prolongation of QT-mean and QTc-mean intervals. QT dispersion, QTc dispersion, and JTc-mean interval were not affected. JT and JTc dispersions were transiently prolonged. No serious ventricular arrhythmias were recorded during Holter monitoring, either before or after the procedure. There were no significant correlations between the left ventricular outflow tract pressure gradient and QTc, QT-d, QTc-d, JTc, JT-d, JTc-d, or QRS duration before and after ablation. CONCLUSIONS Alcohol septal ablation for HOCM induces significant changes in the resting ECG in most patients, despite the occlusion of a relatively small artery. The changes include new Q waves, new bundle branch block, transient anterior ST segment elevation, atrioventricular block, and transient prolongation of QT interval.
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Affiliation(s)
- J Kazmierczak
- Department of Cardiology, Pomeranian Medical School, Szczecin, Poland
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29
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Karagounis LA, Anderson JL, Moreno FL, Sorensen SG. Multivariate associates of QT dispersion in patients with acute myocardial infarction: primacy of patency status of the infarct-related artery. TEAM-3 Investigators. Third trial of Thrombolysis with Eminase in Acute Myocardial Infarction. Am Heart J 1998; 135:1027-35. [PMID: 9630107 DOI: 10.1016/s0002-8703(98)70068-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND QT dispersion (QTd; QT interval maximum minus minimum) has been shown to reflect regional variations in ventricular repolarization and is increased in patients with life-threatening ventricular arrhythmias. METHODS To determine correlates of QTd in patients who had had myocardial infarction (MI), 207 patients (158 men, aged 57 +/- 11 years) with acute MI who were treated with alteplase or anistreplase within 2.7 +/- 0.9 hours of symptom onset were studied. Angiograms at a median of 27 hours after thrombolysis showed reperfusion (Thrombolysis in Myocardial Infarction grade > or =2) in 184 (88%) patients. QT was measured in 10 +/- 2 leads on discharge electrocardiograms with a computerized analysis program interfaced with a digitizer. Associations of QTd with 24 variables related to patient characteristics, acute MI, angiography, interventions, and radionuclide ventriculography were evaluated by univariate and multivariate regression. RESULTS Univariate associations with QTd (p < or = 0.10) were Thrombolysis in Myocardial Infarction flow grade 0/1 versus 2/3 (QTd = 75 +/- 33 msec vs 53 +/- 22 msec, p < 0.0001), minimal luminal diameter (p = 0.007), left ventricular ejection fraction at discharge (p = 0.007), reinfarction (p = 0.01), number of leads with ST elevation (p = 0.05), end-systolic volume at discharge (p = 0.04), time to peak creatine kinase (p = 0.06), and YST elevation (p = 0.10). Independent associates of QTd were Thrombolysis in Myocardial Infarction grade 0/1 versus 2/3 (p < 0.0001), reinfarction (p = 0.005), and ejection fraction (p = 0.02). CONCLUSIONS Successful thrombolysis is associated with less QTd in patients after acute MI. Our results support the hypothesis that QTd after MI depends on reperfusion status, reinfarction, and left ventricular function. Reduction in QTd may be an additional mechanism by which the benefit of thrombolytic therapy is realized.
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Affiliation(s)
- L A Karagounis
- University of Utah School of Medicine, LDS Hospital, Salt Lake City 84132, USA
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30
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Balaji S, Sokoloski MC, Case CL, Gillette PC. JT dispersion in Wolff-Parkinson-White syndrome: effect of eccentric ventricular depolarization on the dispersion of repolarization. Pacing Clin Electrophysiol 1998; 21:576-9. [PMID: 9558690 DOI: 10.1111/j.1540-8159.1998.tb00101.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is much interest in QT dispersion for noninvasive risk stratification of patients at risk of arrhythmias. However, little is known about the genesis of abnormal QT dispersion. In particular, whether eccentric ventricular depolarization, as seen in preexcitation, can lead to abnormal dispersion of repolarization is unknown. We studied 24 children aged 1-19 years (mean +/- SD, 11 +/- 5 years) with manifest preexcitation due to Wolff-Parkinson-White syndrome who had successful catheter ablation. Standard ECGs done preablation, early postablation (< 1 week), mid postablation (> 1 week, < 2 months), and late postablation (> 2 months) were reviewed. The QRS duration prior to ablation ranged from 90-160 ms (mean +/- SD, 123 +/- 21 ms). On the preablation ECG, the JT and JTc dispersions showed no relationship to the QRS duration (r = 0.04 and 0.07, respectively). There was no change in JT dispersion when the preablation (42 +/- 15 ms) ECG was compared to early (43 +/- 15 ms), mid (44 +/- 13 ms), and late postablation (48 +/- 19 ms) ECGs. There was no significant change in JTc dispersion as well. Thus, JT dispersion is unrelated to QRS duration and unaffected by catheter ablation in patients with Wolff-Parkinson-White syndrome. Eccentric ventricular depolarization does not lead to abnormal dispersion of repolarization.
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Affiliation(s)
- S Balaji
- South Carolina Children's Heart Center, Medical University of South Carolina, Charleston 29425, USA
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Abstract
QT dispersion as a measure of interlead variations of QT interval duration in the surface 12-lead ECG is believed to reflect regional differences in repolarization heterogeneity and thus, may provide an indirect marker of arrhythmogenicity. Methodology for determining QT dispersion and reproducibility of this parameter vary significantly between studies and, together with some other unresolved problems with QT dispersion assessment, often lead to contradictory suggestions about potential clinical utility of this parameter. The results of our own study in 213 survivors of myocardial infarction, together with a comprehensive review of the literature, suggest that most of these inconsistencies reflect incomplete understanding of electrocardiographic correlates of both normal and abnormal ventricular repolarization. The application of more objective techniques, such as spectral analysis or combined assessment of different parameters (e.g., area beneath the T wave and its symmetricity) may add a new dimension to the noninvasive assessment of ventricular repolarization.
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Affiliation(s)
- J Kautzner
- Department of Cardiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
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Pak PH, Nuss HB, Tunin RS, Kääb S, Tomaselli GF, Marban E, Kass DA. Repolarization abnormalities, arrhythmia and sudden death in canine tachycardia-induced cardiomyopathy. J Am Coll Cardiol 1997; 30:576-84. [PMID: 9247535 DOI: 10.1016/s0735-1097(97)00193-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES This study sought to determine whether the canine model of tachycardia-induced heart failure (HF) is an effective model for sudden cardiac death (SCD) in HF. BACKGROUND Such a well established HF model that also exhibits arrhythmias and SCD, along with repolarization abnormalities that could trigger them, may facilitate the study of SCD in HF, which still eludes effective treatment. METHODS Twenty-five dogs were VVI-paced at 250 beats/min for 3 to 5 weeks. Electrocardiograms were obtained, and left ventricular endocardial monophasic action potentials (MAPs) were recorded at six sites at baseline and after HF. Weekly Holter recordings were made with pacing suspended for 24 h. RESULTS Six animals (24%) died suddenly, one with Holter-documented polymorphic ventricular tachycardia (VT). Holter recordings revealed an increased incidence of VT as HF progressed. Repolarization was significantly (p < 0.05) prolonged, as indexed by a corrected QT interval (mean [+/-SD] 311 +/- 25 to 338 +/- 25 ms) and MAP duration measured at 90% repolarization (MAPD90) (181 +/- 19 to 209 +/- 28 ms), and spatial MAPD90 dispersion rose by 40%. We further tested whether CsCl inhibition of repolarizing K+ currents, which are reportedly downregulated in HF, might preferentially prolong the MAPD90 in HF. With 1 mEq/kg body weight of CsCl, MAPD90 rose by 86 +/- 100 ms in dogs with HF versus only 28 +/- 16 ms in control animals (p = 0.002). Similar disparities in CsCl sensitivity were observed in myocytes isolated from normal and failing hearts. CONCLUSIONS Tachycardia-induced HF exhibits malignant arrhythmia and SCD, along with prolonged, heterogeneous repolarization and heightened sensitivity to CsCl at chamber and cellular levels. Thus, it appears to be a useful model for studying mechanisms and therapy of SCD in HF.
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Affiliation(s)
- P H Pak
- Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
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Trusz-Gluza M, Woźniak-Skowerska I, Giec L, Szydlo K. Dispersion of the QT interval as a predictor of cardiac death in patients with coronary heart disease. Pacing Clin Electrophysiol 1996; 19:1900-4. [PMID: 8945065 DOI: 10.1111/j.1540-8159.1996.tb03249.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Abnormal dispersion of the QT interval (QTd), measured as interlead variability of QT, may reflect a regional variation in duration of ventricular action potential and, hence, of cardiac electrical instability. In this retrospective study, we analyzed the effect of QTd on survival and its relation to other known predictors of subsequent cardiac death (CD) and sudden cardiac death (SCD) in 162 patients with coronary heart disease (CHD). QTd was calculated as the difference between the highest and lowest values measured in each of the 12 ECG leads (Qtmax - QTmin). Seventeen CDs occurred, including nine SCDs, during a 25 +/- 11 month follow-up. There were significant differences in CD (P < 0.001 in log-rank test) and in SCD (P < 0.01). The 1- and 3-year survivals were 87.5% and 76.5% in patients with QTd > 0.060 seconds versus 98% and 93.5% in patients with QTd < 0.060 seconds, respectively. Additionally, a stepwise Cox regression analysis revealed that increased QTd was an independent risk factor of CD and SCD. A cut-off value of 60 ms for QTd had a 53% sensitivity and 79% specificity in discriminating patients who are at risk of CD. The positive and negative prognostic values were 23% and 93%, respectively. Our findings support the hypothesis that increased QTd has a prognostic value in the stratification of patients with CHD independent of other known risk factors.
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Affiliation(s)
- M Trusz-Gluza
- I Clinic of Cardiology, Silesian School of Medicine, Katowice, Poland
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Zaidi M, Robert A, Fesler R, Derwael C, Brohet C. Dispersion of ventricular repolarization in hypertrophic cardiomyopathy. J Electrocardiol 1996; 29 Suppl:89-94. [PMID: 9238384 DOI: 10.1016/s0022-0736(96)80026-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
On an averaged QRS-T cycle from a 15-lead record (12-lead electrocardiogram + XYZ leads) and through interactive editing, four electrocardiographic indices of the dispersion of ventricular repolarization (DVR) are automatically computed and represent the maximal interlead difference of QT and JTend and QT and JTapex. The values of these indices were then examined in three clinical groups matched for age and sex: normal subjects (control), patients with left ventricular hypertrophy (LVH group), and patients with hypertrophic cardiomyopathy (HCM group) without ventricular arrhythmias and without interacting drugs. The mean values of all four DVR indices were significantly increased in the HCM group compared with the control group and the LVH group of another origin (ie, for the QTe dispersion index, the mean values and the 97.5th percentiles were, respectively, 65 +/- 18 ms and 97 ms in the HCM group, 41 +/- 25 ms and 79 ms in the LVH group, and 31 +/- 15 ms and 58 ms in the control group). The maximal QT interval was also significantly longer in the HCM group (464 +/- 30 ms) than in the LVH group (436 +/- 32 ms) and the control group (428 +/- 25 ms).
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Affiliation(s)
- M Zaidi
- Division of Cardiology, Cliniques Universitaires Saint Luc, Brussels, Belgium
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Buja G. Short- and long-term reproducibility of QT, QTc, and QT dispersion measurement in healthy subjects. Pacing Clin Electrophysiol 1994; 17:1833-5. [PMID: 7838796 DOI: 10.1111/j.1540-8159.1994.tb03755.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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