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Cardiac rehabilitation in heart failure with severely reduced ejection fraction: effects on mortality. Heart Fail Rev 2023; 28:1-19. [PMID: 35596876 DOI: 10.1007/s10741-022-10242-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/11/2022] [Indexed: 02/07/2023]
Abstract
Thirty years ago, patients with low ejection fraction (EF) have often been excluded from rehabilitation programs due to concern about possibility of sudden death or other adverse cardiovascular events during exercise sessions. Recent studies have highlighted the fact that cardiac rehabilitation could improve exercise capacity, cardiac function, and health-related quality of life in congestive heart failure patients. This encouraged us to write a review article and update our latest knowledge about the outcome of rehabilitation program in patients with severely depressed cardiac function. We were particularly interested in effect of cardiac rehabilitation on exercise capacity, quality of life, vascular effects, neuro-hormonal changes, and mortality. We also conducted a mini-systematic review and meta-analysis on randomized controlled trials comparing exercise training with usual care in patients with severely reduced left ventricular ejection fraction, for the mortality subsection to obtain precise estimates of overall treatment benefit on mortality. It is our privilege to submit our manuscript for possible publication in your prestigious journal.
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Saramet EE, Negru RD, Oancea A, Constantin MML, Ancuta C. 24 h Holter ECG Monitoring of Patients with Rheumatoid Arthritis-A Potential Role for a Precise Evaluation of QT Interval Duration and Associated Arrhythmic Complications. Diagnostics (Basel) 2022; 12:diagnostics12030638. [PMID: 35328191 PMCID: PMC8946977 DOI: 10.3390/diagnostics12030638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/22/2022] [Accepted: 03/01/2022] [Indexed: 02/01/2023] Open
Abstract
Background: Patients with rheumatoid arthritis (RA) have increased systemic inflammatory burden associated with elevated cardiovascular mortality. Prolonged ventricular repolarisation evaluated by QT interval duration is a risk factor for cardiovascular and total mortality. In RA, mortality risk is correlated with dynamics and cumulative incidence of QTc prolongation rather than QTc value. The aim is to evaluate if QT parameters evaluated with 24 h Holter ECG are a better option to complete the cardiovascular profile of RA patients than parameters from short ECG recordings. Materials and methods: A total of 58 patients (22 males, 36 females) with RA were submitted to short ECG recordings at admission and to 24 h Holter ECG. QT interval parameters and ventricular ectopy generated from both types of recordings were analyzed. Results: QTc interval values obtained from Holter ECG were significantly higher than the values from short term ECG and were correlated with severity of inflammatory process. The number of QRS complexes with QTc > 450 ms recorded during 24 h Holter was strongly correlated with the number of ventricular events and severity of the inflammatory process. Conclusions: In patients with RA, the Holter ECG recordings could realize a more precise evaluation of the extent and dynamics of QTc interval duration and of ventricular ectopic events with potential risk of sudden death.
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Yılmaz ÖÇ, Ozkan S, Yavuz B. Masked hypertension is related to alteration of myocardial arrhythmia Parameters. Clin Exp Hypertens 2020; 43:81-84. [DOI: 10.1080/10641963.2020.1812625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Ömer Çağlar Yılmaz
- Private Ankara Etimet Hospital , Private Cardiology Clinic, Ankara, Turkey
| | - Selçuk Ozkan
- Department of Cardiology, Yuksek Ihtisas University Faculty of Medicine, Ankara, Turkey
| | - Bunyamin Yavuz
- Department of Cardiology, Yuksek Ihtisas University Faculty of Medicine, Ankara, Turkey
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Caru M, Gravel H, Pathak A, Bousquet M, Galinier M, Jacquemet V, Curnier D. Observations on changes in ventricular repolarization following four weeks of exercise training in chronic heart failure patients. SCAND CARDIOVASC J 2020; 54:369-375. [PMID: 32579078 DOI: 10.1080/14017431.2020.1783458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the effects of exercise training on ventricular repolarization dynamicity and heart rate variability in chronic heart failure patients. DESIGN A total of 22 chronic heart failure patients with reduced ejection fraction in sinus rhythm were included in the study. The patients were in NYHA classes II-III with an ejection fraction of 29.7 ± 7.7%. Before and after 4 weeks of aerobic exercise training, all patients performed a cardiopulmonary exercise test, a standard twelve-lead electrocardiogram and a 24 h Holter recording from which heart rate variability and ventricular repolarization dynamicity were assessed. RESULTS We observed a significant decrease of QTpeak (p < .001) and QTend (p < .001) at RR intervals ranging from 600 to 1000 ms on 24 h QT/RR regressions after 4 weeks of exercise training. Our analyses revealed that short-term exercise training induced significant changes in the frequency and time domain HRV parameters on an overall time-period of 24 h. CONCLUSION Four weeks of exercise training induced significant changes in ventricular repolarization dynamicity in chronic heart failure patients. In addition, short-term exercise training was enough to improve patients' heart rate variability.
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Affiliation(s)
- Maxime Caru
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada.,Research Center, Sainte-Justine University Health Center, Montreal, Canada
| | - Hugo Gravel
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Atul Pathak
- INSERM U586, Laboratory of Medical and Clinical Pharmacology, Faculty of Medicine, Toulouse, France
| | - Marc Bousquet
- Clinic of Saint-Orens, Cardiovascular and Pulmonary Rehabilitation Center, Saint-Orens, France
| | - Michel Galinier
- INSERM U586, Laboratory of Medical and Clinical Pharmacology, Faculty of Medicine, Toulouse, France
| | - Vincent Jacquemet
- Department of Pharmacology and Physiology, University of Montreal, Montreal, Canada.,Hôpital du Sacré-Coeur de Montréal, Research Center, Montreal, QC, Canada
| | - Daniel Curnier
- Laboratory of Pathophysiology of EXercise (LPEX), School of Kinesiology and Physical Activity Sciences, Faculty of Medicine, University of Montreal, Montreal, Canada.,Research Center, Sainte-Justine University Health Center, Montreal, Canada
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van Duijvenboden S, Ramírez J, Young WJ, Mifsud B, Orini M, Tinker A, Munroe PB, Lambiase PD. Genetic Basis and Prognostic Value of Exercise QT Dynamics. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 13:e002774. [PMID: 32527199 PMCID: PMC7439940 DOI: 10.1161/circgen.119.002774] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Abnormal QT interval responses to heart rate (QT dynamics) is an independent risk predictor for cardiovascular disease in patients, but its genetic basis and prognostic value in a population-based cohort have not been investigated. Methods: QT dynamics during exercise and recovery were derived in 56 643 individuals from UK Biobank without a history of cardiovascular events. Genome-wide association studies were conducted to identify genetic variants and bioinformatics analyses were performed to prioritize candidate genes. The prognostic value of QT dynamics was evaluated for cardiovascular events (death or hospitalization) and all-cause mortality. Results: Heritability of QT dynamics during exercise and recovery were 10.7% and 5.4%, respectively. Genome-wide association studies identified 20 loci, of which 4 loci included genes implicated in mendelian long-QT syndrome. Five loci did not overlap with previously reported resting QT interval loci; candidate genes included KCNQ4 and KIAA1755. Genetic risk scores were not associated with cardiovascular events in 357 882 unrelated individuals from UK Biobank. We also did not observe associations of QT dynamics during exercise and recovery with cardiovascular events. Increased QT dynamics during recovery was significantly associated with all-cause mortality in the univariate Cox regression analysis (hazard ratio, 1.09 [95% CI, 1.05–1.13], P=2.28×10-5), but the association was not significant after adjusting for clinical risk factors. Conclusions: QT interval dynamics during exercise and recovery are heritable markers but do not carry independent prognostic information for clinical outcomes in the UK Biobank, a population-based cohort. Their prognostic importance may relate to cardiovascular disease cohorts where structural heart disease or ischemia may influence repolarization dynamics. The strong overlap between QT dynamics and resting QT interval loci suggests common biological pathways; however, nonoverlapping loci suggests alternative mechanisms may exist that underlie QT interval dynamics.
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Affiliation(s)
- Stefan van Duijvenboden
- Institute of Cardiovascular Science, University College London, United Kingdom (S.v.D., J.R., M.O., P.D.L.).,Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Julia Ramírez
- Institute of Cardiovascular Science, University College London, United Kingdom (S.v.D., J.R., M.O., P.D.L.).,Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - William J Young
- Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom.,Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom (W.J.Y., P.D.L.)
| | - Borbala Mifsud
- Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom.,College of Health and Life Sciences, Doha, Qatar (B.M.)
| | - Michele Orini
- Institute of Cardiovascular Science, University College London, United Kingdom (S.v.D., J.R., M.O., P.D.L.).,Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Andrew Tinker
- Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom.,NIHR Barts Cardiovascular Biomedical Research Unit (A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Patricia B Munroe
- Clinical Pharmacology, William Harvey Research Institute (S.v.D., J.R., W.J.Y., B.M., M.O., A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom.,NIHR Barts Cardiovascular Biomedical Research Unit (A.T., P.B.M.), Barts & The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Pier D Lambiase
- Institute of Cardiovascular Science, University College London, United Kingdom (S.v.D., J.R., M.O., P.D.L.).,Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom (W.J.Y., P.D.L.)
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Jalanko M, Väänänen H, Tarkiainen M, Sipola P, Jääskeläinen P, Lauerma K, Laitinen T, Laitinen T, Laine M, Heliö T, Kuusisto J, Viitasalo M. Fibrosis and wall thickness affect ventricular repolarization dynamics in hypertrophic cardiomyopathy. Ann Noninvasive Electrocardiol 2018; 23:e12582. [PMID: 29974557 DOI: 10.1111/anec.12582] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 05/11/2018] [Accepted: 06/06/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is characterized by ventricular repolarization abnormalities and risk of ventricular arrhythmias. Our aim was to study the association between the phenotype and ventricular repolarization dynamics in HCM patients. METHODS HCM patients with either the MYBPC3-Q1061X or TPM1-D175N mutation (n = 46) and control subjects without mutation and hypertrophy (n = 35) were studied with 24-hr ambulatory ECG recordings by measuring time intervals of rate-adapted QT (QTe), maximal QT, and T-wave apex to wave end (TPE) intervals and the QTe/RR slope. Findings were correlated to specified echocardiographic and cardiac magnetic resonance imaging (CMRI) findings. RESULTS Rate-adapted QTe interval was progressively longer in HCM patients with decreasing heart rates compared to control subjects (p = 0.020). The degree of hypertrophy correlated with measured QTe values. HCM patients with maximal wall thickness higher than the mean (20.6 mm) had longer maximum QTe and median TPE intervals compared to control subjects and HCM patients with milder hypertrophy (p < 0.001 and p = 0.014, respectively). HCM patients with late gadolinium enhancement (LGE) on CMRI had steeper QTe/RR slopes compared to HCM patients without LGE and control subjects (p = 0.044 and p = 0.001, respectively). LGE was an independent predictor of QTe/RR slope (p = 0.023, B = 0.043). CONCLUSION Dynamics of ventricular repolarization in HCM are affected by hypertrophy and fibrosis. LGE may confer an independent effect on QT dynamics which may increase the arrhythmogenic potential in HCM.
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Affiliation(s)
- Mikko Jalanko
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Heikki Väänänen
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Mika Tarkiainen
- Department of Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Petri Sipola
- Department of Radiology, Kuopio University Hospital, Kuopio, Finland
| | | | - Kirsi Lauerma
- Department of Radiology, Helsinki University Hospital, Helsinki, Finland
| | - Tiina Laitinen
- Department of Clinical Physiology, Kuopio University Hospital, Kuopio, Finland
| | - Tomi Laitinen
- Department of Clinical Physiology, Kuopio University Hospital, Kuopio, Finland
| | - Mika Laine
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Tiina Heliö
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Johanna Kuusisto
- Centre for Medicine and Clinical Research, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland
| | - Matti Viitasalo
- Department of Cardiology, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Middleton TL, Wong J, Molyneaux L, Brooks BA, Yue DK, Twigg SM, Wu T. Cardiac Effects of Sulfonylurea-Related Hypoglycemia. Diabetes Care 2017; 40:663-670. [PMID: 28223296 DOI: 10.2337/dc16-1972] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 02/05/2017] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine the effect of sulfonylurea-related hypoglycemia on cardiac repolarization and ectopy in the setting of well-controlled type 2 diabetes. RESEARCH DESIGN AND METHODS Thirty subjects with sulfonylurea-treated type 2 diabetes underwent 48 h of concurrent continuous glucose monitoring and ambulatory electrocardiography. Ventricular repolarization (QTc) and QT dynamicity were analyzed during periods of hypoglycemia (<3.5 mmol/L for >20 min) and compared with periods of euglycemia and hyperglycemia combined. Cardiac ectopy rates during hypoglycemia were compared with ectopy rates when blood glucose was 4-10 mmol/L. RESULTS Mean HbA1c was 6.9% (52 mmol/mol). Hypoglycemia was detected in 9 of 30 subjects (30%); episodes were typically nocturnal (67%) and asymptomatic (73%). Hypoglycemia-associated QTc prolongation was seen in five of nine subjects with a large variation in individual response. Higher QT dynamicity, a poor prognostic factor in cardiac disease, was seen in subjects who experienced hypoglycemia compared with subjects who did not (0.193 vs. 0.159 for the nocturnal period; P = 0.01). This finding persisted after the hypoglycemic event. The rates of ventricular and supraventricular ectopy demonstrated a nonsignificant trend toward an increase during hypoglycemia (median rate ratio 1.58 and 1.33, respectively). Similar, nonsignificant results were observed in a separate insulin-treated cohort. CONCLUSIONS Hypoglycemia, often unrecognized, is a frequent finding in well-controlled sulfonylurea-treated type 2 diabetes. It is associated with the novel finding of increased QT dynamicity and QTc prolongation in some individuals. Our findings suggest sulfonylurea-related hypoglycemia can have detrimental cardiovascular sequelae. Similar effects are also seen in the setting of insulin therapy.
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Affiliation(s)
- Timothy L Middleton
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia .,Department of Medicine, University of Sydney, Sydney, New South Wales, Australia
| | - Jencia Wong
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.,Department of Medicine, University of Sydney, Sydney, New South Wales, Australia
| | - Lynda Molyneaux
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Belinda A Brooks
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.,School of Nursing, University of Sydney, Sydney, New South Wales, Australia
| | - Dennis K Yue
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.,Department of Medicine, University of Sydney, Sydney, New South Wales, Australia
| | - Stephen M Twigg
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.,Department of Medicine, University of Sydney, Sydney, New South Wales, Australia
| | - Ted Wu
- Diabetes Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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Abstract
Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave (QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.
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Monitillo F, Leone M, Rizzo C, Passantino A, Iacoviello M. Ventricular repolarization measures for arrhythmic risk stratification. World J Cardiol 2016; 8:57-73. [PMID: 26839657 PMCID: PMC4728107 DOI: 10.4330/wjc.v8.i1.57] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 09/04/2015] [Accepted: 11/04/2015] [Indexed: 02/06/2023] Open
Abstract
Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave (QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.
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10
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Sakamoto N, Sato N, Talib AK, Sugiyama E, Minoshima A, Tanabe Y, Fujino T, Takeuchi T, Akasaka K, Saijo Y, Kawamura Y, Hasebe N. Late Gadolinium Enhancement on Cardiac MRI Correlates with QT Dynamicity Represented by QT/RR Relationship in Patients with Ventricular Arrhythmias. Ann Noninvasive Electrocardiol 2015; 21:126-35. [PMID: 26104916 DOI: 10.1111/anec.12280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/10/2015] [Accepted: 04/21/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The distribution of late gadolinium enhancement (LGE) on the cardiac MRI (CMR) indicates myocardial fibrosis and provides information of possible reentry substrates. QT dynamicity reflecting repolarization abnormalities has gained attention as a potential prognostic predictive factor. OBJECTIVE To clarify the correlation between the LGE distribution on CMR and QT dynamicity represented by the QT/RR relationship. METHODS CMR and QT/RR analyses using Holter monitoring were performed in 34 patients (24 males, 60 ± 11 years) with ventricular tachycardia (VT) and/or ventricular fibrillation (VF). The LGE on CMR was scored using a 4-point score in 17 left ventricular segments. The sum of the LGE scores was calculated for each patient. The QT/RR slope and daytime/nighttime QT/RR ratio (day/night ratio) were calculated. The correlation between the slope or the day/night QT/RR ratio and late enhancement findings was analyzed. RESULTS All patients were divided into 23 LGE positive (LGE(+)) and 11 LGE negative (LGE(-)) patients. The slopes of the QTe/RR and QTa /RR were significantly steeper in the LGE(+) than in LGE(-) patients (0.21 ± 0.03 vs 0.13 ± 0.02; P < 0.001, 0.19 ± 0.03 vs 0.13 ± 0.02; P < 0.001, respectively), and both slopes were significantly correlated with the total LGE scores (r = 0.83, P < 0.001; r = 0.71, P < 0.001, respectively). In the LGE(+) patients, the QTe day/night (1.37 ± 0.38 vs 0.91 ± 0.33; P = 0.002) and QTa day/night ratios (1.33 ± 0.26 vs 1.06 ± 0.30; P = 0.011) were significantly greater than those in the LGE(-) patients. CONCLUSION The LGE distribution was closely related to the QT dynamicity, suggesting that a combination of these markers can be a powerful tool for understanding the background pathophysiology.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Yasuaki Saijo
- Division of Community Medicine and Epidemiology Department of Health Science, Asahikawa Medical University, Asahikawa, Japan
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11
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Quinteiro RA, Biagetti MO, Fernandez A, Borzone FR, Gargano A, Casabe HJ. Can QT/RR relationship differentiate between low- and high-risk patients with hypertrophic cardiomyopathy? Ann Noninvasive Electrocardiol 2015; 20:386-93. [PMID: 25639818 DOI: 10.1111/anec.12230] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Abnormal dynamicity of repolarization is considered to be a marker of myocardial vulnerability contributing to increased risk of arrhythmic events and sudden death. However, little is known about QT dynamics in hypertrophic cardiomyopathy (HCM). In this study, we aimed to evaluate ventricular repolarization by QT dynamicity in patients with HCM, focusing on its value to define if it is able to differentiate among low- and high-risk HCM patients. METHODS The linear regression slopes of the QT interval, measured to the apex and to the end of the T wave plotted against RR intervals (QTapex/RR and QTend/RR slopes, respectively) were calculated from 24-hour Holter recordings using a standard algorithm in 36 HCM patients and 64 control subjects. RESULTS QTapex/RR and QTend/RR slopes were significantly steeper in the HCM patients in contrary to healthy control subjects (QTapex/RR = 0.22 + 0.08 vs 0.20 + 0.05, P = 0.0367; QTend/RR = 0.25 + 0.10 vs 0.20 + 0.06, P = 0.023). Moreover, the slopes of QTend/RR and QTapex/RR of high-risk patients were significantly steeper than those of control subjects while no significant differences were found among low-risk HCM patients and control subjects and only QTe/RR of high-risk patients was significantly different between low- and high-risk HCM patients. CONCLUSIONS Our study results suggest that QT dynamicity is impaired in patients with HCM and may help to differentiate among low- and high-risk patients. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired ventricular repolarization in patients with HCM.
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Affiliation(s)
- Ricardo A Quinteiro
- Cardiac Electrophysiology Laboratory, Favaloro University, Buenos Aires, Argentina
| | - Marcelo O Biagetti
- Cardiac Electrophysiology Laboratory, Favaloro University, Buenos Aires, Argentina
| | - Adrian Fernandez
- the Cardiology Division of the University Hospital, Favaloro University, Buenos Aires, Argentina
| | - Francisco R Borzone
- Cardiac Electrophysiology Laboratory, Favaloro University, Buenos Aires, Argentina
| | - Agustina Gargano
- the Cardiology Division of the University Hospital, Favaloro University, Buenos Aires, Argentina
| | - Horacio J Casabe
- the Cardiology Division of the University Hospital, Favaloro University, Buenos Aires, Argentina
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12
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Massie C, Hudson M, Tatibouet S, Steele R, Huynh T, Fritzler MJ, Baron M, Pineau CA. Absence of an association between anti-Ro antibodies and prolonged QTc interval in systemic sclerosis: a multicenter study of 689 patients. Semin Arthritis Rheum 2014; 44:338-44. [PMID: 25128430 DOI: 10.1016/j.semarthrit.2014.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 06/05/2014] [Accepted: 07/09/2014] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To examine the association between anti-Ro antibodies, namely anti-Ro60/SS-A and anti-Ro52/TRIM21, together and separately, and a prolonged QT interval corrected for heart rate (QTc) in systemic sclerosis (SSc) patients. METHODS A total of 689 SSc patients enrolled in a multicenter cohort study underwent a 12-lead resting EKG at baseline. The QTc interval was measured, and a QTc ≥ 440ms was considered prolonged. Detailed clinical data and sera of these patients were collected and positivity for anti-Ro60/SS-A and anti-Ro52/TRIM21 antibodies was determined using an addressable laser bead immunoassay (ALBIA). RESULTS QTc prolongation was common in this SSc cohort (25%). In a univariate analysis, Ro antibodies, together or separately, were not associated with prolongation of the QTc interval [mean difference in QTc in anti-Ro antibody positive versus negative subjects was -2.2ms (p = 0.5748), in anti-Ro60/SS-A antibody positive versus negative subjects was 1.3ms (p = 0.8616), and in anti-Ro52/TRIM21 antibody positive versus negative subjects was -3.3ms (p = 0.4106)]. In a multivariate logistic regression analysis adjusting for possible confounders, there was no association between prolonged QTc and anti-Ro antibodies [odds ratio (OR) = 0.74, 95% confidence interval (CI): 0.45, 1.22], anti-Ro60/SS-A antibodies (OR = 1.57, 95% CI: 0.72, 3.41), and anti-Ro52/TRIM21 antibodies (OR = 0.76, 95% CI: 0.46, 1.26). However, in both univariate and multivariate analyses, QTc prolongation was associated with longer disease duration, greater disease severity, and the presence of anti-RNA polymerase III antibodies. CONCLUSIONS QTc prolongation is common in SSc, although anti-Ro antibodies do not seem to be associated with it as is the case in systemic lupus erythematosus. The reasons for this difference as well as the cause of abnormalities in cardiac repolarization in SSc will require additional studies.
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Affiliation(s)
- Charles Massie
- Department of Medicine, McGill University, Montréal, Quebec, Canada
| | - Marie Hudson
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Rheumatology, Jewish General Hospital, Room A-725, 3755 Côte Sainte-Catherine Rd, Montréal, Quebec, Canada H3T 1E2; Lady Davis Institute, Jewish General Hospital, Montréal, Quebec, Canada.
| | - Solène Tatibouet
- Lady Davis Institute, Jewish General Hospital, Montréal, Quebec, Canada
| | - Russell Steele
- Lady Davis Institute, Jewish General Hospital, Montréal, Quebec, Canada; Department of Mathematics, McGill University, Montréal, Quebec, Canada
| | - Thao Huynh
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Cardiology, McGill University Health Center, Montreal, Quebec, Canada
| | - Marvin J Fritzler
- Faculty of Medicine, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Murray Baron
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Rheumatology, Jewish General Hospital, Room A-725, 3755 Côte Sainte-Catherine Rd, Montréal, Quebec, Canada H3T 1E2
| | - Christian A Pineau
- Department of Medicine, McGill University, Montréal, Quebec, Canada; Division of Rheumatology, McGill University Health Center, Montreal, Quebec, Canada
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Xue J, Rowlandson I. The detection of T-wave variation linked to arrhythmic risk: an industry perspective. J Electrocardiol 2013; 46:597-607. [PMID: 24210024 DOI: 10.1016/j.jelectrocard.2013.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Indexed: 01/10/2023]
Abstract
Although the scientific literature contains ample descriptions of peculiar patterns of repolarization linked to arrhythmic risk, the objective quantification and classification of these patterns continues to be a challenge that impacts their widespread adoption in clinical practice. To advance the science, computerized algorithms spawned in the academic environment have been essential in order to find, extract and measure these patterns. However, outside the strict control of a core lab, these algorithms are exposed to poor quality signals and need to be effective in the presence of different forms of noise that can either obscure or mimic the T-wave variation (TWV) of interest. To provide a practical solution that can be verified and validated for the market, important tradeoffs need to be made that are based on an intimate understanding of the end-user as well as the key characteristics of either the signal or the noise that can be used by the signal processing engineer to best differentiate them. To illustrate this, two contemporary medical devices used for quantifying T-wave variation are presented, including the modified moving average (MMA) for the detection of T-wave Alternans (TWA) and the quantification of T-wave shape as inputs to the Morphology Combination Score (MCS) for the trending of drug-induced repolarization abnormalities.
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Marynissen T, Floré V, Heidbuchel H, Nuyens D, Ector J, Willems R. Heart rate turbulence predicts ICD-resistant mortality in ischaemic heart disease. Europace 2013; 16:1069-77. [PMID: 24196450 DOI: 10.1093/europace/eut303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AIMS In high-risk patients, implantable cardioverter-defibrillators (ICDs) can convert the mode of death from arrhythmic to pump failure death. Therefore, we introduced the concept of 'ICD-resistant mortality' (IRM), defined as death (a) without previous appropriate ICD intervention (AI), (b) within 1 month after the first AI, or (c) within 1 year after the initial ICD implantation. Implantable cardioverter-defibrillator implantation in patients with a high risk of IRM should be avoided. METHODS AND RESULTS Implantable cardioverter-defibrillator patients with ischaemic heart disease were included if a digitized 24 h Holter was available pre-implantation. Demographic, electrocardiographic, echocardiographic, and 24 h Holter risk factors were collected at device implantation. The primary endpoint was IRM. Cox regression analyses were used to test the association between predictors and outcome. We included 130 patients, with a mean left ventricular ejection fraction (LVEF) of 33.6 ± 10.3%. During a follow-up of 52 ± 31 months, 33 patients died. There were 21 cases of IRM. Heart rate turbulence (HRT) was the only Holter parameter associated with IRM and total mortality. A higher New York Heart Association (NYHA) class and a lower body mass index were the strongest predictors of IRM. Left ventricular ejection fraction predicted IRM on univariate analysis, and was the strongest predictor of total mortality. The only parameter that predicted AI was non-sustained ventricular tachycardia. CONCLUSION Implantable cardioverter-defibrillator implantation based on NYHA class and LVEF leads to selection of patients with a higher risk of IRM and death. Heart rate turbulence may have added value for the identification of poor candidates for ICD therapy. Available Holter parameters seem limited in their ability to predict AI.
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Affiliation(s)
- Thomas Marynissen
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Vincent Floré
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Hein Heidbuchel
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Dieter Nuyens
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Joris Ector
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Rik Willems
- Department of Cardiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
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Canpolat U, Tokgözoğlu L, Yorgun H, Bariş Kaya E, Murat Gürses K, Şahiner L, Bozdağ G, Kabakçi G, Oto A, Aytemir K. The association of premature ovarian failure with ventricular repolarization dynamics evaluated by QT dynamicity. Europace 2013; 15:1657-63. [PMID: 23592757 DOI: 10.1093/europace/eut093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The association between premature ovarian failure (POF) and cardiovascular diseases has been investigated in a few studies, but none have looked at ventricular repolarization abnormalities in these patients. In this study, we aimed to evaluate the ventricular repolarization by QT dynamicity in patients with POF. METHODS AND RESULTS We enrolled 26 female patients (mean age 37.5 ± 10.1 years) with primary POF and 31 healthy female subjects (mean age 37.5 ± 9.0 years). The linear regression slopes of the QT interval measured to the apex and to the end of the T-wave plotted against RR intervals (QTapex/RR and QTend/RR slopes, respectively) were calculated from 24 h Holter recordings using a standard algorithm. QTapex/RR and QTend/RR slopes were more steeper in the POF patients in contrary to healthy control subjects (QTapex/RR = 0.184 ± 0.022 vs. 0.131 ± 0.019, P < 0.001; QTend/RR = 0.164 ± 0.021 vs. 0.128 ± 0.018, P < 0.001). Pearson's correlation analyses revealed a stronger negative correlation between oestradiol (E2) and QTapex/RR (r = -0.715, P < 0.001). There was also a moderate negative correlation between E2 and QTend/RR (r = -0.537, P < 0.001). Serum follicle-stimulating hormone level was positively correlated with QTapex/RR (r = 0.681, P < 0.001) and QTend/RR (r = 0.531, P < 0.001). CONCLUSIONS Our study results suggest that QT dynamicity is impaired in patients with POF despite the absence of overt cardiovascular involvement. Further studies are needed to elucidate the prognostic significance and clinical implications of impaired ventricular repolarization in patients with POF.
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Affiliation(s)
- Uğur Canpolat
- Department of Cardiology, Faculty of Medicine, Hacettepe University, 06100 Sihhiye, Ankara, Turkey
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Pueyo E, Malik M, Laguna P. Beat-to-beat Adaptation of QT Interval to Heart Rate. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2012; 2005:2475-8. [PMID: 17282739 DOI: 10.1109/iembs.2005.1616970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An adaptive approach is presented to investigate the QT interval response to heart rate variations on a beat-to-beat basis. The relationship between the QT interval and the RR interval is modelled by considering a time-variant system composed of a linear filter followed by a zero-memory nonlinearity approximated by a Taylor expansion. The linear portion describes the influence of previous RR intervals on each QT measurement, while the nonlinear portion expresses how the QT values evolve as a function of the averaged RR measurement at the output of the linear filter. For identification of the unknown system, a Kalman-based procedure is developed that simultaneously estimates all the parameters of the global system. The methodology has been first tested over artificially generated data, showing very good agreement between estimated and theoretical values. Results on data measured over real ECG recordings confirm that the QT interval response is delayed with respect to the RR interval, specially for decelerating heart rate changes. It is also shown that the beat-to-beat evolution of the nonlinearity coefficients is considerably altered when abrupt rate variations occur.
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Affiliation(s)
- Esther Pueyo
- Communications Technology Group (GTC) at the Aragón Institute for Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
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17
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Isik M, Cankurtaran M, Yavuz B, Deniz A, Yavuz B, Halil M, Ulger Z, Aytemir K, Arıoğul S. Blunted baroreflex sensitivity: An underestimated cause of falls in the elderly? Eur Geriatr Med 2012. [DOI: 10.1016/j.eurger.2011.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Fam JM, Ching CK. Review on Non-Invasive Risk Stratification of Sudden Cardiac Death. PROCEEDINGS OF SINGAPORE HEALTHCARE 2011. [DOI: 10.1177/201010581102000404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sudden cardiac death (SCD) is one of the most significant and challenging problems facing modern medicine today given its unpredictable nature. The evaluation of the patient at risk for sudden cardiac death still remains a complex task. The use of ICDs (implantable cardioverter defibrillators) remains the mainstay of primary prevention of sudden cardiac death. However, much remains to be determined on how best to identify patients at high risk of sudden cardiac death who would most benefit from ICD implantations. This paper will review the current issues in the risk assessment of sudden cardiac death and non-invasive markers of sudden death.
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Affiliation(s)
- Jiang Ming Fam
- Department of Cardiovascular Medicine, National Heart Centre, Singapore
| | - Chi Keong Ching
- Department of Cardiovascular Medicine, National Heart Centre, Singapore
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19
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Risk Stratification and Prevention of Sudden Death in Patients with Heart Failure. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2011; 13:517-27. [DOI: 10.1007/s11936-011-0144-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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20
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Low hemoglobin levels during normovolemia are associated with electrocardiographic changes in pigs. Shock 2011; 35:375-81. [PMID: 20856175 DOI: 10.1097/shk.0b013e3181f6aa44] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We studied whether low hemoglobin concentrations during normovolemia change the myocardial electrical current (electrocardiogram) in a pig model. Normovolemic anemia was achieved by stepwise replacing blood with colloids (hydroxyethyl starch 6%). We measured the length of the PQ-, QT-, QTc, and the ST interval as well as the amplitude of the Q wave and T wave at hemoglobin concentrations of 9.5, 8.0, 5.5, 3.8, and 3.3 g·dL. Normovolemic anemia is accompanied by a gradual prolongation of the QT and QTc interval and a reduction in the amplitude of the T wave. The QRS complex is partly diminished in amplitude. Results were verified performing a time-frequency analysis on single heartbeats. During severe anemia and normovolemia, electrocardiographic changes can be detected. Further investigations are warranted to elucidate whether these changes indicate myocardial hypoxia.
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Johnson NP, Holly TA, Goldberger JJ. QT dynamics early after exercise as a predictor of mortality. Heart Rhythm 2010; 7:1077-84. [PMID: 20478405 DOI: 10.1016/j.hrthm.2010.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Accepted: 05/01/2010] [Indexed: 11/16/2022]
Abstract
BACKGROUND Exercise and QT dynamics during ambulatory monitoring impact mortality in a variety of populations. Heart rate recovery (HRR) after exercise is a known strong predictor of mortality. OBJECTIVE This study assessed the independent prognostic significance of the QT response to changing heart rate (QT dynamics) during recovery from exercise. METHODS The cohort included patients referred for treadmill exercise stress testing over a 5-year period. Patients had to have at least 4 electrocardiographic tracings within 5 minutes of peak exercise. One had to be recorded 60 seconds into recovery to calculate the HRR. Linear regression of the QT-RR relation during recovery was used to predict the QT interval at cycle lengths of 500 and 600 ms (QT-500 and QT-600). Only studies with an R(2) > or = 0.9 (72%) were retained. Optimal binary cut points were chosen. All-cause mortality was determined from either the Social Security Death Index or hospital records. RESULTS A total of 2,994 patients met inclusion criteria; 228 (7.6%) died during an average follow-up of 7.6 +/- 1.9 years. Abnormal QT-500 (>316 ms) was the strongest univariate QT dynamics predictor in a Cox proportional hazards model (hazard ratio = 2.13, P <.001). It remained an independent predictor of mortality after adjustment for age, exercise capacity, medications, single photon emission computed tomography defects, and abnormal (<12 beats/min) HRR (hazard ratio = 1.46, P = .014). CONCLUSION An abnormal predicted QT interval at 500 ms (120 beats/min) during recovery from exercise independently predicts all-cause mortality. Because QT dynamics in recovery incorporate information on both repolarization and autonomic responsiveness, its role in risk prediction for sudden cardiac death should be further explored.
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Affiliation(s)
- Nils P Johnson
- Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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22
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Williams SM, Velez DR, Menon R. Geographic ancestry and markers of preterm birth. Expert Rev Mol Diagn 2010; 10:27-32. [PMID: 20014920 DOI: 10.1586/erm.09.70] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Several biomarkers associated with spontaneous preterm birth (PTB) have been discovered over the last decade. Many of these markers, such as cytokines, are associated with infection and inflammation. As such, these biomarkers represent biologically plausible candidates for assessing those at risk of PTB. However, in the early association studies of biomarker-pregnancy outcome, the geographic ancestry of subjects was not considered. Based on more recent data, it is becoming increasingly evident that these biomarkers, and a universal approach that uses a single biomarker, fail to provide adequate assessment of risk in all subjects. Rather, recent data support the conclusion that some markers associate in subjects of African descent and another nonoverlapping set associates in subjects of European descent. These data indicate that diagnostic or predictive tests will have to use different biomarkers for different sets of subjects. If this is true, it poses severe restrictions on how to predict outcome or perform tests of association, and may make it impossible to determine risk or provide proper intervention. An alternative is presented that, although not yet proven, may make it possible to use a common set of biomarkers and their relationships to assess risk.
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Affiliation(s)
- Scott M Williams
- Department of Molecular Physiology and Biophysics, Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232, USA.
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23
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Chao CC, Wang TL, Chong CF, Lin YM, Chen CC, Tang GJ, Yen DHT. Prognostic value of QT parameters in patients with acute hemorrhagic stroke: a prospective evaluation with respect to mortality and post-hospitalization bed confinement. J Chin Med Assoc 2009; 72:124-32. [PMID: 19299219 DOI: 10.1016/s1726-4901(09)70037-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND This prospective study was performed to evaluate the prognostic prediction value of QT parameters and clinical characteristics exhibited by patients with acute hemorrhagic stroke at the time of presenting to the emergency department (ED). METHODS One hundred and sixty-six patients admitted to the ED of Taipei Veterans General Hospital from January 2006 to October 2006 because of acute hemorrhagic stroke were enrolled. Glasgow Coma Scale (GCS) scores between 3 and 8 were taken to indicate severe neurologic deficits. QT parameters (QT max, QT min, QT dispersion, QTc max, QTc min, QTc dispersion) and other pertinent clinical variables were determined on admission. Logistic regression model was applied to evaluate prognostic prediction values. RESULTS Mortality was higher among stroke patients with low GCS scores (p < 0.01). Leukocyte counts and systolic blood pressures were significantly higher among non-surviving patients (p = 0.04). No association was found between QT parameters and mortality (all p > 0.05). Among survivors, post-hospitalization bed confinement was required for those significantly older (p = 0.01) and those with higher QT max and QTc max values in multivariate analyses (p = 0.04 and p < 0.01, respectively). CONCLUSION Low GCS scores, increased leukocyte counts, and elevated systolic blood pressures predict increased mortality for subjects with acute hemorrhagic stroke. Advanced age and prolongations in QTc and QT max at the time of stroke predicted poor functional recovery for these subjects.
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Affiliation(s)
- Chun-Chieh Chao
- Department of Emergency Medicine, Zhong-Xiao Branch, Taipei City Hospital, Taipei, Taiwan, Republic of China
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CYGANKIEWICZ IWONA, ZAREBA WOJCIECH, VAZQUEZ RAFAEL, ALMENDRAL JESUS, BAYES-GENIS ANTONI, FIOL MIQUEL, VALDES MARIANO, MACAYA CARLOS, GONZALEZ-JUANATEY JOSER, CINCA JUAN, DE LUNA ANTONIBAYES. Prognostic Value of QT/RR Slope in Predicting Mortality in Patients with Congestive Heart Failure. J Cardiovasc Electrophysiol 2008; 19:1066-72. [DOI: 10.1111/j.1540-8167.2008.01210.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ciarka A, Borne PVD, Pathak A. Myocardial infarction, heart failure and sympathetic nervous system activity: new pharmacological approaches that affect neurohumoral activation. Expert Opin Investig Drugs 2008; 17:1315-30. [DOI: 10.1517/13543784.17.9.1315] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Ding L, Hua W, Niu H, Chen K, Zhang S. Primary prevention of sudden cardiac death using implantable cardioverter defibrillators. Europace 2008; 10:1034-41. [PMID: 18559335 DOI: 10.1093/europace/eun150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Despite substantial advances in prevention and treatment of cardiovascular diseases, sudden cardiac death (SCD) remains a leading cause of death in industrialized countries. Implantable cardioverter defibrillator (ICD) has been demonstrated to be an attractive option for primary prevention of SCD in high-risk patients. This review discusses the progress in the risk stratification for selecting high-risk patients, highlights the clinical trials of primary prevention for SCD, outlines the efficacy of combined use of cardiac resynchronization therapy with ICD, and analyses the cost-effectiveness issue of this device.
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Affiliation(s)
- Ligang Ding
- Center of Arrhythmia, Fuwai Cardiovascular Hospital, Peking Union Medical College, Beijing, China
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27
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Due-Andersen R, Høi-Hansen T, Larroude CE, Olsen NV, Kanters JK, Boomsma F, Pedersen-Bjergaard U, Thorsteinsson B. Cardiac repolarization during hypoglycaemia in type 1 diabetes: impact of basal renin-angiotensin system activity. Europace 2008; 10:860-7. [PMID: 18534966 DOI: 10.1093/europace/eun137] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
AIMS Hypoglycaemia-induced cardiac arrhythmias may be involved in the pathogenesis of the 'dead-in-bed syndrome' in patients with type 1 diabetes. Evidence suggests that the renin-angiotensin system (RAS) influences the occurrence of arrhythmias. The aim of this study was to explore if basal RAS activity affects cardiac repolarization during hypoglycaemia, thereby potentially carrying prognostic information on risk of the 'dead-in-bed syndrome'. METHODS AND RESULTS Nine subjects with high RAS activity and nine subjects with low RAS activity were subjected to single-blinded placebo-controlled hypoglycaemia (nadir plasma glucose 2.4 mmol/L). QTc/QTcF and QT dynamics were registered by Holter monitoring. QTc prolonged during [8 (+/-2.3) ms, P < 0.01] and after [11 (+/-3) ms, P < 0.001] hypoglycaemia. Dynamic QT parameters reacted ambiguously. Low RAS activity was associated with a slightly more pronounced QT prolongation [6 (+/-3) ms, P = 0.04]. Adrenaline tended to increase more in the low-RAS group (P = 0.08) and was correlated to QTc (r = 0.67, P < 0.01) and QTcF (r = 0.58, P < 0.05) during hypoglycaemia. CONCLUSION Low basal RAS activity may be associated with a slightly more pronounced QT prolongation during hypoglycaemia, when compared with high RAS activity. The impact, however, is modest and the clinical consequence is unclear.
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Affiliation(s)
- Rikke Due-Andersen
- Endocrinology Section, Department of Cardiology and Endocrinology, Hillerød Hospital, Helsevej 2, DK-3400 Hillerød, Denmark.
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Halámek J, Jurák P, Villa M, Novák M, Vondra V, Soucek M, Frána P, Somers VK, Kára T. Dynamic QT/RR coupling in patients with pacemakers. ACTA ACUST UNITED AC 2008; 2007:919-22. [PMID: 18002107 DOI: 10.1109/iembs.2007.4352441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The dynamic coupling between heart rate intervals (RR) and ventricular repolarization (QT) is analyzed. The analysis is based on measurements of 11 patients with pacemaker. In each measurement, there are at least 4 abrupt changes of RR preset by the pacemaker. With such a protocol, RR changes are important and well defined while disturbing factors and noise sources (such as those related with motion of patient) are minimized. The QT/RR coupling was described by 3 parameters (a1, b2, b3) transfer function (TRF) selected on the basis of a statistical analysis of performances of different TRF models. We found that our model is by far the best in its class: with more parameters (higher order models) the residuals remain almost the same while the extra parameters display variability much larger than that of our parameters. For all measurements, our TRF model describes more than 70% of QT variability. Within the patient set, we found interesting differences concerning dynamic non-linearity (response times longer with decreasing RR intervals than with increasing RR).
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Affiliation(s)
- J Halámek
- Institute of Scientific Instruments, AS CR, Brno, 612 64 CZ.
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29
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Pueyo E, Malik M, Laguna P. A dynamic model to characterize beat-to-beat adaptation of repolarization to heart rate changes. Biomed Signal Process Control 2008. [DOI: 10.1016/j.bspc.2007.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Xhaët O, Argacha JF, Pathak A, Gujic M, Houssiere A, Najem B, Degaute JP, Van de Borne P. Sympathoexcitation increases the QT/RR slope in healthy men: differential effects of hypoxia, dobutamine, and phenylephrine. J Cardiovasc Electrophysiol 2007; 19:178-84. [PMID: 18081764 DOI: 10.1111/j.1540-8167.2007.01039.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Dynamic ventricular repolarization assessed by QT/RR slopes studies the effects of modifications in cardiac repolarization independently of variations in RR interval (RR). The effects of changes in sympathetic and vagal activity on the QT/RR slope are controversial. We tested the hypothesis that sympathoexcitation is an important determinant of the QT/RR slope. METHODS AND RESULTS We compared the effects of a reflex sympathetic activation in response to hypoxia, to the direct effects of the infusion of the beta-adrenergic agent dobutamine, on the QTa (apex) and QTe (end)/RR slopes. Dobutamine was titrated to obtain similar increases in cardiac output than with hypoxia. Cardiac vagal activity was estimated by rMSSD and pNN50. In a second group of healthy subjects, we assessed the effect of a reflex cardiac vagal activation in response to phenylephrine infusion on the same variables. We observed a similar increase in QTa and QTe slopes during hypoxia and dobutamine (both P < 0.017 vs. normoxia), despite divergent changes in cardiac vagal activity, as rMSSD and pNN50 decreased with hypoxia compared to normoxia (P < 0.001) but increased during dobutamine infusion compared to hypoxia (P < 0.017). In contrast, these slopes did not change during the rises in rMSSD and pNN50 elicited by phenylephrine (P > 0.7). CONCLUSION Beta-adrenergic stimulation induces comparable increases in the QT/RR slopes than hypoxia, but in the presence of a larger cardiac vagal activity. Vagal cardiac activation by phenylephrine does not change the QT slopes. This reveals that the sympathetic system is an important determinant of QT/RR dynamicity in healthy men.
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Affiliation(s)
- Olivier Xhaët
- Department of Cardiology, Erasme University Hospital, Brussels, Belgium.
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31
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Halámek J, Jurák P, Villa M, Soucek M, Frána P, Nykodým J, Eisenberger M, Leinveber P, Vondra V, Somers VK, Kara T. Dynamic coupling between heart rate and ventricular repolarisation. BIOMED ENG-BIOMED TE 2007; 52:255-63. [PMID: 17561787 DOI: 10.1515/bmt.2007.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A novel model for the coupling between ventricular repolarisation and heart rate (QT/RR) is presented. It is based upon a transfer function (TRF) formalism that describes the static and dynamic properties of this coupling, i.e., the behaviour after a sudden change in heart rate. Different TRF models were analysed by comparing their capability to describe experimental data collected from 19 healthy volunteers using several RR stimulation protocols: (i) rest with deep breathing at 0.1 Hz; (ii) tilt with controlled breathing at 0.1 and 0.33 Hz; and (iii) cycling. A search for the best TRF led to unambiguous identification of a three-parameter model as the most suitable descriptor of QT/RR coupling. Compared with established static models (linear or power-law), our model predictions are substantially closer to the experimental results, with errors approximately 50% smaller. The shape of the frequency and step responses of the TRF presented is essentially the same for all subjects and protocols. Moreover, each TRF may be uniquely identified by three parameters obtained from the step response, which are believed to be of physiological relevance: (i) gain for slow RR variability; (ii) gain for fast RR variability; and (iii) time during which QT attains 90% of its steady-state value. The TRF successfully describes the behaviour of the RR control following an abrupt change in RR interval, and its parameters may offer a tool for detecting pharmacologically induced changes, particularly those leading to increased arrhythmogenic risk.
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Affiliation(s)
- Josef Halámek
- Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Brno 612 64, Czech Republic.
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Iacoviello M, Forleo C, Guida P, Romito R, Sorgente A, Sorrentino S, Catucci S, Mastropasqua F, Pitzalis M. Ventricular repolarization dynamicity provides independent prognostic information toward major arrhythmic events in patients with idiopathic dilated cardiomyopathy. J Am Coll Cardiol 2007; 50:225-31. [PMID: 17631214 DOI: 10.1016/j.jacc.2007.02.071] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/06/2007] [Accepted: 02/12/2007] [Indexed: 01/08/2023]
Abstract
OBJECTIVES The purpose of this work was to evaluate whether ventricular repolarization dynamicity predicts major arrhythmic events in patients with idiopathic dilated cardiomyopathy (DCM). BACKGROUND Arrhythmic risk stratification in patients with DCM is still an open issue. Ventricular repolarization analysis should provide relevant information, but QT interval and QT dispersion failed in predicting arrhythmic risk. METHODS The following parameters were evaluated in 179 consecutive DCM patients without history of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) at enrollment: QRS duration, QT interval corrected for heart rate, and QT dispersion at electrocardiogram (ECG); left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter at echocardiogram; and nonsustained ventricular tachycardia (NSVT), heart rate variability (standard deviation of RR intervals), and ventricular repolarization dynamicity as measured by means of 24-h ECG monitoring, by calculating the slope of linear regression analysis of QT end and RR intervals (QTe-slope) and the value of mean QT end corrected for heart rate. RESULTS During a mean follow-up of 39 months, 9 patients died suddenly and 15 experienced VT and/or VF. At multivariate analysis, LVEF (p = 0.047), NSVT (p = 0.022), and QTe-slope (p = 0.034) were significantly associated with arrhythmic events. Among the patients with a low LVEF, NSVT and/or steeper QTe-slope identified a subgroup at highest arrhythmic risk. CONCLUSIONS In patients with DCM, QT dynamicity is independently associated with the occurrence of major arrhythmic events and improves the predictive accuracy of stratifying arrhythmic risk of these patients.
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Yavuz B, Deniz A, Abali G, Ciftci O, Sahiner L, Aytemir K, Tokgozoglu L, Oto A. Impaired ventricular electrical stability and sympathetic hyperactivity in patients with multivessel coronary artery disease. Coron Artery Dis 2007; 18:241-5. [PMID: 17496486 DOI: 10.1097/mca.0b013e3280ad4373] [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: 11/26/2022]
Abstract
OBJECTIVES The extent of atherosclerotic disease is identified as one of the most important predictors of long-term cardiac events in patients with coronary artery disease. Heart rate variability and QT dynamicity have been used as independent predictors for sudden death in coronary artery disease. Heart rate variability and QT dynamicity, however, have never been investigated in multivessel coronary artery disease. The aim of this study was to identify autonomic nervous system activity and ventricular vulnerability in multivessel coronary artery disease. METHODS We examined 204 patients who underwent coronary angiography. According to the number of the three major coronary vessels with significant stenosis (>70%), we divided the patients into three groups: normal coronary arteries (n=61), single-vessel coronary artery disease (n=53) and the multivessel coronary artery disease (n=90). Twenty-four-hour ambulatory electrocardiographic recording was performed by a three-channel recorder. Heart rate variability and QT dynamicity parameters were obtained by ELA TEC software. RESULTS Baseline characteristics were similar in multivessel coronary artery disease, single-vessel coronary artery disease and controls. SDNN (90+/-35, 117+/-52, 134+/-53, respectively; P<0.001) and HFnu (9.6+/-8.2, 8.9+/-3.7, 12.2+/-7.4, respectively; P=0.011) were significantly lower, whereas LFnu (27.2+/-11.3, 26.1+/-8.4, 22.0+/-13.4, respectively; P=0.014) and LF/HF ratio (4.4+/-3.2, 3.3+/-1.4, 2.1+/-1.6, respectively; P<0.001) were significantly higher in multivessel coronary artery disease. QTend/RR and QTapex/RR slopes were more significantly increased in multivessel coronary artery disease than in single-vessel coronary artery disease and control participants [QTend/RR: 0.15 (0.04-0.66), 0.12 (0.02-0.33), 0.12 (0.01-0.22), respectively; P=0.002; QTapex/RR: 0.16 (0.06-0.30), 0.12 (0.02-0.29), 0.11 (0.01-0.19), respectively; P<0.001]. CONCLUSIONS Heart rate variability and QT dynamicity are impaired in patients with multivessel coronary artery disease. Our results may indicate that heart rate variability and QT dynamicity parameters can be useful noninvasive methods that may detect autonomic nervous system activity and ventricular vulnerability in multivessel coronary artery disease.
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Affiliation(s)
- Bunyamin Yavuz
- Department of Cardiology, Kecioren Research Hospital, Ankara, Turkey.
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Bonnemeier H. [Clinical significance of dynamic QT-interval-analyses]. Herzschrittmacherther Elektrophysiol 2007; 18:30-8. [PMID: 17401702 DOI: 10.1007/s00399-007-0551-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 02/01/2007] [Indexed: 05/14/2023]
Abstract
Dynamic parameters of ventricular repolarization as Holter derived parameters expressed as QT-interval adaptation to heart rate changes (QT/RR-slope) and QT-interval-variability are being more and more frequently used to identify patients with increased risk for ventricular arrhythmias. Steep QT-RR-slopes, reflecting inadequate adaptation of ventricular repolarization to heart rate changes, as well as increased QT-interval-variability, reflecting temporal inhomogeneity of ventricular repolarization duration, are frequently observed in patients at risk for sudden cardiac death. Additionally, there is strong evidence for significant alterations in the dynamics of action potential duration restitution in patients with structural heart disease. This review gives an up-to-date overview about the current research in methods of assessment and clinical relevance of dynamic parameters of ventricular repolarization.
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Affiliation(s)
- H Bonnemeier
- Medizinische Klinik II, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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Lieb W, Voss C, Ortak J, Barantke M, Hengstenberg C, Loewel H, Holmer S, Erdmann J, Schunkert H, Bonnemeier H. Impact of Diabetes on QT Dynamicity in Patients With and Without Myocardial Infarction: The KORA Family Heart Study. Pacing Clin Electrophysiol 2007; 30 Suppl 1:S183-7. [PMID: 17302701 DOI: 10.1111/j.1540-8159.2007.00634.x] [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: 11/28/2022]
Abstract
INTRODUCTION Patients with diabetes mellitus (DM) have an unfavorable prognosis after myocardial infarction (MI), partially due to a higher risk of sudden cardiac death (SCD). QT dynamicity is an independent predictor of SCD in post-MI patients. However, the effects of diabetes on QT dynamicity in patients with MI have not been described. METHODS We studied 468 survivors of MI (67 with DM) from the population-based MONICA registry (KORA Family Heart Study), Augsburg, Germany, by standardized questionnaire, anthropometry, electrocardiogram (ECG), 30-minute-Holter-ECG-recordings and echocardiography. In addition, 422 siblings without prior MI (22 with DM) were studied by the same protocol. RESULTS Among post-MI patients, the QT/RR slope was significantly steeper in diabetics than in nondiabetics (0.096 +/- 0.057 vs 0.077 +/- 0.045; P = 0.002). Likewise, among siblings without MI, the QT/RR slope was steeper in diabetics than in nondiabetics (0.104 +/- 0.053 vs 0.080 +/- 0.042; P = 0.008). The association of DM with steeper QT/RR slope remained significant in multivariate models in post-MI patients (beta: -0.14; P = 0.004) as well as in individuals without MI (beta: -0.10; P = 0.047). CONCLUSIONS In a large population of survivors of MI and unaffected siblings, patients and siblings presenting with DM exhibited an abnormal QT rate-dependence, compared with individuals without DM in both groups. Thus, diabetes itself may be a major determinant of ventricular arrhythmias, independently of a previous MI. These observations might in part explain the higher incidence of sudden cardiac death and ventricular arrhythmias in patients with DM.
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Affiliation(s)
- Wolfgang Lieb
- Medizinische Klinik 2, Universitatsklinikum Schleswig-Holstein, Campus Lubeck, Lubeck, Germany
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Flevari P, Parissis JT, Leftheriotis D, Panou F, Kourea K, Kremastinos DT. Effect of levosimendan on ventricular arrhythmias and prognostic autonomic indexes in patients with decompensated advanced heart failure secondary to ischemic or dilated cardiomyopathy. Am J Cardiol 2006; 98:1641-5. [PMID: 17145226 DOI: 10.1016/j.amjcard.2006.07.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 07/03/2006] [Accepted: 07/03/2006] [Indexed: 11/21/2022]
Abstract
Positive inotropes used for the treatment of heart failure have been arrhythmogenic. Levosimendan is a novel calcium sensitizer with vasodilating properties and a complex mechanism of action. Its effect on ventricular arrhythmias and 24-hour Holter electrocardiographically derived prognostic autonomic nervous system-related markers, because it occurs in parallel with changes in cardiac function and neurohormonal response, has not been systematically assessed. Forty-five patients (mean age 65 +/- 1.3 years) with heart failure refractory to conventional therapy and a mean ejection fraction of 23 +/- 1.2%, randomized to levosimendan or placebo, were studied. After Holter electrocardiographic recording, 1 drug was infused for 24 hours (levosimendan at a dose of 0.1 mug/kg/min). During this period, another Holter recording was performed to assess changes in ventricular arrhythmogenesis, 24-hour heart rate variability indexes, QTc, QT variability, and QT/RR slope. Clinical evaluation, echocardiography, and B-type natriuretic peptide measurements were performed at baseline and after treatment. After levosimendan, clinical and echocardiographic improvement was observed, associated with beneficial neurohormonal modulation (mean B-type natriuretic peptide level after levosimendan 668 +/- 108 vs 1,009 +/- 122 pg/ml at baseline, p <0.05). Episodes of nonsustained ventricular tachycardia increased with levosimendan (21.9 +/- 9.6 vs 3.0 +/- 1.2, p <0.05). Levosimendan and placebo exerted a neutral effect on all autonomic markers assessed. In conclusion, levosimendan at low doses increases nonsustained ventricular arrhythmias, without affecting Holter-derived, prognostically significant autonomic markers. At the same time, it is associated with improvements in cardiac function and neurohormonal response. These findings may have important clinical and prognostic implications.
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Affiliation(s)
- Panayota Flevari
- Second Department of Cardiology, Attikon University Hospital, Athens, Greece.
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Yavuz B, Duman U, Abali G, Dogan OF, Yazicioglu A, Sahiner L, Aytemir K, Tokgozoglu L, Demircin M, Nazli N, Kabakci G, Oto A. Coronary Artery Bypass Grafting Is Associated with a Significant Worsening of QT Dynamicity and Heart Rate Variability. Cardiology 2006; 106:51-5. [PMID: 16612069 DOI: 10.1159/000092599] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 03/01/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND Imbalance in autonomic nervous system and impaired myocardial repolarization has been shown to increase the risk for arrhythmias in patients with coronary artery disease. This study evaluated the effects of coronary artery bypass grafting (CABG) on heart rate variability and QT interval dynamicity in subjects with coronary artery disease undergoing elective CABG surgery. METHODS The study group consisted of 68 consecutive patients (mean age +/-SD: 61 +/- 9 years) with coronary artery disease who underwent elective CABG. Twenty-four-hour Holter monitoring was performed 2-5 days before cardiac surgery and was repeated 10 days after CABG. ELATEC holter software was used to calculate heart rate variability and QT dynamicity parameters. All subjects had a complete history, laboratory examination and transthoracic echocardiography. RESULTS All patients had beta-blocking agent medication pre- and postoperatively. Standard deviation of all NN intervals for a selected time period, square root of the mean of the sum of the squares of differences between adjacent RR intervals, the proportion of differences in successive NN intervals greater than 50 ms, normalized low-frequency power, and normalized high-frequency power were significantly decreased after CABG surgery, whereas low-frequency/high-frequency ratio was significantly increased after CABG. QT/RR slopes over 24 h were significantly increased after CABG surgery for QT end and QT apex (QTapex/RR: 0.16 +/- 0.13 vs. 0.28 +/- 0.19, p < 0.001; QTend/RR: 0.18 +/- 0.13 vs. 0.36 +/- 0.23, p < 0.001). CONCLUSION This prospective study showed for the first time that CABG was associated with a significant worsening of heart rate variability and QT dynamicity parameters in the postoperative period.
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Affiliation(s)
- Bunyamin Yavuz
- Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
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Larroude CE, Jensen BT, Agner E, Toft E, Torp-Pedersen C, Wachtell K, Kanters JK. Beat-to-beat QT dynamics in paroxysmal atrial fibrillation. Heart Rhythm 2006; 3:660-4. [PMID: 16731466 DOI: 10.1016/j.hrthm.2006.02.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Accepted: 02/15/2006] [Indexed: 11/30/2022]
Abstract
BACKGROUND QT dynamics parameters are used only in sinus rhythm. However, because many patients with paroxysmal atrial fibrillation undergo antiarrhythmic treatment that changes QT, developing methods for measuring QT dynamics during atrial fibrillation is important. OBJECTIVES The purpose of this study was to evaluate whether QT dynamics in atrial fibrillation can be measured more reliably if additional RR intervals are included in the QT calculation. METHODS QT and RR intervals were measured in 15 patients with atrial fibrillation and sinus rhythm on the same 24-hour Holter recording. Full QT adaptation is not instantaneous but lags behind over several beats. To correct for this lag, we adapted a weighted average method using five successive RR intervals. Linear regression was performed on (QT, RR) and (QT, RR(modified)) pairs. Variability ratio (standard deviation of all QT intervals/standard deviation of all RR intervals) and modified variability ratio (standard deviation of all QT intervals/modified standard deviation of all RR intervals) were calculated. RESULTS QT-RR slope was reduced in atrial fibrillation compared with sinus rhythm (0.076 +/- 0.009 vs 0.113 +/- 0.0013, P = .0005). When correcting for lag, using the QT-RR(modified) slope, the slope in atrial fibrillation became similar to the slope in sinus rhythm (0.126 +/- 0.013 vs 0.126 +/- 0.013, P = .9547). The variability ratio was reduced in atrial fibrillation compared with sinus rhythm (0.175 +/- 0.017 vs 0.240 +/- 0.031, P = .009), but when correcting for the lag, the modified variability ratio was similar in atrial fibrillation and sinus rhythm (0.262 +/- 0.029 vs 0.267 +/- 0.038, P = .80). CONCLUSION The results of this study demonstrate that QT dynamics can be measured reliably in atrial fibrillation using 24-hour Holter recordings.
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Affiliation(s)
- Charlotte E Larroude
- Laboratory of Experimental Cardiology, Department of Medical Physiology, University of Copenhagen, Denmark
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