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Zhang YT, Li HY, Sun XT, Tong XW, Shan YY, Xu YX, Pu SD, Gao XY. Relationship Between Index of Cardiac Electrophysiological Balance, Frontal QRS-T Angle and Retinopathy in People with Type 2 Diabetes. Diabetes Metab Syndr Obes 2023; 16:861-871. [PMID: 36974327 PMCID: PMC10039660 DOI: 10.2147/dmso.s403210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/14/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Diabetic retinopathy (DR) is strongly associated with cardiovascular disease, which is a risk factor for sudden cardiac death (SCD). The index of cardiac electrophysiological balance (iCEB) and the frontal QRS-T angle are recommended to predict the risk of ventricular arrhythmias more than other ECG parameters. However, the relationships between these two markers and DR have not yet been explored. The aim of this study was to investigate the variation in the iCEB, corrected iCEB (iCEBc) and frontal QRS-T angle in different stages of DR and determine whether there are associations between these markers and DR. METHODS The sample comprised 665 patients with Type 2 diabetes mellitus (T2DM) who were classified into three groups: no DR (NDR), mild to moderate non-proliferative DR (NPDR), and vision-threatening DR (VTDR). Twelve-lead ECG was performed and the QT, QTc, QRS duration, iCEB, iCEBc and frontal QRS-T angle were recorded and compared across the groups. RESULTS The VTDR group had a significantly higher iCEBc and frontal QRS-T angle than the NDR and NPDR groups. After controlling for confounding variables, the correlations between the iCEBc (OR=2.217, 95% CI=1.464-3.358, P<0.001), frontal QRS-T angle (OR=1.017, 95% CI=1.008-1.025, P<0.001) and DR risk remained (P<0.05). Subjects in the fourth iCEBc quartile (adjusted OR=2.612, 95% CI=1.411-4.834, p=0.002) had a much higher chance of developing DR compared to those in the first quartile. In comparison to the first frontal QRS-T angle quartile, subjects in the third (adjusted OR=1.998, 95% CI=1.167-3.422, P=0.012) and fourth (adjusted OR=2.430, 95% CI=1.420-4.160, P=0.001) frontal QRS-T angle quartiles had significantly greater risks of DR. CONCLUSION With the progression of DR, the iCEBc and frontal QRS-T angle increase. An increased iCEBc and frontal QRS-T angle are associated with an increased risk of DR.
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Affiliation(s)
- Yi-Tong Zhang
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Hui-Yao Li
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Xiao-Tong Sun
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Xue-Wei Tong
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Yong-Yan Shan
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Yu-Xin Xu
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Sheng-Dan Pu
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
| | - Xin-Yuan Gao
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, People’s Republic of China
- Correspondence: Xin-Yuan Gao, Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Harbin, 150001, People’s Republic of China, Email
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Xia R, Tomsits P, Loy S, Zhang Z, Pauly V, Schüttler D, Clauss S. Cardiac Macrophages and Their Effects on Arrhythmogenesis. Front Physiol 2022; 13:900094. [PMID: 35812333 PMCID: PMC9257039 DOI: 10.3389/fphys.2022.900094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022] Open
Abstract
Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.
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Affiliation(s)
- Ruibing Xia
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Philipp Tomsits
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Simone Loy
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Zhihao Zhang
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Valerie Pauly
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Dominik Schüttler
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
| | - Sebastian Clauss
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Institute of Surgical Research at the Walter-Brendel-Centre of Experimental Medicine, University Hospital Munich, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich, Munich Heart Alliance, Munich, Germany
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Zayas-Arrabal J, Alquiza A, Tuncay E, Turan B, Gallego M, Casis O. Molecular and Electrophysiological Role of Diabetes-Associated Circulating Inflammatory Factors in Cardiac Arrhythmia Remodeling in a Metabolic-Induced Model of Type 2 Diabetic Rat. Int J Mol Sci 2021; 22:ijms22136827. [PMID: 34202017 PMCID: PMC8268936 DOI: 10.3390/ijms22136827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/29/2022] Open
Abstract
Background: Diabetic patients have prolonged cardiac repolarization and higher risk of arrhythmia. Besides, diabetes activates the innate immune system, resulting in higher levels of plasmatic cytokines, which are described to prolong ventricular repolarization. Methods: We characterize a metabolic model of type 2 diabetes (T2D) with prolonged cardiac repolarization. Sprague-Dawley rats were fed on a high-fat diet (45% Kcal from fat) for 6 weeks, and a low dose of streptozotozin intraperitoneally injected at week 2. Body weight and fasting blood glucose were measured and electrocardiograms of conscious animals were recorded weekly. Plasmatic lipid profile, insulin, cytokines, and arrhythmia susceptibility were determined at the end of the experimental period. Outward K+ currents and action potentials were recorded in isolated ventricular myocytes by patch-clamp. Results: T2D animals showed insulin resistance, hyperglycemia, and elevated levels of plasma cholesterol, triglycerides, TNFα, and IL-1b. They also developed bradycardia and prolonged QTc-interval duration that resulted in increased susceptibility to severe ventricular tachycardia under cardiac challenge. Action potential duration (APD) was prolonged in control cardiomyocytes incubated 24 h with plasma isolated from diabetic rats. However, adding TNFα and IL-1b receptor blockers to the serum of diabetic animals prevented the increased APD. Conclusions: The elevation of the circulating levels of TNFα and IL-1b are responsible for impaired ventricular repolarization and higher susceptibility to cardiac arrhythmia in our metabolic model of T2D.
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Affiliation(s)
- Julian Zayas-Arrabal
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Amaia Alquiza
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, 06100 Ankara, Turkey;
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Lokman Hekim University, 06510 Ankara, Turkey;
| | - Monica Gallego
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
| | - Oscar Casis
- Departament of Physiology, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria-Gasteiz, Spain; (J.Z.-A.); (A.A.); (M.G.)
- Correspondence: ; Tel.: +34-945013033
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Eren H, Kaya Ü, Öcal L, Öcal AG, Genç Ö, Genç S, Evlice M. Presence of fragmented QRS may be associated with complex ventricular arrhythmias in patients with type-2 diabetes mellitus. Acta Cardiol 2021; 76:67-75. [PMID: 31775006 DOI: 10.1080/00015385.2019.1693117] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Ventricular arrhythmias (VAs) are frequent in diabetes mellitus (DM) patients. Myocardial fibrosis is one of the components of diabetic cardiomyopathy secondary to DM. Fragmented QRS (fQRS) on electrocardiography (ECG) has been shown to be a marker of myocardial fibrosis. In this study, we aimed to investigate the association between fQRS and complex VAs in patients with DM. METHODS Three hundred and thirty-six consecutive patients who were diagnosed with DM were included in the study. The control group consisted of 275 age- and sex-matched healthy individuals. ECG and transthoracic echocardiography were performed in all the patients. fQRS was defined as additional R' wave or notching/splitting of S wave in two contiguous ECG leads. All the patients underwent 24-h Holter monitoring and VAs were classified using Lown's scoring system. Lown class ≥ 3 VAs were considered as complex VAs. RESULTS As compared to the healthy individuals, prevalence of fQRS (37.5% vs. 6.9%, p < .001) and complex VAs (14% vs. 0%, p < .001) were significantly higher in patients with DM. Furthermore, complex VAs (28.4% vs. 6.4%, p < .001) were significantly higher in DM patients with fQRS. In multiple logistic regression analysis, DM duration (OR: 1.510, 95% CI:1.343 to 1.698; p < .001) and presence of fQRS (OR: 3.262, 95% CI: 1.443 to 7.376; p = .004) were independent predictors for complex VAs. CONCLUSIONS The presence of fQRS may be associated with complex VAs in patients with DM. Therefore, fQRS may be used as a predictor of complex VAs and the risk of sudden death in patients with DM.
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Affiliation(s)
- Hayati Eren
- Department of Cardiology, Elbistan State Hospital, Kahramanmaraş, Turkey
| | - Ülker Kaya
- Department of Cardiology, Elbistan State Hospital, Kahramanmaraş, Turkey
| | - Lütfi Öcal
- Department of Cardiology, Kosuyolu Kartal Heart Training and Research Hospital, Istanbul, Turkey
| | - Aslı Gözek Öcal
- Department of Internal Medicine, Kartal Dr Lütfi Kırdar Training and Research Hospital, Istanbul, Turkey
| | - Ömer Genç
- Department of Internal Medicine, Kahramanmaraş Necip Fazıl City Hospital, Kahramanmaraş, Turkey
| | - Selin Genç
- Department of Internal Medicine, Türkoğlu Kemal Beyazıt State Hospital, Kahramanmaraş, Turkey
| | - Mert Evlice
- Department of Cardiology, Universtiy of Health Sciences Adana Health Practices and Research Center, Adana, Turkey
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Risk of sudden cardiac arrest and ventricular arrhythmia with sulfonylureas: An experience with conceptual replication in two independent populations. Sci Rep 2020; 10:10070. [PMID: 32572080 PMCID: PMC7308403 DOI: 10.1038/s41598-020-66668-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/22/2020] [Indexed: 11/12/2022] Open
Abstract
Sulfonylureas are commonly used to treat type 2 diabetes mellitus. Despite awareness of their effects on cardiac physiology, a knowledge gap exists regarding their effects on cardiovascular events in real-world populations. Prior studies reported sulfonylurea-associated cardiovascular death but not serious arrhythmogenic endpoints like sudden cardiac arrest (SCA) or ventricular arrhythmia (VA). We assessed the comparative real-world risk of SCA/VA among users of second-generation sulfonylureas: glimepiride, glyburide, and glipizide. We conducted two incident user cohort studies using five-state Medicaid claims (1999–2012) and Optum Clinformatics commercial claims (2000–2016). Outcomes were SCA/VA events precipitating hospital presentation. We used Cox proportional hazards models, adjusted for high-dimensional propensity scores, to generate adjusted hazard ratios (aHR). We identified 624,406 and 491,940 sulfonylurea users, and 714 and 385 SCA/VA events, in Medicaid and Optum, respectively. Dataset-specific associations with SCA/VA for both glimepiride and glyburide (vs. glipizide) were on opposite sides of and could not exclude the null (glimepiride: aHRMedicaid 1.17, 95% CI 0.96–1.42; aHROptum 0.84, 0.65–1.08; glyburide: aHRMedicaid 0.87, 0.74–1.03; aHROptum 1.11, 0.86–1.42). Database differences in data availability, populations, and documentation completeness may have contributed to the incongruous results. Emphasis should be placed on assessing potential causes of discrepancies between conflicting studies evaluating the same research question.
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Cassis P, Cerullo D, Zanchi C, Corna D, Lionetti V, Giordano F, Novelli R, Conti S, Casieri V, Matteucci M, Locatelli M, Taraboletti G, Villa S, Gastoldi S, Remuzzi G, Benigni A, Zoja C. ADAMTS13 Deficiency Shortens the Life Span of Mice With Experimental Diabetes. Diabetes 2018; 67:2069-2083. [PMID: 29976618 DOI: 10.2337/db17-1508] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/18/2018] [Indexed: 11/13/2022]
Abstract
In patients with diabetes, impaired activity of ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13), the plasma metalloprotease that cleaves highly thrombogenic von Willebrand factor multimers, is a major risk factor of cardiovascular events. Here, using Adamts13-/- mice made diabetic by streptozotocin, we investigated the impact of the lack of ADAMTS13 on the development of diabetes-associated end-organ complications. Adamts13-/- mice experienced a shorter life span than their diabetic wild-type littermates. It was surprising that animal death was not related to the occurrence of detectable thrombotic events. The lack of ADAMTS13 drastically increased the propensity for ventricular arrhythmias during dobutamine-induced stress in diabetic mice. Cardiomyocytes of diabetic Adamts13-/- mice exhibited an aberrant distribution of the ventricular gap junction connexin 43 and increased phosphorylation of Ca2+/calmodulin-dependent kinase II (CaMKII), and with the consequent CaMKII-induced disturbance in Ca2+ handling, which underlie propensity for arrhythmia. In vitro, thrombospondin 1 (TSP1) promoted, in a paracrine manner, CaMKII phosphorylation in murine HL-1 cardiomyocytes, and ADAMTS13 acted to inhibit TSP1-induced CaMKII activation. In conclusion, the deficiency of ADAMTS13 may underlie the onset of lethal arrhythmias in diabetes through increased CaMKII phosphorylation in cardiomyocytes. Our findings disclose a novel function for ADAMTS13 beyond its antithrombotic activity.
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Affiliation(s)
- Paola Cassis
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Domenico Cerullo
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Cristina Zanchi
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Daniela Corna
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Vincenzo Lionetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
- UOS Anesthesia and Intensive Care, Fondazione Toscana "G. Monasterio," Pisa, Italy
| | - Fabrizio Giordano
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Rubina Novelli
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Sara Conti
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | | | - Marco Matteucci
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Monica Locatelli
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Giulia Taraboletti
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Sebastian Villa
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Sara Gastoldi
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Giuseppe Remuzzi
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
- Unit of Nephrology and Dialysis, Azienda Socio-Sanitaria Territoriale (ASST), Papa Giovanni XXIII, Bergamo, Italy
- "L. Sacco" Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Ariela Benigni
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Carlamaria Zoja
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
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7
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Leonard CE, Brensinger CM, Aquilante CL, Bilker WB, Boudreau DM, Deo R, Flory JH, Gagne JJ, Mangaali MJ, Hennessy S. Comparative Safety of Sulfonylureas and the Risk of Sudden Cardiac Arrest and Ventricular Arrhythmia. Diabetes Care 2018; 41:713-722. [PMID: 29437823 PMCID: PMC5860838 DOI: 10.2337/dc17-0294] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 11/18/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To examine the association between individual antidiabetic sulfonylureas and outpatient-originating sudden cardiac arrest and ventricular arrhythmia (SCA/VA). RESEARCH DESIGN AND METHODS We conducted a retrospective cohort study using 1999-2010 U.S. Medicaid claims from five large states. Exposures were determined by incident use of glyburide, glimepiride, or glipizide. Glipizide served as the reference exposure, as its effects are believed to be highly pancreas specific. Outcomes were ascertained by a validated ICD-9-based algorithm indicative of SCA/VA (positive predictive value ∼85%). Potential confounding was addressed by adjustment for multinomial high-dimensional propensity scores included as continuous variables in a Cox proportional hazards model. RESULTS Of sulfonylurea users under study (N = 519,272), 60.3% were female and 34.9% non-Hispanic Caucasian, and the median age was 58.0 years. In 176,889 person-years of sulfonylurea exposure, we identified 632 SCA/VA events (50.5% were immediately fatal) for a crude incidence rate of 3.6 per 1,000 person-years. Compared with glipizide, propensity score-adjusted hazard ratios for SCA/VA were 0.82 (95% CI 0.69-0.98) for glyburide and 1.10 (0.89-1.36) for glimepiride. Numerous secondary analyses showed a very similar effect estimate for glyburide; yet, not all CIs excluded the null. CONCLUSIONS Glyburide may be associated with a lower risk of SCA/VA than glipizide, consistent with a very small clinical trial suggesting that glyburide may reduce ventricular tachycardia and isolated ventricular premature complexes. This potential benefit must be contextualized by considering putative effects of different sulfonylureas on other cardiovascular end points, cerebrovascular end points, all-cause death, and hypoglycemia.
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Affiliation(s)
- Charles E Leonard
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Colleen M Brensinger
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Christina L Aquilante
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, Anschutz Medical Campus, University of Colorado, Aurora, CO
| | - Warren B Bilker
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Neuropsychiatry Section, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Denise M Boudreau
- Kaiser Permanente Washington Health Research Institute, Seattle, WA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA
| | - Rajat Deo
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - James H Flory
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Division of Comparative Effectiveness, Department of Healthcare Policy and Research, Weill Cornell Medical Center, Cornell University, New York, NY
- Memorial Sloan Kettering Cancer Center, New York, NY
| | - Joshua J Gagne
- Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Margaret J Mangaali
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sean Hennessy
- Center for Pharmacoepidemiology Research and Training, Center for Clinical Epidemiology and Biostatistics, and Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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8
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Leonard CE, Hennessy S, Han X, Siscovick DS, Flory JH, Deo R. Pro- and Antiarrhythmic Actions of Sulfonylureas: Mechanistic and Clinical Evidence. Trends Endocrinol Metab 2017; 28:561-586. [PMID: 28545784 PMCID: PMC5522643 DOI: 10.1016/j.tem.2017.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 12/19/2022]
Abstract
Sulfonylureas are the most commonly used second-line drug class for treating type 2 diabetes mellitus (T2DM). While the cardiovascular safety of sulfonylureas has been examined in several trials and nonrandomized studies, little is known of their specific effects on sudden cardiac arrest (SCA) and related serious arrhythmic outcomes. This knowledge gap is striking, because persons with DM are at increased risk of SCA. In this review, we explore the influence of sulfonylureas on the risk of serious arrhythmias, with specific foci on ischemic preconditioning, cardiac excitability, and serious hypoglycemia as putative mechanisms. Elucidating the relationship between individual sulfonylureas and serious arrhythmias is critical, especially as the diabetes epidemic intensifies and SCA incidence increases in persons with diabetes.
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Affiliation(s)
- Charles E Leonard
- Center for Pharmacoepidemiology Research and Training, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Sean Hennessy
- Center for Pharmacoepidemiology Research and Training, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xu Han
- Center for Pharmacoepidemiology Research and Training, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David S Siscovick
- The New York Academy of Medicine, New York, NY 10029, USA; Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98195, USA
| | - James H Flory
- Center for Pharmacoepidemiology Research and Training, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Healthcare Policy and Research, Division of Comparative Effectiveness, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA; Memorial Sloan Kettering Cancer Center, New York, NY 10022, USA
| | - Rajat Deo
- Center for Pharmacoepidemiology Research and Training, Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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9
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Monnerat G, Alarcón ML, Vasconcellos LR, Hochman-Mendez C, Brasil G, Bassani RA, Casis O, Malan D, Travassos LH, Sepúlveda M, Burgos JI, Vila-Petroff M, Dutra FF, Bozza MT, Paiva CN, Carvalho AB, Bonomo A, Fleischmann BK, de Carvalho ACC, Medei E. Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice. Nat Commun 2016; 7:13344. [PMID: 27882934 PMCID: PMC5123037 DOI: 10.1038/ncomms13344] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/24/2016] [Indexed: 02/08/2023] Open
Abstract
Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice. IL-1β causes prolongation of the action potential duration, induces a decrease in potassium current and an increase in calcium sparks in cardiomyocytes, which are changes that underlie arrhythmia propensity. IL-1β-induced spontaneous contractile events are associated with CaMKII oxidation and phosphorylation. We further show that DM-induced arrhythmias can be successfully treated by inhibiting the IL-1β axis with either IL-1 receptor antagonist or by inhibiting the NLRP3 inflammasome. Our results establish IL-1β as an inflammatory connection between metabolic dysfunction and arrhythmias in DM.
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MESH Headings
- Action Potentials
- Animals
- Antirheumatic Agents/pharmacology
- Arrhythmias, Cardiac/etiology
- Arrhythmias, Cardiac/immunology
- Arrhythmias, Cardiac/metabolism
- Calcium/metabolism
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Caspase 1/metabolism
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/immunology
- Diabetes Mellitus, Experimental/metabolism
- Inflammasomes/antagonists & inhibitors
- Interleukin 1 Receptor Antagonist Protein/pharmacology
- Interleukin-1beta/genetics
- Interleukin-1beta/immunology
- Interleukin-1beta/metabolism
- Macrophages/immunology
- Mice
- Mice, Transgenic
- Myocardial Contraction
- Myocytes, Cardiac/immunology
- Myocytes, Cardiac/metabolism
- NLR Family, Pyrin Domain-Containing 3 Protein/antagonists & inhibitors
- NLR Family, Pyrin Domain-Containing 3 Protein/genetics
- NLR Family, Pyrin Domain-Containing 3 Protein/immunology
- Potassium/metabolism
- Receptors, Interleukin-1/antagonists & inhibitors
- Receptors, Interleukin-1/genetics
- Receptors, Interleukin-1/immunology
- Tachycardia, Ventricular/etiology
- Tachycardia, Ventricular/immunology
- Tachycardia, Ventricular/metabolism
- Toll-Like Receptor 2/genetics
- Toll-Like Receptor 2/immunology
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Affiliation(s)
- Gustavo Monnerat
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Micaela L. Alarcón
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Luiz R. Vasconcellos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Camila Hochman-Mendez
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Guilherme Brasil
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Rosana A. Bassani
- Center for Biomedical Engineering, University of Campinas, Campinas 13.083-970, Brazil
| | - Oscar Casis
- Departamento de Fisiología, Facultad de Farmacia, Universidad del País Vasco UPV/EHU, 01006 Vitoria, Spain
| | - Daniela Malan
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Leonardo H. Travassos
- LIRS-Laboratory of Immunoreceptors and Signaling, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marisa Sepúlveda
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Juan Ignacio Burgos
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Martin Vila-Petroff
- Centro de Investigaciones Cardiovasculares, Conicet La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina
| | - Fabiano F. Dutra
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Marcelo T. Bozza
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Claudia N. Paiva
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bastos Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Adriana Bonomo
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- FIOCANCER/ VPPLR/FIOCRUZ, FIOCRUZ-Manguinhos, Rio de Janeiro 21040-360, Brazil
| | - Bernd K. Fleischmann
- Institute of Physiology I, Life and Brain Center, University of Bonn, Bonn D-53127, Germany
| | - Antonio Carlos Campos de Carvalho
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
| | - Emiliano Medei
- Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
- National Center for Structural Biology and Bioimaging—CENABIO/UFRJ, Rio de Janeiro 21941-902, Brazil
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10
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Kenttä T, Tulppo MP, Nearing BD, Karjalainen JJ, Hautala AJ, Kiviniemi AM, Huikuri HV, Verrier RL. Effects of exercise rehabilitation on cardiac electrical instability assessed by T-wave alternans during ambulatory electrocardiogram monitoring in coronary artery disease patients without and with diabetes mellitus. Am J Cardiol 2014; 114:832-7. [PMID: 25107578 DOI: 10.1016/j.amjcard.2014.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/25/2014] [Accepted: 06/25/2014] [Indexed: 10/25/2022]
Abstract
Effects of exercise rehabilitation on electrocardiographic markers of risk for sudden cardiac death have not been adequately studied. We examined effects of controlled exercise training on T-wave alternans (TWA) in 24-hour ambulatory electrocardiogram recordings in patients with stable coronary artery disease (CAD) without and with type 2 diabetes mellitus (DM). Consecutive patients with angiographically confirmed CAD were recruited to join the ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) study. Exercise (n = 65) and control groups (n = 65) were matched on age, sex, DM, and previous myocardial infarction. Ambulatory electrocardiograms were recorded before and after a 2-year training period. TWA was assessed using time domain-modified moving average method by an investigator blinded to patients' clinical status. Average TWA values decreased in the rehabilitation group but not in control patients (rehabilitation [mean ± SEM]: 52.8 ± 1.7 μV vs 48.7 ± 1.5 μV, p <0.001; control: 53.7 ± 1.7 μV vs 54.3 ± 1.6 μV, p = 0.746). Changes in TWA differed between the groups (rehabilitation: -4.1 ± 1.2 μV vs controls: +0.6 ± 1.1 μV, p = 0.005). In CAD + DM patients, 50% (n = 9) of the 18 positive TWA cases were converted with exercise versus 10% (n = 2 of 20) of controls (p = 0.020). In CAD patients, 30% (n = 8 of 27) of positive TWA cases were converted with exercise versus 4% (n = 1 of 28) of controls (p = 0.012). In conclusion, this is the first report of the effectiveness of exercise rehabilitation to reduce TWA, a marker of sudden cardiac death risk, in patients with stable CAD.
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11
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Nerbonne JM. Mouse models of arrhythmogenic cardiovascular disease: challenges and opportunities. Curr Opin Pharmacol 2014; 15:107-14. [PMID: 24632325 DOI: 10.1016/j.coph.2014.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 12/27/2022]
Abstract
Arrhythmogenic cardiovascular disease is associated with significant morbidity and mortality and, in spite of therapeutic advances, remains an enormous public health burden. The scope of this problem motivates efforts to delineate the molecular, cellular and systemic mechanisms underlying increased arrhythmia risk in inherited and acquired cardiac and systemic disease. The mouse is used increasingly in these efforts owing to the ease with which genetic strategies can be exploited and mechanisms can be probed. The question then arises whether the mouse has proven to be a useful model system to delineate arrhythmogenic cardiovascular disease mechanisms. Rather than trying to provide a definite answer, the goal here is to consider the issues that arise when using mouse models and to highlight the opportunities.
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Affiliation(s)
- Jeanne M Nerbonne
- Department of Developmental Biology, Washington University Medical School, St. Louis, MO 63110, USA; Department of Internal Medicine, Washington University Medical School, St. Louis, MO 63110, USA.
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12
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Stables CL, Musa H, Mitra A, Bhushal S, Deo M, Guerrero-Serna G, Mironov S, Zarzoso M, Vikstrom KL, Cawthorn W, Pandit SV. Reduced Na⁺ current density underlies impaired propagation in the diabetic rabbit ventricle. J Mol Cell Cardiol 2014; 69:24-31. [PMID: 24412579 DOI: 10.1016/j.yjmcc.2013.12.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 12/23/2013] [Accepted: 12/31/2013] [Indexed: 12/12/2022]
Abstract
Diabetes is associated with an increased risk of sudden cardiac death, but the underlying mechanisms remain unclear. Our goal was to investigate changes occurring in the action potential duration (APD) and conduction velocity (CV) in the diabetic rabbit ventricle, and delineate the principal ionic determinants. A rabbit model of alloxan-induced diabetes was utilized. Optical imaging was used to record electrical activity in isolated Langendorff-perfused hearts in normo-, hypo- and hyper-kalemia ([K(+)]o=4, 2, 12 mM respectively). Patch clamp experiments were conducted to record Na(+) current (I(Na)) in isolated ventricular myocytes. The mRNA/protein expression levels for Nav1.5 (the α-subunit of I(Na)) and connexin-43 (Cx43), as well as fibrosis levels were examined. Computer simulations were performed to interpret experimental data. We found that the APD was not different, but the CV was significantly reduced in diabetic hearts in normo-, hypo-, and, hyper-kalemic conditions (13%, 17% and 33% reduction in diabetic vs. control, respectively). The cell capacitance (Cm) was increased (by ~14%), and the density of INa was reduced by ~32% in diabetic compared to control hearts, but the other biophysical properties of I(Na) were unaltered. The mRNA/protein expression levels for Cx43 were unaltered. For Nav1.5, the mRNA expression was not changed, and though the protein level tended to be less in diabetic hearts, this reduction was not statistically significant. Staining showed no difference in fibrosis levels between the control and diabetic ventricles. Computer simulations showed that the reduced magnitude of I(Na) was a key determinant of impaired propagation in the diabetic ventricle, which may have important implications for arrhythmogenesis.
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Affiliation(s)
- Catherine L Stables
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Hassan Musa
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Aditi Mitra
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Sandesh Bhushal
- Department of Engineering, Norfolk State University, Norfolk, VA, USA
| | - Makarand Deo
- Department of Engineering, Norfolk State University, Norfolk, VA, USA
| | - Guadalupe Guerrero-Serna
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Sergey Mironov
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Manuel Zarzoso
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Karen L Vikstrom
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - William Cawthorn
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sandeep V Pandit
- Center for Arrhythmia Research, Department of Internal Medicine-Cardiology, University of Michigan, Ann Arbor, MI, USA.
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13
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Abstract
Obesity is now recognized as a major health epidemic in the United States and around the world, both in adults and children, and has coincided with the increase in the availability of high calorie/low nutrient foods and changes in lifestyle, particularly the decrease in physical activity. Obese individuals have shorter life spans, increased risk for sudden cardiac death and a number of comorbidities such as diabetes mellitus, venous thromboembolism and respiratory dysfunction, which can negatively affect their quality of life. The increased prevalence of obesity has affected every field of medicine and the costs of treating obesity and its complications are staggering. Forensic pathology has been impacted as well, with obese and morbidly obese decedents posing major technical and practical challenges in transport, handling and autopsy procedures. This article will review the epidemiology and causes of obesity and address the impact of obesity on mortality and the everyday practice of forensic pathology.
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Affiliation(s)
- Irini Scordi-Bello
- Medical Examiner at the Office of Chief Medical Examiner in New York City and a Clinical New York University
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14
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Virág L, Jost N, Papp R, Koncz I, Kristóf A, Kohajda Z, Harmati G, Carbonell-Pascual B, Ferrero JM, Papp JG, Nánási PP, Varró A. Analysis of the contribution of I(to) to repolarization in canine ventricular myocardium. Br J Pharmacol 2012; 164:93-105. [PMID: 21410683 DOI: 10.1111/j.1476-5381.2011.01331.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The contribution of the transient outward potassium current (I(to)) to ventricular repolarization is controversial as it depends on the experimental conditions, the region of myocardium and the species studied. The aim of the present study was therefore to characterize I(to) and estimate its contribution to repolarization reserve in canine ventricular myocardium. EXPERIMENTAL APPROACH Ion currents were recorded using conventional whole-cell voltage clamp and action potential voltage clamp techniques in canine isolated ventricular cells. Action potentials were recorded from canine ventricular preparations using microelectrodes. The contribution of I(to) to repolarization was studied using 100 µM chromanol 293B in the presence of 0.5 µM HMR 1556, which fully blocks I(Ks). KEY RESULTS The high concentration of chromanol 293B used effectively suppressed I(to) without affecting other repolarizing K(+) currents (I(K1), I(Kr), I(p)). Action potential clamp experiments revealed a slowly inactivating and a 'late' chromanol-sensitive current component occurring during the action potential plateau. Action potentials were significantly lengthened by chromanol 293B in the presence of HMR 1556. This lengthening effect induced by I(to) inhibition was found to be reverse rate-dependent. It was significantly augmented after additional attenuation of repolarization reserve by 0.1 µM dofetilide and this caused the occurrence of early afterdepolarizations. The results were confirmed by computer simulation. CONCLUSIONS AND IMPLICATIONS The results indicate that I(to) is involved in regulating repolarization in canine ventricular myocardium and that it contributes significantly to the repolarization reserve. Therefore, blockade of I(to) may enhance pro-arrhythmic risk.
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Affiliation(s)
- L Virág
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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15
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Ren L, Fang X, Wang Y, Qi G. T-wave alternans and heart rate variability: a comparison in patients with myocardial infarction with or without diabetes mellitus. Ann Noninvasive Electrocardiol 2011; 16:232-8. [PMID: 21762250 DOI: 10.1111/j.1542-474x.2011.00437.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate the differences in T-wave alternans (TWA) and heart rate variability (HRV) among patients with myocardial infarction with or without diabetes mellitus and the relationship between TWA and HRV. METHODS The study population included 133 patients: 59 patients with myocardial infarction (MI) (group post-MI without diabetes); 40 myocardial infarction with diabetes (group post-MI with diabetes); and 34 controls (group control). Cardiac autonomic neuropathy assessment was made using frequency domain (low-frequency [LF] power, high-frequency [HF] power, LF/HF) and time domain (SDNN, standard deviation of the averaged normal sinus RR intervals for all 5-minute segments [SDANN]) of HRV indexes. Both TWA and HRV were measured on the Holter monitor, and TWA was calculated automatically using the time-domain modified moving average method. RESULTS TWA values differed significantly between controls (40 ± 16 μV) and group post-MI with (62 ± 17 μV, P < 0.05) or without (60 ± 15 μV, P < 0.05) diabetes. In addition, group post-MI with diabetes had lower standard deviation of all normal sinus RR intervals (SDNN), standard deviation of the averaged normal sinus RR intervals for all 5-minute segments (SDANN), and HF, indicating depressed vagus nerve activity, and higher LF/HF ratio, indicating elevated sympathetic nerve activity, than controls and group post-MI without diabetes (P < 0.05). TWA correlated with SDNN and SDANN (r = 0.29, 0.31; P < 0.001). CONCLUSIONS TWA was elevated in patients following myocardial infarction, both in those with or without diabetes. Myocardial infarction patients had a lower time domain, HF, and a higher LF/HF ratio HRV, especially in those with diabetes. The analysis of modified moving agerage (MMA)-based TWA and HRV can be a useful tool for identifying post-myocardial infarction patients at high risk of arrhythmic events.
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Affiliation(s)
- LiNa Ren
- Department of Cardiology, the First Hospital of China Medical University, Shenyang, China
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16
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Forslund AS, Söderberg S, Jansson JH, Lundblad D. Trends in incidence and outcome of out-of-hospital cardiac arrest among people with validated myocardial infarction. Eur J Prev Cardiol 2011; 20:260-7. [DOI: 10.1177/1741826711432032] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Ann-Sofie Forslund
- The Northern Sweden MONICA Myocardial Registry, Department of Research, Norrbotten County Council, Luleå, Sweden
- Division of Nursing, Department of Health Science, Luleå University of Technology, Luleå, Sweden
| | - Siv Söderberg
- Division of Nursing, Department of Health Science, Luleå University of Technology, Luleå, Sweden
| | - Jan-Håkan Jansson
- Department of Medicine, Skellefteå Hospital, Skellefteå, Sweden
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
| | - Dan Lundblad
- Department of Public Health and Clinical Medicine, University of Umeå, Umeå, Sweden
- Department of Medicine, Sunderby Hospital, Luleå, Sweden
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17
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Bonapace S, Targher G, Molon G, Rossi A, Costa A, Zenari L, Bertolini L, Cian D, Lanzoni L, Barbieri E. Relationship Between Early Diastolic Dysfunction and Abnormal Microvolt T-Wave Alternans in Patients With Type 2 Diabetes. Circ Cardiovasc Imaging 2011; 4:408-14. [DOI: 10.1161/circimaging.110.962951] [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] [Indexed: 01/07/2023]
Abstract
Background—
Abnormal microvolt T-wave alternans (MTWA), a marker of ventricular arrhythmic risk, is a highly prevalent condition in patients with type 2 diabetes mellitus (T2DM) and is correlated with glycemic control. However, there is uncertainty as to whether central or peripheral hemodynamic factors are associated with abnormal MTWA in T2DM individuals.
Methods and Results—
We studied 50 consecutive, well-controlled T2DM outpatients without a history of ischemic heart disease and with normal systolic function. All patients underwent a complete echocardiographic Doppler evaluation with spectral tissue Doppler analysis. MTWA analysis was performed noninvasively during submaximal exercise. Effective arterial elastance, arterial compliance, and heart rate variability were also measured. Compared with patients with MTWA negativity (n=38), those with MTWA abnormality (n=12, 24%) had significantly lower e′ (7.6±1.3 versus 9.1±1.7 cm/s;
P
<0.01), a′ (10.2±1.6 versus 12.7±1.9 cm/s;
P
<0.001) and s′ velocities (8.7±1.1 versus 10.2±1.5 cm/s;
P
=0.001) and higher indexed left ventricular mass (121.3±16.4 versus 107.5±16.5 g/m
2
;
P
=0.016), indexed left atrial volume (33.5±11.9 versus 23.6±5.6 mL/m
2
;
P
<0.001), and E/e′ ratio (8.8±1.4 versus 6.5±1.3;
P
<0.001). Multivariable logistic regression analysis revealed that higher E/e′ ratio was the only independent correlate of abnormal MTWA (adjusted odds ratio, 3.52; 95% confidence interval, 1.19 to 10.6;
P
=0.02) after controlling for glycemic control and other potential confounders.
Conclusions—
In this pilot study, we found that early diastolic dysfunction, as measured by tissue Doppler imaging, is independently associated with MTWA abnormality in T2DM individuals with normal systolic function. Further larger studies are needed to examine the reproducibility of these results.
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Affiliation(s)
- Stefano Bonapace
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Giovanni Targher
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Giulio Molon
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Andrea Rossi
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Alessandro Costa
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Luciano Zenari
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Lorenzo Bertolini
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Debora Cian
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Laura Lanzoni
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
| | - Enrico Barbieri
- From the Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy (S.B., G.M., A.C., D.C., L.L., E.B.); the Section of Endocrinology and Metabolism, Department of Medicine, University of Verona, Italy (G.T.); the Section of Cardiology, Department of Medicine, University of Verona, Italy (A.R.); and the Diabetes Unit, Sacro Cuore Hospital, Negrar (VR), Italy (L.Z., L.B.)
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Rahnema P, Shimoni Y, Nygren A. Reduced conduction reserve in the diabetic rat heart: role of iPLA2 activation in the response to ischemia. Am J Physiol Heart Circ Physiol 2010; 300:H326-34. [PMID: 21037228 DOI: 10.1152/ajpheart.00743.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hearts from streptozotocin (STZ)-induced diabetic rats have previously been shown to have impaired intercellular electrical coupling, due to reorganization (lateralization) of connexin43 proteins. Due to the resulting reduction in conduction reserve, conduction velocity in diabetic hearts is more sensitive to conditions that reduce cellular excitability or intercellular electrical coupling. Diabetes is a known risk factor for cardiac ischemia, a condition associated with both reduced cellular excitability and reduced intercellular coupling. Activation of Ca(2+)-independent phospholipase A(2) (iPLA(2)) is known to be part of the response to acute ischemia and may contribute to the intercellular uncoupling by causing increased levels of arachidonic acid and lysophosphatidyl choline. Normally perfused diabetic hearts are known to exhibit increased iPLA(2) activity and may thus be particularly sensitive to further activation of these enzymes. In this study, we used voltage-sensitive dye mapping to assess changes in conduction velocity in response to acute global ischemia in Langendorff-perfused STZ-induced diabetic hearts. Conduction slowing in response to ischemia was significantly larger in STZ-induced diabetic hearts compared with healthy controls. Similarly, slowing of conduction velocity in response to acidosis was also more pronounced in STZ-induced diabetic hearts. Inhibition of iPLA(2) activity using bromoenol lactone (BEL; 10 μM) had no effect on the response to ischemia in healthy control hearts. However, in STZ-induced diabetic hearts, BEL significantly reduced the amount of conduction slowing observed beginning 5 min after the onset of ischemia. BEL treatment also significantly increased the time to onset of sustained arrhythmias in STZ-induced diabetic hearts but had no effect on the time to arrhythmia in healthy control hearts. Thus, our results suggest that iPLA(2) activation in response to acute ischemia in STZ-induced diabetic hearts is more pronounced than in control hearts and that this response is a significant contributor to arrhythmogenic conduction slowing.
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Affiliation(s)
- Parisa Rahnema
- Department of Electrical and Computer Engineering, University of Calgary, Calgary, Alberta, Canada
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Forslund AS, Lundblad D, Söderberg S. Sudden cardiac death among people with diabetes: preventive measures documented in their medical records. J Clin Nurs 2010; 19:3401-9. [PMID: 20946443 DOI: 10.1111/j.1365-2702.2010.03334.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The purpose of this study was to examine how prevention of complications for people with diabetes mellitus had been conducted, as described in their medical records, focusing particularly on sudden cardiac death. A further aim was to compare the documentation with guidelines for diabetes care. BACKGROUND Diabetes mellitus is associated with an increased risk of cardiovascular disease, death and sudden cardiac death. About half of those affected by sudden cardiac death are assumed to have had one or more risk factors for cardiovascular disease that could have been treated effectively resulting in a reduced risk of sudden death. DESIGN Survey. METHOD Fifty-six people diagnosed with diabetes mellitus, who had died of a sudden cardiac arrest between the years 2003-2005, from the Northern Sweden MONICA myocardial registry were included. These people's medical records were examined with regard to documentation of the care given during the year prior to the person's sudden cardiac death. RESULTS The qualitative content analysis resulted in four categories: individualised goals for diabetes care; prevention of complications; self-care; and factors which may affect ability to adhere to treatment. The quantitative analysis showed that few people with diabetes mellitus achieved goals for metabolic control, compared with those set in guidelines for diabetes mellitus care. CONCLUSION To prevent complications for people with diabetes mellitus, it is a challenge for nurses and physicians to involve people with diabetes mellitus in their own care to improve the prognosis. RELEVANCE TO CLINICAL PRACTICE Examination of medical records of people with diabetes mellitus showed that documentation could be more informative and systematic. It is important to achieve better adherence to treatment and to increase people's understanding of their illness.
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Affiliation(s)
- Ann-Sofie Forslund
- The Northern Sweden MONICA Myocardial Registry, Department of Research, Norrbotten County Council, Luleå, Sweden.
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Yuill KH, Tosh D, Hancox JC. Streptozotocin-induced diabetes modulates action potentials and ion channel currents from the rat atrioventricular node. Exp Physiol 2010; 95:508-17. [PMID: 19946031 DOI: 10.1113/expphysiol.2009.050286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The present study was conducted to evaluate whether experimentally induced type 1 diabetes results in alterations to atrioventricular nodal (AVN) electrophysiology at the cellular level. Spontaneous action potentials (APs) and ionic currents were recorded from AVN myocytes isolated from the hearts of control rats and from those with streptozotocin-induced diabetes. Perforated patch-clamp recordings were used to assess changes in cellular AP parameters and in ionic currents. Type 1 diabetes significantly increased AP duration, whilst reducing AP firing rate, upstroke velocity and rate of diastolic depolarization. The diabetes-induced changes in AP parameters were accompanied by a significant leftward shift in the zero current potential under voltage clamp, a reduction in peak L-type Ca(2+) current density and reduced amplitude of delayed rectifier and hyperpolarization-activated currents. These findings demonstrate that experimentally induced type 1 diabetes can lead to remodelling of AVN cellular electrophysiology.
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Affiliation(s)
- Kathryn H Yuill
- Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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21
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Siscovick DS, Sotoodehnia N, Rea TD, Raghunathan TE, Jouven X, Lemaitre RN. Type 2 diabetes mellitus and the risk of sudden cardiac arrest in the community. Rev Endocr Metab Disord 2010; 11:53-9. [PMID: 20195771 PMCID: PMC3413310 DOI: 10.1007/s11154-010-9133-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The reduction of mortality from sudden cardiac arrest (SCA) in the setting of coronary heart disease (CHD) remains a major challenge, especially among patients with type 2 diabetes. Diabetes is associated with an increased risk of SCA, at least in part, from an increased presence and extent of coronary atherosclerosis (macrovascular disease). Diabetes also is associated with microvascular disease and autonomic neuropathy; and, these non-coronary atherosclerotic pathophysiologic processes also have the potential to increase the risk of SCA. In this report, we review the absolute and relative risk of SCA associated with diabetes. We summarize recent evidence that suggests that the increase in risk in patients with diabetes is not specific for SCA, as diabetes also is associated with a similar increase in risk for non-SCA CHD death and non-fatal myocardial infarction. These data are consistent with prior observations that coronary atherosclerosis is a major contributor to the increased SCA risk associated with diabetes. We also present previously published and unpublished data that demonstrates that both clinically-recognized microvascular and autonomic neuropathy also are associated with the risk of SCA among treated patients with diabetes, after taking into account prior clinically-recognized heart disease and other risk factors for SCA. We then discuss how these data might inform research and clinical efforts to prevent SCA. Although the prediction of SCA in this "high" risk population is likely to remain a challenge, as it is in other "high" risk clinical populations, we suggest that current recommendations for the prevention of SCA in the community, related to both lifestyle prescriptions and risk factor reduction, are likely to reduce mortality from SCA among patients with diabetes.
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Affiliation(s)
- David S Siscovick
- Medicine and Epidemiology, University of Washington, Cardiovascular Health Research Unit, 1730 Minor Avenue, Seattle, WA 98101, USA.
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Martin DT, Shoraki A, Nesto RW, Rutter MK. Influence of diabetes and/or myocardial infarction on prevalence of abnormal T-wave alternans. Ann Noninvasive Electrocardiol 2010; 14:355-9. [PMID: 19804512 DOI: 10.1111/j.1542-474x.2009.00325.x] [Citation(s) in RCA: 9] [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] Open
Abstract
BACKGROUND Subjects with microvolt-level T-wave alternans (TWA) in association with structural heart disease have an increased risk for sudden cardiac death. The presence of diabetes (DM) is associated with an increased risk of sudden death but there is limited data on the impact of DM and previous myocardial infarction (MI) on TWA prevalence. METHODS We performed a case-control cross-sectional study in 140 patients referred for routine exercise testing within a large multispecialty clinic. All patients with a history of DM and MI status within the past year were eligible: group 1 (no DM or MI), group 2 (DM only), group 3 (MI only), group 4 (DM and MI). Patients performed a symptom-limited Bruce protocol exercise test with assessment of TWA by the spectral method using commercially available equipment. We used published criteria for the blinded interpretation of TWA; all tests not unequivocally negative were considered abnormal. RESULTS Age and gender were similar in all groups. The prevalence of abnormal TWA in groups 1-4 was 24%, 20%, 48%, and 62%, respectively (between group P = 0.002). Logistic regression analysis in all patients showed that abnormal TWA was related to prior MI [OR (95% CI): 4.0 (1.8-8.9), P < 0.001] but not to prevalent DM [0.9 (0.4-1.8), P = 0.72]. In patients with DM, the prevalence of abnormal TWA was related to reduced ejection fraction (P = 0.034) but not to BMI, DM duration, glycemic control, insulin use, or the presence of microvascular complications. CONCLUSION The presence of DM alone does not increase risk of abnormal TWA. Prospective studies are required to establish the prognostic value of TWA in patients with DM.
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Affiliation(s)
- David T Martin
- Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA 01805, USA.
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Ghaly HA, Boyle PM, Vigmond EJ, Shimoni Y, Nygren A. Simulations of reduced conduction reserve in the diabetic rat heart: response to uncoupling and reduced excitability. Ann Biomed Eng 2009; 38:1415-25. [PMID: 19953318 DOI: 10.1007/s10439-009-9855-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 11/20/2009] [Indexed: 10/20/2022]
Abstract
Experimental results have shown that action potential (AP) conduction in ventricular tissue from streptozotocin-diabetic (STZ) rats is compromised. This was manifest as increased sensitivity of conduction velocity (CV) to the gap junction uncoupler heptanol, as well as increased sensitivity of CV to reduced cellular excitability due to elevated extracellular K(+) concentration, in the STZ hearts. This "reduced conduction reserve" has been suggested to be due to lateralization of connexin43 (Cx43) proteins, rendering them nonfunctional, resulting in compromised intercellular electrical coupling. In this study, we have used computer simulations of one-dimensional AP conduction in a model of rat ventricular myocytes to verify this interpretation. Our results show that compromised intercellular coupling indeed reduces conduction reserve and predict a response to gap junction uncoupling with heptanol that is consistent with experiments. However, our simulations also show that compromised intercellular coupling is insufficient to explain the increased sensitivity to reduced cellular excitability. A thorough investigation of possible underlying mechanisms, suggests that subtle alterations in the voltage-dependence of steady-state gating for the Na(+) current (I (Na)), combined with compromised intercellular coupling, is a likely mechanism for these observations.
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Affiliation(s)
- Haisam A Ghaly
- Department of Electrical & Computer Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
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Shimoni Y, Chen K, Emmett T, Kargacin G. Aldosterone and the autocrine modulation of potassium currents and oxidative stress in the diabetic rat heart. Br J Pharmacol 2008; 154:675-87. [PMID: 18414392 DOI: 10.1038/bjp.2008.114] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Aldosterone plays a major role in cardiac pathology. This study was designed to investigate the role of cardiac aldosterone in modulating K(+) currents and oxidative stress in the streptozotocin-induced diabetic rat heart. EXPERIMENTAL APPROACH Transient and sustained K(+) currents were measured in ventricular myocytes by voltage clamp. Plasma and cellular aldosterone were measured by ELISA. Fluorescent dihydroethidium (DHE) was used to assess superoxide ions as markers of oxidative stress. KEY RESULTS The mineralocorticoid antagonist spironolactone (1 microM, 5-9 h) significantly augmented both K(+) currents in diabetic males, with a concomitant shortening of the action potential but had no effect in myocytes from control males or from diabetic females. Effects of spironolactone were restored in ovariectomized diabetic females and abolished in orchidectomized diabetic males. The aldosterone synthase inhibitor FAD286 (1 microM, 5-9 h) significantly augmented K(+) currents in cells from diabetic males, but not females. Spironolactone and FAD286 significantly reduced oxidative stress in cells from diabetic males. Plasma aldosterone content was elevated in diabetic males (relative to control), but not in females. Cellular aldosterone was also elevated, but not significantly. The elevation in aldosterone was only partly dependent on a concomitant increase in cellular angiotensin II. CONCLUSIONS AND IMPLICATIONS A gender-related, sex-hormone-dependent elevation in plasma and cardiac cell aldosterone contributed to oxidative stress and to attenuation of K(+) currents in diabetic male rats. Aldosterone may thus contribute to diabetes-associated cardiac arrhythmias. Aldosterone elevation was partly related to levels of angiotensin II, but residual, angiotensin II-independent, aldosterone maintains functional relevance.
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Affiliation(s)
- Y Shimoni
- Department of Physiology and Biophysics, Health Sciences Centre, University of Calgary, Calgary, Alberta, Canada.
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Petursson P, Gudbjörnsdottir S, Aune S, Svensson L, Oddby E, Sjöland H, Herlitz J. Patients with a history of diabetes have a lower survival rate after in-hospital cardiac arrest. Resuscitation 2008; 76:37-42. [PMID: 17697737 DOI: 10.1016/j.resuscitation.2007.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 06/12/2007] [Accepted: 06/21/2007] [Indexed: 11/17/2022]
Abstract
AIM To describe the association between a history of diabetes and outcome among patients suffering an in-hospital cardiac arrest. METHOD All patients suffering an in-hospital cardiac arrest in whom cardiopulmonary resuscitation (CPR) was attempted at Sahlgrenska University Hospital in Göteborg between 1994 and 2006 and at nine further hospitals in Sweden between 2005 and 2006. RESULTS In all, 1810 patients were included in the survey, 395 (22%) of whom had a previous history of diabetes. Patients with a history of diabetes differed from those without such a history by having a higher prevalence of previous myocardial infarction, stroke, heart failure and renal disease. They were more frequently treated with anti-arrhythmic drugs during resuscitation. Whereas immediate survival did not differ between groups (51.7% and 53.1%, respectively), patients with diabetes were discharged alive from hospital (29.3%) less frequently compared with those without diabetes (37.6%). When correcting for dissimilarities at baseline, the adjusted odds ratio for being discharged alive (diabetes/no diabetes) was 0.57 (95% CL 0.40-0.79). CONCLUSION Among patients suffering an in-hospital cardiac arrest in Sweden in whom CPR was attempted, 22% had a history of diabetes. These patients had a lower survival rate, which cannot simply be explained by different co-morbidity.
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Affiliation(s)
- P Petursson
- Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital, SE 413 45 Göteborg, Sweden.
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Montagnana M, Lippi G, Franchini M, Targher G, Cesare Guidi G. Sudden cardiac death: prevalence, pathogenesis, and prevention. Ann Med 2008; 40:360-75. [PMID: 18484348 DOI: 10.1080/07853890801964930] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sudden cardiac death (SCD), also known as sudden arrest, is a major health problem worldwide. It is usually defined as an unexpected death from a cardiac cause occurring within a short time in a person with or without preexisting heart disease. The pathogenesis of SCD is complex and multifaceted. A dynamic triggering factor usually interacts with an underlying heart disease, either genetically determined or acquired, and the final outcome is the development of lethal tachyarrhythmias or, less frequently, bradycardia. It has increasingly been highlighted that a reliable clinical and diagnostic approach might be effective to unmask the most important genetic and environmental factors, allowing the construction of a rational personalized medicine framework that can be applied in both the preclinical and clinical settings of SCD. The aim of the present article is to provide a concise overview of prevalence, pathogenesis, clinical presentation, and diagnostic approach to this challenging disorder.
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Affiliation(s)
- Martina Montagnana
- Sezione di Chimica e Microscopia Clinica, Dipartimento di Scienze Morfologico-Biomediche, Universita degli Studi di Verona, Italy.
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Krentz AJ, Clough G, Byrne CD. Interactions between microvascular and macrovascular disease in diabetes: pathophysiology and therapeutic implications. Diabetes Obes Metab 2007; 9:781-91. [PMID: 17924862 DOI: 10.1111/j.1463-1326.2007.00670.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Convention partitions the complications of diabetes into two main subtypes. First are the diabetes-specific microvascular complications of retinopathy, nephropathy and neuropathy; second are the atherothrombotic macrovascular complications that account for the majority of premature deaths. Pathological interactions between microvascular and macrovascular complications, for example, nephropathy and macrovascular disease, are common. Similar mechanisms and shared risk factors drive the development and progression of both small and large vessel disease. This concept has therapeutic implications. Mounting evidence points to the need for multifactorial strategies to prevent vascular complications in subjects with diabetes and/or the metabolic syndrome. We advocate a combined therapeutic approach that addresses small and large vessel disease. Preferential use should be made of drug regimens that (i) maximize vascular protection, (ii) reduce the risk of iatrogenic vascular damage and (iii) minimize the increasing problem of polypharmacy.
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Affiliation(s)
- Andrew J Krentz
- Department of Diabetes and Endocrinology, Southampton General Hospital, Southampton SO16 6YD, UK.
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Molon G, Costa A, Bertolini L, Zenari L, Arcaro G, Barbieri E, Targher G. Relationship Between Abnormal Microvolt T-Wave Alternans and Poor Glycemic Control in Type 2 Diabetic Patients. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2007; 30:1267-72. [PMID: 17897130 DOI: 10.1111/j.1540-8159.2007.00849.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Abnormal microvolt T-wave alternans (TWA) predicts the risk of ventricular arrhythmias and sudden cardiac death. Although type 2 diabetes is associated with an increased risk of these events, there is a dearth of available data on microvolt TWA measurements in type 2 diabetic populations. METHODS We studied 59 consecutive type 2 diabetic outpatients without manifest cardiovascular disease (CVD) and 35 non-diabetic controls who were matched for age, sex, and blood pressure values. Microvolt TWA analysis was performed non-invasively using the CH-2000 system during a sub-maximal exercise with the patient sitting on a bicycle ergometer. RESULTS The frequency of abnormal TWA was significantly higher in diabetic patients than in controls (25.4 vs 5.7%; P < 0.01). Among diabetic patients, those with abnormal TWA (n = 15) had remarkably higher hemoglobin A1c (HbA1c) (8.1 +/- 0.9 vs 7.1 +/- 0.8%, P < 0.001) and slightly smaller time-domain heart rate variability parameters (i.e., RMSSD, root mean square of difference of successive R-R intervals) than those with normal TWA (n = 44). Gender, age, body mass index, lipids, blood pressure values, cigarette smoking, diabetes duration, microvascular complication status, QTc interval, and current use of medications did not significantly differ between the groups. In multivariate regression logistic analysis, HbA1c (OR 13.6, 95% CI 2.0-89.1; P = 0.0076) predicted abnormal TWA independent of RMSSD values and other potential confounders. CONCLUSIONS Our findings suggest that abnormal TWA is a very common condition (approximately 25%) among people with type 2 diabetes without manifest CVD and is closely correlated to glycemic control.
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Affiliation(s)
- Giulio Molon
- Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Verona, Italy
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Morphology and topography of nucleus ambiguus projections to cardiac ganglia in rats and mice. Neuroscience 2007; 149:845-60. [PMID: 17942236 DOI: 10.1016/j.neuroscience.2007.07.062] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 06/30/2007] [Accepted: 08/18/2007] [Indexed: 12/13/2022]
Abstract
Vagal efferent axons from the nucleus ambiguus (NA) innervate ganglionated plexuses in the dorsal surface of cardiac atria, which in turn, may have different functional roles in cardiac regulation. However, the morphology and topography of vagal efferent projections to these ganglionated plexuses in rats and mice have not been well delineated. In the present study, we injected the tracer 1,1'-dioctadecyl-3,3,3',3' tetramethylindocarbocyanine methanesulfonate (DiI) into the left NA to label vagal efferent axons and terminals in cardiac ganglia and administered Fluoro-Gold (FG) i.p. to stain cardiac ganglia. Then, we used confocal microscopy and a Neurolucida 3-D Digitization System to qualitatively and quantitatively examine the distribution and structure of cardiac ganglia, and NA efferent projections to cardiac ganglia in the whole-mounts of Sprague-Dawley (SD) rats and FVB mice. Our observations were: 1) Cardiac ganglia of different shapes and sizes were distributed in the sinoatrial (SA) node, atrioventricular (AV) node, and lower pulmonary vein (LPV) regions on the dorsal surface of the atria. In each region, several ganglia formed a ganglionated plexus. The plexuses at different locations were interconnected by nerves. 2) Vagal efferent fibers ramified within cardiac ganglia, formed a complex network of axons, and innervated cardiac ganglia with very dense basket endings around individual cardiac principal neurons (PNs). 3) The percent of the PNs in cardiac ganglia which were innervated by DiI-labeled axons was 54.3+/-3.2% in mice vs. 53.2+/-3.2% in rats (P>0.10). 4) The density of axonal putative-synaptic varicosities on the surface of PNs was 0.15+/-0.02/microm(2) in mice vs. 0.16+/-0.02/microm(2) in rats (P>0.10). Thus, the distributions of cardiac ganglia and vagal efferent projections to cardiac ganglia in mice and rats were quite similar both qualitatively and quantitatively. Our study provides the structural foundation for future investigation of functional differentiation of ganglionated plexuses and the brain-heart circuitry in rodent models of human disease.
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Wang H, Lei W, Li Y, Xu T. The epidemiology of non-traumatic prehospital sudden death in Macau. Resuscitation 2007; 74:222-6. [PMID: 17382450 DOI: 10.1016/j.resuscitation.2007.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/25/2006] [Accepted: 01/09/2007] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To understand the epidemiology of non-traumatic prehospital sudden death (NPSD) in Macau, and to discuss potential diseases related to NPSD. METHODS We analysed the epidemiological characteristics of 605 NPSD cases occurred between January 1, 2003 and December 31, 2005 in Macau. Four hundred NPSD victims' medical records were reviewed to collect information regarding associated diseases. RESULTS NPSD was more common in males than females (56.5% versus 43.5%). Male patients were 7.9 years younger than female patients (68.8+/-17.7 versus 76.7+/-16.7, p=0.000). NPSD had a higher incidence in the months December to March. There were 21.8 NPSD cases per month on an average during this period. NPSD occurred more frequently during daylight hours. The following diagnoses were frequently found in the patients' medical records: hypertension (39.5%), cerebral vascular accident (18.5%), type 2 diabetes mellitus (17.8%), congestive heart failure (13.3%), chronic renal failure (11.3%), and chronic obstructive pulmonary disease (11%). Coronary artery disease was diagnosed in only 9.2% in all NPSD cases. CONCLUSIONS NPSD has similar epidemiological characters with sudden cardiac death. Most NPSD should be presumed to be of cardiac aetiology. Chronic diseases that affect cardiovascular system have close relations with NPSD. Coronary artery disease in these patients should be recognised early.
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Affiliation(s)
- Houli Wang
- Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, PR China.
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Movahed MR, Hashemzadeh M, Jamal M. Increased prevalence of ventricular fibrillation in patients with type 2 diabetes mellitus. Heart Vessels 2007; 22:251-3. [PMID: 17653519 DOI: 10.1007/s00380-006-0962-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 11/25/2006] [Indexed: 01/19/2023]
Abstract
Diabetes mellitus (DM) is an independent risk for cardiovascular disease. Furthermore, patients with DM have increased risk for ventricular arrhythmia that is thought to be secondary to coronary artery disease (CAD) or congestive heart failure (CHF). We hypothesized that DM may cause ventricular arrhythmias independent of CAD or CHF. Using a large database, we evaluated the occurrence of ventricular fibrillation in patients with DM adjusting for CAD and CHF. We used patient treatment files (PTF), documents of inpatients' admissions containing discharge diagnoses (ICD-9 codes) from all Veterans Health Administration Hospitals. The patients were stratified in two groups: ICD-9 code for DM (293 124) and a control group with ICD-code for hypertension (HTN) but no DM (552 623). ICD-9 codes for ventricular fibrillation were used for this study. We performed uni- and multivariant analysis adjusting for comorbid conditions. Ventricular fibrillation was present in 563 (0.2%) vs 781 (0.1%) in the control group. Using multivariate analysis, DM remained independently associated with ventricular fibrillation (odds ratio: 1.7; confidence interval: 1.5-1.9; P < 0.000). Patients with DM have significantly higher prevalence of ventricular fibrillation independent of CAD or CHF, which in part may explain the higher risk of sudden death in patients with DM.
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Affiliation(s)
- Mohammad-Reza Movahed
- Department of Medicine, Section of Cardiology, University of Arizona Sarver Heart Center, 1501 North Campbell Avenue, Tucson, AZ 85724-5037, USA.
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Abstract
Diabetes mellitus (DM) is a major risk factor for cardiovascular disease and mortality with increasing prevalence in the ageing population. Coronary artery disease is the major cardiovascular abnormality in DM patients. Cardiomyopathy and left ventricular hypertrophy are two other known associated cardiovascular abnormalities. There are a few non-randomized studies reporting increased prevalence of cardiac conduction abnormalities, such as right bundle branch block (RBBB), bifascicular block and high degree atrioventricular (AV)-block but not left bundle branch block (LBBB), in DM patients. Most clinicians are not aware of this association, and it is rarely mentioned in the published reviews about cardiovascular abnormalities in this population. The cause of cardiac conduction abnormalities in DM patients is not known. If autonomic neuropathy or DM-associated cardiovascular disease plays a role, it remains unknown. The goal of this manuscript is to review the current literature about the risk of conduction abnormalities in DM patients. For this study, Medline, Google and published books were searched and reviewed for any references that matched cardiac conduction abnormalities, AV-block, BBB for bundle branch block, LBBB, RBBB, bifascicular block, autonomic neuropathy and DM.
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Affiliation(s)
- Mohammad-Reza Movahed
- Department of Medicine, Division of Cardiology, University of California, Irvine Medical Center, Orange, CA 92868-4080, USA.
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Nygren A, Olson ML, Chen KY, Emmett T, Kargacin G, Shimoni Y. Propagation of the cardiac impulse in the diabetic rat heart: reduced conduction reserve. J Physiol 2007; 580:543-60. [PMID: 17185336 PMCID: PMC2075555 DOI: 10.1113/jphysiol.2006.123729] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 12/18/2006] [Indexed: 01/22/2023] Open
Abstract
Diabetes mellitus is a growing epidemic with severe cardiovascular complications. Although much is known about mechanical and electrical cardiac dysfunction in diabetes, few studies have investigated propagation of the electrical signal in the diabetic heart and the associated changes in intercellular gap junctions. This study was designed to investigate these issues, using hearts from control and diabetic rats. Diabetic conditions were induced by streptozotocin (STZ), given i.v. 7-14 days before experiments. Optical mapping with the voltage-sensitive dye di-4-ANEPPS, using hearts perfused on a Langendorff apparatus, showed little change in baseline conduction velocity in diabetic hearts, reflecting the large reserve of function. However, both the gap junction uncoupler heptanol (0.5-1 mM) and elevated potassium (9 mM, to reduce cell excitability) produced a significantly greater slowing of impulse propagation in diabetic hearts than in controls. The maximal action potential upstroke velocity (an index of the sodium current) and resting potential was similar in single ventricular myocytes from control and diabetic rats, suggesting similar electrical excitability. Immunoblotting of connexin 43 (Cx43), a major gap junction component, showed no change in total expression. However, immunofluorescence labelling of Cx43 showed a significant redistribution, apparent as enhanced Cx43 lateralization. This was quantified and found to be significantly larger than in control myocytes. Labelling of two other gap junction proteins, N-cadherin and beta-catenin, showed a (partial) loss of co-localization with Cx43, indicating that enhancement of lateralized Cx43 is associated with non-functional gap junctions. In conclusion, conduction reserve is smaller in the diabetic heart, priming it for impaired conduction upon further challenges. This can desynchronize contraction and contribute to arrhythmogenesis.
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Affiliation(s)
- A Nygren
- Department of Electrical and Computer Engineering, University of Calgary, Alberta, Canada
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Ding Y, Zou R, Judd RL, Zhong J. Endothelin-1 receptor blockade prevented the electrophysiological dysfunction in cardiac myocytes of streptozotocin-induced diabetic rats. Endocrine 2006; 30:121-7. [PMID: 17185800 DOI: 10.1385/endo:30:1:121] [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: 03/16/2006] [Revised: 04/21/2006] [Accepted: 06/26/2006] [Indexed: 12/27/2022]
Abstract
Diabetes mellitus is complicated with the development of cardiac contractile dysfunction and electrical instability, which contributes to high morbidity and mortality in diabetic patients. This study examined the possible roles of enhanced endothelin-1 (ET-1) on diabetes-induced alterations in ventricular myocyte electrophysiology. Type 1 diabetic rats were induced by single dose injection of streptozotocin (STZ) and treated with or without ET-1 receptor antagonist bosentan for 8 wk before myocyte isolation. Action potential, outward K+ currents, and inward Ca2+ currents in ventricular myocytes were recorded using whole-cell patch clamp technique. STZ-injected rats exhibited hyperglycemia, reduced body weight gain, and elevated plasma ET-1 concentration, indicative of diabetes induction. Ventricular myocytes isolated from diabetic rats exhibited prolonged action potential and reduced all three types of outward K+ currents. Resting membrane potential, height of action potential, and L-type Ca2+ current were not altered in diabetic myocytes. In vivo chronic treatment of diabetic rats with bosentan significantly augmented K+ currents and reversed action potential prolongation in ventricular myocytes. On the other hand, bosentan treatment had no detectable effect on the electrophysiological properties in control myocytes. In addition, bosentan had no effect on Ltype Ca2+ currents in both control and diabetic myocytes. Our data suggest that altered electrophysiological properties in ventricular myocytes were largely resulted from augmented ET-1 system in diabetic animals.
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Affiliation(s)
- Yanfeng Ding
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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Molon G, Targher G, Costa A, Bertolini L, Barbieri E, Zenari L. Measurement of microvolt T-wave alternans, a new arrhythmic risk stratification test, in Type 2 diabetic patients without clinical cardiovascular disease. Diabet Med 2006; 23:207-10. [PMID: 16433721 DOI: 10.1111/j.1464-5491.2006.01799.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Patients with a positive microvolt T-wave alternans (TWA) are at increased risk of ventricular arrhythmias and sudden cardiac death. Although Type 2 diabetes is associated with an increased risk of these events, there is a dearth of available data on measurements of TWA in people with Type 2 diabetes. METHODS We studied 43 Type 2 diabetic volunteers who were free of diagnosed cardiovascular disease (CVD). Microvolt TWA analysis was performed non-invasively using the CH 2000 system during submaximal exercise with the patients sitting on a bicycle ergometer. RESULTS TWA analysis was positive in 9 (21%) patients, negative in 32 (74.4%) and indeterminate in 2 (4.6%) subjects. TWA positive patients had significantly higher HbA(1c) levels than those with TWA negativity (8.1 +/- 0.9 vs. 7.2 +/- 0.8%, P < 0.01). Age, sex, BMI, blood pressure, lipids, 24-h heart rate variability, QTc interval duration, smoking history, diabetes duration and treatment, and microvascular complication status did not differ between the groups. In regression logistic analysis, HbA(1c) was the only significant predictor of TWA positivity (odds ratio 5.7, 95% CI 1.3-26, P = 0.023) after controlling for potential confounders. CONCLUSIONS These results suggest that in Type 2 diabetic patients without clinically manifest CVD, TWA positivity is common (approximately 20%) and is closely correlated with glycaemic control.
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Affiliation(s)
- G Molon
- Division of Cardiology, Sacro Cuore Hospital, Negrar (VR), Italy
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Billimoria FR, Katyare SS, Patel SP. Insulin status differentially affects energy transduction in cardiac mitochondria from male and female rats. Diabetes Obes Metab 2006; 8:67-74. [PMID: 16367884 DOI: 10.1111/j.1463-1326.2005.00470.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The incidence of coronary heart diseases (CHD), congestive heart failure (CHF) and myocardial infarction is higher in diabetic patients than in non-diabetic groups, with these incidences being more in women than in the men. Hence, we examined involvement of mitochondrial energy transduction functions. METHODS Mitochondrial energy metabolism in cardiomyopathy was studied using streptozotocin (STZ)-diabetic male and female rats as the model system. Effects of insulin treatment were also evaluated. RESULTS The body and heart weights decreased in both male and female diabetic rats. Insulin treatments resulted in significant increase in the body and heart weights in the female rats. Mitochondrial respiration rates with all the substrates tested decreased in diabetic condition in both males and females. Treatment with two dose-regimens of insulin had differential restorative effect on mitochondrial substrate oxidation in the males but caused hyper-stimulation in the females. Diabetic state brought about 19% decrease in the cytochrome aa(3) content in the female rats. Treatment with 0.6 units of insulin significantly increased the cytochrome contents in general in both the sexes whereas higher dose (1.0 unit) caused decrease in the cytochromes content in the females. Diabetic state resulted in decreased dehydrogenases activities; insulin treatments had differential effect on the dehydrogenase activity in the males and the females. The results suggest that insulin treatment-induced hyper-stimulation of respiration in female rats may lead to increased production of reactive oxygen species. Besides, increased formation of advanced glycosylated end products may further lead to increased risk of CHF and CHD. CONCLUSIONS The results suggest that differential effects of STZ-diabetes and insulin treatments in the female rats than in males may be the underlying cause for increased incidence of diabetic cardiomyopathies in the females.
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Movahed MR, Hashemzadeh M, Jamal MM. Increased Prevalence of Third-Degree Atrioventricular Block in Patients With Type II Diabetes Mellitus. Chest 2005; 128:2611-4. [PMID: 16236932 DOI: 10.1378/chest.128.4.2611] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Diabetes mellitus (DM) is a major risk for cardiovascular disease and mortality. There is some evidence that third-degree atrioventricular (AV) block occurs more commonly in patients with DM. In this study, we evaluated any possible association between DM and third-degree AV block using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes in a very large inpatient database. METHOD We used patient treatment files containing discharge diagnoses using ICD-9 codes of inpatient treatment from all Veterans Health Administration hospitals. The cohort was stratified using the ICD-9-CM code for DM (n = 293,124), a control group with hypertension but no DM (n = 552,623), and the ICD-9 code for third-degree AV block (426.0) and smoking (305.1, V15.82). We performed multivariate analysis adjusting for coronary artery disease, congestive heart failure, smoking, and hyperlipidemia. Continuous and binary variables were analyzed using chi2 and Fisher exact tests. RESULTS Third-degree AV block diagnosis was present in 3,240 of DM patients (1.1%) vs 3,367 patients (0.6%) in the control group. Using multivariate analysis, DM remained strongly associated with third-degree AV block (odds ratio, 3.1; 95% confidential interval, 3.0 to 3.3; p < 0.0001). CONCLUSION Third-degree AV block occurs significantly more in patients with DM. This finding may, in part, explain the high cardiovascular mortality in DM patients.
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Affiliation(s)
- Mohammad-Reza Movahed
- Division of Cardiology, Department of Medicine, Medical Center, University of California, Irvine, 101 The City Dr, Bldg 53, Rm 100, Orange, CA 92868-4080, USA.
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