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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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Yaghoobian R, Hosseini Dolama R, Soleimani H, Saeidi S, Mashayekhi M, Mirzayi P, Alavi Tabatabaei G, Hosseini K. Incidence of atrioventricular block after isolated coronary artery bypass grafting: a systematic review and pooled-analysis. Front Cardiovasc Med 2023; 10:1225833. [PMID: 37593149 PMCID: PMC10427724 DOI: 10.3389/fcvm.2023.1225833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023] Open
Abstract
Background and objectives Atrioventricular block (AVB) is a serious complication following coronary artery bypass grafting (CABG) surgery, and its high-grade form may necessitate the implantation of a permanent pacemaker (PPM). AVB is associated with increased morbidity and mortality rates. This study aims to estimate the incidence of AVB and subsequent PPM implantation after isolated CABG surgery. Material and methods We searched electronic databases of PubMed, Embase, and Scopus from inception to 18 November 2022. Clinical trials and observational studies reporting the incidence of post-CABG AVB or subsequent PPM implantation in adult patients were included. The total incidence for all included outcomes was calculated using the inverse variance method, and the I2 statistic was reported to evaluate the heterogeneity of studies. Results A total of 28 studies met the inclusion criteria. Four studies [3 cohorts, 1 randomized controlled trial (RCT)] reported AVB without specifying its type; one (cohort) reported different degrees of AVB, 20 (12 cohorts, 8 RCTs) reported complete heart block (CHB) (or AVB requiring temporary pacing), and nine (8 cohorts, 1 RCT) reported the number of PPM inserted due to AVB. The pooled incidence of AVB, CHB (or AVB requiring temporary pacing), and PPM due to AVB was 1.16%, 1.73%, and 0.58%, respectively. Meta-regression analysis revealed that age, gender, diabetes, hypertension, hyperlipidemia, or smoking were not significantly associated with AVB, CHB, or PPM implantation. Conclusion This study highlights the incidence of AVB and the need for PPM implantation following CABG surgery. The findings emphasize the importance of postoperative monitoring and surveillance to improve patient outcomes. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022377181, identifier PROSPERO CRD42022377181.
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Affiliation(s)
- Ramin Yaghoobian
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Hosseini Dolama
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran
| | - Hamidreza Soleimani
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Sahar Saeidi
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahtab Mashayekhi
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Parsa Mirzayi
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghazaal Alavi Tabatabaei
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Kaveh Hosseini
- Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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Choudhury M, Kumar N, Chalil S, Abozguia K. Refractory hypertensive emergency associated with complete heart block resolved after permanent pacemaker implantation: A case report. Clin Case Rep 2022; 10:e5964. [PMID: 35765295 PMCID: PMC9207116 DOI: 10.1002/ccr3.5964] [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: 03/02/2022] [Revised: 04/21/2022] [Accepted: 05/16/2022] [Indexed: 12/02/2022] Open
Abstract
Severe hypertension sometimes improves with treatment of bradycardia but this phenomenon is under-reported. Here, an elderly gentleman with complete heart block and a hypertensive emergency was refractory to medical therapies and blood pressure only improved following pacemaker implantation. We discuss the possible mechanisms relating to heart rate and artificial pacing.
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Affiliation(s)
| | - Narendra Kumar
- Lancashire Cardiac Centre, Blackpool Victoria HospitalBlackpoolUK
| | - Shajil Chalil
- Lancashire Cardiac Centre, Blackpool Victoria HospitalBlackpoolUK
| | - Khalid Abozguia
- Lancashire Cardiac Centre, Blackpool Victoria HospitalBlackpoolUK
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Spalla I, Smith GW, Chang YM, Luis Fuentes V, Connolly DJ. Paroxysmal high-grade second-degree and persistent third-degree atrioventricular block in cats. J Vet Cardiol 2021; 36:20-31. [PMID: 34051641 DOI: 10.1016/j.jvc.2021.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/01/2021] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Both paroxysmal high-grade second-degree and persistent third-degree atrioventricular block (AVB) are recognised in cats. Our aim was to document the presentation, echocardiographic data, comorbidities and outcome in affected cats from a single referral hospital, including those that underwent epicardial pacemaker implantation (EPI). ANIMALS, MATERIALS AND METHODS This retrospective study included 64 cats diagnosed with persistent third-degree or paroxysmal high-grade AVB, for which detailed patient history was available. Non-parametric testing, Kaplan-Meier curves and Cox proportional hazard testing were performed. RESULTS Atrioventricular block was persistent in 43 cats (67%) and paroxysmal in 21 (33%). Forty-seven cats (74%) were referred for cardiac complaints (e.g. collapse, arrhythmia, tachypnea), 6 (9%) had non-specific complaints and AVB was an incidental finding in 11 cats (17%). Median duration of clinical signs prior to presentation was 21 days (1-1138 days). Thirty-nine (63%) cats had echocardiographic abnormalities; 13 (20%) presented with congestive heart failure. Forty-five (70%) cats had one or more comorbidities. Fifteen cats underwent EPI with immediate resolution of signs in 12 cats. Following EPI, two and four cats experienced major and minor complications, respectively. Forty-seven cats died; median survival time was 799 days (all-cause mortality). Cardiac-related death occurred in 17 cats (36%); median survival in these cats was 132 days. Heart failure on presentation was the only independent risk factor for cardiac death (p=0.002). CONCLUSIONS Outcome in cats with AVB was variable, although most had good medium- to long-term survival. Cardiac death occurred in a minority of cats. Pacemaker implantation was effective in relieving clinical signs.
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Affiliation(s)
- I Spalla
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom; Ospedale Veterinario San Francesco, via Isaac Newton 2, 20148 Milano, Italy.
| | - G W Smith
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - Y-M Chang
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - V Luis Fuentes
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - D J Connolly
- Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
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Harvey R, Chong A, Hill J, Korczyk D. Transiently elevated estimated pulmonary pressures in a patient with complete heart block undergoing permanent pacing: a case report. Eur Heart J Case Rep 2020; 4:1-4. [PMID: 32617473 PMCID: PMC7319818 DOI: 10.1093/ehjcr/ytaa072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/04/2019] [Accepted: 03/12/2020] [Indexed: 11/30/2022]
Abstract
Background Complete heart block (CHB) is a frequent cause for acute admission in older patients with significant cardiac conduction disease. Common presenting symptoms are syncope and dyspnoea. Some patients may exhibit clinical and radiological signs of left ventricular (LV) decompensation, despite preserved LV ejection fraction on transthoracic echocardiography (TTE) and absent pre-existing LV dysfunction. Case summary In this clinical report, we present a case of CHB associated with transient but severe elevation in pulmonary artery systolic pressure, measured as the equivalent right ventricular systolic pressure (RVSP = 99 mmHg) by TTE in the absence of right ventricular outflow tract obstruction, that subsequently ‘normalized’ after implantation of a permanent pacemaker. After searching our echocardiogram database, we did find other cases with similar findings. Discussion There is limited literature describing transient acute elevation in estimated pulmonary pressures in the setting of new CHB that is subsequently reversed by permanent pacing. The true prevalence and mechanism of transient estimated pulmonary pressure as a result of CHB remains unknown. Based on our limited assessment, we postulate that the acute elevation in estimated pulmonary pressures is predominantly related to a compensatory augmentation of RV stroke volume and is caused by the underlying bradycardia and need to maintain forward cardiac output. This phenomenon may require further investigation and validation in future studies.
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Affiliation(s)
- Robert Harvey
- Cardiology Department, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - Adrian Chong
- Cardiology Department, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - John Hill
- Cardiology Department, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Brisbane, Queensland 4102, Australia
| | - Dariusz Korczyk
- Cardiology Department, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, Brisbane, Queensland 4102, Australia
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Kim NK, Wolfson D, Fernandez N, Shin M, Cho HC. A rat model of complete atrioventricular block recapitulates clinical indices of bradycardia and provides a platform to test disease-modifying therapies. Sci Rep 2019; 9:6930. [PMID: 31061413 PMCID: PMC6502940 DOI: 10.1038/s41598-019-43300-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 04/09/2019] [Indexed: 11/09/2022] Open
Abstract
Complete atrioventricular block (CAVB) is a life-threatening arrhythmia. A small animal model of chronic CAVB that properly reflects clinical indices of bradycardia would accelerate the understanding of disease progression and pathophysiology, and the development of therapeutic strategies. We sought to develop a surgical model of CAVB in adult rats, which could recapitulate structural remodeling and arrhythmogenicity expected in chronic CAVB. Upon right thoracotomy, we delivered electrosurgical energy subepicardially via a thin needle into the atrioventricular node (AVN) region of adult rats to create complete AV block. The chronic CAVB animals developed dilated and hypertrophied ventricles with preserved systolic functions due to compensatory hemodynamic remodeling. Ventricular tachyarrhythmias, which are difficult to induce in the healthy rodent heart, could be induced upon programmed electrical stimulation in chronic CAVB rats and worsened when combined with β-adrenergic stimulation. Focal somatic gene transfer of TBX18 to the left ventricular apex in the CAVB rats resulted in ectopic ventricular beats within days, achieving a de novo ventricular rate faster than the slow atrioventricular (AV) junctional escape rhythm observed in control CAVB animals. The model offers new opportunities to test therapeutic approaches to treat chronic and severe CAVB which have previously only been testable in large animal models.
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Affiliation(s)
- Nam Kyun Kim
- Department of Pediatrics, Emory University, Atlanta, GA, USA.,Department of Pediatrics, Yonsei University College of Medicine, Seoul, South Korea
| | - David Wolfson
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | | | - Minji Shin
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Hee Cheol Cho
- Department of Pediatrics, Emory University, Atlanta, GA, USA. .,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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da Cunha DNQ, Pereira VG, Favarato LSC, Okano BS, Daibert APF, Monteiro BS, Araujo MR, Carvalho PH, Hamlin RL, Del Carlo RJ. Acute and chronic observations of complete atrioventricular block in rats. Lab Anim 2014; 48:237-249. [PMID: 24759570 DOI: 10.1177/0023677214530905] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The mechanisms of production, and gross, microscopic and electrocardiograhic findings of surgically-induced complete heart block (CHB) in the adult rat are presented. This is an effective in vivo model for establishing alternative methods to electronic pacemakers and for providing detailed information aimed at replacement, reduction and refinement of the technique. Sternal thoracotomy was employed to identify the epicardial fat pad by the aortic root, used as a landmark for cauterization of the atrioventricular (AV) node. Stable CHB was produced in 60 rats with a 70% survival rate. The best survival rate was observed in 8-week-old animals weighing 221 ± 27.6 g. Heart rate before cauterization was 387 ± 55 bpm, reduced after cauterization to 126 ± 40 bpm in the survival and to 65 ± 19 bpm in the non-survival groups. At 30 days findings were: elevated left ventricular end-diastolic pressure (21 ± 5.4 mmHg, P < 0.05); maximal rate of rise of left ventricular pressure (LVP) during isovolumetric contraction (2192 ± 235 mmHg/s, P < 0.05); maximal rate of decrease of LVP (-1658 ± 191 mmHg/s, P < 0.05); isovolumetric relaxation constant (5.7 ± 0.8 ms, P < 0.05) with wet-to-dry lung-weight ratio (78.1 ± 0.4, P < 0.05); heart weight/body weight (0.6 ± 0.1, P < 0.05); heart volume (1.8 ± 0.3 mL, P < 0.05); longitudinal diameter (20.2 ± 1.91 mm, P < 0.05); and transversal diameter (17.0 ± 1.4 mm, P < 0.05) with supported dilated cardiomyopathy which culminated in chronic heart failure. CHB hearts had increased preload and replacement of myofibrils by collagen. CHB was achieved reproducibly by cauterization of the rat AV node and/or His bundle. This led to electrophysiological, hemodynamic, and structural remodeling, and could be useful in long-term cardiac remodeling assessments and potential therapy development.
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Affiliation(s)
| | | | | | - Barbara S Okano
- Veterinary Department, Federal University of Viçosa, Viçosa, Brazil
| | - Ana P F Daibert
- Veterinary Department, Federal University of Viçosa, Viçosa, Brazil
| | | | - Marta R Araujo
- Veterinary Department, Federal University of Viçosa, Viçosa, Brazil
| | - Pablo H Carvalho
- Veterinary Department, Federal University of Viçosa, Viçosa, Brazil
| | - Robert L Hamlin
- Veterinary Biosciences Department, The Ohio State University, Columbus, Ohio, USA
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Groenke S, Larson ED, Alber S, Zhang R, Lamp ST, Ren X, Nakano H, Jordan MC, Karagueuzian HS, Roos KP, Nakano A, Proenza C, Philipson KD, Goldhaber JI. Complete atrial-specific knockout of sodium-calcium exchange eliminates sinoatrial node pacemaker activity. PLoS One 2013; 8:e81633. [PMID: 24278453 PMCID: PMC3836769 DOI: 10.1371/journal.pone.0081633] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/25/2013] [Indexed: 11/18/2022] Open
Abstract
The origin of sinoatrial node (SAN) pacemaker activity in the heart is controversial. The leading candidates are diastolic depolarization by "funny" current (If) through HCN4 channels (the "Membrane Clock" hypothesis), depolarization by cardiac Na-Ca exchange (NCX1) in response to intracellular Ca cycling (the "Calcium Clock" hypothesis), and a combination of the two ("Coupled Clock"). To address this controversy, we used Cre/loxP technology to generate atrial-specific NCX1 KO mice. NCX1 protein was undetectable in KO atrial tissue, including the SAN. Surface ECG and intracardiac electrograms showed no atrial depolarization and a slow junctional escape rhythm in KO that responded appropriately to β-adrenergic and muscarinic stimulation. Although KO atria were quiescent they could be stimulated by external pacing suggesting that electrical coupling between cells remained intact. Despite normal electrophysiological properties of If in isolated patch clamped KO SAN cells, pacemaker activity was absent. Recurring Ca sparks were present in all KO SAN cells, suggesting that Ca cycling persists but is uncoupled from the sarcolemma. We conclude that NCX1 is required for normal pacemaker activity in murine SAN.
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Affiliation(s)
- Sabine Groenke
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Eric D. Larson
- Department of Physiology & Biophysics, University of Colorado School of Medicine, Denver, Colorado, United States of America
| | - Sarah Alber
- Department of Physiology & Biophysics, University of Colorado School of Medicine, Denver, Colorado, United States of America
| | - Rui Zhang
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Scott T. Lamp
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Xiaoyan Ren
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Haruko Nakano
- Department of Molecular, Cell and Developmental Biology, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California, United States of America
| | - Maria C. Jordan
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Hrayr S. Karagueuzian
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Kenneth P. Roos
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Atsushi Nakano
- Department of Molecular, Cell and Developmental Biology, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California, United States of America
| | - Catherine Proenza
- Department of Physiology & Biophysics, University of Colorado School of Medicine, Denver, Colorado, United States of America
| | - Kenneth D. Philipson
- Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Joshua I. Goldhaber
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
- * E-mail:
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Are the different patterns of stress-induced (Takotsubo) cardiomyopathy explained by regional mechanical overload and demand: supply mismatch in selected ventricular regions? Med Hypotheses 2013; 81:954-60. [PMID: 24075594 DOI: 10.1016/j.mehy.2013.09.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/03/2013] [Accepted: 09/03/2013] [Indexed: 12/16/2022]
Abstract
Takotsubo cardiomyopathy (TCM) or stress-induced cardiomyopathy is an increasingly recognized syndrome characterized by severe regional left ventricular dysfunction in the absence of an explanatory coronary lesion. TCM may lead to lethal complications but is completely reversible if the patient survives the acute phase. The pathogenesis of TCM and the mechanism behind this remarkable recovery are unknown. Plasma levels of catecholamine are elevated in many TCM patients and exogenously administered catecholamine induces TCM-like cardiac dysfunction in both humans and rats. A catecholamine excess increases myocardial metabolic demand by increasing the force of contraction as well as the heart rate, and also alters cardiac depolarization patterns. We propose that an altered spatiotemporal pattern of cardiac contraction and excessive force of contraction may lead to a redistribution of wall stresses in the left ventricle. This redistribution of wall stress causes regional mechanical overload of regions where wall tension becomes disproportionately great and renders these cardiomyocytes "metabolically insufficient". In other words, these cardiomyocytes experience a demand: supply mismatch on the basis of excessive metabolic demand. In order to prevent the death of these cardiomyocytes and to prevent excessive wall tension from developing in neighboring regions, a protective metabolic shutdown occurs in the affected cardiomyocytes. This metabolic shutdown, i.e., acute down regulation of non-vital cellular functions, serves to protect the affected regions from necrosis and explains the apparently complete recovery observed in TCM. We propose that this phenomenon may share important characteristics with phenomena such as ischemic conditioning, stunning and hibernation. In this manuscript, we discuss our hypothesis in the context of available knowledge and discuss important experiments that would help to corroborate or refute the hypothesis.
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Bevan AK, Hutchinson KR, Foust KD, Braun L, McGovern VL, Schmelzer L, Ward JG, Petruska JC, Lucchesi PA, Burghes AHM, Kaspar BK. Early heart failure in the SMNDelta7 model of spinal muscular atrophy and correction by postnatal scAAV9-SMN delivery. Hum Mol Genet 2010; 19:3895-905. [PMID: 20639395 DOI: 10.1093/hmg/ddq300] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Proximal spinal muscular atrophy (SMA) is a debilitating neurological disease marked by isolated lower motor neuron death and subsequent atrophy of skeletal muscle. Historically, SMA pathology was thought to be limited to lower motor neurons and the skeletal muscles they control, yet there are several reports describing the coincidence of cardiovascular abnormalities in SMA patients. As new therapies for SMA emerge, it is necessary to determine whether these non-neuromuscular systems need to be targeted. Therefore, we have characterized left ventricular (LV) function of SMA mice (SMN2+/+; SMNΔ7+/+; Smn-/-) and compared it with that of their unaffected littermates at 7 and 14 days of age. Anatomical and physiological measurements made by electrocardiogram and echocardiography show that affected mouse pups have a dramatic decrease in cardiac function. At 14 days of age, SMA mice have bradycardia and develop a marked dilated cardiomyopathy with a concomitant decrease in contractility. Signs of decreased cardiac function are also apparent as early as 7 days of age in SMA animals. Delivery of a survival motor neuron-1 transgene using a self-complementary adeno-associated virus serotype 9 abolished the symptom of bradycardia and significantly decreased the severity of the heart defect. We conclude that severe SMA animals have compromised cardiac function resulting at least partially from early bradycardia, which is likely attributable to aberrant autonomic signaling. Further cardiographic studies of human SMA patients are needed to clarify the clinical relevance of these findings from this SMA mouse.
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Affiliation(s)
- Adam K Bevan
- Department of Gene Therapy, The Research Institute, Nationwide Children’s Hospital, Columbus, OH 43205, USA
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