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Exercise Preconditioning as a Cardioprotective Phenotype. Am J Cardiol 2021; 148:8-15. [PMID: 33675772 DOI: 10.1016/j.amjcard.2021.02.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/11/2021] [Accepted: 02/19/2021] [Indexed: 12/24/2022]
Abstract
Cardiovascular disease (CVD) is potentiated by risk factors including physical inactivity and remains a leading cause of morbidity and mortality. Although regular physical activity does not reverse atherosclerotic coronary disease, precursory exercise improves clinical outcomes in those experiencing life-threatening CVD events. Exercise preconditioning describes the cardioprotective phenotype whereby even a few exercise bouts confer short-term multifaceted protection against acute myocardial infarction. First described decades ago in animal investigations, cardioprotective mechanisms responsible for exercise preconditioning have been identified through reductionist preclinical studies, including the upregulation of endogenous antioxidant enzymes, improved calcium handling, and enhanced bioenergetic regulation during a supply-demand mismatch. Until recently, translation of this research was only inferred from clinically-directed animal models of exercise involving ischemia-reperfusion injury, and reinforced by the gene products of exercise preconditioning that are common to mammalian species. However, recent clinical investigations confirm that exercise preconditions the human heart. This discovery means that simply the initiation of a remedial exercise regimen in those with abnormal CVD risk factor profiles will provide immediate cardioprotective benefits and improved clinical outcomes following acute cardiac events. In conclusion, the prophylactic biochemical adaptations to aerobic exercise are complemented by the long-term adaptive benefits of vascular and architectural remodeling in those who adopt a physically active lifestyle.
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Sung YL, Wu CE, Syu JY, Kuo TBJ, Li JY, Chen CW, Weng CH, Hsu WH, Chen SA, Hu YF, Lin SF. Effects of long-term exercise on arrhythmogenesis in aged hypertensive rats. Comput Biol Med 2018; 102:390-395. [PMID: 30144936 DOI: 10.1016/j.compbiomed.2018.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/24/2018] [Accepted: 08/13/2018] [Indexed: 12/16/2022]
Abstract
Chronic hypertension is a multifactorial disease that is highly associated with cardiovascular disorders. Physical activity, such as long-term exercise, is advocated as a treatment for hypertension, but the responses of different age groups to long-term exercise are unknown. We used aged spontaneous hypertensive rats (SHRs, 80 weeks old) to test the hypothesis that long-term exercise compensated for deficient autonomic control and reduced susceptibility to ventricular tachycardia (VT) and ventricular fibrillation (VF) in this animal model. The aged SHRs were divided into control and voluntary exercise groups. Ambulatory electrocardiography was recorded for the heart rate variability (HRV) analysis. Programmed stimulation was applied to exposed hearts to induce ventricular arrhythmia in situ. Then, the hearts were isolated for an optical mapping study. The results showed that increased HRV indices were broadly related to vagal dominance in the high-intensity exercise group. Exercise altered the electrical propagation dynamic properties, such as the action potential duration restitution (APDR). Furthermore, the VF inducibility decreased with increased exercise intensity. Taken together, our results suggest that long-term exercise reduces the risk of arrhythmogenesis in aged SHRs through enhanced vagal control and stabilized electrical dynamics.
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Affiliation(s)
- Yen-Ling Sung
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Chih-En Wu
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Jhen-Yang Syu
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Terry B J Kuo
- Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei, Taiwan
| | - Jai-Yi Li
- Department of Health and Leisure Management, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Chieh-Wen Chen
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Hui Weng
- Division of Cardiology, Department of Medicine, Taipei Veteran General Hospital, Taipei, Taiwan
| | - Wei-Hsuan Hsu
- Division of Cardiology, Department of Medicine, Taipei Veteran General Hospital, Taipei, Taiwan
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veteran General Hospital, Taipei, Taiwan; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Feng Hu
- Division of Cardiology, Department of Medicine, Taipei Veteran General Hospital, Taipei, Taiwan; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
| | - Shien-Fong Lin
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
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Soares RN, Schneider A, Valle SC, Schenkel PC. Regular Physical Activity Increases the Systolic Blood Pressure Response to Acute Caffeine Ingestion in Nonhabitual Caffeine Consumers. JOURNAL OF CAFFEINE RESEARCH 2017. [DOI: 10.1089/jcr.2016.0017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | - Augusto Schneider
- Nutrition Department at Federal University of Pelotas, Pelotas, Brazil
| | | | - Paulo Cavalheiro Schenkel
- Departamento de Fisiologia do Instituto de Ciências Básicas da Saúde da Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Dor-Haim H, Berenfeld O, Horowitz M, Lotan C, Swissa M. Reduced Ventricular Arrhythmogeneity and Increased Electrical Complexity in Normal Exercised Rats. PLoS One 2013; 8:e66658. [PMID: 23825553 PMCID: PMC3688953 DOI: 10.1371/journal.pone.0066658] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/09/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The mechanisms whereby aerobic training reduces the occurrence of sudden cardiac death in humans are not clear. We test the hypothesis that exercise-induced increased resistance to ventricular tachycardia and fibrillation (VT/VF) involve an intrinsic remodeling in healthy hearts. METHODS AND RESULTS Thirty rats were divided into a sedentary (CTRL, n = 16) and two exercise groups: short- (4 weeks, ST, n = 7) and long-term (8 weeks, LT, n = 7) trained groups. Following the exercise program hearts were isolated and studied in a Langendorff perfusion system. An S1-S2 pacing protocol was applied at the right ventricle to determine inducibility of VT/VF. Fast Fourier transforms were applied on ECG time-series. In-vivo measurements showed training-induced increase in aerobic capacity, heart-to-body weight ratio and a 50% low-to-high frequency ratio reduction in the heart rate variability (p<0.05). In isolated hearts the probability for VF decreased from 26.1±14.4 in CTRL to 13.9±14.1 and 6.7±8.5% in the ST and LT, respectively (p<0.05). Duration of VF also decreased from 19.0±5.7 in CTRL to 8.8±7.1 and 6.0±5.8 sec in ST and LT respectively (p<0.05). Moreover, the pacing current required for VF induction increased following exercise (2.9±1.7 vs. 5.4±2.1 and 8.5±0.9 mA, respectively; p<0.05). Frequency analysis of ECG revealed an exercise-induced VF transition from a narrow single peak spectrum at 17 Hz in CTRL to a broader range of peaks ranging between 8.8 and 22.5 Hz in the LT group (p<0.05). CONCLUSION Exercise in rats leads to reduced VF propensity associated with an intrinsic cardiac remodeling related to a broader spectral range and faster frequency components in the ECG.
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Affiliation(s)
- Horesh Dor-Haim
- Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michal Horowitz
- Department of Physiology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Chaim Lotan
- Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Moshe Swissa
- Cardiac Research Center, Kaplan Medical Center, Rehovot, Israel
- * E-mail:
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Lujan HL, Janbaih H, Feng HZ, Jin JP, DiCarlo SE. Myocardial ischemia, reperfusion, and infarction in chronically instrumented, intact, conscious, and unrestrained mice. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1384-400. [PMID: 22538514 DOI: 10.1152/ajpregu.00095.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the United States alone, the National Heart, Lung, and Blood Institute (NHLBI) has invested several hundred million dollars in pursuit of myocardial infarct-sparing therapies. However, due largely to methodological limitations, this investment has not produced any notable clinical application or cardioprotective therapy. Among the major methodological limitations is the reliance on animal models that do not mimic the clinical situation. In this context, the limited use of conscious animal models is of major concern. In fact, whenever possible, studies of cardiovascular physiology and pathophysiology should be conducted in conscious, complex models to avoid the complications associated with the use of anesthesia and surgical trauma. The mouse has significant advantages over other experimental models for the investigation of infarct-sparing therapies. The mouse is inexpensive, has a high throughput, and presents the ability of one to create genetically modified models. However, successful infarct-sparing therapies in anesthetized mice or isolated mouse hearts may not be successful in more complex models, including conscious mice. Accordingly, a conscious mouse model of myocardial ischemia and reperfusion has the potential to be of major importance for advancing the concepts and methods that drive the development of infarct-sparing therapies. Therefore, we describe, for the first time, the use of an intact, conscious, and unrestrained mouse model of myocardial ischemia-reperfusion and infarction. The conscious mouse model permits occlusion and reperfusion of the left anterior descending coronary artery in an intact, complex model free of the confounding influences of anesthetics and surgical trauma. This methodology may be adopted for advancing the concepts and ideas that drive cardiovascular research.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Lujan HL, DiCarlo SE. Partial hindlimb occlusion reduced the susceptibility to sustained ventricular tachycardia in conscious rats. J Cardiovasc Pharmacol Ther 2009; 14:199-206. [PMID: 19721132 PMCID: PMC2907158 DOI: 10.1177/1074248409340160] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Remote conditioning induced by ischemia in distant organs protects the heart from ischemia/reperfusion injury; however, its effect on ischemia-induced ventricular arrhythmias is unknown. Therefore, we tested the hypothesis that partial hindlimb occlusion during coronary artery occlusion increases the ventricular arrhythmia threshold (VAT) induced by coronary artery occlusion. Rats (n = 7) were instrumented with a radio-telemetry device for recording arterial pressure, electrocardiogram (ECG), and body temperature. A Doppler ultrasonic flow probe and vascular occluder were placed around the terminal aorta. Finally, a snare was placed around the left main coronary artery. The VAT was determined without and, on an alternate day, during partial hindlimb occlusion (remote conditioning) in conscious rats. Without remote conditioning, the VAT was 4.56 + 0.15 minutes. Importantly, remote conditioning significantly increased the VAT (6.29 + 0.49 minutes), suggesting that ischemia in a distant organ may delay the development of ischemia-induced ventricular arrhythmias.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University, Detroit, Michigan 48201, USA.
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Lujan HL, Dicarlo SE. Sex differences to myocardial ischemia and beta-adrenergic receptor blockade in conscious rats. Am J Physiol Heart Circ Physiol 2008; 294:H1523-9. [PMID: 18263711 DOI: 10.1152/ajpheart.01241.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We recently documented sex differences in the susceptibility to reperfusion-induced sustained ventricular tachycardia and beta-adrenergic receptor blockade in conscious rats. However, the effect of sex on ischemia-induced ventricular arrhythmias and beta-adrenergic receptor blockade is under-investigated. Therefore, we tested the hypothesis that gonadal hormones influence the ventricular arrhythmia threshold (VAT) induced by coronary artery occlusion as well as the response to beta-adrenergic receptor blockade. The VAT was defined as the time from coronary occlusion to sustained ventricular tachycardia resulting in a reduction in arterial pressure. Male and female intact and gonadectomized (GnX) rats were instrumented with a radiotelemetry device for recording arterial pressure, temperature, and ECG, as well as a Doppler ultrasonic flow probe to measure cardiac output and a snare around the left main coronary artery. The VAT was determined in conscious rats by pulling on the snare. The VAT was significantly longer in intact females (5.56 +/- 0.19) vs. intact males (4.31 +/- 0.14 min). This sex difference was abolished by GnX. Specifically, GnX decreased the VAT in females (4.55 +/- 0.22) and increased the VAT in males (5.14 +/- 0.30 min). Thus male sex hormones increase and female sex hormones decrease the susceptibility to ischemia-induced sustained ventricular tachycardia. beta-Adrenergic receptor blockade increased the VAT in intact males and GnX females only. Thus gonadal hormones influence the response to beta-adrenergic receptor blockade. Uncovering major differences between males and females in the pathophysiology of the cardiovascular system may result in sex-specific optimization of patient treatments.
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Affiliation(s)
- Heidi L Lujan
- Wayne State Univ. School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201, USA.
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Lujan HL, Kramer VJ, DiCarlo SE. Sex influences the susceptibility to reperfusion-induced sustained ventricular tachycardia and β-adrenergic receptor blockade in conscious rats. Am J Physiol Heart Circ Physiol 2007; 293:H2799-808. [PMID: 17630345 DOI: 10.1152/ajpheart.00596.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reperfusion after a brief period of cardiac ischemia can lead to potentially lethal arrhythmias. Importantly, there are sex-related differences in cardiac physiology and in the types and severity of cardiac arrhythmias. Therefore, we tested the hypothesis that gonadal hormones influence the susceptibility to reperfusion-induced sustained ventricular tachycardia (VT), as well as the response to β-adrenergic receptor blockade. Male and female intact and gonadectomized rats were instrumented, and arterial pressure, temperature, ECG, and cardiac output were recorded. In addition, a snare was placed around the left main coronary artery. Tension was applied to the snare for determination of susceptibility to sustained VT produced by 3 min of occlusion and reperfusion of the left main coronary artery in conscious rats. Reperfusion culminated in sustained VT in 77% (10 of 13 susceptible) of female rats and 56% (9 of 16 susceptible) of male rats ( P > 0.05, male vs. female). β-Adrenergic receptor blockade prevented sustained VT in females only [1 of 9 susceptible females (11%) vs. 6 of 9 susceptible males (67%), P < 0.05]. Ovariectomy did not significantly reduce the susceptibility to reperfusion arrhythmias [5 of 9 susceptible (56%)]. In sharp contrast, orchidectomy significantly increased the susceptibility to reperfusion arrhythmias [9 of 9 susceptible (100%)]. Finally, β-adrenergic receptor blockade prevented sustained VT in ovariectomized females [0 of 4 susceptible (0%)] and orchidectomized males [0 of 7 susceptible (0%)], but the protective effect of β-blockade was due to a reduction in heart rate in males only. Thus gonadal hormones influence the susceptibility to reperfusion-induced arrhythmias, as well as the effects and mechanisms of β-adrenergic receptor blockade.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Lujan HL, DiCarlo SE. T5 spinal cord transection increases susceptibility to reperfusion-induced ventricular tachycardia by enhancing sympathetic activity in conscious rats. Am J Physiol Heart Circ Physiol 2007; 293:H3333-9. [PMID: 17933964 DOI: 10.1152/ajpheart.01019.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We recently documented that paraplegia (T(5) spinal cord transection) alters cardiac electrophysiology and increases the susceptibility to ventricular tachyarrhythmias induced by programmed electrical stimulation. However, coronary artery occlusion is the leading cause of death in industrially developed countries and will be the major cause of death in the world by the year 2020. The majority of these deaths result from tachyarrhythmias that culminate in ventricular fibrillation. beta-Adrenergic receptor antagonists have been shown to reduce the incidence of sudden cardiac death. Therefore, we tested the hypothesis that chronic T(5) spinal cord transection increases the susceptibility to clinically relevant ischemia-reperfusion-induced sustained ventricular tachycardia due to enhanced sympathetic activity. Intact and chronic (4 wk after transection) T(5) spinal cord-transected (T(5)X) male rats were instrumented to record arterial pressure, body temperature, and ECG. In addition, a snare was placed around the left main coronary artery. The susceptibility to sustained ventricular tachycardia produced by 2.5 min of occlusion and reperfusion of the left main coronary artery was determined in conscious rats by pulling on the snare. Reperfusion culminated in sustained ventricular tachycardia in 100% of T(5)X rats (susceptible T(5)X, 10 of 10) and 0% of intact rats [susceptible intact, 0 of 10 (P < 0.05, T(5)X vs. intact)]. Beta-adrenergic receptor blockade prevented reperfusion-induced sustained ventricular tachycardia in T(5)X rats [susceptible T(5)X 0 of 8, 0% (P < 0.05)]. Thus paraplegia increases the susceptibility to reperfusion-induced sustained ventricular tachycardia due to enhanced sympathetic activity.
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Affiliation(s)
- Heidi L Lujan
- Wayne State University School of Medicine, 540 E. Canfield Avenue, Detroit, MI 48201, USA
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Lujan HL, Kramer VJ, DiCarlo SE. Electroacupuncture decreases the susceptibility to ventricular tachycardia in conscious rats by reducing cardiac metabolic demand. Am J Physiol Heart Circ Physiol 2007; 292:H2550-5. [PMID: 17209007 DOI: 10.1152/ajpheart.00979.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reperfusion after a brief period of cardiac ischemia can lead to potentially lethal arrhythmias. Clinical observations and experimental work with animals suggest that acupuncture may have therapeutic effects for individuals with coronary heart disease, certain arrhythmias, and myocardial ischemia. Therefore, we tested the hypothesis that electroacupuncture reduces the susceptibility to ischemia-reperfusion-mediated ventricular tachyarrhythmias. To test this hypothesis, we measured the susceptibility to ventricular tachyarrhythmias produced by 3 min of occlusion and reperfusion of the left main coronary artery in conscious rats under two experimental conditions: 1) control and 2) with electroacupuncture. Acupuncture was simulated by electrically stimulating the median nerves, corresponding to the Jianshi-Neiguan [pericardial meridian (P) 5-6] acupoints. Results document a significantly lower incidence of ventricular tachyarrhythmias with electroacupuncture (2 of 8, 25%) relative to control (14 of 14, 100%) rats. The decreased susceptibility to tachyarrhythmias with electroacupuncture was associated with a reduced cardiac metabolic demand (lower rate-pressure product and ST-segment elevation) during ischemia.
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Affiliation(s)
- Heidi L Lujan
- Wayne State University School of Medicine, 540 E. Canfield Avenue, Detroit, MI 48201, USA.
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Lujan HL, Britton SL, Koch LG, DiCarlo SE. Reduced susceptibility to ventricular tachyarrhythmias in rats selectively bred for high aerobic capacity. Am J Physiol Heart Circ Physiol 2006; 291:H2933-41. [PMID: 16891405 DOI: 10.1152/ajpheart.00514.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reperfusion after a brief period of cardiac ischemia can lead to potentially lethal arrhythmias. Human epidemiological studies and experimental work with animals indicate that regular physical activity is associated with reductions in cardiovascular disease (CVD) risk factors and sudden cardiac death. Similarly, artificial selection of rats for high aerobic treadmill-running capacity (high-capacity runners; HCR) has been shown to reduce CVD risk factors relative to rats selected as low-capacity runners (LCR). Therefore, we tested the hypothesis that HCR, relative to LCR rats, would be less susceptible to ischemia-reperfusion-mediated ventricular tachyarrhythmias. To test this hypothesis, we measured the susceptibility to ventricular tachyarrhythmias produced by 3 min of occlusion and reperfusion of the left main coronary artery in conscious LCR and HCR rats. Results document a significantly lower incidence of ventricular tachyarrhythmias in HCR (3 of 11, 27.3%) relative to LCR (6 of 7, 85.6%) rats. The decreased susceptibility to tachyarrhythmias in HCR rats was associated with a reduced cardiac metabolic demand during ischemia (lower rate-pressure product and ST segment elevation) as well as a wider range for the autonomic control of heart rate. The HCR and LCR represent a unique substrate for evaluation of the mechanisms underlying ischemia-mediated cardiac arrhythmogenesis.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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