ascorbic-acid and Atrial-Fibrillation

The effects of vitamin C administration on clinical outcome in critically ill patients remain controversial.. Online databases were searched up to October 1, 2018.. We included randomized controlled trials on the use of vitamin C (any regimen) in adult critically ill patients versus placebo or no therapy.. Risk ratio for dichotomous outcome and standardized mean difference for continuous outcome with 95% CI were calculated using random-effects model meta-analysis.. Forty-four randomized studies, 16 performed in ICU setting (2,857 patients) and 28 in cardiac surgery (3,598 patients), published between 1995 and 2018, were included in the analysis. In ICU patients, vitamin C administration was not associated with a difference in mortality (risk ratio, 0.90; 95% CI, 0.74-1.10; p = 0.31), acute kidney injury, ICU or hospital length of stay compared with control. In cardiac surgery, vitamin C was associated to a reduction in postoperative atrial fibrillation (risk ratio, 0.64; 95% CI, 0.52-0.78; p < 0.0001), ICU stay (standardized mean difference, -0.28 d; 95% CI, -0.43 to -0.13 d; p = 0.0003), and hospital stay (standardized mean difference, -0.30 d; 95% CI, -0.49 to -0.10 d; p = 0.002). Furthermore, no differences in postoperative mortality, acute kidney injury, stroke, and ventricular arrhythmia were found.. In a mixed population of ICU patients, vitamin C administration is associated with no significant effect on survival, length of ICU or hospital stay. In cardiac surgery, beneficial effects on postoperative atrial fibrillation, ICU or hospital length of stay remain unclear. However, the quality and quantity of evidence is still insufficient to draw firm conclusions, not supporting neither discouraging the systematic administration of vitamin C in these populations. Vitamin C remains an attractive intervention for future investigations aimed to improve clinical outcome.

Topics: Acute Kidney Injury; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Critical Illness; Humans; Intensive Care Units; Length of Stay; Postoperative Complications; Randomized Controlled Trials as Topic; Survival Rate; Treatment Outcome

We undertook a systematic review and meta-analysis to evaluate the effect of vitamin C supplementation (vitamin C solely or as adjunct to other therapy) on prevention of postoperative atrial fibrillation (POAF) in patients after cardiac surgery. PubMed, Embase, Web of Science, and Cochrane Library were systematically searched to identify randomized controlled trials assessing the effect of vitamin C supplementation in adult patients undergoing cardiac surgery, and the meta-analysis was performed with a random-effects model. Thirteen trials involving 1956 patients were included. Pooling estimate showed a significantly reduced incidence of POAF (relative risk [RR]: 0.68, 95% confidence interval [CI]: 0.54 to 0.87, P = 0.002) both in vitamin C alone (RR: 0.75, 95% CI: 0.63 to 0.90, P = 0.002) and as an adjunct to other therapy (RR: 0.32, 95% CI: 0.20 to 0.53, P < 0.001). The results remain stable and robust in subgroup and sensitivity analyses, and trial sequential analysis also confirmed that the evidence was sufficient and conclusive. Additionally, vitamin C could significantly decrease intensive care unit length of stay (weighted mean difference: -0.24 days, 95% CI: -0.45 to -0.03, P = 0.023), hospital length of stay (weighted mean difference: -0.95 days, 95% CI: -1.64 to -0.26, P = 0.007), and risk of adverse events (RR: 0.45, 95% CI: 0.21 to 0.96, P = 0.039). Use of vitamin C alone and as adjunct to other therapy can prevent POAF in patients undergoing cardiac surgery and should be recommended for patients receiving cardiac surgery for prevention of POAF.

Topics: Aged; Anti-Arrhythmia Agents; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Dietary Supplements; Female; Humans; Incidence; Length of Stay; Male; Middle Aged; Odds Ratio; Randomized Controlled Trials as Topic; Risk Factors; Time Factors; Treatment Outcome

Antioxidant supplement is an option in preventing postoperative atrial fibrillation (AF) after cardiac surgery. However, the benefits and adverse effects of vitamin C have not been well assessed. We aimed to systematically evaluate the efficacy and safety of vitamin C in preventing postoperative AF in adult patients after cardiac surgery.. PubMed, EMBASE, and the Cochrane library databases from inception to September 2016 were searched. Randomized controlled trials (RCTs) that evaluated the efficacy and safety of vitamin C in preventing postoperative AF in adult patients after cardiac surgery were identified. The primary outcome was the incidence of postoperative AF. Secondary outcomes included the length of intensive care unit (ICU) stay, length of hospital stay, and stroke events.. Eight RCTs incorporating 1060 patients were included. Compared with placebo group, vitamin C treatment was associated with a substantial reduction in postoperative AF (OR, 0.47; 95% CI, 0.36-0.62; evidence rank: moderate), with no significant heterogeneity (I. Short-term treatment with vitamin C is safe, and may reduce the incidence of postoperative AF after cardiac surgery. Future studies as well as more high quality RCTs are still warranted to confirm the effects of different durations of vitamin C on cardiac surgery.

Topics: Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Humans; Postoperative Care; Randomized Controlled Trials as Topic

Atrial fibrillation (AF), a common arrhythmia contributing substantially to cardiac morbidity, is associated with oxidative stress and, being an antioxidant, vitamin C might influence it.. We searched the Cochrane CENTRAL Register, MEDLINE, and Scopus databases for randomised trials on vitamin C that measured AF as an outcome in high risk patients. The two authors independently assessed the trials for inclusion, assessed the risk of bias, and extracted data. We pooled selected trials using the Mantel-Haenszel method for the risk ratio (RR) and the inverse variance weighting for the effects on continuous outcomes.. We identified 15 trials about preventing AF in high-risk patients, with 2050 subjects. Fourteen trials examined post-operative AF (POAF) in cardiac surgery patients and one examined the recurrence of AF in cardioversion patients. Five trials were carried out in the USA, five in Iran, three in Greece, one in Slovenia and one in Russia. There was significant heterogeneity in the effect of vitamin C in preventing AF. In 5 trials carried out in the USA, vitamin C did not prevent POAF with RR = 1.04 (95% CI: 0.86-1.27). In nine POAF trials conducted outside of the USA, vitamin C decreased its incidence with RR = 0.56 (95% CI: 0.47-0.67). In the single cardioversion trial carried out in Greece, vitamin C decreased the risk of AF recurrence by RR = 0.13 (95% CI: 0.02-0.92). In the non-US cardiac surgery trials, vitamin C decreased the length of hospital stay by 12.6% (95% CI 8.4-16.8%) and intensive care unit (ICU) stay by 8.0% (95% CI 3.0-13.0%). The US trials found no effect on hospital stay and ICU stay. No adverse effects from vitamin C were reported in the 15 trials.. Our meta-analysis indicates that vitamin C may prevent post-operative atrial fibrillation in some countries outside of the USA, and it may also shorten the duration of hospital stay and ICU stay of cardiac surgery patients. Vitamin C is an essential nutrient that is safe and inexpensive. Further research is needed to determine the optimal dosage protocol and to identify the patient groups that benefit the most.

Topics: Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Chi-Square Distribution; Female; Humans; Incidence; Length of Stay; Male; Middle Aged; Odds Ratio; Oxidative Stress; Postoperative Complications; Randomized Controlled Trials as Topic; Recurrence; Risk Factors; Time Factors; Treatment Outcome

This systematic review with meta-analysis sought to determine the strength of evidence in terms of the impact of common antioxidant supplementations, such as N-acetylcysteine (NAC), vitamin C, and polyunsaturated fatty acids (PUFA) on perioperative outcomes after cardiac surgery with particular focus on the incidence of atrial fibrillation (AF) and acute kidney injury (AKI) with associated mortality. A total of 29 trials were identified that reported incidence of AF and 17 trials that reported incidence of AKI. Pooled analysis reported that NAC (OR=0.5; P=.001), vitamin C (OR=0.4; P=.001), and PUFA (OR=0.8; P=.01) administration were associated with significantly reduced incidence of AF. In terms of postoperative AKI, only NAC was shown to be a beneficial supplement that was able to significantly reduce the incidence of AKI (OR=0.7; P=.01), and NAC could also significantly decrease overall mortality (OR=0.3; P=.03) following cardiac surgery. The use of NAC in patients undergoing cardiac surgery should be strongly recommended due to its combined cardio-renal protective effects and reduced mortality. Also, PUFA and vitamin C might be able to significantly decrease the incidence of arrhythmia; however, reno-protective effects and impact on overall mortality of these supplements seem to be less impressive.

Topics: Acetylcysteine; Acute Kidney Injury; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Dietary Supplements; Fatty Acids, Unsaturated; Humans; Incidence; Odds Ratio; Risk Factors; Treatment Outcome

Results of a systematic review and meta-analysis of published data on use of ascorbic acid to prevent postoperative atrial fibrillation (POAF) after cardiac surgery are presented.. MEDLINE and other sources were searched for reports on trials evaluating the effects of preoperative and/or postoperative use of ascorbic acid in patients undergoing cardiac surgery. For each study selected for meta-analysis, an assessment for risks of methodological bias was performed. Data on POAF frequency and length of stay (LOS) outcomes were pooled and analyzed via random-effects modeling.. The 11 identified studies involved patients receiving coronary artery bypass grafts with or without valve replacement; both i.v. and oral ascorbic acid formulations were used. Analysis of pooled outcomes data on treatment and control groups indicated that ascorbic acid prophylaxis was associated with reductions in POAF frequency (odds ratio, 0.44; 95% confidence interval [CI], 0.32 to 0.61), intensive care unit (ICU) LOS (difference in means, -0.24 day; 95% CI, -0.45 to -0.03 day), and total hospital LOS (difference in means, -0.94 day; 95% CI, -1.65 to -0.23 day). Significant statistical, methodological, and clinical heterogeneity were observed.. A meta-analysis revealed that, compared with use of a placebo or a nonplacebo control, perioperative administration of ascorbic acid to patients undergoing cardiac surgery was associated with a reduced frequency of POAF and a shorter ICU LOS and total hospital LOS.

Topics: Anti-Arrhythmia Agents; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Humans; Postoperative Complications; Randomized Controlled Trials as Topic

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery that occurs in up to 60% of patients. POAF is associated with increased risk of cardiovascular mortality, stroke and other arrhythmias that can impact on early and long term clinical outcomes and health economics. Many factors such as disease-induced cardiac remodelling, operative trauma, changes in atrial pressure and chemical stimulation and reflex sympathetic/parasympathetic activation have been implicated in the development of POAF. There is mounting evidence to support a major role for inflammation and oxidative stress in the pathogenesis of POAF. Both are consequences of using cardiopulmonary bypass and reperfusion following ischaemic cardioplegic arrest. Subsequently, several anti-inflammatory and antioxidant drugs have been tested in an attempt to reduce the incidence of POAF. However, prevention remains suboptimal and thus far none of the tested drugs has provided sufficient efficacy to be widely introduced in clinical practice. A better understanding of the cellular and molecular mechanisms responsible for the onset and persistence of POAF is needed to develop more effective prediction and interventions.

Topics: Adrenal Cortex Hormones; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Colchicine; Fatty Acids, Omega-3; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Inflammation Mediators; Myocardial Reperfusion Injury; Oxidative Stress; Postoperative Complications; Reactive Oxygen Species; Risk Factors; Systemic Inflammatory Response Syndrome; Vitamin E

This systematic review with meta-analysis sought to determine the impact of antioxidants (N-acetylcysteine [NAC], polyunsaturated fatty acids [PUFAs] and vitamins) on incidence of postoperative atrial fibrillation (POAF) and duration of length of hospital stay. Medline, Embase, Elsevier, Sciences online database and Google Scholar literature search was made for studies in randomized controlled trials. The effect sizes measured were odds ratio (OR) for categorical variable and standard mean difference (SMD) with 95% confidence interval (CI) for calculating differences between mean values of duration of hospitalization in intervention and control groups. A value of P < 0.1 for Q-test or I(2) > 50% indicated significant heterogeneity between the studies. Literature search of all major databases retrieved 355 studies. After screening, a total of 23 trials were identified that reported outcomes of 4278 patients undergoing cardiac surgery. Pooled effects estimates on POAF showed a significant reduction after NAC (OR: 0.56, 95% CI: 0.40-0.77, P < 0.001), PUFA (OR: 0.84, 95% CI: 0.71-0.99, P = 0.03) and vitamin C treatment (OR: 0.50, 95% CI: 0.27-0.91, P = 0.02). Hospital length of stay was not reduced after NAC therapy (SMD: 0.082, 95% CI -0.09 to 0.25, P = 0.3), but could be decreased with PUFA (SMD: -0.185, 95% CI: -0.35 to -0.018, P = 0.03) and vitamin C (SMD: -0.325, 95% CI -0.50 to -0.14, P < 0.01). In conclusion, perioperative antioxidant supplementations with NAC, PUFA and vitamin C prevent atrial fibrillation after cardiac surgery. Moreover, PUFA and vitamin C are capable to reduce hospital stay, whereas NAC lacks this capacity.

Topics: Acetylcysteine; Anti-Arrhythmia Agents; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Dietary Supplements; Fatty Acids, Unsaturated; Humans; Length of Stay; Odds Ratio; Randomized Controlled Trials as Topic; Risk Factors; Time Factors; Treatment Outcome

The effects of omega-3 polyunsaturated fatty acids (PUFA) on the prevention of postoperative atrial fibrillation (POAF) are inconclusive in current studies. Moreover, the most appropriate composition of PUFA to play the protective role is unclear. The aim of this meta-analysis was to ascertain the protective role of PUFA on POAF and the most appropriate composition.. Studies were identified through PubMed, CENTRAL, EMBASE, reviews and reference lists of relevant papers. The odds ratio (OR) was calculated for POAF. Statistical analyses were performed with Review Manager 5.0.. Eleven randomised controlled trials with 3137 patients were included in the analysis. The use of PUFA alone did not reduce the incidence of POAF compared with the control (OR: 0.76; 95% confidence interval [CI]: 0.57-1.03; P=0.08; I(2)=52%). However, combination therapy with PUFA and vitamins C and E reduced the incidence of POAF by 68% (OR: 0.32; 95%CI: 0.17-0.60; P=0.0005; I(2)=38%). Subgroup analysis indicated that the ratio of EPA/DHA 1:2 was effective in preventing POAF (OR: 0.35; 95%CI: 0.24-0.50; P<0.00001; I(2)=0%), while the ratio not 1:2 failed.. Combination therapy with PUFA and vitamins C and E is effective in the prevention of POAF while PUFA alone is not. The ratio of EPA/DHA may influence the incidence of POAF, and 1:2 may be most appropriate. Studies about PUFA on the prevention of POAF are still worthwhile to be conducted in the future.

Topics: Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Fatty Acids, Omega-3; Female; Humans; Male; Postoperative Complications; PubMed; Randomized Controlled Trials as Topic; Vitamin E; Vitamins

Oxidative stress has been strongly involved in the underlying mechanism of atrial fibrillation, particularly in the arrhythmia occurring in patients undergoing cardiac surgery with extracorporeal circulation (postoperative atrial fibrillation). The ischemia/reperfusion injury thus occurring in the myocardial tissue contributes to the development of tissue remodeling, thought to be responsible for the functional heart impairment. Consequently, structural changes due to the cardiac tissue biomolecules attack by reactive oxygen and/or nitrogen species could account for functional changes in ion channels, transporters, membrane conductance, cytosolic transduction signals, and other events, all associated with the occurrence of arrhythmic consequences. The lack of success and significant side effects of anti-arrhythmic drugs have given rise to attempts aimed to develop alternative novel pharmacologic treatments. On this line, the biological properties of the antioxidant vitamins C and E suggest that they could decrease the vulnerability of the heart to the oxidative damage. Nevertheless, very few studies to assess their anti-arrhythmic effects have been reported in humans. The clinical and experimental evidence supporting the view that the pharmacological use of antioxidant vitamins could contribute to prevent postoperative atrial fibrillation is presented.

Topics: Antioxidants; Ascorbic Acid; Atrial Fibrillation; Humans; Myocardial Reperfusion Injury; Oxidative Stress; Postoperative Complications; Vitamin E

Atrial fibrillation (AF) is the most common heart rhythm disorder, with increasing prevalence in the aging US population and affecting more than 2.3 million people. Current approaches for managing AF are rate- or rhythm-control strategies, both using anti-thrombotic therapy to prevent thromboembolism. While great advances have been made in understanding the pathophysiology of AF, few new strategies have shown promise in prevention or treatment of AF. Recent data suggest that non-antiarrhythmic medication may be useful in modifying the substrate that allows AF precipitation and perpetuation. This article reviews the data on the role of these agents in the prevention and management of AF as an adjunct to standard therapy.

Topics: Adrenal Cortex Hormones; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Anti-Arrhythmia Agents; Anti-Inflammatory Agents; Ascorbic Acid; Atrial Fibrillation; Calcium Channel Blockers; Fatty Acids, Omega-3; Fibrinolytic Agents; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors

Dietary factors might affect the risk of atrial fibrillation (AF), but available studies have provided inconsistent results. A review of published observational studies and randomized trials identified 4 dietary exposures that had been investigated regarding AF risk: alcohol, fish-derived n-3 polyunsaturated fatty acids, caffeine, and ascorbic acid. Though studies were highly heterogeneous in their design and results, they showed a consistently increased risk of AF in heavy alcohol drinkers, but no risk associated with moderate alcohol intake. High coffee intake was not clearly associated with an increased risk of AF, and a potential U-shaped association (lower AF risk in moderate drinkers) could exist. High intake of fish-derived n-3 polyunsaturated fatty acids from diet or supplements might prevent AF episodes following cardiovascular events, but no consistent evidence supports an effect in primary prevention. Additional large, well-conducted randomized experiments are necessary to address the role of diet in AF prevention.

Topics: Alcohol Drinking; Animals; Ascorbic Acid; Atrial Fibrillation; Caffeine; Diet; Fatty Acids, Omega-3; Fishes; Humans; Risk

There is mounting evidence to support the influence of inflammation in the pathogenesis of atrial fibrillation (AF). Indeed, AF is associated with increased levels of known inflammatory markers, even after adjustment for confounding factors. The renin-angiotensin-aldosterone system (RAAS) appears to play a key role in this process. Atrial biopsies from patients with AF have also confirmed the presence of inflammation. Furthermore, there is preliminary evidence to support a number of drug therapies that have the potential to reduce the clinical burden of AF. In this review, we present an overview of the evidence supporting a link between inflammation and AF, and some of the drug therapies, such as the angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, steroids, fish oils, and vitamin C, that might be efficacious in the prevention of AF by modulating inflammatory pathways.

Topics: Ascorbic Acid; Atrial Fibrillation; Biomarkers; C-Reactive Protein; Coronary Thrombosis; Cytokines; Fish Oils; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Myocarditis; Pericarditis; Renin-Angiotensin System; Steroids

Atrial fibrillation is the most common arrhythmia following cardiac surgery. It is associated with increased hemodynamic instability, systemic embolization, and complications linked to anticoagulant therapy. Oxidative stress and consequent electrophysiological remodeling have been proposed as a cause of postoperative atrial fibrillation. Ascorbic acid supplementation was suggested as a novel and effective preventive agent. The aim of this study was to evaluate the capability of ascorbic acid to reduce the incidence of postoperative atrial fibrillation in coronary artery bypass grafting (CABG) patients.. A prospective randomized single-center trial was conducted in patients scheduled for an elective on-pump CABG surgery. Subjects in the ascorbic acid group received 2g of ascorbic acid 24h and 2h before the surgery and 1g twice a day for five days after the surgery. Postoperatively, the patients were monitored for atrial fibrillation and other complications.. The ascorbic acid group consisted of 52 patients and the control group included 53 patients. The groups were well matched for baseline demographics, preoperative medications, comorbidities, and had similar intraoperative characteristics. The incidence of atrial fibrillation in the ascorbic acid group was 13.5% and 18.9% in the control group (p=0.314). No difference was found between groups in the time of occurrence of atrial fibrillation (3.71±1.89 vs. 2.91±1.58 days after the surgery; p=0.342). There was also no difference in the other observed postoperative complications.. The results of this study do not support the effectiveness of ascorbic acid supplementation in reducing the incidence of postoperative atrial fibrillation in elective on-pump CABG patients.

Topics: Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Female; Humans; Incidence; Male; Middle Aged; Perioperative Care; Postoperative Complications; Prospective Studies

Some evidences have shown the role of antioxidant vitamins in preventing atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery. We sought to determine the effect of oral vitamin C on the incidence of postoperative AF in patients undergoing elective isolated on-pump CABG surgery.. One-hundred patients who underwent isolated CABG surgery were prospectively assigned into two groups: Group 1 - 50 patients received 2 g of oral vitamin C before and 500 mg twice daily lasting for 5 days after surgery; Group 2 - 50 patients as the control group did not receive any. All patients were continuously monitored after surgery in the intensive careunit (ICU), and then Holter monitoring was implemented for 72 h.. The mean of patients' age was 61.31 ± 6.42 years. Postoperative AF occurred in 16 and 4 patients in control and treatment groups, respectively (32% vs. 8%, p = 0.003). The ICU stay was 1.79 ± 0.313 and 2.10 ± 0.61 days for vitamin C and control groups, respectively (p = 0.002). The hospital stay was significantly lower in vitamin C group compared with that of the control group (5.32 ± 0.59 vs. 5.74 ± 1.30 days, respectively, p = 0.041). Baseline erythrocyte sedimentation rate (OR 1.030, 95% CI 1.003-1.058, p = 0.030) and taking vitamin C (OR 8.068, 95% CI 1.783-36.517, p = 0.007) were the independent predictors of postoperative AF.. Oral vitamin C can be safely used to decrease the incidence of postoperative AF in patients undergoing elective isolated on-pump CABG surgery.

Topics: Administration, Oral; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Coronary Artery Disease; Dose-Response Relationship, Drug; Elective Surgical Procedures; Electrocardiography, Ambulatory; Female; Follow-Up Studies; Humans; Male; Middle Aged; Postoperative Complications; Prospective Studies; Treatment Outcome; Vitamins

Ischemia-reperfusion has been reported to be associated with augmented oxidative stress in the course of surgery, which might be causally involved in the onset of atrial fibrillation (AF), the most common arrhythmia after cardiac surgery. We hypothesized that supplementation of antioxidants and n-3 polyunsaturated fatty acids (n-3 PUFAs) might lower the incidence of AF following coronary artery bypass graft (CABG) surgery. In the present study, by monitoring oxidative stress in the course of CABG surgery, we analyzed the efficacy of vitamins (ascorbic acid and α-tocopherol) and/or n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid). Subjects (n = 75) were divided into 4 subgroups: control, vitamins, n-3 PUFAs, and a combination of vitamins and n-3 PUFAs. Fluorescent techniques were used to measure the antioxidative capacity, i.e. ability to inhibit oxidation. Total peroxides, endogenous peroxidase activity, and antibodies against oxidized LDL (oLAb) were used as serum oxidative stress biomarkers. Post-operative increase in oxidative stress was associated with the consumption of antioxidants and a simultaneous onset of AF. This was confirmed through an increased peroxide level and a decreased oLAb titer in control and n-3 PUFAs groups, indicating the binding of antibodies to oxidative modified epitopes. In both subgroups that were supplemented with vitamins, total peroxides decreased, and the maintenance of a constant IgG antibody titer was facilitated. However, treatment with vitamins or n-3 PUFAs was inefficient with respect to AF onset and its duration. We conclude that the administration of vitamins attenuates post-operative oxidative stress in the course of CABG surgery.

Topics: alpha-Tocopherol; Antibodies; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Biomarkers; Coronary Artery Bypass; Fatty Acids, Omega-3; Fluorescence; Humans; Lipoproteins, LDL; Oxidation-Reduction; Oxidative Stress; Peroxidase; Peroxides

This study was designed to assess whether the reinforcement of the antioxidant system, through n-3 fatty acids plus antioxidant vitamin supplementation, could reduce the incidence of post-operative atrial fibrillation.. Therapy to prevent post-operative atrial fibrillation remains suboptimal. Although oxidative stress plays a key role in the pathogenesis of this arrhythmia, antioxidant reinforcement has produced controversial results.. A total of 203 patients scheduled for on-pump cardiac surgery were randomized to placebo or supplementation with n-3 polyunsaturated fatty acids (2 g/day) (eicosapentaenoic acid:docosahexaenoic acid ratio 1:2), vitamin C (1 g/day), and vitamin E (400 IU/day). The primary outcome was the occurrence of post-operative atrial fibrillation. Secondary outcomes were the biomarkers related to oxidative stress and inflammation.. Post-operative atrial fibrillation occurred in 10 of 103 patients (9.7%) in the supplemented group versus 32 of 100 patients (32%) in the placebo group (p < 0.001). Early after surgery, placebo patients presented with increased levels of biomarkers of inflammation and oxidative stress, which were markedly attenuated by antioxidant supplementation. The activity of catalase, superoxide dismutase, and glutathione peroxidase in atrial tissue of the supplemented patients was 24.0%, 17.1%, and 19.7% higher than the respective placebo values (p < 0.05). The atrial tissue of patients who developed atrial fibrillation showed NADPH oxidase p47-phox subunit protein and mRNA expression 38.4% and 35.7% higher, respectively, than patients in sinus rhythm (p < 0.05).. This safe, well-tolerated, and low-cost regimen, consisting of n-3 polyunsaturated fatty acids plus vitamins C and E supplementation, favorably affected post-operative atrial fibrillation, increased antioxidant potential, and attenuated oxidative stress and inflammation. (Prevention of Post-Operative Atrial Fibrillation: Pathophysiological Characterization of a Pharmacological Intervention Based on a Novel Model of Nonhypoxic Pre-Conditioning; ISRCTN45347268).

Topics: Antioxidants; Ascorbic Acid; Atrial Fibrillation; Biomarkers; Cardiac Surgical Procedures; Dietary Supplements; Drug Monitoring; Fatty Acids, Omega-3; Female; Humans; Inflammation; Male; Middle Aged; Outcome Assessment, Health Care; Oxidative Stress; Postoperative Complications; Treatment Outcome; Vitamin E

Extracorporeal circulation is associated with ischaemia-reperfusion-induced oxidative stress and atrial fibrillation (AF). Ageing is the major risk factor for this arrhythmia. Reinforcing the antioxidant defence system would be expected to protect the myocardium against ischaemia-reperfusion damage. We studied the effect of antioxidant reinforcement and ageing on the occurrence of postoperative AF.. A randomized, double-blind, placebo-controlled trial was performed in patients scheduled for cardiac surgery with extracorporeal circulation. Supplementation with omega-3 polyunsaturated fatty acid (PUFA) and vitamins C and E, or placebo was administered to 152 patients divided by age: young patients (30-59 years) and old patients (60-80 years). For the detection of AF, we used 12-lead and Holter EKGs. Antioxidant enzyme activity was determined in atrial tissue. Oxidative stress was assessed through plasma malondialdehyde levels.. Supplemented patients over 60 years old showed higher glutathione peroxidase activity than control patients in the same age range. There was no difference between the supplemented and placebo groups in patients under 60 years old. The decrease in the incidence of postoperative AF in supplemented patients was more marked in the older patients than in the younger ones.. Since the antioxidant supplementation with n-3 PUFAs and vitamins C and E resulted in a more marked reduction of postoperative AF in older patients, it could be suggested that the efficacy of this therapy improves with ageing.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Aging; Analysis of Variance; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Biomarkers; Cardiac Surgical Procedures; Catalase; Chile; Dietary Supplements; Double-Blind Method; Drug Therapy, Combination; Electrocardiography, Ambulatory; Extracorporeal Circulation; Fatty Acids, Omega-3; Glutathione Peroxidase; Heart Atria; Humans; Kaplan-Meier Estimate; Malondialdehyde; Middle Aged; Oxidative Stress; Predictive Value of Tests; Proportional Hazards Models; Risk Assessment; Risk Factors; Superoxide Dismutase; Time Factors; Treatment Outcome; Vitamin E

Atrial fibrillation occurs after approximately 25% to 45% of coronary artery bypass graft (CABG) surgeries. Oxidative stress and related electrophysiological remodeling has been proposed as a potential cause of this atrial fibrillation. Perioperative supplementation of the antioxidant ascorbic acid has been evaluated as a preventive agent. The current investigation was conducted to evaluate the efficacy of ascorbic acid in reducing atrial fibrillation in CABG patients.. A prospective, randomized, placebo-controlled, triple-blind, single-institution study was conducted in nonemergency CABG patients. Subjects were monitored for episodes of arrhythmia and other complications.. Eighty-nine treatment and 96 control subjects completed the study protocol. Demographics, comorbidities, and preoperative drugs were similar between groups. Surgical characteristics and postoperative medication use also were similar. The incidence of atrial fibrillation was 30.3% in the treatment group and 30.2% in the control group (P = .985). No difference was found in postoperative complications or mortality.. Our data indicate that supplementation of ascorbic acid in addition to routine postoperative care does not reduce atrial fibrillation after coronary artery bypass grafting.

Topics: Administration, Oral; Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Dietary Supplements; Double-Blind Method; Drug Administration Schedule; Enteral Nutrition; Female; Humans; Incidence; Male; Middle Aged; Perioperative Care; Postoperative Complications; Prospective Studies; Treatment Outcome

Atrial fibrillation (AF) is a common arrhythmia that occurs postoperatively in cardiac surgery. There is evidence for the role of oxidative stress in the etiology of AF. In our study, we examined whether antioxidant ascorbic acid (vitamin C), could help in the reduction of the incidence of postoperative AF. Patients who were scheduled to undergo elective isolated on-pump coronary artery bypass grafting (CABG) were included in our study. One hundred and seventy patients were randomly divided in two groups: Group A (n=85) received vitamin C preoperatively and postoperatively whereas Group B (n=85) did not receive any (control group). The incidence of AF was 44.7% in the vitamin C group and 61.2% in the control group (P=0.041). The hospitalization time, the intensive care unit stay and the time interval for the conversion of AF into sinus rhythm was significantly shorter in the vitamin C group. Patients that developed AF also had longer hospital length of stay (9.5±2.8 days vs. 6.7±1.9, P=0.034). Supplementation of vitamin C reduces the incidence of postCABG AF, and decreases the time needed for rhythm restoration and length of hospital stay.

Topics: Aged; Analysis of Variance; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Coronary Disease; Elective Surgical Procedures; Female; Follow-Up Studies; Humans; Length of Stay; Male; Myocardial Revascularization; Pilot Projects; Postoperative Care; Postoperative Complications; Preoperative Care; Prospective Studies; Risk Assessment; Statistics, Nonparametric; Survival Rate; Treatment Outcome

The effect of ascorbic acid on inflammatory markers after cardiothoracic surgery (CTS) was studied.. In this randomized, double-blind, placebo-controlled trial, patients undergoing cardiopulmonary bypass graft surgery or valve replacement surgery from April 2009 through March 2010 at Hartford Hospital were randomized to receive ascorbic acid (2-g loading dose followed by 500 mg every 12 hours) or matching placebo the evening before surgery and for four days postoperatively. Inflammatory mediators were measured preoperatively and on postoperative days 1-4. Intergroup comparisons were performed using two-tailed t tests and Fisher's exact test. Multiple comparisons were conducted using repeated analyses of variance with Bonferroni tests.. Of the 62 patients screened, 24 met the study inclusion criteria. Of these, 13 were assigned to receive ascorbic acid and 11 received placebo. Ascorbic acid did not affect the natural course of inflammatory marker rise for C-reactive protein (CRP) concentration, white blood cell (WBC) count, or fibrinogen concentration versus placebo at any evaluated time point (p > 0.05 for all intergroup comparisons). Intragroup analyses demonstrated significant differences among baseline and postoperative measures of all inflammatory mediators (p < 0.05). No significant differences were noted in inflammatory markers between patients undergoing cardiothoracic surgery with or without cardiopulmonary bypass, regardless of treatment group.. Ascorbic acid did not attenuate the rise in inflammatory markers after CTS when compared with placebo. The use of off-pump surgery did not significantly change the levels of CRP and fibrinogen or the WBC count postoperatively when compared with on-pump surgery with a biocompatible polymer coating.

Topics: Aged; Ascorbic Acid; Atrial Fibrillation; Biomarkers; C-Reactive Protein; Cardiac Surgical Procedures; Coronary Artery Bypass; Coronary Artery Bypass, Off-Pump; Double-Blind Method; Female; Fibrinogen; Heart Valve Diseases; Humans; Inflammation; Leukocyte Count; Male; Middle Aged; Vitamins

Because adrenergic beta antagonists are not sufficient to prevent atrial fibrillation after coronary artery bypass grafting, this prospective, randomized trial was designed to evaluate the effects of ascorbic acid as an adjunct to beta-blockers. Fifty patients formed our ascorbic acid group, and another 50 patients formed our control group. All patients were older than 50 years, were scheduled to undergo coronary artery bypass grafting, and had been treated with beta-blockers for at least 1 week before surgery. The mean age of the population was 60.19+/-7.14 years; 67% of the patients were men. Patients in the ascorbic acid group received 2 g of ascorbic acid on the night before the surgery and 1 g twice daily for 5 days after surgery. Patients in the control group received no ascorbic acid. Patients in both groups continued to receive beta-blockers after surgery. Telemetry monitoring was performed in the intensive care unit, and Holter monitoring was performed for 4 days thereafter. The incidence of postoperative atrial fibrillation was 4% in the ascorbic acid group and 26% in the control group (odds ratio, 0.119; 95% confidence interval, 0.025-0.558, P = 0.002). We conclude that ascorbic acid is effective, in addition to being well-tolerated and relatively safe. Therefore, it can be prescribed as an adjunct to beta-blockers for the prophylaxis of post-bypass atrial fibrillation.

Topics: Adrenergic beta-Antagonists; Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Drug Therapy, Combination; Female; Humans; Length of Stay; Logistic Models; Male; Middle Aged; Prospective Studies

Inflammation and oxidative stress have been recently implicated in the pathophysiology of atrial fibrillation (AF). The aim of this study was to examine the potential benefit of vitamin C on the early recurrence rates and on inflammatory indices after successful cardioversion of persistent AF, as well as to investigate the time course of changes in these indices post-cardioversion.. We prospectively studied 44 consecutive patients after successful electrical cardioversion of persistent AF. All patients received standard treatment and were randomised in one to one fashion to either oral vitamin C administration or no additional therapy. We followed-up the patients for 7 days performing successive measurements of white blood cell (WBC) count, C-reactive protein (CRP), fibrinogen, and ferritin levels.. One week after successful cardioversion, AF recurred in 4.5% of patients in the vitamin C group and in 36.3% of patients in the control group (p=0.024). Compared to baseline values, inflammatory indices decreased after cardioversion in patients receiving vitamin C but did not change significantly in the control group. A significant variance was found in the serial measurements of WBC counts (F=5.86, p=0.001) and of fibrinogen levels (F=4.10, p=0.0084) in the two groups. In the vitamin C group CRP levels were lower on the seventh day (p<0.05). CRP and fibrinogen levels were higher in patients who relapsed into AF compared to patients who maintained sinus rhythm (F=2.77, p=0.044 and F=3.51, p=0.017, respectively).. These findings suggest that vitamin C reduces the early recurrence rates after cardioversion of persistent AF and attenuates the associated low-level inflammation. These effects indicate that therapeutic approaches targeting at inflammation and oxidative stress may exert favourable effects on atrial electrical remodeling.

Topics: Administration, Oral; Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Biomarkers; C-Reactive Protein; Echocardiography; Electric Countershock; Electrocardiography; Female; Ferritins; Fibrinogen; Follow-Up Studies; Heart Atria; Humans; Incidence; Inflammation; Leukocyte Count; Male; Myocarditis; Nephelometry and Turbidimetry; Oxidative Stress; Prospective Studies; Secondary Prevention; Treatment Outcome

Atrial fibrillation (AF), the most common chronic arrhythmia, increases the risk of stroke and is an independent predictor of mortality. Available pharmacological treatments have limited efficacy. Once initiated, AF tends to self-perpetuate, owing in part to electrophysiological remodeling in the atria; however, the fundamental mechanisms underlying this process are still unclear. We have recently demonstrated that chronic human AF is associated with increased atrial oxidative stress and peroxynitrite formation; we have now tested the hypothesis that these events participate in both pacing-induced atrial electrophysiological remodeling and in the occurrence of AF following cardiac surgery. In chronically instrumented dogs, we found that rapid (400 min(-1)) atrial pacing was associated with attenuation of the atrial effective refractory period (ERP). Treatment with ascorbate, an antioxidant and peroxynitrite decomposition catalyst, did not directly modify the ERP, but attenuated the pacing-induced atrial ERP shortening following 24 to 48 hours of pacing. Biochemical studies revealed that pacing was associated with decreased tissue ascorbate levels and increased protein nitration (a biomarker of peroxynitrite formation). Oral ascorbate supplementation attenuated both of these changes. To evaluate the clinical significance of these observations, supplemental ascorbate was given to 43 patients before, and for 5 days following, cardiac bypass graft surgery. Patients receiving ascorbate had a 16.3% incidence of postoperative AF, compared with 34.9% in control subjects. In combination, these studies suggest that oxidative stress underlies early atrial electrophysiological remodeling and offer novel insight into the etiology and potential treatment of an enigmatic and difficult to control arrhythmia. The full text of this article is available at http://www.circresaha.org.

Topics: Aged; Animals; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Pacing, Artificial; Coronary Artery Bypass; Dogs; Electrophysiology; Female; Heart Atria; Humans; Male; Middle Aged; Multivariate Analysis; Nitrates; Time Factors; Treatment Outcome; Tyrosine

Topics: Ascorbic Acid; Atrial Fibrillation; Humans; Mendelian Randomization Analysis; Vitamins

Topics: Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Humans; Randomized Controlled Trials as Topic; Vitamins

Atrial fibrillation is one of the most frequent complications and a major risk of morbidity and mortality after cardiac surgery. Antioxidants such as vitamin C are used for prevention of this arrhythmia. Different results of studies have been reported, but most of them have shown efficiency of vitamin C in prophylaxis of postoperative AF. We tried to examine this efficacy with larger sample size.. Three hundred and fourteen on pump coronary artery bypass graft surgery alone. Patients were divided into two groups: The intervention group received vitamin C (N = 160) and the control group did not receive any (N = 154). Intervention group was administered two grams of vitamin C intravenously (IV) 24 hours preoperatively, 500 mg every 12 hours IV for 48 hours in ICU, and 500 mg every 12 hours PO for 48 hours in ward. Continuous monitoring in ICU and three times a day ECG was used for AF detection. The two groups were compared.. The two groups were matched in terms of age, sex, LA size, ejection fraction, functional class, and TSH level. Of the patients, 244 were male. Mean age was 62 years (40-84 years) in both groups. M/F ratio was four in both groups. Functional class and ejection fraction were the same in both groups. There was no mean TSH level difference. AF occurrence in vitamin C group was 7.6 % and in control group was 7.8 %. There was no difference in ICU or hospital stay.. Prophylactic use of vitamin C does not further reduce postoperative atrial fibrillation in on pump CABG patients.

Topics: Adult; Aged; Aged, 80 and over; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Coronary Artery Bypass; Coronary Artery Disease; Double-Blind Method; Female; Humans; Incidence; Iran; Length of Stay; Male; Middle Aged; Postoperative Care; Postoperative Complications; Prognosis; Survival Rate

Topics: Anticoagulants; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Humans; Postoperative Complications; Sample Size; Stroke

Topics: Anti-Arrhythmia Agents; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Cardiac Surgical Procedures; Humans; Postoperative Complications; Publication Bias; Treatment Outcome

Fruit and vegetable intake has been associated with lower risk for cardiovascular risk factors and disease. Data on its association with atrial fibrillation are lacking.. We examined the prospective association of plasma vitamin C concentration as a biomarker for fruit and vegetable intake with the risk of hospitalisation with diagnosis of atrial fibrillation in apparently healthy 8,760 men and 10,530 women aged 39-79 participating in the EPIC-study in Norfolk. The hazard ratios of atrial fibrillation comparing each quartile of plasma vitamin C concentration with the lowest were 0.76 (95% CI 0.57-1.00), 0.73 (95% CI 0.55-0.98) and 0.77 (95% CI 0.58-1.01) in women (p for trend 0.05) and 0.81 (95% CI 0.63-1.03), 0.96 (95% CI 0.76-1.22) and 1.01 (95% CI 0.79-1.28) in men (p for trend 0.66) after adjustment for age, smoking, alcohol consumption, physical activity, systolic blood pressure, diabetes, use of blood pressure medication and body-mass index, with a significant gender × vitamin C interaction (p=0.03). Assuming a linear association, a 20 μmol/l increase in plasma vitamin C concentration (1 standard deviation) was associated with a 13% (95% CI 3-22%) relative reduction in risk of atrial fibrillation in women.. Plasma vitamin C was inversely associated with the risk of atrial fibrillation in women, but there was no such association in men. Our findings suggest that intake of food rich in vitamin C might be preventive for atrial fibrillation with a significant benefit particularly in women with low baseline intake.

Topics: Adult; Aged; Ascorbic Acid; Atrial Fibrillation; Biomarkers; Female; Follow-Up Studies; Health Surveys; Hospitalization; Humans; Male; Middle Aged; Prospective Studies; Risk Factors; United Kingdom

Oxidative stress and pulmonary veins (PVs) play critical roles in the pathophysiology of atrial fibrillation. The purpose of the present study was to investigate whether oxidative stress and antioxidant agents can change the electrophysiological characteristics of the left atrium (LA) and PVs.. Conventional microelectrodes were used to record the action potentials (APs) in isolated rabbit PV and LA specimens before and after H(2)O(2) administration with or without ascorbic acid or N-mercaptopropionyl-glycine (N-MPG, a free radical .OH scavenger). H(2)O(2) (0.02 and 0.2 mmol/L) decreased the PV spontaneous rates from 2.0+/-0.1 Hz to 1.6+/-0.1 Hz, and 1.7+/-0.1 Hz (n=10, P<0.05), but H(2)O(2) (2 mmol/L) increased PV spontaneous rates from 2.0+/-0.1 Hz to 2.8+/-0.2 Hz. H(2)O(2) easily induced PV burst firing and early afterdepolarizations, but not in the LA. H(2)O(2) shortened the AP duration and increased the contractile force to a greater extent in the LA than in PVs. In addition, the H(2)O(2)-induced PV burst firing and increasing spontaneous rates were suppressed or attenuated by pretreatment with ascorbic acid (1 mmol/L) or N-MPG (10 mmol/L).. H(2)O(2) significantly changed the electrophysiological characteristics of PV and LA through activation of free radicals and may facilitate the occurrence of atrial fibrillation.

Topics: Action Potentials; Animals; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Electrophysiologic Techniques, Cardiac; Free Radicals; Heart Atria; Hydrogen Peroxide; Oxidative Stress; Pulmonary Veins; Rabbits

Topics: Aged; Antioxidants; Ascorbic Acid; Ascorbic Acid Deficiency; Atrial Fibrillation; Coronary Artery Disease; Humans; Male; Myocardial Revascularization; Postoperative Complications; Risk Factors

Topics: Adrenergic beta-Antagonists; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Beverages; Coronary Artery Bypass; Drug Therapy, Combination; Humans; Postoperative Complications

Endothelial dysfunction and underperfusion of exercising muscle contribute to exercise intolerance, hyperventilation, and breathlessness in atrial fibrillation (AF). Cardioversion (CV) improves endothelial function and exercise performance. We examined whether CV is equally beneficial in diabetes and hypertension, diseases that cause endothelial dysfunction and are often associated with AF. Cardiopulmonary exercise and pulmonary and endothelial (brachial artery flow-mediated dilation) function were tested before and after CV in patients with AF alone (n = 18, group 1) or AF with hypertension (n = 19, group 2) or diabetes (n = 19, group 3). Compared with group 1, peak exercise workload, O2 consumption (Vo2), O2 pulse, aerobic efficiency (Delta Vo2/Delta WR), and ratio of brachial diameter changes to flow changes (Delta D/Delta F) were reduced in group 2 and, to a greater extent, in group 3; exercise ventilation efficiency (Ve/Vco2 slope) and dead space-to-tidal volume ratio (Vd/Vt) were similar among groups. CV had less effect on peak workload (+7% vs. +18%), peak Vo2 (+12% vs. +17%), O2 pulse (+33% vs. +50%), Delta Vo2/Delta WR (+7% vs. +12%), Ve/Vco2 slope (-6% vs. -12%), Delta D/Delta F (+7% vs. +10%), and breathlessness (Borg scale) in group 2 than in group 1 and was ineffective in group 3. The antioxidant vitamin C, tested in eight additional patients in each cohort, improved flow-mediated dilation in groups 1 and 2 before, but not after, CV and was ineffective in group 3, suggesting that the oxidative injury is least in lone AF, greater in hypertension with AF, and greater still in diabetes with AF. Comorbidities that impair endothelial activity worsen endothelial dysfunction and exercise intolerance in AF. The advantages of CV appear to be inversely related to the extent of the underlying oxidative injury.

Topics: Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Brachial Artery; Diabetes Complications; Diabetes Mellitus; Diabetes Mellitus, Type 2; Echocardiography; Electric Countershock; Endothelium, Vascular; Exercise Test; Female; Humans; Hypertension; Male; Middle Aged; Myocytes, Cardiac; Reactive Oxygen Species; Regional Blood Flow

Exercising muscle hypoperfusion stimulates afferents (metaboreceptors) involved in the regulation of ventilation. Atrial fibrillation (AF), particularly when combined with diseases causing endothelial (ED) impairment, such as hypertension (HP) and diabetes mellitus (DM), depresses the ED activity and enhances exercise hyperventilation. The relationship between these two functions and the underlying mechanisms have not been explored previously. In lone AF or AF associated with HP or DM (12 subjects in each cohort), we investigated the brachial artery flow-mediated dilatation (ED function) and ventilation during the recovery phase of handgrip (metaboreflex) exercise for subjects receiving placebo or oral vitamin C (double-blind crossover), both before and after cardioversion (CV) to sinus rhythm. Baseline ED impairment was increasingly more severe and the ergoreflex activity more pronounced in AF + HP and AF + DM compared with lone AF. Vitamin C and CV significantly improved both flow-mediated dilatation and metaboreflex activity in lone AF and AF + HP, and vitamin C did not produce any additive effect when administered after CV. In AF + DM, neither vitamin C nor CV was effective. This study provides the following information: AF generates oxidative injury, which is less when the arrhythmia is lone AF and greater when the arrhythmia is associated with HP. In DM, the oxidative injury generated by AF is refractory to a rather weak antioxidant, like vitamin C, or the baseline damage is such as to prevent any additive influence of AF. In AF, a cause-effect link exists between ED dysfunction and metaboreflex activity. Ventilatory advantages of CV seem to be inversely related with the extension of the underlying ED oxidative impairment.

Topics: Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Brachial Artery; Diabetes Complications; Diabetes Mellitus, Type 2; Double-Blind Method; Echocardiography; Electric Countershock; Endothelium, Vascular; Exercise; Female; Humans; Hypertension; Male; Middle Aged; Reflex; Regional Blood Flow

Topics: Aged; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Biomarkers; Fibrinogen; Humans; Inflammation; Interleukin-6; Middle Aged; Thromboembolism

Topics: Anti-Inflammatory Agents; Antioxidants; Ascorbic Acid; Atrial Fibrillation; C-Reactive Protein; Electric Countershock; Humans; Inflammation; Myocarditis

There is evidence for a role of oxidant stress and inflammation in atrial fibrillation (AF). Statins have both antioxidant and antiinflammatory properties. We compared the effects of simvastatin with those of antioxidant vitamins on AF promotion by atrial tachycardia in dogs.. We studied dogs subjected to atrial tachypacing (ATP) at 400 bpm in the absence and presence of treatment with simvastatin, vitamin C, and combined vitamins C and E. Serial closed-chest electrophysiological studies were performed in each dog at baseline and 2, 4, and 7 days after tachypacing onset. Atrioventricular block was performed to control ventricular rate. Mean duration of induced AF was increased from 42+/-18 to 1079+/-341 seconds at terminal open-chest study after tachypacing alone (P<0.01), and atrial effective refractory period (ERP) at a cycle length of 300 ms was decreased from 117+/-5 to 76+/-6 ms (P<0.01). Tachypacing-induced ERP shortening and AF promotion were unaffected by vitamin C or vitamins C and E; however, simvastatin suppressed tachypacing-induced remodeling effects significantly, with AF duration and ERP averaging 41+/-15 seconds and 103+/-4 ms, respectively, after tachypacing with simvastatin therapy. Tachypacing downregulated L-type Ca2+-channel alpha-subunit expression (Western blot), an effect that was unaltered by antioxidant vitamins but greatly attenuated by simvastatin.. Simvastatin attenuates AF promotion by atrial tachycardia in dogs, an effect not shared by antioxidant vitamins, and constitutes a potentially interesting new pharmacological approach to preventing the consequences of atrial tachycardia remodeling.

Topics: Animals; Antioxidants; Ascorbic Acid; Atrial Fibrillation; Calcium Channels, L-Type; Cardiac Pacing, Artificial; Dogs; Drug Evaluation, Preclinical; Drug Therapy, Combination; Gene Expression Regulation; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Oxidative Stress; Refractory Period, Electrophysiological; Simvastatin; Vitamin E

Topics: Ascorbic Acid; Atrial Fibrillation; Cardiac Catheterization; Cardiovascular Diseases; Diagnosis; Endocardium; Heart Function Tests; Humans; Tricuspid Valve Insufficiency

Topics: Adult; Ascorbic Acid; Atrial Fibrillation; Cardiac Catheterization; Diagnosis, Differential; Electrocardiography; Female; Heart Atria; Heart Septal Defects, Atrial; Heart Ventricles; Humans; Indicator Dilution Techniques; Male; Mitral Valve Insufficiency; Mitral Valve Stenosis