Dietary intervention with a specific micronutrient combination for the treatment of patients with cardiac arrhythmias: the impact on insulin resistance and left ventricular function.

BACKGROUND: Cardiac arrhythmias (CA) are very common and may occur with or without heart disease. Causes of these disturbances can be components of the metabolic syndrome (MetS) or deficits of micronutrients especially magnesium, potassium, B vitamins and coenzyme Q10. Both causes may also influence each other. Insulin resistance (IR) is a risk factor for diastolic dysfunction. One exploratory outcome of the present pilot study was to assess the impact of a dietary intervention with specific micronutrients on the lowering of IR levels in patients with CA with the goal to improve the left ventricular (LV) function. METHODS: This was a post hoc analysis of the randomized double blind, placebo-controlled pilot study in patients with CA (VPBs, SVPBs, SV tachycardia), which were recruited using data from patients who were 18-75 years of age in an Outpatient Practice of Cardiology. These arrhythmias were assessed by Holter ECG and LV function by standard echocardiography. Glucose metabolism was measured by fasting glucose, fasting insulin level and the Homeostasis Model Assessment of IR (HOMA-IR) at baseline and after 6 weeks of dietary supplementation. RESULTS: A total of 54 randomized patients with CA received either a specific micronutrient combination or placebo. Dietary intervention led to a significant decrease in fasting insulin ≥58 pmol/l (p = 0.020), and HOMA-IR (p = 0.053) in the verum group after 6 weeks. At the same time, parameters of LV diastolic function were improved after intervention in the verum group: significant reduction of LV mass index (p = 0.003), and in tendency both a decrease of interventricular septal thickness (p = 0.053) as well as an increase of E/A ratio (p = 0.051). On the other hand, the premature beats (PBs) were unchanged under verum. CONCLUSIONS: In this pilot study, dietary intervention with specific micronutrient combination as add-on to concomitant cardiovascular drug treatment seems to improve cardio metabolic health in patients with CA. Further studies are required. STUDY REGISTRATION: The study was approved by the Freiburg Ethics Commission International and was retrospectively registered with the U.S. National Institutes of Health Clinical Trials gov ID NCT 02652338 on 16 December 2015.

The pro- or antiarrhythmic actions of polyunsaturated fatty acids and of cholesterol.

In this review, the pro- and anti-arrhythmic effects of a diet rich in fish oil fatty acids and of hypercholesterolemia will be discussed in relation to two major mechanisms of arrhythmogenesis (triggered activity and re-entry). Whereas a diet rich in fish oil is pro-arrhythmic in relation to re-entry based arrhythmias (as occur in acute myocardial ischemia) and anti-arrhythmic in relation to triggered activity based arrhythmias (as occur in heart failure), the reverse is true for hypercholesterolemia. Changing the lipid composition of cardiomyocytes likely has powerful pro- or anti-arrhythmic consequences, depending on the mechanism of arrhythmias, and has corresponding therapeutic potential.

[Using L-carnitine to improve the adaptation of young athletes to physical load and the correction of stress-induced cardiomyopathy].

The mechanisms of L-carnitine action and ergogenic pleiotropic effects of drugs, which play important role in sports medicine are described. Results of a comparative, parallel-group randomized clinical trial of L-carnitine (Elkar, PikFarma) in young athletes (football players, walkers) are reported. Elkar increases the body adaptation to physical stress and has a pronounced therapeutic effect in athletes with stress-induced cardiomyopathy by reducing the representation of potentially dangerous arrhythmia (sinus bradycardia less than 2 - 5 centile, 2nd degree atrioventricular block type II, T-wave inversion in more than 2 leads, and/or ST segment depression) and severity of benign ECG disturbances and hemodynamic changes, and decreasing the concentration of biochemical markers of myocardial damage (troponin, natriuretic peptide, creatine phosphokinase MB fraction) and cortisol. In general, Elkar contributed to a significant reduction in symptoms of cardiac remodeling in 75% of patients and had a weak effect in 25% of patents. It is concluded that the use of Elkar in playing sports and sports coaching quality of endurance is appropriate, especially in terms of myocardial remodeling.

The anti-arrhythmic effects of n-3 PUFAs.

In the past years, in vitro and animal studies have demonstrated several direct and indirect anti-arrhythmic effects of n-3 polyunsaturated fatty acids (n-3 PUFAs), at least in part mediated by anti-oxidant, anti-inflammatory and antifibrotic properties. Several epidemiological and clinical studies have been conducted to investigate the eventual benefits of fish oils in the prevention of cardiovascular diseases. The aim of this paper is to critically review current evidence on the anti-arrhythmic effects of n-3 PUFAs in the prevention of sudden cardiac death (SCD) and atrial fibrillation (AF). Published data are conflicting, but some benefits have been reported in the prevention of SCD after myocardial infarction and of AF, generally after long-course administration.

n-3 fatty acids, ventricular arrhythmia-related events, and fatal myocardial infarction in postmyocardial infarction patients with diabetes.

OBJECTIVE: We carried out a secondary analysis in high-risk patients with a previous myocardial infarction (MI) and diabetes in the Alpha Omega Trial. We tested the hypothesis that in these patients an increased intake of the n-3 fatty acids eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and α-linolenic acid (ALA) will reduce the incidence of ventricular arrhythmias and fatal MI. RESEARCH DESIGN AND METHODS: A subgroup of 1,014 post-MI patients with diabetes aged 60-80 years was randomly allocated to receive one of four trial margarines, three with an additional amount of n-3 fatty acids and one placebo for 40 months. The end points were ventricular arrhythmia-related events and fatal MI. The data were analyzed according to the intention-to-treat principle, using multivariable Cox proportional hazards models. RESULTS: The patients consumed on average 18.6 g of margarine per day, which resulted in an additional intake of 223 mg EPA plus 149 mg DHA and/or 1.9 g ALA in the active treatment groups. During follow-up, 29 patients developed a ventricular arrhythmia-related events and 27 had a fatal MI. Compared with placebo patients, the EPA-DHA plus ALA group experienced less ventricular arrhythmia-related events (hazard ratio 0.16; 95% CI 0.04-0.69). These n-3 fatty acids also reduced the combined end-point ventricular arrhythmia-related events and fatal MI (0.28; 0.11-0.71). CONCLUSIONS: Our results suggest that low-dose supplementation of n-3 fatty acids exerts a protective effect against ventricular arrhythmia-related events in post-MI patients with diabetes.

Beneficial effects of omega-3 long-chain fatty acids in breast cancer and cardiovascular diseases: voltage-gated sodium channels as a common feature?

Cancers are among the leading causes of death worldwide. Voltage-gated sodium channels, among other ion channels, appear as new molecular players in epithelial cancers. Highly metastatic breast cancer cells express Na(V)1.5, the main isoform expressed in cardiac cells, where the current generated by the flux of sodium ions is responsible for the excitability. Breast cancer cells are not excitable and the protein activity regulates cell invasiveness, through the modulation of activity of acidic cathepsins, a characteristic involved in the metastatic phenotype. Interestingly, it is known that ω-3 LC-PUFA can exert beneficial effects by preventing post-myocardial infarction arrhythmias and by reducing the incidence of metastatic breast cancer. In this review, we compare the effects of some ω-3 LC-PUFA on Na(V)1.5 expressed in both cardiac and MDA-MB-231 breast cancer cells. We propose that some of the effects of ω-3 LC-PUFA act through common mechanisms involved in both diseases.

Effect of fish oil on arrhythmias and mortality: systematic review.

OBJECTIVE: To synthesise the literature on the effects of fish oil-docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)-on mortality and arrhythmias and to explore dose response and formulation effects. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, the Cochrane Library, PubMed, CINAHL, IPA, Web of Science, Scopus, Pascal, Allied and Complementary Medicine, Academic OneFile, ProQuest Dissertations and Theses, Evidence-Based Complementary Medicine, and LILACS. Studies reviewed Randomised controlled trials of fish oil as dietary supplements in humans. DATA EXTRACTION: The primary outcomes of interest were the arrhythmic end points of appropriate implantable cardiac defibrillator intervention and sudden cardiac death. The secondary outcomes were all cause mortality and death from cardiac causes. Subgroup analyses included the effect of formulations of EPA and DHA on death from cardiac causes and effects of fish oil in patients with coronary artery disease or myocardial infarction. DATA SYNTHESIS: 12 studies totalling 32 779 patients met the inclusion criteria. A neutral effect was reported in three studies (n=1148) for appropriate implantable cardiac defibrillator intervention (odds ratio 0.90, 95% confidence interval 0.55 to 1.46) and in six studies (n=31 111) for sudden cardiac death (0.81, 0.52 to 1.25). 11 studies (n=32 439 and n=32 519) provided data on the effects of fish oil on all cause mortality (0.92, 0.82 to 1.03) and a reduction in deaths from cardiac causes (0.80, 0.69 to 0.92). The dose-response relation for DHA and EPA on reduction in deaths from cardiac causes was not significant. CONCLUSIONS: Fish oil supplementation was associated with a significant reduction in deaths from cardiac causes but had no effect on arrhythmias or all cause mortality. Evidence to recommend an optimal formulation of EPA or DHA to reduce these outcomes is insufficient. Fish oils are a heterogeneous product, and the optimal formulations for DHA and EPA remain unclear.

Dietary long-chain omega-3 fatty acids of marine origin: a comparison of their protective effects on coronary heart disease and breast cancers.

The relationship between high fish consumption and low mortality following coronary heart disease (CHD) and low incidence of breast cancer was first mentioned 3 decades ago. The fishes of interest are rich in omega-3 long-chain polyunsaturated fatty acids (omega-3 LC-PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which could be the active nutrients. The current consensus about cardioprotection is that omega-3 LC-PUFAs would mainly exert antiarrhythmic effects. One of the proposed mechanisms is that circulating non-esterified LC-PUFAs partition into cardiac cells membrane phospholipids and exert a direct effect on ionic channels and/or modify intracellular calcium homeostasis. In another hypothesis, changes in the metabolism of phosphoinositides would be involved and lead to the differential activation of PKC isoforms. As compared to the mechanisms proposed for the cardioprotective effects of omega-3 LC-PUFAs, less is known about the molecular mechanisms involved in breast cancers prevention. Some proposed mechanisms such as the modulation of phosphoinositides metabolism and/or modulation of intracellular calcium homeostasis, are common to both pathologies. Other hypotheses involve the alteration of the cellular redox status induced by highly peroxidizable polyunsaturated fatty acids (FA), or the modulation of gene expression, both phenomena being tightly linked to apoptosis. In this review, we report and compare some proposed mechanisms for the involvement of omega-3 LC-PUFAs in both cardiac and breast cancer protection. Deliberately, we chose to discuss only the mechanisms, which are less described in other reviews such as ionic channels in cancer, calcium homeostasis, PKC activation or matrix metalloproteinases in both cancer and cardiac models. The leitmotiv along this review is that cardio- and cancero-protective effects use common pathways. Comparison of the cellular effects might therefore help to highlight the "protective" pathways.

Omega-3 fatty acids and sudden arrhythmic death.

Cardiovascular disease is the leading cause of death in developed countries. In Canada, in 1999, cardiovascular disease was responsible for 36% of all deaths. Ischemic heart disease accounts for the greatest percentage of these deaths (20% of all deaths), half of which are due to the acute effects of myocardial infarction. The other half are related to the late manifestations and complications of myocardial infarction. Once coronary arteriosclerosis has reached the point where it results in myocardial infarction, two main complications can ensue, loss of myocardial function and disturbance of cardiac rhythm. Progressive loss of myocardial pump function results in the syndrome of congestive heart failure. Abnormalities of the heart rhythm result in ventricular fibrillation, which is the direct cause of sudden death. Congestive heart failure rates have been easy to track because of the frequent need for hospitalization and we know from analysis of administrative databases that the annual rate of death from heart failure is about 2.5% in Canada. Sudden death, however most often occurs at home and without warning, making it much more difficult to quantitate its impact. However, the most conservative estimates suggest that no less than 25% of deaths in patients with a diagnosis of ischemic heart disease are due to ventricular fibrillation.

Dietary alpha-linolenic acid intake and risk of sudden cardiac death and coronary heart disease.

BACKGROUND: Alpha-linolenic acid, an intermediate-chain n-3 fatty acid found primarily in plants, may decrease the risk of fatal coronary heart disease (CHD) through a reduction in fatal ventricular arrhythmias and sudden cardiac death (SCD). METHODS AND RESULTS: We prospectively examined the association between dietary intake of alpha-linolenic acid assessed via updated food-frequency questionnaires and the risk of SCD, other fatal CHD, and nonfatal myocardial infarction (MI) among 76,763 women participating in the Nurses' Health Study who were free from cancer and completed a dietary questionnaire at baseline in 1984. During 18 years of follow-up, we identified 206 SCDs, 641 other CHD deaths, and 1604 nonfatal MIs. After controlling for coronary risk factors and other fatty acids, including long-chain n-3 fatty acids, the intake of alpha-linolenic acid was inversely associated with the risk of SCD (P for trend, 0.02) but not with the risk of other fatal CHD or nonfatal MI. Compared with women in the lowest quintile of alpha-linolenic acid intake, those in the highest 2 quintiles had a 38% to 40% lower SCD risk. This inverse relation with SCD risk was linear and remained significant even among women with high intakes of long-chain n-3 fatty acids. CONCLUSIONS: These prospective data suggest that increasing dietary intake of alpha-linolenic acid may reduce the risk of SCD but not other types of fatal CHD or nonfatal MI in women. The specificity of the association between alpha-linolenic acid and SCD supports the hypothesis that these n-3 fatty acids may have antiarrhythmic properties.

Membrane basis for fish oil effects on the heart: linking natural hibernators to prevention of human sudden cardiac death.

The concept that diet-induced changes in membrane lipids could modify heart function partly arose from observations that membrane composition and physical properties were closely associated with the capacity of the heart to respond appropriately to torpor and hibernation. Observations of natural hibernators further revealed that behavior of key membrane-bound enzymes could be influenced through the lipid composition of the cell membrane, either by changing the surrounding fatty acids through reconstitution into a foreign lipid milieu of different composition, or by alteration through diet. Myocardial responsiveness to beta-adrenoceptor stimulation, including initiation of spontaneous dysrhythmic contractions, was altered by both hibernation and dietary modulation of membrane fatty acids, suggesting modified vulnerability to cardiac arrhythmia. Subsequent studies using whole-animal models recognized that vulnerability to ventricular fibrillation decreased as the polyunsaturated: saturated fat (P:S) ratio of the diet increased. However, dietary fish oils, which typically contain at least 30% saturated fatty acids and only 30% long-chain n-3 (omega-3) polyunsaturated fatty acids (PUFA), exhibit antiarrhythmic effects that exceed the predicted influence of the P:S ratio, suggesting properties unique to the long-chain n-3 PUFA. Large-scale clinical trials and epidemiology have confirmed the arrhythmia prevention observed in vitro in myocytes, papillary muscles, and isolated hearts and in whole-animal models of sudden cardiac death. Some progress has been made towards a biologically plausible mechanism. These developments highlight nature's ability to provide guidance for the most unexpected applications.

Dietary n-3 fatty acids in the prevention of lethal cardiac arrhythmias.

It has been shown in animals and probably in humans that the n-3 polyunsaturated fatty acids are antiarrhythmic. We report recent studies on the mechanism(s) by which the polyunsaturated fatty acids exert their antiarrhythmic effects. The polyunsaturated fatty acids stabilize the electrical activity of isolated cardiac myocytes by inhibiting sarcolemmal ion channels, so that a stronger electrical stimulus is then required to elicit an action potential and a contraction of the myocyte. This appears at present to be the probable major antiarrhythmic mechanism of the polyunsaturated fatty acids.

[Correction of disorders of cardiac electric stability in post-infarction cardiosclerosis using a diet enriched with polyunsaturated fatty acids]. / Korrektsiia narushenii élektricheskoi stabil'nosti serdtsa pri postinfarktnom kardioskleroze s pomoshch'iu diety, obogashchennnoi polinenasyshchennymi zhirnymi kislotami.

In a 14-20 days after feeding of rats with "eikonole" (cod-liver oil, deduced from skeletal muscle and enriched by eicosapentaenic and docosahexaenic fatty acids). Myocardial infarction by Selie has been induced and in a 30 days of the same feeding, contractile function and heart electrical stability in situ have been investigated. Eikonole increased heart fibrillation threshold by 50%, decreased the frequency of spontaneous extrasystole in 3 times and ectopic activation (extrasystole), induced by n. vagus stimulation, in 2.5 times. Eikonole increased the intensity of structures' functioning in the state of relative physiological rest, but did not influence essentially on pressure and the velocity of myocardial contraction and weakening.

Effect of dietary sunflower seed oil on the severity of reperfusion-induced arrhythmias in anesthetized rats.

Myocardial ischemia followed by reperfusion was produced in artificially respirated, open-chest rats. Coronary artery ligation for 6 min rarely evoked arrhythmias; however, reperfusion after this period rapidly produced severe dysrhythmias in all control animals. Reperfusion after 12 min of ischemia produced less frequent dysrhythmias than after coronary occlusion for 6 min. Feeding of a linoleic acid-rich diet, applying 12% sunflower seed oil in rat food pellet for 4 weeks, decreased the incidence of reperfusion-induced ventricular fibrillation both after 6 min (2/15 vs. 7/11) and 12 min (0/11 vs. 2/8) of myocardial ischemia and the incidence of other arrhythmias was also decreased. The number of animals developing no arrhythmias during reperfusion was increased (8/15 after 6 min of ischemia, 4/11 after 12 min of ischemia vs. 0/11 and 0/8 in controls, respectively). Our results indicate that increased dietary consumption of linoleic acid decreased the occurrence of life-threatening arrhythmias both during the acute phase of myocardial ischemia and during reperfusion in anesthetized rats.