Targeted Natural Therapies
Omega-3 fatty acids are important health-promoting lipids found in certain fish and other seafood as well as specific plant sources (Lavie 2009; Kromhout 2011). Fish oil contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two important omega-3 fatty acids for health (Lavie 2009).
Several studies have shown that moderate consumption of fish oils/omega-3 fatty acids is heart-healthy and provides protection against arrhythmias, including atrial fibrillation and ventricular arrhythmias (Pepe 2010; Lavie 2009). The omega-3 fatty acids potentially act by stabilizing the electrical activity in the heart through reduction of the sodium and calcium currents inside heart muscle cells (Pepe 2010). A large study enrolled 11 324 people within 3 months after having an acute myocardial infarction and treated them with an omega-3 polyunsaturated fatty acid (PUFA) supplement by itself, vitamin E by itself , an omega-3 PUFA supplement together with vitamin E, or placebo. This study showed that 850 mg of EPA and DHA supplementation provided various cardiovascular benefits, mainly due to their antiarrhythmic effects; this included reduced nonfatal heart attack and nonfatal stroke rates, as well as reduced cardiovascular death (Pepe 2010). A similar reduction in ventricular arrhythmia-related events was also noted in a sub-group analysis of 1014 patients with clinically diagnosed heart attack and diabetes who were treated with a combination of DHA, EPA, and alpha linolenic acid (ALA; a plant-based precursor of EPA) (Kromhout 2011). Perhaps the most significant effects of omega-3 supplementation have been observed in patients with atrial fibrillation (Lavie 2009). A study published in 2012 analyzed plasma levels of various omega-3 fatty acids in a population of 3326 individuals without history of atrial fibrillation or heart failure. The results showed that higher levels of omega-3 fatty acids and DHA were associated with a lower risk of atrial fibrillation in older patients (Wu 2012). However, not all studies have confirmed the beneficial effect of fish oil supplementation for the treatment of arrhythmias (Pepe 2010; Lavie 2009; Brouwer 2009). Additionally, caution should be exercised in patients with implantable defibrillator, as some studies show that there may be a slightly higher risk of sudden death in patients with an implantable defibrillator who are treated with fish oil supplements (Jenkins 2008; Marik 2009).
Magnesium and Potassium
As both magnesium and potassium are intricately involved in the heart’s electrical stability, maintaining normal functional blood levels and ratios of each of these ions is important. Low concentrations of magnesium and potassium in the body are associated with increased risk of developing ventricular arrhythmias (Sultan 2012).
Magnesium deficiency may result in congestive heart failure, hypertension, and angina (Guerrera 2009). The American Heart Association recommends administering magnesium sulfate intravenously (up to 2 grams in 2 minutes) to treat some types of ventricular tacharrhythmia. Oral magnesium oxide (15 mg/kg) added to a regimen of beta-blockers helped to improve some markers of imminent ventricular tachyarrhythmia, even in cases where the beta-blockers failed to make a difference on their own (Bachman 2003). Additionally, oral magnesium (3 grams daily for 30 days) improved symptoms of premature ventricular and supraventricular complexes in 93.3% of patients taking magnesium as compared with only 16.7% of patients administered placebo (Falco 2012).
Potassium is important for the maintenance of cardiac electrical stability, and alterations (deficiency or excess) in serum potassium levels, such as can be induced by diuretic drugs, can contribute to the development of cardiac arrhythmias (Zaza 2009; Abdel-Qadir 2010; Berkova 2012). Assessing potassium levels via blood testing and increasing potassium intake via supplementation if levels are found to be low is an arrhythmia treatment consideration. In a study that enrolled 170 patients with symptomatic persistent atrial fibrillation, pre-treatment with intravenous potassium/magnesium improved the success rate of achieving conversion to a normal heart rhythm (Sultan 2012).
Hawthorn is a fruit-bearing shrub whose constituents have been used since the 1800s to support cardiovascular health (Edwards 2012). Modern scientific inquiry has shown that hawthorn is rich in several antioxidant compounds such as flavonoids and anthocyanins, and that it may play a supportive role in several cardiovascular diseases (Rigelsky 2002; Chang 2005; Edwards 2012). It is thought that hawthorn supports heart and vascular health via modulation of ion (eg, potassium and calcium) channels, blood flow, inflammation, and oxygen utilization, as well as by scavenging damaging free radical molecules, which cause oxidative stress (Rigelsky 2002; Tadic 2008).
In an animal model, infusions of hawthorn extracts reduced the number of arrhythmias compared to a control infusion following experimental deprivation and subsequent reinstitution of blood supply to the heart (“ischemia/ reperfusion”), a paradigm that mimics some of the effects of a heart attack (Garjani 2000). In another similarly designed animal model, long-term supplementation with a standardized hawthorn extract was associated with 6-fold fewer incidence of potentially deadly ventricular fibrillation following deprivation and subsequent reinstitution of blood flow to the heart (al Makdessi 1999). A 24-week long human clinical trial involving over 1000 patients with heart failure found that hawthorn supplementation improved heart function and reduced symptoms such as fatigue and palpitations. Supplementation also increased the amount of time subjects’ heart rhythms remained normal (Tauchert 1999).
Oxidative stress and inflammation have been implicated in the development of atrial fibrillation, and this is particularly true in the case of post-operative atrial fibrillation (Ozaydin 2008). Various studies have attempted to determine the usefulness of antioxidants in the treatment of atrial fibrillation (Rasoli 2011).
The beneficial effects of N-acetyl-cysteine (NAC) treatment are attributed to its antioxidant and anti-inflammatory properties (Ozaydin 2008). Since oxidative stress has been implicated as a factor in post-operative atrial fibrillation, various trials have tried to assess the effectiveness of N-acetyl-cysteine (NAC) in preventing the condition. An analysis of data from 8 separate trials that included a combined population of over 500 patients concluded that NAC supplementation may effectively reduce the incidence of post-operative atrial fibrillation (Gu 2012). In a trial conducted to study the effects of NAC treatment on post-operative atrial fibrillation, intravenous infusion of NAC was compared to a group receiving saline infusion. Post-operative atrial fibrillation was found in only three patients from the NAC-treated group, as compared with 12 patients from the saline group (Ozaydin 2008).
Vitamins C and E
Vitamins C and E may also exert a protective effect against post-operative atrial fibrillation by virtue of their antioxidant properties. An analysis of data from 5 clinical trials that examined a total of 567 patients demonstrated that vitamin therapy caused a significant reduction in the incidence of post-operative atrial fibrillation and all-cause arrhythmia. This effect was independent of the type of surgery. There is also evidence of a synergistic effect between antioxidant vitamins and beta-blockers (Harling 2011). A separate study that enrolled 100 patients undergoing bypass surgery showed that a combination of oral vitamin C (2 grams on the night prior to surgery and 2 grams daily for 5 days thereafter) and a beta-blocker was more effective in preventing post-operative atrial fibrillation than the beta-blocker treatment alone. The incidence of post-operative atrial fibrillation was only 4% in the vitamin C group as compared with 26% in the control group (Rodrigo 2010). Vitamin C treatment showed similar benefits in another study where a group of 44 patients receiving standard treatment following conversion to normal heart rhythm received either vitamin C or no additional treatment. Atrial fibrillation recurred in only 4.5% of the patients in the vitamin C group, as compared with 36.3% of the patients who did not receive any treatment (Korantzopoulos 2005). Similarly, pre-operative treatment with vitamin E for 28 days followed by vitamin C on days 27-29 reduced the incidence of arrhythmias in a group of 37 patients undergoing bypass surgery (Rasoli 2011).
Resveratrol is a polyphenol found in grapes and Japanese knotweed (Polygonum cuspidatum) with antioxidant and anti-inflammatory properties. An animal model revealed that resveratrol can attenuate inflammatory responses and oxidative stress after myocardial infarction, which can lead to decreased inducibility of ventricular arrhythmias (Xin 2010). A pre-clinical study revealed that resveratrol treatment significantly suppressed myocardial infarction-induced ventricular arrhythmias and improved long-term survival. Resveratrol acts by a variety of mechanisms, and exerts its effects in a concentration-dependent manner, by inhibiting the calcium current, which reduces the intracellular calcium overload, or opening certain potassium channels (Hung 2004; Chen 2008).
Coenzyme Q10 (CoQ10) is a powerful antioxidant and an important component of cellular energy production. A number of studies have revealed a therapeutic role for CoQ10 in conditions of impaired cardiac function, such as heart failure (Singh 2007; Weant 2005). Animal data has shown that CoQ10 can exert powerful antiarrhythmic action following deprivation and subsequent reinstitution of blood flow to the heart (Nagai 1985). Several clinical trials have revealed that CoQ10 possess antiarrhythmic action in situations of impaired cardiac function or metabolic disease such as type 2 diabetes. In a trial involving 27 diabetic individuals, CoQ10 supplementation was found to be beneficial in reducing premature ventricular contractions (Fujioka 1983). A trial involving 2500 heart failure patients found that 3 months of supplementation with 50 – 150 mg of CoQ10 daily was associated with an improvement in arrhythmia signs and symptoms in 62% of subjects (Baggio 1993). Another trial evaluated the effects of CoQ10 supplementation (150 mg daily) for 7 days preceding scheduled coronary artery bypass grafting (CABG) procedures in 40 subjects who were divided to receive CoQ10 or act as a control group. Following CABG, CoQ10 supplementation was associated with lower markers of oxidative stress and significantly lower incidence of potentially deadly ventricular fibrillation (Chello 1994). In a controlled clinical trial among 144 subjects who had a heart attack, 28 days of supplementation with 120 mg of CoQ10 daily was associated with a 2.6-fold reduction in occurrence of arrhythmias. Moreover, subjects receiving CoQ10 also exhibited less evidence of oxidative stress, and levels of other antioxidants such as vitamins A, C, and E increased to a greater degree following heart attack in the group who received CoQ10 than those who received placebo (Singh 1998).
Rhodiola reduced the incidence of ventricular arrhythmias and increased the ventricular fibrillation threshold in an animal model of heart attack (Maslov 2009). Preclinical research suggests the anti-arrhythmic effect of rhodiola may be due to activation of opioid receptors (Maimeskulova 2000). Experimental pre-clinical research has demonstrated pretreatment with rhodiola improved several measures of heart cell health following induced ischemic injury (Wu 2009).