Irregular heartbeat or atrial fibrillation (AF) is a common cardiac arrhythmia wherein atria (two chambers of heart) beat rapidly leading to a disturbed heartbeat pattern. At times, this arrhythmia might be associated with severe consequences such as stroke and heart failure. Various stressful conditions amplify the harmful free radicals in our body and lead to oxidative stress. Oxidative stress is an imbalance between the production of free radicals in our body and our ability to detoxify their harmful effects through neutralization by antioxidants. Oxidative stress is a key factor that can trigger an irregular heartbeat.
Coronary artery bypass grafting is the most common procedure performed by cardiac surgeons. Post-operative atrial fibrillation (AF) is the most common adverse event following CABG, surgery that increases the incidence of stroke, kidney injury and death. Post-operative AF occurs in 20-50% of patients with the highest incidence of AF occurring by the third post-operative day. Reduction of AF by various drugs is moderately effective, but involves either rate control with beta blockers or rate conversion with amiodarone after the myocardial damage processes initiating AF have already occurred. Decreasing the incidence of post-operative AF, and hence the morbidity and mortality of high-risk CABG patients, could be more fruitfully approached by targeting the upstream combined processes of inflammation and coagulation activation induced by the surgical insult and associated ischemia-reperfusion leading to cell damage induced by oxidative stress and could be prevented and/or inhibited by antioxidant supplementation. Specifically high-dose intravenous (IV) vitamin C supplementation will ameliorate reactive oxygen species (ROS) and therefore damp down upstream inflammatory processes, leading to a reduction of downstream adverse events with demonstrable links to inflammation processes, such as AF. A significant body of evidence suggests that antioxidant vitamins, especially vitamin C, have an important role in preventing a number of complications after certain operations, including cardiac surgery.
The incidence of irregular heartbeat is as high as 30% in patients undergoing heart surgery and is partly attributed to oxidative stress. Measures that can render protection against the increased risk of atrial fibrillation after a cardiac surgery are essential. Antioxidants that potentially relieve the oxidative stress might be useful alternatives to tackle such concerns.
A researcher duo reviewed the existing studies related to vitamin C (known to be a powerful antioxidant) to understand its role in prevention of atrial fibrillation in high-risk patients. The review included 15 studies involving 2050 patients who had undergone cardiac surgery. While five of these studies showed no protective effect of vitamin C against atrial fibrillation, nine studies demonstrated that use of vitamin C reduced the risk of developing post-operative atrial fibrillation by 44%.
Vitamin C thus seems to be a safe and low-cost essential nutrient to have a valuable role in the management of cardiac surgery patients. Importantly, ail the component studies of this review were conducted in less wealthy countries. Hence, it would be worthwhile to check if benefits of vitamin C would be more prominent in patients with low documented levels of vitamin C. The optimal dosage of vitamin C that can essentially alleviate the risk of atrial fibrillation should also be identified.
Ref:1. Harri Hemila, Timo Suonsyrja BMC Cardiovasc Disord. Feb I 2017; (Published online) 2017. doi: 10.1186/sl2872-017-0478-5.The article has been contributed by:Dr. Shiva Shankara T.H., MBBS, MD, DM, Cardiologist, Department of Cardiology, Manipal Hospitals, MangaloreE-mail: drshivashankarath@gmail.comDisclaimer: The views and opinions expressed by the Doctors are their independent professional judgment and we do not take any responsibility for the accuracy of their views. This should not be considered as a substitute for Physician's advice. Please consult your treating Physician for more details.
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