A study carried out by the British Heart Foundation (BHF) has shown that metabolic stress can affect your heart wellness, and cause more atrial arrhythmias, such as atrial fibrillation (AF). However, they also found that your wellbeing could be improved nonetheless with drugs that are commonly used for type 2 diabetes.
AF is a common heart condition that causes an irregular and often abnormally fast heart rate, and will affect almost one in four of the UK population at some point in their lifetime. Metabolic stress is a condition which occurs when your heart doesn’t get enough oxygen, and the study, which as led by University of Bristol scientists and published in Circulation: Arrhythmia and Electrophysiology, found that metabolic stress caused marked changes in the electrical activity of the heart’s atria, which are the upper chambers of your heart.
Though scientists have known for years that metabolic stress causes ventricular arrhythmias, which occur in the two lower chambers of the heart (the ventricles) and form the basis to heart attacks, this team, led by Dr Andrew James from the University’s School of Physiology and Pharmacology together with Professor Saadeh Suleiman in the School of Clinical Sciences, is the first to demonstrate that the same thing happens in the atria.
They did this by examining the contribution that a kind of protein underlying the electrical activity of the atria, known as KATP channels, makes during metabolic stress. These proteins allow your cells to respond to changes in your metabolism. For example, the KATP channels in your pancreas help to regulate your secretion of insulin, so type 2 diabetes mellitus has been treated using drugs that target these channels.
The results were that metabolic stress changed the electrical activity of the atrium, which was consistent with the activation of KATP channels. Also, by using drugs that are commonly used to treat patients with type 2 diabetes (glibenclamide and tolbutamide), to block these channels, the team managed to completely reverse the effects of metabolic stress on the electrical activity of the atrium and prevent atrial arrhythmia.
According to Professor Jeremy Pearson, Associate Medical Director at the BHF, ‘Atrial fibrillation is a very common irregular heart rhythm which greatly increases the risk of stroke. This study brings us closer to understanding how it develops, in particular in people whose hearts are under greater pressure due to the effects of a previous history of heart disease. It’s vital that we continue to improve our understanding of this condition so we can find new treatments for patients in the future.’
Lead study author Dr Andrew James added, ‘Further studies are required and a key point to address will be whether differences exist between the properties of atrial, ventricular and pancreatic KATP channels that might be exploited to produce an atrial-selective drug. Perhaps these channels might be useful as targets to treat atrial arrhythmias.’
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