The atrioventricular node - unravelling the intricacies behind our heart beat

Elucidating the basis of cholinergic modulation of electrophysiology of the atrioventricular node

Research that reveals more about how the heartbeat is controlled is important to our understanding of how the heart works and could potentially reveal new ways to treat some types of irregular heartbeat (arrhythmias). Our heart is divided into four chambers – two upper ‘atria’ and two lower ‘ventricles’. Between the atria and ventricles, there is a small region of the heart called the atrioventricular node (AVN). The AVN receives the electrical signal needed for the heart to beat, co-ordinates the electrical activity of the atria and ventricles and helps to control the heart rate, so that the heart can pump blood around the body effectively. Our autonomic nervous system controls how our internal organs work, including the heart. It prevents the AVN from becoming electrically activated by releasing a chemical called acetylcholine (ACh). Scientists know that ACh controls proteins called 'ion channels' on the AVN but they don’t understand exactly how this happens. Professor Jules Hancox and colleagues at the University of Bristol have now received a BHF grant to work out which ion channels in the AVN are controlled by ACh, and how much ACh is needed for certain functions in AVN cell and tissue models. This research will improve our understanding of a key component of the heart’s electrical conduction system and how it is controlled. Their results will help to build a more detailed and accurate model of the heart and may reveal new ways to treat some arrhythmias in the future.