The electrical activity of the heart

IP3 receptor modulation of the atrioventricular node

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 our hearts to beat, co-ordinates the electrical activity of the atria and ventricles and in some circumstances, controls the heartbeat rate so the heart can pump blood around the body effectively. When these electrical processes break down, disturbances in the heart beat called arrhythmias can occur and this can cause serious health problems or even sudden death. Professor Jules Hancox and colleagues at the University of Bristol have recently found that proteins called IP3 receptors (which determine how calcium is used inside some cells) influence how cells from the AVN respond to electrical signals. The BHF has now awarded them a grant to study cells and tissues from the AVN and understand how IP3 receptors affect their response to electrical activity, how they use calcium and how these processes are linked. This research will improve our understanding of the electrical conduction system of the heart and how it is controlled, and may reveal new ways to treat some types of arrhythmia.