Angina is not a sudden onset condition. It’s a more chronic condition where someone gets chest pain when they’re walking, say up a hill or upstairs because the blood supply to the heart is insufficient to meet the demand. So when you’re walking or exercising your heart wants more blood, but if you have a narrowing in the blood supply to the heart, then the supply of blood can’t meet the demand. And that causes, if you like, a cramp in the heart muscle, which is felt as a central chest heaviness, usually during exercise.

Professor David Celermajer is Scandrett Professor of Cardiology and Head of Cardiology at the University of Sydney.