The nuclear heart scan is a method by which we can measure the volume of the left heart chamber. The study will involve the placement of small needle into a vein of the patients forearm. Through this we will inject a primer which will make participants red blood cells very sticky. After twenty minutes we will take a blood sample from the same needle. This sample of blood will be mixed with a radioactive tracer. The tracer will be re-injected through the same needle into the participants’ vein. This tracer will allow us to measure the amount of blood inside the chambers of the participants’ heart with a special camera, a gamma camera. The pictures will be taken with the participants lying on a bed throughout.