The design of this study is that of a cohort study with the common exposure being that of pacemaker therapy. We seek to take detailed haemodynamic and echocardiographic measurements at the time of implantation. This will yield powerful data when cross referenced to cases of adverse ventricular function seen due to pacing at follow up. We aim to perform this pilot study as a feasibility process in order to ascertain the frequency of measurable adverse effects in this population and gain early insights into the markers we can look for. We do not know this data at present. This will allow for a future definitive study to be designed with appropriate participant numbers and follow up periods. The follow up period of 6 months has been set in order to fit within the time constraints of an ongoing MD undertaking.