Dr Marshall qualified in Medicine at Leeds University in 1988. He gained his MRCP in 1992 during general medical training in Sheffield. He moved to the Midlands soon after to specialise in cardiology, working at Dudley Road and Walsgrave Hospitals. He then undertook a period of research in to invasive treatments for atrial fibrillation at Queen Elizabeth Hospital, leading to his M.D. from the University of Birmingham. He continued to subspecialise in cardiac electrophysiology and was appointed as a Consultant at University Hospital Birmingham in 2000. While he continues to contribute to general cardiology, his main field of interest is in the treatment of cardiac rhythm disorders. He performs catheter ablation procedures for all types of tachycardia and has helped establish University Hospital and the BMI Priory as leading ablation centres in the Midlands and the UK, particularly in the treatment of atrial fibrillation. He also has extensive experience at implantation and follow up of pacemakers and implantable defibrillators including resynchronisation devices. Again, he has established University Hospital as the leading cardiac device centre in the West Midlands.