Inclusion Criteria:  Stable coronary artery disease (CAD) not eligible for percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG) Evidence of ischaemia on stress perfusion CMR Angina - Canadian Cardiovascular Society Class II-VI on maximal medical therapy  Exclusion Criteria:  Age<18 years Pregnancy Inability to consent Recent acute coronary syndrome (3 months) Recent revascularisation (6 months) Permanent pacemaker or defibrillator leads in the right heart Severe left ventricular impairment (<25%) Indication for cardiac resynchronisation therapy (CRT) Right atrial pressure ≥15mmHg Life expectancy <1 year Severe renal impairment (eGFR<15) Contraindication to CMR Contraindication to adenosine Ischaemia isolated to inferior wall Ongoing participation in a separate interventional study