Inclusion Criteria:  Age greater than or equal to 18 years Referred for atrioventricular node ablation for any such indication  Exclusion Criteria:  Stroke or transient ischaemic attack (TIA) within 6 months Myocardial infarction within 6 months Medical conditions limiting expected survival to <1 year Moderate to severe aortic stenosis History of aortic or mitral valve replacement Pregnancy or breast feeding women