Modulation of ischaemic induced cardiac dysfunction by remote pre-conditioning

INTERVENTION: Myocardial ischaemia is common in patients with coronary artery disease (CAD) and may be asymptomatic and occur during everyday life. Brief episodes of demand ischaemia, where the increase in coronary blood supply is insufficient to meet the increase in cardiac work, may result in both an adaptive change in metabolism and a transient reduction in regional left ventricular contractile function (stunning). The changes in contractile function can be assessed by echocardiography and from the basis of dobutamine stress echocardiography that is a well‐validated non‐invasive technique for the diagnosis and assessment of patients with CAD. Episodes of ischaemia in a remote organ (such as a limb) may modify the myocardial response to ischaemia and this study will use this technique to assess the myocardial response to dobutamine in patients with single vessel CAD. Using a randomised cross‐over design, a baseline dobutamine stress study will be performed to confirm that stunning can be induced, with two further studies with and without remote preconditioning. The latter will be induced by inflating a blood pressure cuff in the non‐dominant arm to 30 mmHg above systolic blood pressure for 5 min, deflated for 5 min and then repeated three times. At the end of these three cycles (that have previously been performed uneventfully in volunteers) the dobutamine stress echocardiogram will be performed using a standard clinical protocol with myocardial imaging every 3 min during the incremental increases in dobutamine dosage. Imaging will be repeated every 3 min for 3 h after the end of the dobutamine infusion. CONDITION: Cardiovascular: Single vessel coronary disease ; Circulatory System ; Chronic ischaemic heart disease PRIMARY OUTCOME: Added July 2008:; Change in ejection fraction after remote preconditioning, compared to baseline.; SECONDARY OUTCOME: Added July 2008:; 1. Segmental LV wall tissue velocities; 2. Rate pressure product; 3. ECG ST deviation and chest pain score after remote preconditioning, compared to baseline INCLUSION CRITERIA: Added July 2008: 1. Able to consent 2. Age >18 3. Coronary artery disease 4. Normal left ventricular function