Feasibility of the cardiac output response to stress test in suspected heart failure patients by Charman, S, Okwose, NC, Taylor, CJ, Bailey, K, Fuat, A, Ristic, A, Mant, J, Deaton, C, Seferovic, PM, Coats, AJS, Hobbs, FDR, MacGowan, GA, Jakovljevic, DG