RT Journal Article SR Electronic T1 Non-invasive determination of cardiac output by Doppler echocardiography and electrical bioimpedance JF British Heart Journal JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 347 OP 348 DO 10.1136/hrt.64.5.347-b VO 64 IS 5 A1 Silke, Bernard YR 1990 UL http://heart.bmj.com/content/64/5/347.2.abstract AB