001 WAVE INTENSITY ANALYSIS: INSIGHTS IN HAEMODYNAMIC ABNORMALITIES IN HEART FAILURE

S. L. Cunningham¹, J. Mayet¹, K. H. Parker², R. A. Foale¹, S. A. McG Thom¹, A. D. Hughes¹. ¹St Mary’s Hospital, London, ²Physiological Flow Studies Unit, Imperial College, London, UK

Wave intensity analysis (WIA) is a recently described non-invasive technique that provides information on the working state of the heart, wave reflections, and arterio-ventricular interaction. It is a measure of the energy carried by a wave and is the product of instantaneous changes in pressure and flow velocity at any arterial site. We used WIA to investigate the possibility of altered wave reflection and to further understand the haemodynamic changes that occur in heart failure (HF). 29 patients with HF were compared to 29 age-matched subjects with normal systolic function (N). An additional 67 subjects with compensated HF were studied to examine possible relationships between ventricular function and wave dispersion. Brachial BP, carotid arterial pressure (P) and flow velocity (U) were measured by sphygmomanometry, tonometry and pulsed wave Doppler respectively. The intensities of forward and backward waves and carotid pulse wave velocity (c) were calculated. Data are means ± SD, p was calculated by Student’s t-test. P was lower in the HF group [129±21 (N); 120±24 mmHg (HF); p=0.10]. c did not differ [13.6±5.5 (N); 13.2±6.3 ms-1 (HF)]. Peak U was significantly reduced in the heart failure group [0.70±0.15 (N); 0.56±0.17 ms-1 (HF), p=0.006]. Ventricular wave power was dramatically reduced in HF [29.2±9.8 (N); 15.4±7.7 mWm-2 (HF); p<0.00001], as was wave work [232±80 (N); 124±66 Jm-2 (HF); p<0.00001]. Wave reflection from the head [13.3±7.5 (N); 17.5±11.7 % (HF), p=0.08] and the body [1.5±1.7 (N); 5.4±6.1% (HF), p=0.001] were increased in the HF group. The magnitude of the systolic ventricular power wave correlated with SBP (r=0.49 p<0.001) …