ABSTRACTS S40 Abstracts Heart, Lung and Circulation 2008;17S:S1–S209 tricular ejection fraction (LVEF). This may be of particular relevance in the critical care setting, in which 2D images, by which LVEF is derived, are of notoriously poor qual- ity. Our aim therefore was to compare the inter-observer variability between experienced and novice reporters with respect to the assessment of systolic left ventricular (LV) function as measured by (LVEF) and S m in critically ill patients. Methods: We prospectively studied 39 patients referred for urgent transthoracic echocardiography (TTE) in a critical care setting. Evaluation was performed off-line inde- pendently by an experienced and novice echo reporter, blinded to each other’s assessment. LVEF was measured using Simpson’s bi-plane method of discs. S m was mea- sured by tissue Doppler imaging at six points around the mitral annulus. Results: There was closer correlation between novice and experienced reporter in the measurement of mean S m on a 6-point model compared with LVEF. The coefficient of determination was 0.622 (p <0.001) for the LVEF relation- ship, and was 0.995 (p < 0.001) for the mean S m relationship. The mean inter-observer difference in LVEF was 4.6% (S.D. 10.7%) and in mean S m was 0.040 cm/s (S.D. 0.32 cm/s). Concordance Correlation Coefficients (CCC) for mitral annular S m measurements ranged from 0.993 to 0.995 (S.E. 0.001–0.003), suggesting much closer reproducibility than for LVEF (CCC 0.8, S.E. 0.065). Conclusions: Our results suggest that in critically ill patients, in whom image quality is frequently sub-optimal, that measurement of peak systolic mitral annular velocity is more reproducible than left ventricular ejection fraction by a novice compared with an experienced reporter. Clinical implications: Tissue Doppler imaging should be routine in the echocardiographic evaluation of critically ill patients. This modality is particularly useful for inexperi- enced reporters. doi:10.1016/j.hlc.2008.05.092 92 The Clinical Importance of Angle of Insonation with Respect to the Timing and Magnitude of Peak Systolic Mitral Annular Tissue Velocity Darryl Leong 1,∗ , Dennis Wong 2 , Rishi Puri 2 , Suchi Khurana 2 , Stephen Worthley 2 , Prashanthan Sanders 1 1 University of Adelaide, Adelaide, SA, Australia; 2 Royal Ade- laide Hospital, Adelaide, SA, Australia Background and aims: Mitral annular tissue velocity imag- ing has been shown to be of value in the assessment of systolic left ventricular function (as measured by peak systolic mitral annular tissue velocity, S m ) and in the eval- uation of cardiac synchrony (which has been assessed by measuring differences in time-to-peak systolic mitral annular velocity). In addition, it has been shown that at extremes of angles of insonation, tissue velocity-derived data may be inaccurate. It is unknown whether these inaccuracies result in clinically appreciable and signifi- cant differences in the estimation of S m and time-to-S m in routine cardiac imaging. Our aim was to measure the magnitude of change in S m , and in the time-to-S m , from standard apical windows to off-plane images in which the segment of interest moves parallel to the ultrasound beam. Methods: We prospectively studied 37 patients referred for in-patient trans-thoracic echocardiography. Pulsed wave tissue Doppler imaging was acquired in routine apical views at 6 points around the basal mitral annulus. Pulsed wave tissue Doppler imaging was repeated for each seg- ment using off-plane imaging, such that the region of interest was moving parallel to the ultrasound beam. The peak systolic mitral annular tissue velocity (S m ) and time- to-S m for each segment were compared between routine and off-plane images in each patient in instances where the angle of insonation between the former and latter dif- fered by more than 10 ◦ . Results: There were 91 basal segments in which the angle of tissue motion differed from the parallel by at least 10 ◦ in routine apical imaging. Off-plane imaging failed to pro- duce significant changes in either of S m or in time-to-S m (all p > 0.1) on paired t-testing. The sample size had 99% power to detect a difference in time-to-S m of 10 ms, and a 90% power to detect a difference in S m of 0.4 cm/s at α = 0.05. Conclusions: Angle of insonation makes little difference to tissue velocity or cardiac timing measurements in uns- elected individuals’ echocardiograms. This obviates the need for off-plane imaging in routine studies. doi:10.1016/j.hlc.2008.05.093 93 Comparison of Cardiac MRI with TOE for the Assessment of Periaortic Pathology Russell Anscombe ∗ , Wendy Strugnell, Jodie Harker, Emma Ivens, Darryl Burstow, Richard Slaughter The Prince Charles Hospital, Brisbane, Queensland, Australia Background: Transoesophageal echocardiography (TOE) has dramatically improved the detection and assessment of periaortic pathology. However, a subset of patients, par- ticularly those with aortic prostheses, have suboptimal TOE imaging and there is early evidence supporting a role for Cardiac MRI (CMRI) in this patient group. We com- pared TOE with CMRI for the assessment of patients with suspected or clinically proven periaortic pathology. Methods: 27 patients (78% male; mean age 53 years) were referred for TOE and CMRI for the investigation of periaortic pathology. The majority of patients (78%) had a prosthetic aortic valve replacement (41% mechanical, 37% bioprosthetic) with 52% having had previous aortic root replacement. Clinical indications for the investiga- tions were: endocarditis (37%), to determine source of embolism (15%), follow-up type A dissection (8%), known periaortic pathology (40%). CMRI examination consisted of functional imaging of the heart, pre- and post-contrast imaging of the aortic root and a contrast-enhanced MR aortic angiogram. Results: Imaging findings were as follows: periaortic cav- ities (13 patients), periaortic haematomas (4), dissection