Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial (LA) dysfunction is associated with poorer outcomes in many disease processes. Left atrial strain (LAS) is a novel two-dimensional (2D) quantitative analysis of LA function. Cardiac transplantation directly involves the LA during implantation of the donor heart. Traditional echocardiographic indices after transplantation have demonstrated value in correlating with acute cellular rejection (ACR), morbidity and mortality over short- and long-term follow-up. The prognostic value of LA strain has not been previously investigated in this cohort. Purpose We hypothesized that incrementally impaired LA strain in post cardiac transplant patients with varying degrees of ACR may be prognostic of poorer outcomes on long term follow-up. Methods 87 Heart transplant patients, assessed between 2009 and 2015, underwent transthoracic echocardiography and endomyocardial biopsy. 2D strain analysis on the LV and LA were performed along with traditional echocardiographic parameters. Patients were grouped according to peak LAS (PALS) tertiles and rejection burden history was assessed and grouped according to ACR burden at a median of 12 (±5.4) months post transplantation. The primary endpoint was all-cause mortality at follow-up. Results 12 patients met the primary endpoint over a median follow-up of 66 ± 51 months. The mean LA PALS was significantly different across the tertiles (lowest tertile 12.29 ± 2.5% vs middle tertile 17.89 ± 1.1% vs highest tertile 24.54 ± 4.2%; p <0.0001). LA strain dispersion was also significantly different between the tertiles (61.03 ± 25.8ms vs 41.8 ± 15.8ms vs 44.8 ± 18.8ms; p <0.001). All other clinical and echocardiographic parameters were non-significant between the tertiles however, there was a trend towards a lower PALS in the higher rejection burden group. Kaplan Meier curves demonstrated that survival over follow-up was significantly worse in the lower tertile LA PALS group compared to the highest tertiles LA PALS group (Log-rank test = p < 0.0001). The lowest LA PALS tertile had a significantly higher risk of reaching the primary endpoint compared with patients in the highest LA PALS tertile (hazard ratio [HR] 9.802; 95% CI 1.832-52.45; p <0.008). Higher LA PALS and LV GLS (LA PALS HR 0.610 95% CI 0.401-0.926; p 0.02; LV GLS HR 0.638 95% CI 0.418-0.972; p 0.037) were significantly associated with a reduction in reaching the primary endpoint in a multi-variate regression model including clinically relevant traditional and strain-based echocardiographic parameters. Conclusions Lower LA PALS is significantly associated with poorer long-term outcomes in cardiac transplant patients with ACR. Non-invasive LA PALS may be a useful predictor of long-term outcome in patients post cardiac transplantation. Abstract Figure. Survival curves for LA PALS tertiles

Early mitral inflow velocity to mitral annular early diastolic velocity ratio (E/e') is a standard echocardiographic parameter to non-invasively estimate left ventricular filling pressure (LVFP). Prediction of normal and abnormal LVFP is most reliable when the ratio is <8 or >15. However, E/e’ of 8-15, is indeterminate and remains a significant limitation. We hypothesize that left atrial reservoir strain (LAS) may help improve LVFP assessment. Patients enrolled in the CATHARSIS prospective study underwent both echocardiography and invasive left heart catheterization simultaneously. Invasive pre-A LVFP, E/e’ ratio and LAS were measured in all patients by blinded independent observers. Echocardiography was acquired using GE E9 system and strain analysis was performed offline using EchoPAC. Invasive LVFP was obtained in 140 patients (age 62±13, female 22%, ejection fraction 56±11%, pre-A pressure 10±4.1mmHg). Using a cut-off of ≤12mmHg to define normal pre-A pressure, ROC curve analysis demonstrated LAS of <24.10% can identify abnormal LVFP with sensitivity of 78% and specificity of 77% (AUC of 0.79). The mean LAS in patients with normal LVFP was 27.1±7.7% and 20.9±7.0% in patients with elevated LVFP (p=0.001). Patients with E/e’<8 were correctly identified with normal LVFP in 33/38 (87%) cases and patients with E/e’>15 were correctly identified with elevated LVFP in 10/16 (62.5%) of cases. Using E/e’ alone to determine LVFP resulted in indeterminate classification in 86/140 (61%) patients of which 18/86 have elevated LVFP and 68/86 have normal LVFP. Application of LAS cut off of 24.10% to the E/e’ indeterminate group further identified 53/68 (78%) of patients with normal LVFP and 12/18 (67%) of patients with elevated LVFP. The addition of LAS adds incremental value and improves diagnostic accuracy of LVFP prediction in patients with indeterminate E/e’ ratio.

One of the main limitations for incorporating strain imaging into widespread clinical practice is inter-vendor incompatibility. This study sought to compare the variability of two-dimensional speckle-tracking derived global and regional longitudinal strain using vendor-specific software (VSS) and vendor-independent software (VIS) from images acquired by two different commercially available high-end ultrasound systems. 40 subjects underwent two sequential echocardiographic acquisitions using two different ultrasound systems (GE Vivid E9 and Philips iE33). Global longitudinal strain (GLS) and regional peak longitudinal strain were derived using VSS (EchoPAC BT 13 and QLAB version 10.3) and VIS (TomTec Image Arena version 4.6). Agreement (Blan-Altman Bias) and reproducibility of strain values between VSS and VIS were assessed using intraclass correlation coefficient (ICC). GLS values analysed by VIS on images acquired on different ultrasound systems showed no significant difference (TomTec strain analysis on GE images; -18.6±4.8 vs TomTec strain analysis on Philips images; -19.2±4.8, p=0.09). VIS GLS was comparable to VSS GLS, whilst regional strain was lower in agreement compared to GLS. There was good overall agreement using VIS for GLS (Bias: Philips images =-0.02, Bias: GE images =-0.91) and high inter- and intra-observer reproducibility (Interobserver ICC =0.92, Intraobserver ICC =0.96). VIS provides good agreement with VSS for GLS. Variability exists for regional strain between VIS and VSS. Good agreement for VIS strain values from images acquired using different ultrasound systems suggest VIS could potentially be useful for serial follow-up of GLS.

Non-invasive assessment of ventricular filling pressure has typically been confounded by poor correlation of standard echocardiographic parameters vs invasive measurements. The novel measurement of left atrial strain as assessed from the apical four-chamber view on transthoracic echocardiography has been suggested as a surrogate for filling pressure. Patients enrolled in the CATHARSIS study undertook comprehensive echocardiography and contemporaneous left heart catheterization (pre-A pressure) whilst nil by mouth. Left atrial strain was assessed using GE Medical Equipment. Maximum atrial strain (reservoir) was assessed in all patients. 140 patients (age 62.0±12.8, female 22%, ejection fraction 56±11%) had left atrial strain 27.1±7.7% with left ventricular pre-A pressure 10±4mmHg. There was a weak linear correlation between invasive pressures and peak LA Strain (r2=0.2, p=0.001). Using a cut-off of ≤12mmHg for normal pre-A pressure and a cut-off of ≥28% for normal left atrial strain yielded a 92% positive predictive power for normal LA Strain predicting normal pre-A pressure. At a threshold of 28%, a reduced left atrial strain did not accurately predict normal vs raised left atrial pressure. Left atrial strain is a novel and feasible parameter which correlates with left ventricular filling pressures. A normal left atrial strain value (≥28%) is highly predictive of normal left ventricular filling pressures.

Numerous algorithms have been proposed to determine left ventricular filling pressure (LVFP) using echocardiographic parameters. The 2016 guideline algorithm suggests different pathways for patients with and without myocardial disease. Recently, Dr Jae Oh, Mayo Clinic, has proposed a simplified algorithm, ‘The Oh Factor’, for assessment of LVFP in all patients. Patients enrolled in the CATHARSIS study undertook comprehensive echocardiography and contemporaneous left heart catheterization (pre-A pressure) whilst nil by mouth. Filling pressure and diastolic grade determined by the Oh factor was compared to invasive LVFP. Invasive LVFP was obtained in 155 patients (age 64.6±12.1, female 30%, ejection fraction 54.7±11.8%, pre-A pressure 10±4mmHg). Using a cut-off of ≤12mmHg for normal pre-A pressure, the Oh factor accurately identified normal LVFP in 90/103 (87%) of patients and elevated LVFP in 8/14 (57%) of patients, with indeterminate classification in 38/155 patients (25%). Increasing mean invasive LVFP was observed with increasing Oh factor derived diastolic grade (normal 10.2±3.6mmHg, grade 1 9.0±4.4mmHg, indeterminate 10.0±3.7mmHg, grade 2 14.0±4.6, grade 3 15±3.8mmHg), with significant differences between patients with normal and grade 1 diastolic function and patients with grade 2 and grade 3 dysfunction (p=0.003 and 0.009 respectively). The simplified Oh factor algorithm is highly accurate in identifying patients with normal filling pressures and correlates mean invasive pressure and diastolic grade. Further refinement is required to improve accuracy in identification of patients with elevated filling pressures.

Background: Non-invasive detection of obstructive CAD by exercise stress echocardiography (ESE) results in varied sensitivity and specificity due to qualitative interpretation of regional wall motion abnormalities (RWMA). This study sought to determine whether resting global myocardial work (MW) can differentiate between true (TP) and false positive (FP) ESE. Methods: Resting global MW was derived from non-invasive LV pressure-strain loops constructed from GLS and brachial SBP on 70 patients (mean age 56 ± 12 yrs; 31 males) referred for clinically indicated ESE (EF ≥55% with no evidence of RWMA). Indices of constructive work (positive work by myocardial shortening in systole including lengthening during isovolumic relaxation), wasted work (energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation) and MW efficiency (percentage ratio of constructive and wasted work) were obtained. Coronary angiography was performed on those with a positive ESE (N = 18) to determine presence and/or severity of CAD (n = 10 significant CAD; n = 8 no significant CAD). Results: Resting global MW was significantly reduced (p < 0.05) in TP compared with FP ESE (1733 vs 2099 mmHg%). Global MW efficiency was the best differentiator and significantly reduced (p < 0.05) in TP vs FP ESE (94 vs 96%) due to significant reductions (p < 0.05) in constructive MW. 52 patients with a negative ESE showed a significantly higher (p < 0.05) resting GLS (18.6 vs 16.4%) and global MW (1971 vs 1733 mmHg%) compared to TP ESE. Conclusion: Non-invasive estimation of global MW may be a more sensitive tool than GLS to help distinguish between TP and FP ESE.

Background: Non-invasive left ventricular (LV) pressure-strain loop imaging is a novel method of calculating myocardial work (MW). The total area within the pressure-strain loop represents global MW (Figure1A). Myocardial shortening during systole and lengthening during isovolumic relaxation is classified as constructive work (CW) while myocardial lengthening during systole and shortening during isovolumic relaxation is classified as wasted work (WW). Purpose: Non-ischemic (CMPN-ISC) and ischemic cardiomyopathy (CMPISC) heart disease etiology influences management, prognosis as well as electromechanical correlates in heart failure. Differences in global MW and regional MW in patients with CMPN-ISC and CMPISC were assessed. Methods: Strain analysis was performed in 34 patients divided into: 1) Controls (n=10); 2) CMPN-ISC (n=10) (EF<40%; no evidence of significant coronary artery disease); 3) CMPISC (n=14) (EF<40%; coronary artery stenosis) immediately prior to coronary angiography. Dedicated MW software normalized standard LV pressure curves to brachial systolic cuff pressure and isovolumic and ejection duration. MW efficiency (GWE) was derived from the percentage ratio of: CW/(CW+WW). Segmental wasted work between septal and lateral segments were compared between CMPN-ISC and CMPISC. Results: Significantly higher global MW and GWE (p<0.05) was observed in controls. CMPISC demonstrated the lowest global MW (780mmHg%) but was not significantly different to CMPN-ISC (1054mmHg%). CMPN-ISC WW was significantly higher (p<0.05) compared to CMPISC (259 vs 185 mmHg%). Regional septal WW was significantly higher (p<0.05) in CMPN-ISC (459mmHg%) vs lateral WW (174mmHg%) (Figure1C). There was no significant difference between septal (198mmHg%) and lateral (161mmHg%) WW in CMPISC.

Background: Significant coronary artery disease (CAD) detection is important to enable expeditious medical treatment or revascularisation. This study sought to determine whether myocardial work (MW), estimated from non–invasive left ventricular (LV) pressure-strain loops, can predict severe CAD in patients without regional wall motion abnormalities (RWMA) and preserved LV ejection fraction (EF).

Background: Non–ischaemic (CMPN-ISC) and ischaemic cardiomyopathy (CMPISC) differ in management, prognosis and electromechanical relationships. Left ventricular pressure-strain loop between CMPN-ISC and CMPISC can potentially be used to assess differences in global and regional myocardial work (MW).

Background: Diagnosis of acute cellular rejection post–cardiac transplantation requires endomyocardial biopsy. We aim to investigate whether non–invasive two-dimensional strain imaging can detect early subclinical acute cellular rejection.

Clinical impact of strain imaging 1043pendently associated with AI (β=-6.409,p<0.001), mean heart radiation dose (β=2.496,p=0.002) and the use of ACE/ARBs (β=-3.881,p=0.017).In all patients, global longitudinal strain (GLS) decline by 15% or more (GLS15) was observed in 19 (27%) patients at 3Y control.GLS15 rates were similar in LSBrCa and RSBrCa patients at 3Y control (15 [25%] vs 4 [20%] patients, p=0.763).GLS15 was independently associated with the use of aromatase inhibitor (AI) (β=-1.977p=0.001).Conclusions: The initial post-RT changes not only persisted, but a further deterioration and spreading was observed in patients with left-sided breast cancer.Patients with right-sided breast cancer displayed a worsening in left ventricular rotation.AI was independently associated with apical strain and GLS15 decline.The continuing deterioration in function implies a continuing post-RT myocardial process and might indicate further evolution towards later clinical heart disease.

Background: Accurate evaluation of the tricuspid regurgitant maximal velocity (TRVmax) is important during transthoracic echocardiographic (TTE) evaluation for pulmonary hypertension (PHT). Contrast enhancement improves the spectral Doppler backscatter signal. However, its incremental benefit with contemporary scanners is less well established. Aim: Audit of patients who had a contrast echocardiogram (CE) using contemporary echo scanners and assess if the TR spectral Doppler envelope was improved following microsphere contrast administration compared to unenhanced imaging (UE). Methods: Retrospective analysis of patients who underwent UE then CE TR interrogation was performed. TR signal was graded 1 (clear-high level of confidence of interpretation and complete spectral Doppler envelope), 2 (sub-optimal with medium-low level of confidence of interpretation and incomplete envelope), 3 (poor-absent if no spectral Doppler signal or an unreliable or mostly incomplete spectral Doppler envelope). TRVmax was defined as the peak velocity that could be clearly identified. Results: 169 patients (males=120, mean age 57.6±15.2 years). TR assessed in RV inflow view and apical 4 chamber view. Mean heart rate 75.3±16.3. TRVmax could be be measured in 35.2% of patients with UE TTE (grade 1-2 in 119/338 clips) and in 56.2% with CE TTE (grade 1-2 in 190/338). Wilcoxon signed rank test demonstrated significant improvement (p<0.0001) in the TR spectral Doppler signal quality with CE TTE (mean score 2.11±0.87) vs. UE TTE (mean score 2.4±0.81). Mean TRVmax with UE TTE=2.54±0.48 m/s vs. CE TTE 2.6±0.43 m/s (p=0.008). Conclusion: In the era of contemporary scanners, CE TTE still improved the ability to detect and measure TRVmax.

Introduction: Single-beat three-dimensional (SB3D) assessment of left ventricular end-diastolic volume (LVEDV) and ejection fraction (EF) overcomes multi-beat limitations of long acquisition times, complex processing and stitch artefacts from irregular rhythms, all of which have impeded its use in routine practice. Through automated contour algorithms, SB3D provides more reproducible results and therefore may be more feasible for serial assessment. This study analyses the reproducibility of SB3D LVEDV and EF between an experienced and novice 3D sonographer. Method: 100 consecutive patients were included regardless of image quality, clinical referral or cardiac rhythm. SB3D images were obtained, optimised for image quality and highest volume rates (23.5±12.7vps) on the Siemens SC2000 ultrasound system. Two blinded observers (1 SB3D experienced, one novice) independently measured 3D LVEDV and EF from SB3D data sets using auto-contouring algorithms with adjustments to alignment and tracking made when deemed necessary. Results: SB3D LVEDV and EF were possible for both observers in 83.8% of cases, including studies with technically difficult images, atrial fibrillation (5.1%) and complex congenital heart disease (14.1%). 3D LVEDV was higher for novice (148±47mls) than experienced observer (143± 47mls), however there was a positive strong correlation with no significant difference between observers for both 3D LVEDV (r=0.94, p=0.51) and 3D LVEF (r=0.8, p=0.89). Conclusion: Despite complex cases and technically difficult images, correlation was excellent between sonographers. SB3D fully automated LVEDV and EF is feasible for routine clinical use and is not limited by the same constraints of multi-beat capture.