Strain imaging provides an accessible, feasible and non-invasive technique to assess cardiac mechanics. Speckle tracking echocardiography (STE) is the primary modality with the utility for detection of subclinical ventricular dysfunction. Investigation and adoption of this technique has increased significantly in both the research and clinical environment. It is therefore important to provide information to guide the sonographer on the production of valid and reproducible data. The focus of this review is to (1) describe cardiac physiology and mechanics relevant to strain imaging, (2) discuss the concepts of strain imaging and STE and (3) provide a practical guide for the investigation and interpretation of cardiac mechanics using STE.
Christopher Johnson, Katherine Kuyt, David Oxborough and Martin Stout
Caroline Schneider, Lynsey Forsythe, John Somauroo, Keith George and David Oxborough
Left ventricular (LV) function is dependent on load, intrinsic contractility and relaxation with a variable impact on specific mechanics. Strain (ε) imaging allows the assessment of cardiac function; however, the direct relationship between volume and strain is currently unknown. The aim of this study was to establish the impact of preload reduction through head-up tilt (HUT) testing on simultaneous left ventricular (LV) longitudinal and transverse function and their respective contribution to volume change.
A focused transthoracic echocardiogram was performed on 10 healthy male participants (23 ± 3 years) in the supine position and following 1 min and 5 min of HUT testing. Raw temporal longitudinal ε (Ls) and transverse ε (Ts) values were exported and divided into 5% increments across the cardiac cycle and corresponding LV volumes were traced at each 5% increment. This provided simultaneous LV longitudinal and transverse ε and volume loops (deformation volume analysis – DVA).
There was a leftward shift of the ε-volume loop from supine to 1 min and 5 min of HUT (P < 0.001). Moreover, longitudinal shortening was reduced (P < 0.001) with a concomitant increase in transverse thickening from supine to 1 min, which was further augmented at 5 min (P = 0.018).
Preload reduction occurs within 1 min of HUT but does not further reduce at 5 min. This decline is associated with a decrease in longitudinal ε and concomitant increase in transverse ε. Consequently, augmented transverse relaxation appears to be an important factor in the maintenance of LV filling in the setting of reduced preload. DVA provides information on the relative contribution of mechanics to a change in LV volume and may have a role in the assessment of clinical populations.
Rachel N Lord, Keith George, Helen Jones, John Somauroo and David Oxborough
This study aimed to establish feasibility for myocardial speckle tracking (MST) and intra-observer reliability of both MST and tissue velocity imaging (TVI)-derived right ventricular (RV) strain (ε) and strain rate (SR) at rest and during upright incremental exercise. RV ε and SR were derived using both techniques in 19 healthy male participants. MST-derived ε and SR were feasible at rest (85% of segments tracked appropriately). Feasibility reduced significantly with progressive exercise intensity (3% of segments tracking appropriately at 90% maximum heart rate (HRmax)). Coefficient of variations (CoVs) of global ε values at rest was acceptable for both TVI and MST (7–12%), with low bias and narrow limits of agreement. Global SR data were less reliable for MST compared with TVI as demonstrated with CoV data (systolic SR=15 and 61%, early diastolic SR=16 and 17% and late diastolic SR=26 and 31% respectively). CoVs of global RV ε and SR obtained at 50% HRmax were acceptable using both techniques. As exercise intensity increased to 70 and 90% HRmax, reliability of ε and SR values reduced with larger variability in MST. We conclude that RV global and regional ε and SR data are feasible, comparable and reliable at rest and at 50% HRmax using both MST and TVI. Reliability was reduced during higher exercise intensities with only TVI acceptable for clinical and scientific use.
Mohammad Qasem, Victor Utomi, Keith George, John Somauroo, Abbas Zaidi, Lynsey Forsythe, Sanjeev Bhattacharrya, Guy Lloyd, Bushra Rana, Liam Ring, Shaun Robinson, Roxy Senior, Nabeel Sheikh, Mushemi Sitali, Julie Sandoval, Richard Steeds, Martin Stout, James Willis and David Oxborough
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited pathology that can increase the risk of sudden death. Current task force criteria for echocardiographic diagnosis do not include new, regional assessment tools which may be relevant in a phenotypically diverse disease. We adopted a systematic review and meta-analysis approach to highlight echocardiographic indices that differentiated ARVC patients and healthy controls.
Data was extracted and analysed from prospective trials that employed a case–control design meeting strict inclusion and exclusion as well as a priori quality criteria. Structural indices included proximal RV outflow tract (RVOT1) and RV diastolic area (RVDarea). Functional indices included RV fractional area change (RVFAC), tricuspid annular systolic excursion (TAPSE), peak systolic and early diastolic myocardial velocities (S′ and E′, respectively) and myocardial strain.
Patients with ARVC had larger RVOT1 (mean ± s.d.; 34 vs 28 mm, P < 0.001) and RVDarea (23 vs 18 cm2, P < 0.001) compared with healthy controls. ARVC patients also had lower RVFAC (38 vs 46%, P < 0.001), TAPSE (17 vs 23 mm, P < 0.001), S′ (9 vs 12 cm/s, P < 0.001), E′ (9 vs 13 cm/s, P < 0.001) and myocardial strain (−17 vs −30%, P < 0.001).
The data from this meta-analysis support current task force criteria for the diagnosis of ARVC. In addition, other RV measures that reflect the complex geometry and function in ARVC clearly differentiated between ARVC and healthy controls and may provide additional diagnostic and management value. We recommend that future working groups consider this data when proposing new/revised criteria for the echocardiographic diagnosis of ARVC.
Hisham Sharif, Stephen Ting, Lynsey Forsythe, Gordon McGregor, Prithwish Banerjee, Deborah O’Leary, David Ditor, Keith George, Daniel Zehnder and David Oxborough
This study sought to examine layer-specific longitudinal and circumferential systolic and diastolic strain, strain rate (SR) and diastolic time intervals in hypertensive patients with and without diastolic dysfunction. Fifty-eight treated hypertensive patients were assigned to normal diastolic function (NDF, N = 39) or mild diastolic dysfunction (DD, N = 19) group. Layer-specific systolic and diastolic longitudinal and circumferential strains and SR were assessed. Results showed no between-group difference in left ventricular mass index (DD: 92.1 ± 18.1 vs NDF: 88.4 ± 16.3; P = 0.44). Patients with DD had a proportional reduction in longitudinal strain across the myocardium (endocardial for DD −13 ± 4%; vs NDF −17 ± 3, P < 0.01; epicardial for DD −10 ± 3% vs NDF −13 ± 3%, P < 0.01; global for DD: −12 ± 3% vs NDF: −15 ± 3, P = 0.01), and longitudinal mechanical diastolic impairments as evidenced by reduced longitudinal strain rate of early diastole (DD 0.7 ± 0.2 L/s vs NDF 1.0 ± 0.3 L/s, P < 0.01) and absence of a transmural gradient in the duration of diastolic strain (DD endocardial: 547 ± 105 ms vs epicardial: 542 ± 113 ms, P = 0.24; NDF endocardial: 566 ± 86 ms vs epicardial: 553 ± 77 ms, P = 0.03). Patients with DD also demonstrate a longer duration of early circumferential diastolic strain (231 ± 71 ms vs 189 ± 58 ms, P = 0.02). In conclusion, hypertensive patients with mild DD demonstrate a proportional reduction in longitudinal strain across the myocardium, as well as longitudinal mechanical diastolic impairment, and prolonging duration of circumferential mechanical relaxation.
Thomas Mathew, Lynne Williams, Govardhan Navaratnam, Bushra Rana, Richard Wheeler, Katherine Collins, Allan Harkness, Richard Jones, Dan Knight, Kevin O'Gallagher, David Oxborough, Liam Ring, Julie Sandoval, Martin Stout, Vishal Sharma, Richard P Steeds and on behalf of the British Society of Echocardiography Education Committee
Heart failure (HF) is a debilitating and life-threatening condition, with 5-year survival rate lower than breast or prostate cancer. It is the leading cause of hospital admission in over 65s, and these admissions are projected to rise by more than 50% over the next 25 years. Transthoracic echocardiography (TTE) is the first-line step in diagnosis in acute and chronic HF and provides immediate information on chamber volumes, ventricular systolic and diastolic function, wall thickness, valve function and the presence of pericardial effusion, while contributing to information on aetiology. Dilated cardiomyopathy (DCM) is the third most common cause of HF and is the most common cardiomyopathy. It is defined by the presence of left ventricular dilatation and left ventricular systolic dysfunction in the absence of abnormal loading conditions (hypertension and valve disease) or coronary artery disease sufficient to cause global systolic impairment. This document provides a practical approach to diagnosis and assessment of dilated cardiomyopathy that is aimed at the practising sonographer.
Gill Wharton, Richard Steeds, Jane Allen, Hollie Phillips, Richard Jones, Prathap Kanagala, Guy Lloyd, Navroz Masani, Thomas Mathew, David Oxborough, Bushra Rana, Julie Sandoval, Richard Wheeler, Kevin O'Gallagher and Vishal Sharma
There have been significant advances in the field of echocardiography with the introduction of a number of new techniques into standard clinical practice. Consequently, a ‘standard’ echocardiographic examination has evolved to become a more detailed and time-consuming examination that requires a high level of expertise. This Guideline produced by the British Society of Echocardiography (BSE) Education Committee aims to provide a minimum dataset that should be obtained in a comprehensive standard echocardiogram. In addition, the layout proposes a recommended sequence in which to acquire the images. If abnormal pathology is detected, additional views and measurements should be obtained with reference to other BSE protocols when appropriate. Adherence to these recommendations will promote an increased quality of echocardiography and facilitate accurate comparison of studies performed either by different operators or at different departments.
Daniel X Augustine, Lindsay D Coates-Bradshaw, James Willis, Allan Harkness, Liam Ring, Julia Grapsa, Gerry Coghlan, Nikki Kaye, David Oxborough, Shaun Robinson, Julie Sandoval, Bushra S Rana, Anjana Siva, Petros Nihoyannopoulos, Luke S Howard, Kevin Fox, Sanjeev Bhattacharyya, Vishal Sharma, Richard P Steeds, Thomas Mathew and the British Society of Echocardiography Education Committee
Pulmonary hypertension is defined as a mean arterial pressure of ≥25 mmHg as confirmed on right heart catheterisation. Traditionally, the pulmonary arterial systolic pressure has been estimated on echo by utilising the simplified Bernoulli equation from the peak tricuspid regurgitant velocity and adding this to an estimate of right atrial pressure. Previous studies have demonstrated a correlation between this estimate of pulmonary arterial systolic pressure and that obtained from invasive measurement across a cohort of patients. However, for an individual patient significant overestimation and underestimation can occur and the levels of agreement between the two is poor. Recent guidance has suggested that echocardiographic assessment of pulmonary hypertension should be limited to determining the probability of pulmonary hypertension being present rather than estimating the pulmonary artery pressure. In those patients in whom the presence of pulmonary hypertension requires confirmation, this should be done with right heart catheterisation when indicated. This guideline protocol from the British Society of Echocardiography aims to outline a practical approach to assessing the probability of pulmonary hypertension using echocardiography and should be used in conjunction with the previously published minimum dataset for a standard transthoracic echocardiogram.
David Oxborough, Saqib Ghani, Allan Harkness, Guy Lloyd, William Moody, Liam Ring, Julie Sandoval, Roxy Senior, Nabeel Sheikh, Martin Stout, Victor Utomi, James Willis, Abbas Zaidi and Richard Steeds
The aim of the study is to establish the impact of 2D echocardiographic methods on absolute values for aortic root dimensions and to describe any allometric relationship to body size. We adopted a nationwide cross-sectional prospective multicentre design using images obtained from studies utilising control groups or where specific normality was being assessed. A total of 248 participants were enrolled with no history of cardiovascular disease, diabetes, hypertension or abnormal findings on echocardiography. Aortic root dimensions were measured at the annulus, the sinus of Valsalva, the sinotubular junction, the proximal ascending aorta and the aortic arch using the inner edge and leading edge methods in both diastole and systole by 2D echocardiography. All dimensions were scaled allometrically to body surface area (BSA), height and pulmonary artery diameter. For all parameters with the exception of the aortic annulus, dimensions were significantly larger in systole (P<0.05). All aortic root and arch measurements were significantly larger when measured using the leading edge method compared with the inner edge method (P<0.05). Allometric scaling provided a b exponent of BSA0.6 in order to achieve size independence. Similarly, ratio scaling to height in subjects under the age of 40 years also produced size independence. In conclusion, the largest aortic dimensions occur in systole while using the leading edge method. Reproducibility of measurement, however, is better when assessing aortic dimensions in diastole. There is an allometric relationship to BSA and, therefore, allometric scaling in the order of BSA0.6 provides a size-independent index that is not influenced by the age or gender.
David Oxborough, Daniel Augustine, Sabiha Gati, Keith George, Allan Harkness, Thomas Mathew, Michael Papadakis, Liam Ring, Shaun Robinson, Julie Sandoval, Rizwan Sarwar, Sanjay Sharma, Vishal Sharma, Nabeel Sheikh, John Somauroo, Martin Stout, James Willis and Abbas Zaidi
Sudden cardiac death (SCD) in an athlete is a rare but tragic event. In view of this, pre-participation cardiac screening is mandatory across many sporting disciplines to identify those athletes at risk. Echocardiography is a primary investigation utilized in the pre-participation setting and in 2013 the British Society of Echocardiography and Cardiac Risk in the Young produced a joint policy document providing guidance on the role of echocardiography in this setting. Recent developments in our understanding of the athlete’s heart and the application of echocardiography have prompted this 2018 update.