Strain and strain rate parametric imaging. A new method for post processing to 3-/4-dimensional images from three standard apical planes. Preliminary data on feasibility, artefact and regional dyssynergy visualisation

BACKGROUND: We describe a method for 3-/4D reconstruction of tissue Doppler data from three standard apical planes, post processing to derived data of strain rate / strain and parametric colour imaging of the data. The data can be displayed as M-mode arrays from all six walls, Bull's eye projection and a 3D surface figure that can be scrolled and rotated. Numerical data and waveforms can be re-extracted. METHODS: Feasibility was tested by Strain Rate Imaging in 6 normal subjects and 6 patients with acute myocardial infarction. Reverberation artefacts and dyssynergy was identified by colour images. End systolic strain, peak systolic and mid systolic strain rate were measured. RESULTS: Infarcts were visualised in all patients by colour imaging of mid systolic strain rate, end systolic strain and post systolic shortening by strain rate. Reverberation artefacts were visible in 3 of 6 normals, and 2 of 6 patients, and were identified both on bull's eye and M-mode display, but influenced quantitative measurement. Peak systolic strain rate was in controls minimum -1.11, maximum -0.89 and in patients minimum -1.66, maximum 0.02 (p = 0.04). Mid systolic strain rate and end systolic strain did not separate the groups significantly. CONCLUSION: 3-/4D reconstruction and colour display is feasible, allowing quick visual identification of infarcts and artefacts, as well as extension of area of post systolic shortening. Strain rate is better suited to colour parametric display than strain

Moderate continuous or high intensity interval exercise in heart failure with reduced ejection fraction : Differences between ischemic and non-ischemic etiology

publishedVersio

Baseline and exercise predictors of VO2peak in systolic heart failure patients : Results from SMARTEX-HF

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by American College of Sports Medicine in Medicine & Science in Sports & Exercise on 04/11/2019.Available online: https://journals.lww.com/acsm-msse/FullText/2020/04000/Baseline_and_Exercise_Predictors_of_V_O2peak_in.5.aspxacceptedVersio

Flow propagation velocity is not a simple index of diastolic function in early filling. A comparative study of early diastolic strain rate and strain rate propagation, flow and flow propagation in normal and reduced diastolic function

BACKGROUND: Strain Rate Imaging shows the filling phases of the left ventricle to consist of a wave of myocardial stretching, propagating from base to apex. The propagation velocity of the strain rate wave is reduced in delayed relaxation. This study examined the relation between the propagation velocity of strain rate in the myocardium and the propagation velocity of flow during early filling. METHODS: 12 normal subjects and 13 patients with treated hypertension and normal systolic function were studied. Patients and controls differed significantly in diastolic early mitral flow measurements, peak early diastolic tissue velocity and peak early diastolic strain rate, showing delayed relaxation in the patient group. There were no significant differences in EF or diastolic diameter. RESULTS: Strain rate propagation velocity was reduced in the patient group while flow propagation velocity was increased. There was a negative correlation (R = -0.57) between strain rate propagation and deceleration time of the mitral flow E-wave (R = -0.51) and between strain rate propagation and flow propagation velocity and there was a positive correlation (R = 0.67) between the ratio between peak mitral flow velocity / strain rate propagation velocity and flow propagation velocity. CONCLUSION: The present study shows strain rate propagation to be a measure of filling time, but flow propagation to be a function of both flow velocity and strain rate propagation. Thus flow propagation is not a simple index of diastolic function in delayed relaxation

Myocardial performance assessment in neonates by one-segment strain and strain rate analysis by tissue Doppler - a quality improvement cohort study

Objectives To investigate one-segment strain and strain rate indices as measures of myocardial performance in asphyxiated term neonates. Design Quality improvement cohort study. Setting Newborns admitted to a neonatal intensive care unit at a Norwegian University Hospital for perinatal asphyxia and non-asphyxiated newborn recruited from the maternity ward at the same hospital. Participants Twenty asphyxiated and 48 non-asphyxiated term neonates. Primary outcome measure Strain and strain rate indices and repeatability measures. One-segment longitudinal strain and strain rate by tissue Doppler were assessed on days 1, 2 and 3 of life in nine heart walls. Repeatability was compared against measurements from two-segment analyses previously performed in the same images. Results The 95% limits of agreement were significantly better for the one-segment than two-segment repeatability analyses, the inter-rater peak systolic strain (PSS) was (−3.1, 3.3) vs (−11.4, 18.3)%, the inter-rater peak systolic strain rate (PSSR) was (−0.38, 0.40) vs (−0.79, 1.15)/s, the intra-rater PSS was (−2.5, 2.6) vs (−8.0, 9.8)% and the intra-rater PSSR was (−0.23, 0.25) vs (−0.75, 0.80)/s (p0.05). Conclusions One-segment strain and strain rate assessed the reduced myocardial performance in asphyxiated neonates with significantly improved reproducibility as compared with two-segment analysis and was therefore more feasible than two-segment analyses for assessment of myocardial performance after perinatal asphyxia

Physiological significance of pre- and post-ejection left ventricular tissue velocities and relations to mitral and aortic valve closures

Background: Tissue Doppler shows short duration velocity spikes during pre- and post-ejection (protodiastole). They have been assumed to be isovolumic contraction and relaxation movements, but this is not in accordance with newer studies. Methods: We examined 22 healthy volunteers. Valve closures and openings were determined from spectral Doppler from LVOT and mitral inflow and transferred to colour tissue Doppler recordings for comparison with tissue velocities, colour M-mode and strain rate (SR). Results: Pre-ejection positive velocity spikes were simultaneous in both walls, starting ca. 24.8 ± 10.1 ms after start QRS, duration 51.5 ± 10.8 ms, ending 10.2 ± 11.5 ms after mitral valve closure (MVC) (p < 0.001). There were corresponding colour tracings and negative strain rate. Protodiastolic lengthening was predominant in the septum. Negative velocity spikes had a duration of 35.5 ± 10.7 ms, ending 9.5 ± 14.7 ms after aortic valve closure (AVC, p < 0.001) in septum. During isovolumic relaxation, strain rate showed apical lengthening (Peak SR-0.72 ± 0.50 s-1 ) and basal shortening (Peak SR 0.44 ± 0.63 s-1 ). Conclusion: Electromechanical activation of the LV is simultaneous in septum and lateral wall, occurs before MVC, is terminated by MVC itself and is thus not isovolumic. Protodiastole is a short event of lengthening, predominantly in the septum. It may be the mechanism for valve closure and ends by AVC itself. Isovolumic relaxation occurs after this velocity spike, and is characterized by elongation of the apex, shortening of the base, thus showing a volume shift from base towards apex

Left ventricular global strains by linear measurements in three dimensions: interrelations and relations to age, gender and body size in the HUNT Study

Strain is a relative deformation and has three dimensions, in the left ventricle (LV) usually longitudinal (εL), transmural (εT) and circumferential (εC) strain. All three components can be measured generically by the basic systolic and diastolic dimension measures of LV wall length, wall thickness and diameter. In this observational study we aimed to study the relations of normal generic strains to age, body size and gender, as well as the interrelations between the three strain components. Generic strains derived from dimension measures by longitudinal and cross-sectional M-mode in all three dimensions were measured in 1266 individuals without heart disease from the Nord-Trøndelag Health Study. The mean εL was −16.3%, εC was −22.7% and εT was 56.5%. Normal values by age and gender are provided. There was a gradient of εC from the endocardial, via the midwall to the external level, lowest at the external. All strains decreased in absolute values by increasing body surface area (BSA) and age, relations were strongest for εL. Gender differences were mainly a function of BSA differences. The three strain components were strongly interrelated through myocardial incompressibility. Global systolic strain is the total deformation of the myocardium; the three strain components are the spatial coordinates of this deformation, irrespective of the technology used for measurement. Normal values are method-dependent and not normative across methods. Interrelation of strains indicates a high degree of myocardial incompressibility and that longitudinal strain carries most of the total information

Over all variability of mitral annular plane peak systolic velocity and peak global longitudinal strain rate in relation to age, body size, and sex: The HUNT Study

BACKGROUND: Left ventricular (LV) systolic global function can be assessed by peak annular systolic velocity S'. Global longitudinal strain rate (GLSR) is relative LV shortening rate, equivalent to normalizing S' for LV length (S'n ). It has previously been shown that mitral annular plane systolic excursion (MAPSE) and global longitudinal strain (GLS) have similar biological variability, but GLS normalizes for one dimension only, inducing a systematic error, increasing body size dependence. The objective of this study was to compare S' with GLSR in the same way, comparing biological variability and body size dependence. METHODS AND RESULTS: A total of 1266 subjects from the third wave of Nord-Trøndelag Health Study (HUNT), without evidence of heart disease, were examined. Strain rate, S' and wall lengths were measured in the four walls of the two- and four-chamber views. Mean S' was 8.4 (1.4) cm/s, (S'n ) was 0.7 (0.14)s-1 and GLSR 1.02 (0.14)s-1 . All measures declined with age. Normalization of mitral annular velocities for LV length, or the use of GLSR, did not reduce overall biological variability compared with S'. S' did show a weak, positive correlation to BSA, while S'n and GLSR a slightly stronger, negative correlation to BSA. CONCLUSIONS: S', S'n , and GLSR have similar biological variability, which is mainly due to age, not body size variation. Normalizing S' for LV length (as in Sn or GLSR) reverses correlation with BSA inducing a systematic error, due to the one-dimensional normalization for one dimension only