Reliability of echocardiographic speckle-tracking derived bi-atrial strain assessment under different hemodynamic conditions

Abstract

The aim of this study was to assess intra- and inter-observer variability of left (LA) and right atrial (RA) strain indices obtained by two-dimensional speckle-tracking echocardiography (2D-STE) in a healthy group of individuals at low-altitude and after rapid ascent to high-altitude in order to provoke altered systemic and pulmonary hemodynamics otherwise seen in various cardiac diseases. Twenty healthy subjects underwent transthoracic echocardiography during a baseline examination at low-altitude (424 m) as well as 7, 20 and 44 h after arrival at high-altitude (4559 m). Atrial strain indices (i.e. reservoir, conduit and contractile strain) were determined off-line by two independent observers. Intra- and inter-observer reproducibility of variables was assessed by intra-class correlation coefficients (ICCs), coefficients of variation and Bland Altman plots. Heart rate, systemic blood pressure and pulmonary artery pressure increased significantly from low-altitude to the first examination at high-altitude. Intra-observer ICCs were ≥0.90 except for RA conduit strain with an ICC of 0.86. The mean intra-observer differences were small and limits of agreement of relative differences were narrow for all atrial strain parameters (<3 and <16%, respectively). Inter-observer ICCs (0.80–0.90), mean biases and limits of agreement (<4 and <20%, respectively) were greater than intra-observer results for all parameters. Intra- and inter-obserer ICCs for all atrial strain variables did not differ between low- and high-altitude. 2D-STE-derived bi-atrial strain indices have excellent intra- and moderate inter-observer reproducibility with no effect of high-altitude-induced hemodynamic changes on reliability results.

Impairment of left atrial mechanics does not contribute to the reduction in stroke volume after active ascent to 4559 m

“…Consequently, 2D‐STE‐derived atrial reservoir‐, conduit‐, and contractile‐strains were calculated as illustrated in Figure . We already demonstrated high intra‐ as well as interobserver reliability of these variables in our laboratory …”

“…We already demonstrated high intra-as well as interobserver reliability of these variables in our laboratory. 11 Increased LVEDP was defined using recommended variables and cutoffs using a multiparametric approach: (a) LAVI>34 mL/m2, (b) E/e'>14, (c) e' med <7 cm/s or e' lat <10 cm/s. Increased sPAP could not be used as an estimate for increased LVEDP as recommended at sea level because in hypoxic conditions, its increase is considered physiologic.…”

“…Still, these variables are angle‐ as well as load‐dependent and fall short of sufficiently extracting and analyzing a main contributor of diastolic LV function, that is, the left atrium (LA) which has been suggested to compensate for LV diastolic alterations under acute hypoxia . Advances in echocardiographic imaging and mainly the advent of 2D speckle tracking echocardiography (STE) myocardial strain assessment enabled a reliable and more independent insight into LA function by visualizing and calculating each of the atrial phases, that is, the reservoir, conduit, and contraction phase , separately . Furthermore, LA reservoir strain has recently been shown to decrease with increasing LVEDP and to correlate with invasively obtained LVEDP even better than established Doppler‐derived surrogates .…”

“…3 Advances in echocardiographic imaging and mainly the advent of 2D speckle tracking echocardiography (STE) myocardial strain assessment enabled a reliable and more independent insight into LA function by visualizing and calculating each of the atrial phases, that is, the reservoir, conduit, and contraction phase, separately. [9][10][11] Furthermore, LA reservoir strain has recently been shown to decrease with increasing LVEDP and to correlate with invasively obtained LVEDP even better than established Doppler-derived surrogates. 12 Subsequently, LA reservoir strain was proposed as an additional parameter in grading diastolic dysfunction.…”

Preserved right ventricular function but increased right atrial contractile demand in altitude-induced pulmonary hypertension

“…2D-Transthoracic echocardiography (TTE) enables volumetric determination of phasic RA function and can be even performed in field conditions at high altitude. Recently, the advent of 2D speckle tracking echocardiography (STE)derived strain analysis has added less angle-, load and cardiac translation-influenced information about intrinsic myocardial function and reliability of this technique has already been reported for RA analysis [9].…”