ABSTRACT
BACKGROUND: Aging affects left atrial (LA) function, which can be assessed by two-dimensional (2D) speckle tracking echocardiography (STE). The aim of this study was to determine (1) the feasibility and accuracy of measuring LA volume with 2DSTE and (2) the effects of aging on LA function. METHODS: 2DSTE of the LA was acquired from the apical 4-chamber view (frame rate: 63 +/- 11 /sec, iE33) using prototype speckle tracking software (QLAB, Philips Medical Systems, Andover, MA) in 140 healthy volunteers (3-79 years, 74 men). LA wall was tracked on a frame-by-frame basis, and LA volume waveforms were generated. Maximum LA volume (LAVmax) and minimal LA volume (LAVmin), and the LA volume before atrial contraction (LAVpre-a) were measured. Passive emptying percent of total emptying (LA conduit function) and active emptying percent of total emptying (booster function) were calculated as ([LAVmax-LAVpre-a]/[LAVmax-LAVmin]) x 100 and ([LAVa-LAVmin]/[LAVmax-LAVmin]) x 100. RESULTS: Adequate LA volume waveforms were obtained in all subjects. A good correlation was obtained between speckle tracking-derived LA volume measurements and manually traced LA volume measurements of the identical 2D image (LAVmax: r = 0.93, P <.001, LAVmin: r = 0.88, P <.001, LAVpre-a: r = 0.92, P <.001). Passive and active emptying indices had a significant age dependency (r = 0.80, P <.001). Overall, passive emptying accounted for 67% of the total LA emptying ranging from 83% in the youngest to 42% in the oldest decade. CONCLUSION: Aging significantly affects LA conduit and booster function. 2DSTE can effectively and easily measure LA volume and has a potential for the noninvasive assessment of LA function.
Subject(s)
Aging/physiology , Algorithms , Atrial Function, Left/physiology , Echocardiography/methods , Heart Atria/diagnostic imaging , Image Interpretation, Computer-Assisted/methods , Pattern Recognition, Automated/methods , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Image Enhancement/methods , Male , Reproducibility of Results , Sensitivity and Specificity , Young AdultABSTRACT
AIMS: Two-dimensional speckle tracking echocardiography (2DSTE) allows measurements of left ventricular (LV) volumes and LV ejection fraction (LVEF) without manual tracings. Our goal was to determine the accuracy of 2DSTE against real-time 3D echocardiography (RT3DE) and against cardiac magnetic resonance (CMR) imaging. METHODS AND RESULTS: In Protocol 1, 2DSTE data in the apical four-chamber view (iE33, Philips) and CMR images (Philips 1.5T scanner) were obtained in 20 patients. The 2DSTE data were analysed using custom software, which automatically performed speckle tracking analysis throughout the cardiac cycle. LV volume curves were generated using the single-plane Simpson's formula, from which end-diastolic volume (LVEDV), end-systolic volume (LVESV), and LVEF were calculated. In Protocol 2, the 2DSTE and RT3DE data were acquired in 181 subjects. RT3DE data sets were acquired, and LV volumes and LVEF were measured using QLab software (Philips). In Protocol 1, excellent correlations were noted between the methods for LVEDV (r=0.95), ESV (r=0.95), and LVEF (r=0.88). In Protocol 2, LV volume waveforms suitable for analysis were obtained from 2DSTE images in all subjects. The time required for analysis was <2 min per patient. Excellent correlations were noted between the methods for LVEDV (r=0.95), ESV (r=0.97), and LVEF (r=0.92). However, 2DSTE significantly underestimated LVEDV, resulting in a mean of 8% underestimation in LVEF. Intra- and inter-observer variabilities of 2DSTE were 7 and 9% in LV volume and 6 and 8% in LVEF, respectively. CONCLUSIONS: Two-dimensional speckle tracking echocardiography measurements resulted in a small but significant underestimation of LVEDV and EF compared with RT3DE. However, the accuracy, low intra- and inter-observer variabilities and speed of analysis make 2DSTE a potentially useful modality for LV functional assessment in the routine clinical setting.
