TY - JOUR
T1 - Time to onset of regional relaxation
T2 - Feasibility, variability and utility of a novel index of regional myocardial function by strain rate imaging
AU - Abraham, Theodore P.
AU - Belohlavek, Marek
AU - Thomson, Helen L.
AU - Pislaru, Cristina
AU - Khandheria, Bijoy
AU - Seward, James B.
AU - Pellikka, Patricia A.
PY - 2002/5/1
Y1 - 2002/5/1
N2 - OBJECTIVES. Time to onset of regional relaxation (TR) has been proposed as a novel index of regional myocardial function. This study sought to prospectively establish the feasibility and variability of TR in healthy volunteers (CONTROL) and to examine its utility in patients with inducible ischemia (PATIENT). BACKGROUND. Strain rate imaging (SRI) depicts myocardial deformation and enables quantitation of regional myocardial function with high temporal and spatial resolution. Thus, regional mechanical events can be accurately timed with SRI. The time point of regional transition from contraction to relaxation is altered in pathologic states. METHODS. Resting mean segmental TR was determined in 60 subjects: 20 in the CONTROL group and 40 in the PATIENT group. TR was also measured at peak dobutamine stress in the PATIENT group. An automated image analysis program determined the time point of transition from regional contraction to relaxation activity, and calculated TR, defined as the time, in milliseconds, from the electrocardiogram R-wave to this transition point. RESULTS. Automated TR measurements were feasible in more than 90% of the segments in CONTROL and PATIENT groups. Mean TR was 353 ± 24 ms and was shorter in the mid segments compared to apical and basal segments. Intra- and interobserver variability were low (6% and 9%, respectively). In the PATIENT group, the percent decrease in TR during dobutamine stress was significantly higher in normal compared to ischemic segments (30% vs. 19%, respectively, p = 0.01). A percent change >20% in TR identified patients with an ischemic response during dobutamine infusion (sensitivity 92%, specificity 75%). CONCLUSIONS. TR, a novel quantitative index of regional myocardial function, can be determined with low variability and satisfactory feasibility in routine clinical settings. Percent change in TR identifies ischemic segments during dobutamine stress echocardiography (DSE) and may allow quantitative assessment of DSE.
AB - OBJECTIVES. Time to onset of regional relaxation (TR) has been proposed as a novel index of regional myocardial function. This study sought to prospectively establish the feasibility and variability of TR in healthy volunteers (CONTROL) and to examine its utility in patients with inducible ischemia (PATIENT). BACKGROUND. Strain rate imaging (SRI) depicts myocardial deformation and enables quantitation of regional myocardial function with high temporal and spatial resolution. Thus, regional mechanical events can be accurately timed with SRI. The time point of regional transition from contraction to relaxation is altered in pathologic states. METHODS. Resting mean segmental TR was determined in 60 subjects: 20 in the CONTROL group and 40 in the PATIENT group. TR was also measured at peak dobutamine stress in the PATIENT group. An automated image analysis program determined the time point of transition from regional contraction to relaxation activity, and calculated TR, defined as the time, in milliseconds, from the electrocardiogram R-wave to this transition point. RESULTS. Automated TR measurements were feasible in more than 90% of the segments in CONTROL and PATIENT groups. Mean TR was 353 ± 24 ms and was shorter in the mid segments compared to apical and basal segments. Intra- and interobserver variability were low (6% and 9%, respectively). In the PATIENT group, the percent decrease in TR during dobutamine stress was significantly higher in normal compared to ischemic segments (30% vs. 19%, respectively, p = 0.01). A percent change >20% in TR identified patients with an ischemic response during dobutamine infusion (sensitivity 92%, specificity 75%). CONCLUSIONS. TR, a novel quantitative index of regional myocardial function, can be determined with low variability and satisfactory feasibility in routine clinical settings. Percent change in TR identifies ischemic segments during dobutamine stress echocardiography (DSE) and may allow quantitative assessment of DSE.
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U2 - 10.1016/S0735-1097(02)01768-0
DO - 10.1016/S0735-1097(02)01768-0
M3 - Article
C2 - 11985919
AN - SCOPUS:0036568918
SN - 0735-1097
VL - 39
SP - 1531
EP - 1537
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 9
ER -