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Helen L Thomson

Publications and source records attributed to Helen L Thomson.

3 recordsLinked to original sources
PubMed2005

Analysis of the interaction between segmental relaxation patterns and global diastolic function by strain echocardiography.

BACKGROUND: Strain echocardiography can depict segmental mechanical activity with high temporal and spatial accuracy, and may allow assessment of segmental relaxation not possible with conventional echocardiography. METHODS: Conventional and strain echocardiography were performed in healthy volunteers (young [group 1] and old [group 2]) and patients with normal 2-dimensional and stress echocardiography, with either normal global diastolic function (group 3a) or grade I or II global diastolic dysfunction (DD) (group 3b). Standard echocardiography criteria were used to define global DD. Early to late diastolic strain rate ratio less than 1.1 was defined as altered segmental relaxation. RESULTS: All participants had normal wall motion and ejection fraction. Participants of group 1 had normal segmental and global diastolic function. Participants of groups 2 and 3a demonstrated a wide range of altered segmental relaxation in the absence of global DD. All patients of group 3b had 12 or more segments with altered relaxation and global DD. Age and hypertension were associated with a larger number of altered segments, a lower mean early to late diastolic strain rate ratio, and global DD. CONCLUSIONS: A wide range of altered segmental relaxation can exist in the absence of global DD. Age and hypertension are associated with altered segmental relaxation and global DD. Assessment of segmental relaxation may be beneficial in the elderly and patients with hypertension.

Adult↗
PubMed2002

Time to onset of regional relaxation: feasibility, variability and utility of a novel index of regional myocardial function by strain rate imaging.

OBJECTIVES: Time to onset of regional relaxation (T(R)) has been proposed as a novel index of regional myocardial function. This study sought to prospectively establish the feasibility and variability of T(R) 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 T(R) was determined in 60 subjects: 20 in the CONTROL group and 40 in the PATIENT group. T(R) 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 T(R), defined as the time, in milliseconds, from the electrocardiogram R-wave to this transition point. RESULTS: Automated T(R) measurements were feasible in more than 90% of the segments in CONTROL and PATIENT groups. Mean T(R) 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 T(R) during dobutamine stress was significantly higher in normal compared to ischemic segments (30% vs. 19%, respectively, p = 0.01). A percent change >20% in T(R) identified patients with an ischemic response during dobutamine infusion (sensitivity 92%, specificity 75%). CONCLUSIONS: T(R), a novel quantitative index of regional myocardial function, can be determined with low variability and satisfactory feasibility in routine clinical settings. Percent change in T(R) identifies ischemic segments during dobutamine stress echocardiography (DSE) and may allow quantitative assessment of DSE.

Adult↗