Background: The sequence of impairment of long and short axis function in the failing heart was not clearly investigated. We investigated each axis function by analyzing longitudinal (LS) and radial strain (RS) of LV with fluctuating systolic dysfunction.
Methods: Twenty five patients (M:F=11:14, mean age=55.0±16.3) with fluctuating LV systolic function (ΔLVEF >5%) were enrolled and sixty eight tests of 2-D speckle tracking echocardiography (2DSTE) were analyzed for myocardial strain. Exclusion criteria covered regional wall motion abnormality of LV. LS from apical four and two chamber views and RS from mid-LV short axis view were taken for the study.
Result: The median follow-up duration was 210 days. When individual tests were rearranged in order of LVEF, LS decreased more rapidly over LVEF>40% (ΔLS/ΔLVEF= -0.38±0.9 with LVEF>40%, ΔLS/ΔLVEF= -0.10±0.9 with LVEF<40%, p=0.021)(Fig.A). The rate of decrease in RS was not different irrespective of LVEF. When sixty eight echocardiographies were divided into quintiles (Q1 with LVEF ≥ 60%; Q2 with 50~60%; Q3 with 40~50%; Q4 with 30~40%; Q5<30%), longitudinal strain was continuously decreased from Q1 to Q3 (p=0.000, between Q1/ Q2, p=0.000 between Q2/ Q3), while radial strain was decreased from Q3 to Q5 (p=0.000, between Q3/ Q4, p=0.014 between Q4/ Q5) (Fig.B).
Conclusions: Longitudinal strain mainly decreased from mild to moderate grade of LV systolic dysfunction, while radial strain was preserved during mild grade and decreased from moderate to severe grade. Further investigation with more patients is required to confirm this finding.
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