European Heart Journal Advance Access originally published online on January 29, 2008
European Heart Journal 2008 29(6):825-826; doi:10.1093/eurheartj/ehn006
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Reduced and delayed untwisting of the left ventricle in patients with hypertension and left ventricular hypertrophy: a study using two-dimensional speckle tracking imaging: reply
Second Department of Internal Medicine
University of Occupational and Environmental Health
School of Medicine
1-1 Iseigaoka, Yahatanishi-ku
Kitakyushu 807-8555
Japan
Tel: +81 93 603 1611
Fax: +81 93 691 6913
Email: takeuchi{at}med.uoeh-u.ac.jp
Noninvasive Cardiac Imaging Laboratory
Section of Cardiology
Department of Medicine
University of Chicago Medical Center
Chicago, IL
USA
We thank Dr Burns for the interest in our work1 and on the appropriate comments about the methodological issues in the use of 2D speckle tracking imaging (STI) to assess left ventricular (LV) twist, i.e. interpolation of STI data and measurement of untwisting.2
Left ventricular twist has been defined as apical rotation–basal rotation.1,3,4 If time-domain analysis is required, bottom line is that frame rate and heart rate in both views should be the same. To accomplish this, we always acquired both level of images with the same depth and the sector size to ensure frame rate is identical. In addition, we are very keen about the heart rate when we acquired images. If the differences of heart rate from both level were than >5 b.p.m., we tried to obtain another image to reduce the difference in heart rate. Because held respiration during image acquisition often makes heart rate slow, it is not always easy to obtain the same heart rate in both images. However, minor differences in heart rate between the two images produce only two or three frames more in one view. This does not tremendously affect the calculation of LV twist, because the number of frames during systole is usually the same, and only differences would be occurred in the later part of diastole, which does not affect our calculation of untwisting and untwisting rate. Although Dr Burns claimed cubic spline interpolation of the temporally normalized apical and basal rotation data might overcome this issue, careful acquisition of images could alleviate this problem.
Left ventricular untwisting, which is thought to contribute diastolic LV suction, is predominantly observed during isovolumic relaxation period in normal heart.5 Thus, untwisting should be evaluated from aortic valve closure to early diastolic phase. A negative value of untwisting at t = 5% in our study (Table 3) reflects the presence and severity of delayed onset of untwisting after the aortic valve closure, and it also suggests that LV still continuously twists for the first 5% of diastolic period, resulting in the adverse impact on LV early diastolic filling.
Finally, we apologize the unit of untwisting is not degree/ms but %/ms as the authors suggested. Although 2D STI assessment of LV untwisting is a promising method for providing new indices in the evaluation of early diastolic function, further technological refinements and more user-friendly software is mandatory to expand this technology in the daily clinical practice.
References
- Takeuchi M, Borden W, Nakai H, Nishikage T, Kokumai M, Nagakura T, Otani S, Lang R. Reduced and delayed untwisting of the left ventricle in patients with hypertension and left ventricular hypertrophy: a study using two-dimensional speckle tracking imaging. Eur Heart J (2007) 28:2756–2762.
[Abstract/Free Full Text] - Burns A, La Gerche A, Prior D, MacIsaac A. Reduced and delayed untwisting of the left ventricle in patients with hypertension and left ventricular hypertrophy: a study using two-dimensional speckle tracking imaging. Eur Heart J. (in press).
- Nakai H, Takeuchi M, Nishikage T, Kokumai M, Otani S, Lang R. Effect of aging on twist-displacement loop by 2-dimensional speckle tracking imaging. J Am Soc Echocardiogr (2006) 19:880–885.[CrossRef][Web of Science][Medline]
- Takeuchi M, Nishikage T, Nakai H, Kokumai M, Otani S, Lang R. The assessment of left ventricular twist in anterior wall myocardial infarction using two-dimensional speckle tracking imaging. J Am Soc Echocardiogr (2007) 20:36–44.[CrossRef][Web of Science][Medline]
- Dong S, Hees P, Siu C, Weiss J, Shapiro E. MRI assessment of LV relaxation by untwisting rate: a new isovolumic phase measure of tau. Am J Physiol Heart Circ Physiol (2001) 281:H2002–H2009.
[Abstract/Free Full Text]
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