HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH RSS TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Song, Z.-Z. Search for Related Content PubMed PubMed Citation Articles by Song, Z.-Z.

Can LV Dyssynchrony as Assessed with Phase Analysis on Gated Myocardial Perfusion SPECT Preferably Predict Response to CRT?

Zhejiang University
Hangzhou, China

TO THE EDITOR: I read with great interest the study by Henneman et al. (1) suggesting that response to cardiac resynchronization therapy (CRT) is related to the presence of left ventricular (LV) dyssynchrony as assessed by phase analysis with gated myocardial perfusion SPECT. The study confirmed that responders and nonresponders had comparable baseline characteristics, except for histogram bandwidth, which was significantly larger in responders than in nonresponders. The methods and interpretation of the results, however, raise several concerns:

It is well known that normal myocardial motion is complex, with 3 separate components: radial contraction, longitudinal shortening, and rotation. Myocardium has a transmural heterogeneity of contraction under normal conditions: Contractility decreases from subendocardium to subepicardium, and during a reduction of myocardial perfusion capable of inducing myocardial ischemia, the subendocardial layer undergoes contractility impairment even in the absence of functional impairment of the subepicardial layer (2,3). A study by Helm et al. (4) confirmed that dyssynchrony as assessed by longitudinal motion could be of a sensitivity different from that of dyssynchrony as assessed by circumferential motion, follows a time course different from that of dyssynchrony as assessed by circumferential motion, and may manifest a benefit from CRT during specific cardiac phases depending on pacing mode. In a study by Henneman et al. (1), however, a total of 90 projections was obtained over a 360° circular orbit and data were reconstructed by filtered backprojection and then reoriented to yield gated short-axis images. That is to say, LV dyssynchrony was assessed from circumferential motion. Are the sensitivity and specificity for the prediction of response to CRT by gated myocardial perfusion SPECT better if LV dyssynchrony is assessed from longitudinal motion? Are the sensitivity and specificity for the prediction of response to CRT by gated myocardial perfusion SPECT better if LV dyssynchrony is assessed from both longitudinal motion and circumferential motion?

FOOTNOTES

COPYRIGHT © 2008 by the Society of Nuclear Medicine, Inc.

References

1. Henneman MM, Chen J, Dibbets-Schneider P, et al. Can dyssynchrony as assessed with phase analysis on gated myocardial perfusion SPECT predict response to CRT? J Nucl Med. 2007;48:1104–1111.[Abstract/Free Full Text]
2. Song ZZ, Ma J. Analysis of myocardial deformation based on ultrasonic pixel tracking to determine transmurality in chronic myocardial infarction. Eur Heart J. 2007;28:1173–1174.[Free Full Text]
3. Lima JAC, Jeremy R, Guier W, et al. Accurate systolic wall thickening by nuclear magnetic resonance imaging with tissue tagging: correlation with sonomicrometers in normal and ischemic myocardium. J Am Coll Cardiol. 1993;21:1741–1751.[Abstract]
4. Helm RH, Leclercq C, Faris OP, et al. Cardiac dyssynchrony analysis using circumferential versus longitudinal strain: implications for assessing cardiac resynchronization. Circulation. 2005;111:2760–2767.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Song, Z.-Z. Search for Related Content PubMed PubMed Citation Articles by Song, Z.-Z.