Novel strain rate index of contractility loss caused by mechanical dyssynchrony: A predictor of response to cardiac resynchronization therapy

Hiroyuki Iwano, Satoshi Yamada, Masaya Watanabe, Hirofumi Mitsuyama, Hisao Nishino, Shinobu Yokoyama, Sanae Kaga, Mutsumi Nishida, Hisashi Yokoshiki, Hisao Onozuka, Taisei Mikami, Hiroyuki Tsutsui

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Abstract

Background: Time-delay indexes are limited in predicting the response to cardiac resynchronization therapy (CRT), partly because they do not reflect the residual left ventricular (LV) contractility. We computed a novel index of LV contractility loss due to dyssynchrony (the strain rate (SR) dispersion index: SRDI) by using the speckletracking SR and compared the efficacy of the SRDI, time-delay indexes, and strain delay index (SDI), the previously reported index of wasted energy due to dyssynchrony, for predicting the acute response to CRT. Methods and Results: Echocardiography was performed in 19 heart failure patients (LV ejection fraction (EF) 25±6%) before and 2 weeks after CRT. The standard deviation of time to peak velocity, or strain, was calculated as time-delay indexes. The SRDI was calculated as the average of segmental peak systolic SR minus global peak systolic SR. Longitudinal SDI (L-SDI), longitudinal SRDI (L-SRDI), and circumferential SRDI (C-SRDI) significantly correlated with the change in global longitudinal strain (Δglobal LSt), whereas the time-delay indexes did not. Although the time-delay indexes were comparable between responders (Δglobal LSt ≥0.3%) and nonresponders, the L-SDI, L-SRDI, and C-SRDI were greater in responders. The area under the receiver operating characteristic curve of the L-SRDI, L-SDI, and C-SRDI for predicting responders was 0.89, 0.81, and 0.78, respectively. Conclusions: The SRDI correlated fairly well with an improvement in global LV systolic function after CRT.

Original languageEnglish
Pages (from-to)2167-2175
Number of pages9
JournalCirculation Journal
Volume75
Issue number9
DOIs
Publication statusPublished - Sep 2011

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

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    Iwano, H., Yamada, S., Watanabe, M., Mitsuyama, H., Nishino, H., Yokoyama, S., Kaga, S., Nishida, M., Yokoshiki, H., Onozuka, H., Mikami, T., & Tsutsui, H. (2011). Novel strain rate index of contractility loss caused by mechanical dyssynchrony: A predictor of response to cardiac resynchronization therapy. Circulation Journal, 75(9), 2167-2175. https://doi.org/10.1253/circj.CJ-10-1099