Skip to main content

Paced segment characteristics predict clinical response to cardiac resynchronization therapy: results from the multimodality imaging assessment of pacing intervention in heart failure (MAPIT-HF) study

Introduction

Cardiac Resynchronization Therapy (CRT) has been shown to improve quality of life and decrease mortality in heart failure patients. However, up to 40% of patients fail to respond to this therapy. Validation of a response prediction model that incorporates both myocardial scar and dyssynchrony of the paced myocardial segments would allow for a targeted approach to CRT lead delivery.

Methods

Patients planned for CRT under standard indications were prospectively enrolled. Serial short-axis tagged cine and delayed enhancement MRI was performed using standard imaging protocols. Echocardiography and gated CT Angiography (CTA) were performed at baseline and 3 months post-implantation. The repeat CTA was performed for accurate lead tip localization to a 16-segment model. Dyssynchrony was measured for each segment (time to maximal radial strain, Trs) from serial short-axis tagged MRI and expressed in milliseconds from onset of pulse trigger (InTag, OsirX). A segmental scar score was then assigned using a blinded visual interpretation (score 0 to 4). The number of response prediction rules met was determined for each patient as follows: 1) LV lead tip placed on a dyssynchronous segment (Trs > 130msec), 2) LV lead tip placed on a viable segment (scar score <2), 3) RV lead tip placed on a viable segment (scar score <2). Clinical response to CRT, defined as a >=15% reduction in LVESV by echocardiography, was correlated to the number of prediction rules met.

Results

Forty consecutive patients were enrolled with a mean age and ejection fraction of 67.0 ± 8.6 years and 25.6 ± 6.6%, respectively. Twenty four patients (60%) met clinical response criteria with a mean reduction in LVESV of 20.5 ± 16.5% compared to a rise of 1.4 ± 6.3% in non-responders (p<0.001). A strong correlation was seen between the number of prediction rules met and clinical response to CRT. In patients with 3, 2, 1 and 0 prediction rules met, the response rates were 100%, 92%, 58% and 40%, respectively (p<0.001). A strong correlation was also seen between the number of prediction rules and the mean reduction in LVESV [28%, 14% and 5% reduction in those with 3, 2 and 1 rules met, respectively (p=0.002)].

Conclusions

Dyssynchrony and scar characteristics of the paced myocardial segments are strongly correlated with clinical response to CRT. A simple 3-point prediction model incorporating these variables appears to be highly predictive of response, and may be valuable for the selection of optimal pacing targets for CRT.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Jorge A Wong.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and Permissions

About this article

Cite this article

Wong, J.A., Scholl, D., Yee, R. et al. Paced segment characteristics predict clinical response to cardiac resynchronization therapy: results from the multimodality imaging assessment of pacing intervention in heart failure (MAPIT-HF) study. J Cardiovasc Magn Reson 13, O50 (2011). https://doi.org/10.1186/1532-429X-13-S1-O50

Download citation

Keywords

  • Cardiac Resynchronization Therapy
  • Prediction Rule
  • Myocardial Segment
  • Response Prediction
  • Viable Segment