Author + information
- Received March 27, 2008
- Revision received April 21, 2008
- Accepted April 28, 2008
- Published online September 1, 2008.
- Kenneth C. Bilchick, MD, FACC⁎,
- Veronica Dimaano, MD⁎,
- Katherine C. Wu, MD⁎,
- Robert H. Helm, MD⁎,
- Robert G. Weiss, MD⁎,
- Joao A. Lima, MD⁎,
- Ronald D. Berger, MD, PhD⁎,
- Gordon F. Tomaselli, MD, FAHA, FACC, FHRS⁎,
- David A. Bluemke, MD, PhD, FAHA§,
- Henry R. Halperin, MD, FAHA⁎,†,§,
- Theodore Abraham, MBBS, MD⁎,
- David A. Kass, MD, FAHA⁎,†,‡ and
- Albert C. Lardo, PhD, FACC, FAHA⁎,†,‡,⁎ ()
Reprint requests and correspondence:
Dr. Albert C. Lardo, Johns Hopkins School of Medicine, Image Guided Cardiotherapy Laboratory, Division of Cardiology, 720 Rutland Avenue, 1042 Ross Building, Baltimore, Maryland 21205
Objectives We tested a circumferential mechanical dyssynchrony index (circumferential uniformity ratio estimate [CURE]; 0 to 1, 1 = synchrony) derived from magnetic resonance-myocardial tagging (MR-MT) for predicting clinical function class improvement following cardiac resynchronization therapy (CRT).
Background There remains a significant nonresponse rate to CRT. MR-MT provides high quality mechanical activation data throughout the heart, and delayed enhancement cardiac magnetic resonance (DE-CMR) offers precise characterization of myocardial scar.
Methods MR-MT was performed in 2 cohorts of heart failure patients with: 1) a CRT heart failure cohort (n = 20; left ventricular ejection fraction of 0.23 ± 0.057) to evaluate the role of MR-MT and DE-CMR prior to CRT; and 2) a multimodality cohort (n = 27; ejection fraction of 0.20 ± 0.066) to compare MR-MT and tissue Doppler imaging septal-lateral delay for assessment of mechanical dyssynchrony. MR-MT was also performed in 9 healthy control subjects.
Results MR-MT showed that control subjects had highly synchronous contraction (CURE 0.96 ± 0.01), but tissue Doppler imaging indicated dyssynchrony in 44%. Using a cutoff of <0.75 for CURE based on receiver-operator characteristic analysis (area under the curve: 0.889), 56% of patients tested positive for mechanical dyssynchrony, and the MR-MT CURE predicted improved function class with 90% accuracy (positive and predictive values: 87%, 100%); adding DE-CMR (% total scar <15%) data improved accuracy further to 95% (positive and negative predictive values: 93%, 100%). The correlation between CURE and QRS duration was modest in all cardiomyopathy subjects (r = 0.58, p < 0.001). The multimodality cohort showed a 30% discordance rate between CURE and tissue Doppler imaging septal-lateral delay.
Conclusions The MR-MT assessment of circumferential mechanical dyssynchrony predicts improvement in function class after CRT. The addition of scar imaging by DE-CMR further improves this predictive value.
Dr. Bilchick recently moved to the University of Virginia, Charlottesville, Virginia. This work was supported by the Donald W. Reynolds Foundation, NIH Grant PO1 HL077180 (to Drs. Tomaselli, Kass, and Lardo), Guidant/Boston Scientific (to Dr. Lardo), and T32 HL07227 (to Dr. Helm). Funding for this study was provided in part by Guidant/Boston Scientific. Drs. Lardo, Kass, Halperin, and Berger are paid consultants for Guidant/Boston Scientific. These relationships are managed by the Johns Hopkins University's Committee on Conflict of Interest.
- Received March 27, 2008.
- Revision received April 21, 2008.
- Accepted April 28, 2008.
- American College of Cardiology Foundation