Left ventricular lead position, mechanical activation, and myocardial scar in relation to left ventricular reverse remodeling and clinical outcomes after cardiac resynchronization therapy: A feature-tracking and contrast-enhanced cardiovascular magnetic resonance study.
BACKGROUND
Late mechanical activation (LMA) and viability in the left ventricular (LV) myocardium have been proposed as targets for LV pacing during cardiac resynchronization therapy (CRT).


OBJECTIVE
The purpose of this study was to determine whether an LV lead position over segments with LMA and no scar improves LV reverse remodeling (LVRR) and clinical outcomes after CRT.


METHODS
Feature-tracking and late gadolinium enhancement images were analyzed retrospectively in patients with heart failure (HF) (n = 89; mean age 66.8 ± 10.8 years; LV ejection fraction = 23.1% ± 9.9%) who underwent cardiovascular magnetic resonance (CMR) scanning before CRT implantation. Lead positions were classified as concordant (no scar and LMA [time to peak systolic circumferential strain]) or nonconcordant (scar and/or no LMA).


RESULTS
LVRR occurred in 68% and 24% of patients with concordant and nonconcordant LV lead positions, respectively (P < .001). Over a median of 4.4 years (range 0.1-8.7 years), LV lead concordance predicted cardiac mortality (adjusted odds ratio [aOR] 0.27; 95% confidence interval [CI] 0.12-0.62) and cardiac mortality or HF hospitalizations (aOR 0.26, 95% CI 0.12-0.58). "No scar" in the paced segment predicted cardiac mortality (aOR 0.24; 95% CI 0.11-0.52) and cardiac mortality or HF hospitalizations (adjusted aOR 0.24; 95% CI 0.12-0.49).


CONCLUSIONS
LV lead deployment over nonscarred LMA segments was associated with better LVRR and clinical outcomes after CRT. LVRR was primarily related to LMA, whereas events were primarily related to scar. These findings support the use of late gadolinium enhancement CMR and feature-tracking CMR in guiding LV lead deployment.
Department of Cardiology, University Hospital Birmingham, Birmingham, United Kingdom; Centre for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom.
Robin J
RJ
Taylor
Department of Cardiology, University Hospital Birmingham, Birmingham, United Kingdom; Centre for Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom.
Fraz
F
Umar
Good Hope Hospital, Sutton Coldfield, United Kingdom.
Jonathan R
JR
Panting
Bakken Research Centre, Medtronic Inc., Maastricht, The Netherlands.
Berthold
B
Stegemann
Department of Cardiology, University Hospital Birmingham, Birmingham, United Kingdom; Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, United Kingdom. Electronic address: f.leyva@aston.ac.uk.
Francisco
F
Leyva
D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods; D058409:Cardiac Resynchronization Therapy Devices; D002921:Cicatrix / Q000175:diagnosis*; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011379:Prognosis; D017755:Prosthesis Fitting / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013318:Stroke Volume; D016896:Treatment Outcome; D006113:United Kingdom; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
D003287:Contrast Media; D005682:Gadolinium
Cardiac resynchronization therapy; Cardiovascular magnetic resonance; Feature-tracking cardiovascular magnetic resonance; Heart failure; Late gadolinium enhancement