Radial strain delay based on segmental timing and strain amplitude predicts left ventricular reverse remodeling and survival after cardiac resynchronization therapy.
BACKGROUND
Dyssynchrony assessment based on the timing of regional contraction is inherently independent of underlying myocardial contractility. We tested the hypothesis that patient selection for cardiac resynchronization therapy (CRT) would be enhanced using a parameter derived from the net radial strain delay (RSD) for the 12 basal and mid-left ventricular segments (calculated radial strain delay RSD [RSDc]), based on not only timing but also amplitude of segmental strain.


RESULTS
Echocardiographic data were analyzed in 240 patients with symptomatic heart failure undergoing CRT (New York Heart Association class III/IV; QRS >120 milliseconds; ejection fraction, 23±7%). RSDc was calculated as the sum of difference between peak radial strain and radial strain at aortic valve closure before CRT implantation. CRT response was defined as >15% reduction in left ventricular end-systolic volume at 6 months. In a derivation group (n=102), RSDc was higher in responders compared with nonresponders (74±39% versus 29±15%; P<0.001) and related to the change in left ventricular end-systolic volume (r=-0.53; P<0.001). RSDc >40% predicted remodeling (sensitivity, 87%; specificity, 88%). In the validation group (n=108), RSDc similarly predicted response (sensitivity, 89%; specificity, 84%). Survival at long-term follow-up was greater in patients with RSDc >40% (P<0.0001).


CONCLUSIONS
RSDc, based on both the timing and the amplitude of segmental strain, has a strong predictive value for CRT remodeling response and long-term survival.
Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK.
Anna C
AC
Kydd
Fakhar Z
FZ
Khan
Denis
D
O'Halloran
Peter J
PJ
Pugh
Munmohan S
MS
Virdee
David P
DP
Dutka
D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D020127:Recovery of Function; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling