Advantage of optimizing V-V timing in cardiac resynchronization therapy devices.
BACKGROUND
There is little consensus as to the benefits of interventricular (V-V) timing optimization in cardiac resynchronization therapy (CRT). A variety of parameters are currently used to optimize device timing. This study was designed to investigate the potential advantage of using 3D ejection fraction (EF) and aortic velocity-time integral (VTI) as measures of global left ventricular (LV) function to optimize ventricular activation in CRT devices.


METHODS
Seventy-four patients seen in the Optimization Clinic with adequate echocardiographic images were included. Three aortic VTI and two 3D EF values were recorded at five V-V settings and the average value used. Aortic VTI and 3D EF were classified as the best, worst, and simultaneous setting values. Data were analyzed using a two-tailed paired t-test.


RESULTS
Comparing the best to worst V-V timing settings, VTI improved by 4.7 ± 7.5 cm (P < 0.0001) and 3D EF by 9.9%± 5.7% (P < 0.0001). Comparing the simultaneous setting to the best V-V timing setting, VTI improved by 2.4 ± 2.1 cm (P < 0.0001) and 3D EF by 3.8%± 4.9% (P < 0.0001). Aortic VTI improved in 85% of patients and 3D EF improved in 72%. However, only 26% of the patients had the same optimal setting using aortic VTI and 3D EF yielding an r(2) value of 0.003.


CONCLUSIONS
Individualized echocardiographic V-V optimization of CRT devices improves global LV function as measured by aortic VTI and 3D EF. Substantial differences in function were seen over an 80-ms range of V-V timing and optimization resulted in improved LV function in the majority of patients.
Duvall
W Lane
WL
Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
Hansalia
Riple
R
Wijetunga
Melanie N
MN
Buckley
Samantha
S
Fischer
Avi
A
D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D058409:Cardiac Resynchronization Therapy Devices; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013318:Stroke Volume; D016896:Treatment Outcome; D014463:Ultrasonography