A prospective randomized evaluation of VV delay optimization in CRT-D recipients: echocardiographic observations from the RHYTHM II ICD study.
BACKGROUND
All current cardiac resynchronization therapy (CRT) devices allow the programming of the atrioventricular (AV/PV) delays and the sequential stimulation of the ventricles via the inter ventricular (VV) delay.


OBJECTIVE
This post hoc analysis of the RHYTHM II study was conducted to compare the reverse remodeling associated with VV delay optimization in patients randomly assigned to simultaneous (SIM) biventricular stimulation versus patients assigned to optimized VV delay programming (OPT) (1:3 randomization scheme).


METHODS
The analysis included 14 patients assigned to the SIM group and 34 patients to the OPT group who completed the 6-month follow-up period with paired echocardiographic recordings.


RESULTS
In both study groups, changes consistent with left ventricular (LV) remodeling were observed between baseline and 6 months, with significant improvements in LV function and decrease in LV dimensions. In the OPT group, there was also a decrease in left atrial diameter and mitral valve closure to opening time. At 6 months, the overall proportion of echocardiographic responders (> or =10% decrease in LV end-systolic volume or > or =5% absolute increase in LV ejection fraction) was similar in both groups. The optimal AV/VV delays, evaluated by maximization of LV outflow tract velocity time integral, changed over time.


CONCLUSIONS
Ventriculo-ventricular delay optimization was associated with better immediate hemodynamic function than simultaneous biventricular stimulation, though did not promote additional reverse remodeling at 6 months and did not increase the proportion of echocardiographic responders to CRT. Optimization of both the AV and VV intervals was patient-specific and optimal values changed over time.
Boriani
Giuseppe
G
Institute of Cardiology, University of Bologna, Azienda Ospedaliera S.Orsola-Malpighi, Bologna, Italy. giuseppe.boriani@unibo.it
Biffi
Mauro
M
Müller
Cord Paul
CP
Seidl
Karl-Heinz
KH
Grove
Rainer
R
Vogt
Jürgen
J
Danschel
Wilfried
W
Schuchert
Andreas
A
Deharo
Jean-Claude
JC
Becker
Thorsten
T
Boulogne
Eric
E
Trappe
Hans Joachim
HJ
D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000517:prevention & control*