Optimal atrioventricular delay in CRT patients can be approximated using surface electrocardiography and device electrograms.
Electrocardiographic AV Delay Adjustment.


BACKGROUND
Optimization of the atrioventricular (AV) delay (AVD) may result in an improvement in cardiac resynchronization therapy (CRT) outcome. Previous studies have shown positive correlation between interatrial conduction time measured invasively during the implant procedure and optimal AVD determined postimplant using Doppler echocardiography. We hypothesized that the optimal AVD can be predicted noninvasively from surface electrocardiogram (ECG).


METHODS
The optimal sensed (SAV) and paced (PAV) AVDs were determined for CRT patients (n = 63) by programming different AVDs (in 20 ms steps, in random sequence) and evaluating Doppler images of the mitral flow (iterative method). The time intervals between atrial sensing (As) and pacing (Ap) to the end of the P-wave (Pend) and to the right ventricular sensing (RVs) were measured from 5 ECG leads (limb, V1, and V3) and device telemetry during sinus rhythm and atrial pacing.


RESULTS
Optimal SAV was 120 ± 30 ms and correlated with As-Pend (R = 0.69, P < 0.0001) and As-RVs (R = 0.45, P = 0.0003). Optimal PAV was 172 ± 38 ms and correlated with Ap-Pend (R = 0.65, P < 0.0001) and Ap-RVs (R = 0.60, P < 0.0001). Regression analysis suggested a simple method of AVD adjustment by pacing the ventricles 40 ms after the end of the sensed P-wave or 30 ms after the end of the paced P-wave but not at the expense of biventricular capture. Such a method would have resulted in significantly lower deviation from echo-optimal AVDs compared with programming fixed values.


CONCLUSIONS
A simple method of providing 30-40 ms separation between the end of the P-wave and ventricular pacing pulse can be used to approximate echocardiographically optimal AV delays.
Centennial Heart Cardiovascular Associates, Nashville, Tennessee, USA.
R Christopher
RC
Jones
Tom
T
Svinarich
Andrew
A
Rubin
Vadim
V
Levin
Robert
R
Phang
Jaime
J
Murillo
Aleksandre
A
Sambelashvili
D018780:Body Surface Potential Mapping / Q000379:methods*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome