Timing of the left ventricular electrogram and acute hemodynamic changes during implant of cardiac resynchronization therapy devices.
OBJECTIVE
To examine the relationship between timing of the left ventricular (LV) electrogram (EGM) and its acute hemodynamic effect on instantaneous change in LV pressure (LVdP/dt(MAX)).


METHODS
In 30 patients (mean = age 67 +/- 7.9 years) who underwent implant of cardiac resynchronization therapy systems, the right ventricular (RV) lead was implanted at the RV apex (n = 23) or RV septum (n = 7). The LV lead was placed in a posterior (n = 14) or posterolateral (n = 16) coronary sinus tributary. QRS duration, interval from Q wave to intrinsic deflection of the LV EGM (Q-LV), and interval between intrinsic deflection of RV EGM and LV EGM (RV-LV interval) were measured. The measurements were correlated with the hemodynamic effects of optimized biventricular (BiV) stimulation, using the Pearson correlation coefficient.


RESULTS
The mean LVdP/dt(MAX) at baseline was 734 +/- 180 mmHg/s, and increased to 905 +/- 165 mmHg/s during simultaneous BiV pacing, and to 933 +/- 172 mmHg/s after V-V interval optimization. The Pearson correlation coefficient R between QRS duration, the Q-LV interval, and the RV-LV interval at the respective LVdP/dt(MAX) was 0.291 (P = 0.66), 0.348 (P = 0.030), and 0.340 (P = 0.033).


CONCLUSIONS
Similar significant correlations were observed between the acute hemodynamic effect of optimized BiV stimulation and the Q-LV and the RV-LV intervals. However, individual measurements showed an 80-ms cut-off for the Q-LV interval, beyond which the increase in LVdP/dt(MAX) was <10%.
van Gelder
Berry M
BM
Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands. carlgr@cze.nl
Meijer
Albert
A
Bracke
Frank A
FA
D000368:Aged; D001794:Blood Pressure; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D009202:Cardiomyopathies / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*