Right ventricular contractility as a measure of optimal interventricular pacing setting in cardiac resynchronization therapy.
OBJECTIVE
The aim of the present study was to assess whether right ventricular (RV) contractility can be used for optimization of the interventricular (VV) interval and to study the acute hemodynamic effect of different VV intervals on right and left ventricular (LV) contractility in patients referred for cardiac resynchronization therapy (CRT).


RESULTS
Intracardiac LV and RV dP/dt were measured with a 0.014-in. sensor-tipped pressure guidewire during pacing at nine different VV intervals ranging from +80 ms (LV pre-excitation) to -80 ms (RV pre-excitation) in 26 patients who received a biventricular pacemaker. No correlation was found between the optimal VV intervals identified by maximum LV dP/dt and RV dP/dt, which were identical in only seven cases (27%). Only when testing slightly broader intervals (+/-20 ms) was there a statistically significant correlation (P= 0.037) between the optimized VV intervals. In the majority of patients (58%) either LV or RV pre-excitation was superior to simultaneous pacing according to LV dP/dt(max) measurements.


CONCLUSIONS
RV dP/dt(max) failed to identify the optimal VV interval when compared with LV dP/dt(max) and can therefore not be recommended for VV optimization in CRT patients.
Sciaraffia
Elena
E
Department of Cardiology, Uppsala University Hospital, S-751 85 Uppsala, Sweden. elena.sciaraffia@akademiska.se
Malmborg
Helena
H
Lönnerholm
Stefan
S
Blomström
Per
P
Blomström Lundqvist
Carina
C
D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006801:Humans; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D018497:Ventricular Dysfunction, Right / Q000150:complications* / Q000175:diagnosis*