B-PO03-192 REDUCTION IN QRS AREA CORRELATES WITH HEMODYNAMIC RESPONSE DURING CARDIAC RESYNCHRONIZATION THERAPY - DEVICE IMPLANTATION

Abstract

Previous studies have shown that reduction in QRS area after cardiac resynchronization therapy (CRT) is associated with improved long-term clinical outcome. To investigate whether reduction in QRS area is associated with hemodynamic improvement and whether QRS area reduction could be used for CRT optimization. A total of 78 patients with an indication for CRT were prospectively included in 4 hospitals. QRS area was calculated from vectorcardiograms synthesized from 12-lead ECGs. Hemodynamic response was assessed invasively as the maximum rate of percentual left ventricular pressure (%LVdP/dtmax) rise. QRS area change was studied in relation to LV-lead position (n=26), proximal versus distal LV lead position (n=27), and VV-delay (n=25). Combining all measurements in all patients showed a significant correlation between QRS area reduction and %LVdP/dTmax increase (R=0.49, P<0.0001). Also, when one fixed routine implantation setting was used for each patient (lateral lead position, distal, AV-delay 120-150ms, VV-delay 0ms) this correlation was present (figure, panel A). In 21 patients in which at least 3 lead positions were available, there was also a significant correlation between QRS area reduction and %LVdP/dtmax increase (panel B). For VV-delay, 25 other patients as well showed a significant correlation (average R=0.53, p<0.0001). Within patients, QRS area reduction is associated with %LVdP/dtmax increase with various LV lead positions and VV-intervals. Therefore, QRS area, which is an easily obtainable and objective parameter, might be a promising tool for optimization of LV lead position and device programming in CRT.