Reduction in QRS area correlates with hemodynamic response during CRT-device implantation

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Previous studies have shown that reduction in QRS area after cardiac resynchronization therapy (CRT) is associated with improved long-term clinical outcome. Purpose To investigate whether reduction in QRS area is associated with hemodynamic improvement and whether QRS area reduction could be used for CRT optimization, with respect to LV lead position and device programming in individual patients. Methods A total of 78 patients with indication for CRT were prospectively included in 4 hospitals. QRS area was calculated from vectorcardiograms that were synthesized from 12-lead ECG’s. Acute hemodynamic response was assessed invasively as the maximum rate of percentual left ventricular (LV) pressure (%LVdP/dtmax) rise. QRS area reduction was studied in relation to LV-lead position (n = 26), proximal versus distal LV lead position (n = 27), and VV-delay (n = 25). Results 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 (R = 0.45, p < 0.0001, 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 (average R = 0.69, p < 0.0001, panel B). For VV-delay, 25 other patients as well showed a significant correlation (average R = 0.53, p < 0.0001). Conclusion 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. Abstract Figure.