Shortening of paced QRS duration after electrocardiographic optimization of left ventricular pacing vector in patients treated with Cardiac Resynchronization Therapy

Abstract

BackgroundChoice of left ventricular pacing vector (LVPV) affects the QRS-duration (QRSd) in patients with Cardiac Resynchronization Therapy (CRT). It is not known whether testing all LVPVs reduces QRSd compared to device-based “standard-programming”. MethodsIn patients implanted with CRT several ECGs were recorded for each usable LVPV (no phrenic nerve stimulation and threshold <3.5 V) and during “standard-programming” after device-based optimization of AV/VV delays. Results22 consecutive patients were included. Average QRSd reduction after CRT + “standard-programming” was 27.3 ± 22 ms. Additional QRSd-reduction was possible in 4 patients by changing the LVPV, and in 5 other patients after optimization of AV- and VV delays without changing LVPV. ConclusionsShortening of QRSd compared to “standard-programming” was possible approximately 40% of these patients treated with CRT by testing all LVPVs and re-optimizing AV/VV delays during follow-up. Studies of clinical effects are needed.