Right carotid Doppler signal to optimize cardiac resynchronisation therapy implant procedure

Abstract

Left-ventricular pre-ejection time (LVPET) varies according to cardiac homodynamic performance and is a predictive factor of clinical response to cardiac resynchronisation therapy (CRT) when > 140 ms. LVPET could then play a role in optimizing CRT implantation. However, its measurement requires the use of echocardiography in apical view, which is hardly compatible with device implantation environment. The objective of this study was to determine the relationship between LVPET measured conventionally from an apical view and time from beginning of QRS to beginning of Doppler signal flow (QWT) recorded at the right carotid. LVPET was measured using M5S probe and pulsed Doppler on aortic flow in apical view using echocardiography. QWT was measured using a Pedoff probe at the right carotid. These measurements were performed during spontaneous rhythm in all patients whenever possible and during left ventricular pacing, right ventricular pacing, and bi-ventricular pacing in CRT patients. LVPET and QWT were measured in 53 patients among whom 11 had a CRT device. A linear relationship between LVPET and QWT was observed (R Pearson coefficient = 0.926, P < 0.001) (Fig. 1). The intra-observatory and inter-observatory variabilities of QWT were 2.3% and 5.7% respectively. According to pacing setting in CRT patients, average variation of LVPET-Ped was equal to 23.3 ± 24.5%. Measurements of QWT from right carotid Doppler signal is an easy, reliable and reproducible method that can be used as a surrogate of LVPET. This could allow optimization of pacing sites location during CRT implant procedure.