Therapeutic Optimization of Atrioventricular Delay in Cardiosurgical ICU Patients by Noninvasive Cardiac Output Measurements versus Pulse Contour Analysis

Abstract

Background: Optimizing atrioventricular (AV) delay improves cardiac output and postoperative outcome. Impedance cardiography (ICG) is a non-invasive method for CO measurement. This study evaluates the ability of two ICG methods to determine the optimal AV delay (OAVD) and to compare ICG with invasive PICCO measurements. Methods: In 14 cardiosurgical ICU patients (age 70.4 ± 12.0 yrs) with temporary pacing wires, OAVD was determined by pulse contour analysis (PICCO) and ICG (conventional ICG [CI] and electrical velocimetry [EV] ICG monitors). Cardiac output (CO) and stroke volume (SV) were measured during DDD pacing with AVD varying from 70 to 270 ms in 20-ms increments. Results: Measured OAV showed a linear correlation between PICCO and ICG: CI (r = 0.82, p < 0.0002) and EV (r = 0.84, p < 0.0002). The mean OAVD deviation between PICCO and ICG was 15.7 ± 21.0 ms (CI) and 17.1 ± 20.5 ms (EV). Hemodynamic parameters (SV increase OAVD against worst case) improved significantly (+ 11.7 ± 7.2 %, p < 0.0001). Conclusion: Inappropriate selection of AVD can compromise the hemodynamic situation of cardiosurgical patients. As it is totally noninvasive, ICG is a reliable and effective tool for tailoring AVD. Both systems (CI and EV) offer valid OAV determination.