Therapeutic optimization of atrioventricular delay in cardiosurgical ICU patients by noninvasive cardiac output measurements versus pulse contour analysis

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 +/- 12.0yrs) 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 ins 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 AVID 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.