Nonlinear dynamic analysis of hemodynamic signals for identifying transitions between ventriculoarterial coupling states

Cardiac surgery can change the coupling between the heart and the subsequent arterial system. This study is a first step for the identification and visualization of disturbed ventriculoarterial coupling. Hemodynamic parameters: left ventricular pressure (LVP), aortic pressure (AOP) and aortic flow (AOF) were digitally recorded (100 Hz) in 8 anaesthetized pigs over a period of 10 minutes. A simulation of disturbance of the ventriculoarterial coupling is performed by a total occlusion of the descending aorta. The three hemodynamic parameters are defined to perform a three dimensional vector V=[LVP(t), AOP(t+Δt), AOF(t+Δt)]. A recurrence plot was derived from this attractor, which describes a space-time correlation of the points on the attractor. Recurrence plots showed a clear state transition after aortic occlusion. The system traveled through several quasi-stable states and in case of reopening the aorta it showed a similar correlation as before the disturbance. Recurrence plots are sensitive for identification of state transitions in the cardiovascular system