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R. Schondorf, J. Benoit, M. Genoulaz, M.J. Lafitte and L. Bernardi. Evaluation Of A Novel Non Model Driven Assessment Of Cardiac Autonomic Activity: Reinnervation After Human Heart Transplantation. Where Is The Fish?. You are watching one particular fish inside a school of fish
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R. Schondorf, J. Benoit, M. Genoulaz, M.J. Lafitte and L. Bernardi Evaluation Of A Novel Non Model Driven Assessment Of Cardiac Autonomic Activity: Reinnervation After Human Heart Transplantation
Where Is The Fish? • You are watching one particular fish inside a school of fish • Where the fish is now depends on where it has been • Where the fish is going depends on where it is now
Where Is The Fish? • This fish can be anywhere within the school of fish • A small school of fish looks just like a small part of a big school of fish
Analysis of R-R Intervals Is Not A Fishing Expedition • By their very nature R-R intervals are discrete events • They display the property of self similarity (behave like fish) • The behavior of R-R intervals is a lot simpler than the Dow Jones
What Was Found Without Knowing What An R-R Interval Is? • Two separate functions describe the kinematics of the system • Because we do not know where we are, each function is expressed as a velocity • Each function can be reduced to a scalar that describes what is most probable
Aim Of The Present Study • To characterize the physiological underpinnings of the present tools using a robust well-characterized data set
Advantage Of This Data Set • Patients with heart transplant are initially cardiodenervated • There are multiple lines of evidence suggesting modest cardiac sympathetic reinnervation over time • There is no evidence that cardiovagal reinnervation occurs
Advantage Of This Data Set • Both controls and patients were subject to rhythmic neck suction at 0.1 Hz • We know what neck suction does
What Do We Know Already • Atropine reduces one of the parameters (the green one) to 0 • Atenolol variably reduces the fluctuations of the other parameter (the blue one) • Head-up tilt increases the magnitude and fluctuation of this other parameter
Conclusions • The response of our 2 parameters to rhythmic neck suction in control subjects approximates well worked out physiology • Our method independently confirms preferential sympathetic reinnervation and essentially absent parasympathetic reinnervation in the transplanted heart
Problems To Be Addressed • What is the meaning of the 2 beat phase shift of the vagal parameter? • What is the cause of the baseline shift in the sympathetic parameter in the absence of parasympathetic cardiac innervation?