Estimation of Cardiac Activation

The broad goal of all electrocardiographic examination is to reveal information about the heart from whatever sources of electrical information are available and using whatever methods of interpreting the measured signals which may be appropriate. By combining both measurement and interpretation modalities, it may be possible to substantially improve overall information content and diagnostic performance. For example, clinicians already combine body-surface electrocardiograms (ECGs) with catheter based electrical measurements to improve localization of ectopic activation or reentrant arrhythmia.

Recent advances in catheter technology allow the use of multiple venous catheters, each containing up to 16 electrodes, to map regions of the epicardial surface of the heart. In previous studies, we showed that signals from such catheters were equivalent to those recorded from nearby sites on the heart surface\cite{RSM:Kue98,RSM:Kue99} and that it was also possible to estimate high resolution activation maps of the complete epicardium from a sparse set of venous catheter measurements. The figure below shows an example of these results for a beat paced from the epicardium of the left ventricle.


Interpolation versus estimation for reconstructing activation maps. All values are activation times.

Here one can see a comparison of different interpolation techniques and our estimation approach in reconstructing the activation sequence from a heart beat. The estimation is based on measurements just along the red lines visible in the image--we interpolated ot estimated all the values between the lines. We have recently, together with Dana Brooks at Northeastern University, begun to combine estimation with inverse solution approaches to reconstruction not activation but the electric potentials on the surface of the heart.


Combination of estimation and inverse solution for reconstructing heart potentials. All values are epicardial voltages.

The figure shows some of our first results for a range of different approaches to both aspects of the solution method.
Last modified: Wed Sep 11 19:37:04 MD 2002