Method for matching the sense length of an impedance measuring catheter to a ventricular chamber

Claim 1

A method for matching the sense length of an intracardiac impedance catheter to the dimensions of a ventricular chamber, comprising the steps of: (a) providing an elongated, flexible, plastic endocardial catheter having a plurality of spaced surface electrodes extending longitudinally and proximally from a distal end of said catheter so as to span a distance known in advance to be greater than an expected length dimension of an adult ventricular chamber; (b) routing said catheter through a patient's vascular system such that said distal end resides in the apex of one ventricular chamber; (c) applying an alternating, constant-current, voltage signal between a most distal one and a predetermined more proximal one of said plurality of electrodes known to be outside of said ventricular chamber; (d) sensing signal characteristics existing between adjacent pairs of said electrodes located between said most distal one and said predetermined more proximal one of said plurality of electrodes due to said alternating current applied in step (c); (e) comparing the characteristics of the signals sensed in step (d) with one another for similarity; (f) identifying the location of a particular pair of electrodes where the characteristics of the signal therebetween differ from the characteristics of the signals between more distal ones of said adjacent pairs of electrodes.

Claim 2

A method for matching the sense length of an intracardiac impedance catheter to the dimensions of a ventricular chamber, comprising the steps of: (a) providing an elongated, flexible, plastic endocardial catheter having a plurality of spaced surface electrodes extending longitudinally and proximally from a distal end of said catheter so as to span a distance known in advance to be greater than an expected length dimension of an adult ventricular chamber; (b) routing said catheter through a patient's vascular system such that said distal end resides in the apex of one ventricular chamber; (c) applying an alternating, constant-current, voltage signal between a most distal one and a predetermined more proximal one of said plurality of electrodes known to be outside of said ventricular chamber; (d) sensing signal characteristics existing between adjacent pairs of said electrodes located between said most distal one and said predetermined more proximal one of said plurality of electrodes due to said alternating current applied in step (c); (e) comparing the characteristics of the signals sensed in step (d) with one another for similarity; (f) identifying the location of a particular pair of electrodes where the characteristics of the signal therebetween differ from the characteristics of the signals between more distal ones of said adjacent pairs of electrodes.

Claim 8

A method for matching the sensing length of an intracardiac impedance catheter to the dimensions of a ventricular chamber, comprising the steps of: (a) providing an elongated, flexible, plastic endocardial catheter having a plurality of spaced surface electrodes extending longitudinally and proximally from a distal end of said catheter so as to span a distance known in advance to be greater than an expected length dimension of an adult ventricular chamber; (b) routing said catheter through a patient's vascular system such that said distal end resides in the apex of one ventricular chamber; (c) applying an alternating constant current voltage signal between a most distal one and a predetermined more proximal one of said plurality of electrodes known to be outside said one ventricular chamber; (d) sensing signal characteristics existing between one or more adjacent pair of said electrodes known to be located in said ventricular chamber, the sensed signal being due to said alternating current applied in step (c); (e) selecting a further adjacent pair of electrodes more proximal than said one or more adjacent pair of electrodes; (f) sensing signal characteristics existing between said further adjacent pair of said electrodes; (g) comparing the characteristics of said signals sensed in step (d) with the characteristics of said signal sensed in step (f) for a match condition; (h) selecting a further adjacent pair of electrodes even more proximal than the electrodes used in step (f); (i) repeating steps (f), (g) and (h) until the signal sensed in step (f) differs in said characteristics from the signals sensed in step (d).

Claim 9

A method for matching the sensing length of an intracardiac impedance catheter to the dimensions of a ventricular chamber, comprising the steps of: (a) providing an elongated, flexible, plastic endocardial catheter having a plurality of spaced surface electrodes extending longitudinally and proximally from a distal end of said catheter so as to span a distance known in advance to be greater than an expected length dimension of an adult ventricular chamber; (b) routing said catheter through a patient's vascular system such that said distal end resides in the apex of one ventricular chamber; (c) applying an alternating constant current voltage signal between a most distal one and a predetermined more proximal one of said plurality of electrodes known to be outside said one ventricular chamber; (d) sensing signal characteristics existing between one or more adjacent pair of said electrodes known to be located in said ventricular chamber, the sensed signal being due to said alternating current applied in step (c); (e) selecting a further adjacent pair of electrodes more proximal than said one or more adjacent pair of electrodes; (f) sensing signal characteristics existing between said further adjacent pair of said electrodes; (g) comparing the characteristics of said signals sensed in step (d) with the characteristics of said signal sensed in step (f) for a match condition; (h) selecting a further adjacent pair of electrodes even more proximal than the electrodes used in step (f); (i) repeating steps (f), (g) and (h) until the signal sensed in step (f) differs in said characteristics from the signals sensed in step (d).