Lesion prediction based in part on tissue characterization
AssigneeSt. Jude Medical, Cardiology Division, Inc.
InventorsJeffrey M. Fish, Lynn E. Clark
Life of this patent
Estimating the term…
Abstract
A method for determining a predicted lesion size formed in a tissue by receiving or calculating a measure of contact force between the electrode and the tissue, determining a tissue characterization, and calculating the predicted lesion size using both the measure of contact force and the tissue characterization. A system comprising an electronic control unit configured to receive or determine a measure of contact force between the electrode and the tissue, characterize the tissue based on both the measure of impedance and the measure of contact force, and cause the tissue characterization to be either (a) presented to a user, or (b) applied to calculate a metric and cause the metric to be presented to the user.
Claims14
A system, comprising:
- an electronic control unit (ECU) configured to:
- measure an impedance at an interface between an electrode of a catheter and tissue of a patient;
- measure contact force between the electrode and the tissue;
- calculate a ratio of the measure of impedance and the measure of contact force, wherein the calculated ratio comprises a fraction which utilizes the measure of impedance as one of the numerator or the denominator and the measure of contact force as the other of the numerator or the denominator;
- and
- characterize the tissue for a clinician by presenting the calculated ratio, or by calculating a metric utilizing the calculated ratio and presenting the metric to the clinician.
A system, comprising:
- an electronic control unit (ECU) configured to:
- receive or determine a measure of energy applied from an electrode to tissue of a patient;
- receive or determine a measure of an impedance between the electrode and the tissue;
- receive or determine a measure of contact force between the electrode and the tissue;
- calculate a ratio of the measure of impedance to the measure of contact force, where the measure of impedance is the denominator and the measure of contact force is the numerator, wherein the impedance is a complex impedance and the ECU is further configured to calculate the denominator of the ratio based on at least a reactance and a resistance of the complex impedance, or a magnitude and a phase angle of the complex impedance;
- calculate a size of a lesion in the tissue according to the measure of energy applied and the ratio of the measure of impedance to the measure of contact force;
- and
- display lesion size to a clinician.
A system comprising:
- a medical catheter including a force sensor and an electrode;
- and
- an electronic control unit (ECU) electrically and/or communicatively coupled to the force sensor and the electrode, the ECU configured and arranged to
- measure electrical parameters at an interface between the electrode and target tissue of a patent,
- measure contact force between the electrode and the target tissue via the force sensor,
- measure energy applied from the electrode to the target tissue during an ablation therapy;
- determine lesion size index according to an equation
- LSI(F,I,t)=k1(f2(1−eF/f1)+f0)*i2(1−e−(I/i1)2)*((1−k0)+k01−e−t/τ/1−e−T/τ),
- wherein F is force in grams, I is current in milliamps, t is a time in seconds, f0, f1, and f2 are force parameter coefficients, i1 and i2 are electrical current coefficients, k0 is a diffusive heating coefficient, k1 is a rescaling coefficient, τ is a characteristic time value, and the output LSI is in millimeters,
- determine electrical coupling index,
- based upon at least one of the determined lesion size index, electrical coupling index and measured energy, characterize the tissue,
- based upon at least one of the determined lesion size index, electrical coupling index and measured energy, predict lesion size and depth of the ablation therapy, and
- output the tissue characterization and lesion size and depth to a clinician.
Dependencies are inferred from the claim text.