# US 2013/0158548 A1 · Sensing contact of ablation catheter using differential temperature measurements

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- Number: US 2013/0158548 A1
- Document ID: US20130158548A1
- Status: Published application
- Kind: A1
- Application number: 13/764,867
- Filed: 2013-02-12
- Published: 2013-06-20
- Earliest claimed: 2009-12-23
- Assignees: Biosense Webster (Israel) Ltd.
- Inventors: Assaf Govari; Christopher Thomas Beeckler; Athanassios Papaioannou
- Web page: https://patentgrep.com/patent/US20130158548A1

## CPC

- A61B 18/1492: {having a flexible, catheter-like structure, e.g. for heart ablation (A61B18/1477 takes precedence)}
- A61B 18/20: using laser
- A61B 2017/320069: {for ablating tissue}
- A61B 2018/00011: {with fluids}
- A61B 2018/00797: {measured by multiple temperature sensors}
- A61B 2018/00821: {measured by a thermocouple}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

Tissue ablation is carried out using insertion tube having at least one ablation electrode, a first temperature sensor disposed on the distal portion sufficiently proximate the ablation electrode to detect heat generated during the ablation procedure, a second temperature sensor disposed on the distal portion sufficiently distant from the ablation electrode to be unable to detect the heat, and electronic logic circuitry linked to the first temperature sensor and the second temperature sensor and programmed to compute a temperature differential between respective temperatures sensed by the first temperature sensor and the second temperature sensor when conveying the electromagnetic energy. Satisfactory contact status between the ablation electrode and the target tissue is indicated when the temperature differential exceeds a predetermined threshold.

## Claims

### Claim 1

A method for treatment, comprising:
bringing a probe into contact with a target tissue in a body of a subject, the probe having first and second temperature sensors on a distal portion of the probe and an ablation electrode thereon, the first and second temperature sensors being disposed on the distal portion, the second temperature sensor being spaced apart from the first temperature sensor such that when the ablation electrode is operationally engaged with the target tissue, the second temperature sensor is less responsive to heat generated at an ablation site comprising the target tissue than the first temperature sensor;
applying energy through the ablation electrode to ablate the target tissue in the body;
reading the first and second temperature sensors in order to compute a temperature difference therebetween; and
determining the contact to be sufficient for the treatment if the temperature difference is greater than a predetermined threshold.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the probe is a lasso catheter.

### Claim 3 (depends on 1)

The method according to claim 1, wherein computing the temperature difference comprises computing a first temperature differential and a second temperature differential when relatively high and low flows of coolant are applied to the ablation electrode, respectively; further comprising indicating an unsatisfactory contact status between the ablation electrode and the target tissue when a difference between the first temperature differential and the second temperature differential fails to exceed the predetermined threshold.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the first temperature sensor and the second temperature sensor are thermocouples.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising discontinuing applying energy when the temperature difference fails to exceed the predetermined threshold.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the probe is configured for insertion through a blood vessel into a heart of the subject for ablation of myocardial tissue in the heart.