Electrical means to normalize ablational energy transmission to a luminal tissue surface of varying size

摘要

Methods and devices for measuring the size of a body lumen and a method for ablating tissue that uses the measurement to normalize delivery of ablational energy from an expandable operative element to a luminal target of varying circumference are provided. The method includes inserting into the lumen an expandable operative element having circuitry with resistivity or inductance that varies with circumference of the operative element, varying the expansion of the operative element with an expansion medium, measuring the resistivity of the circuitry, and relating the resistivity or inductance to a value for the circumference of the operative element. In some embodiments the sizing circuit includes a conductive elastomer wrapped around the operative element. Other embodiments apply to operative elements that include an overlapping energy delivery element support in which the overlap varies inversely with respect to the state of expansion, and electrodes that sense the amount of the overlap.

主权项

1. A device for treating a body lumen comprising: an expandable operative element including an inflatable balloon and an ablation energy delivery element support arranged on an exterior of the inflatable balloon; and a sensing circuitry mounted to the support, wherein a resistivity of the sensing circuitry varies according to an amount of expansion of the inflatable balloon.