Prediction of atrial wall electrical reconnection based on contact force measured during RF ablation

Abstract

A method and device for determining the transmurality and / or continuity of an isolation line formed by a plurality of point contact ablations. In one embodiment, a method for determining the size of a lesion (width, depth and / or volume) is disclosed, based on contact force of the ablation head with the target tissue, and an energization parameter that quantifies the energy delivered to the target tissue during the duration time of the lesion formation. In another embodiment, the sequential nature (sequence in time and space) of the ablation line formation is tracked and quantified in a quantity herein referred to as the “jump index,” and used in conjunction with the lesion size information to determine the probability of a gap later forming in the isolation line.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 13 / 337,896, filed 27 Dec. 2011 (the '896 application), now U.S. Pat. No. 9,149,327, issued 6 Oct. 2015, which claims the benefit of U.S. provisional patent application Nos. 61 / 427,423 (the '423 application) and 61 / 427,425 (the '425 application), both filed on 27 Dec. 2010. The '896, '423, and '425 applications are hereby incorporated by reference in their entirety as though fully set forth herein.BACKGROUND[0002]a. Field[0003]The field of the invention relates generally to the treatment of organic tissues using ablation therapy, and more specifically to the prediction and display of lesion sizes using catheter-based contact ablation delivery systems.[0004]b. Background Art[0005]Atrial fibrillation is a common cardiac arrhythmia involving the two upper chambers (atria) of the heart. In atrial fibrillation, disorganized electrical impulses that originate in the atria and...

AI Technical Summary

Benefits of technology

This patent describes a device and method for predicting the success of catheter-based point contact ablation techniques for the creation of isolation lines. The device predicts the size of the lesion based on the contact force between the ablation head and the target tissue, the energy applied, and the time duration of the ablation. It also tracks the sequential nature of the ablation line formation to improve the quality of the isolation line. The method reduces the need for post-ablation measurement and takes into account various characteristics of lesion formation such as the delay between the force and current, the non-linear nature of lesion growth, and the different results from different energizations. The device and method can help create a more effective isolation line with a low risk of post-operative gaps.

Problems solved by technology

Atrial fibrillation can result in poor contraction of the atria that can cause blood to recirculate in the atria and form clots.

Thus, individuals with atrial fibrillation have a significantly increased risk of stroke.

Atrial fibrillation can also lead to congestive heart failure or, in extreme cases, death.

The left anterior wall is often a difficult area to achieve stable contact during pulmonary vein isolation resulting in higher incidence of local isolation gaps.

While this approach may work in some cases for linear contact ablation techniques, it is generally not effective for point contact ablation techniques because it requires too much time and too many continuity measurements in order to establish a relatively high confidence in the ability to predict whether there will or will not be isolation gaps as a result of incomplete lesion formations during the ablation process of creating the isolation.

In addition, it has been found that intra-operative continuity measurements of the isolation line may not be an accurate predictor of the recurrence of atrial fibrillation as the tissue properties of the lesion just after ablation can change over time and may not be representative of the final lesions associated with the isolation line.

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