The invention relates to an atrial fibrillation RF treatment device and method, and more particularly, the invention relates to a device and method for creating a narrow transmural lesion or discontinuity in tissue, such as heart tissue or other body organs or tissues.
Atrial fibrillation is a condition of the heart in which abnormal electrical signals are generated in the myocardial tissue causing irregular beating of the heart. One method used to treat atrial fibrillation is called the Maze procedure. The Maze procedure involves forming barriers in the heart tissue to prevent the abnormal electrical signals from passing through the heart. The barriers are created by forming several long (i.e., approximately 2-10 cm) scars. The scars are formed by cutting through the heart wall and sewing the wall back together to create the scars which are intended to stop the irregular beating of the heart by preventing the passage of abnormal currents. This procedure is referred to as the Maze procedure because it creates a maze of scars blocking the passage of abnormal electrical currents through the heart. These scars may be formed by cutting or by application of energy.
Procedures for forming the linear scars involve opening the patients chest cavity and forming linear incisions or cuts through the heart wall in specific locations described as the Maze III and other similar atrial fibrillation treatments.
The Maze III procedure using conventional surgical incisions has a success rate of up to 90%. A new technique of cryo-ablation has also been used to create the lesions in the heart wall. This approach has the benefit of reducing the cardiopulmonary bypass pump time and allowing more time for correcting the valvular disease and CABG if needed.
Although catheter techniques have been attempted for minimally invasive treatment of atrial fibrillation, these techniques have not been successful to date. Known catheter devices for forming these lesions include flexible catheters which form lesions from an interior surface of the heart. Examples of these ablation catheters are described in U.S. Pat. Nos. 5,895,417; 5,941,845; and 6,129,724 which are incorporated herein by reference in their entirety.
One drawback with the catheter techniques and devices used on the epicardial surface of the heart is that it is difficult to impossible to assure a transmural lesion or the complete blockage of unwanted electrical signals. In addition, RF energy will not go through fat with currently available devices because of the high impedance of the fat compared to the low impedance of tissue. In addition, current devices have difficulty dealing with varying thickness of tissue through which a transmural lesion is desired. Accordingly, it would be desirable to provide a system for precisely creating transmural lesions on a beating heart or non-beating heart with a minimum of trauma to the patient.
The present invention relates to a device and method for creating a transmural lesion.
In accordance with one aspect of the present invention, an RF treatment device for creating transmural lesions in tissue includes an electrode holder; a plurality of tissue penetrating RF needle electrodes arranged in a single linear array to create a continuous transmural lesion, each of the RF needle electrodes having a length of at least 4 mm; and an RF energy source connected to each of the RF needle electrodes with alternating electrodes connected to opposite polarities of the RF energy source.
In accordance with an additional aspect of the present invention, an RF treatment device for creating transmural lesions in heart tissue includes an electrode holder; a plurality of tissue penetrating RF needle electrodes arranged in a single linear array to create a continuous transmural lesion, each of the RF needle electrodes having a length sufficient to create a transmural lesion through the entire thickness of the tissue of the heart wall; and an RF energy source connected to each of the RF needle electrodes.
In accordance with a further aspect of the invention, a method of treating atrial fibrillations includes the steps of: penetrating heart tissue to be treated with an RF treatment device comprising a plurality of tissue penetrating RF needle electrodes arranged in a single linear array; and applying radio frequency energy to form a transmural lesion which provides a barrier across an entire thickness of the heart tissue to prevent the passage of abnormal electrical currents through the heart tissue.
In accordance with another aspect of the invention, a method of treating atrial fibrillations includes the steps of: positioning a first electrode of a radio frequency forceps on an endocardial surface of a heart at a location to be treated; positioning a second electrode of the radio frequency forceps on an epicardial surface of the heart opposite the first electrode; and applying radio frequency with the first and second electrodes to form a transmural lesion which provides a barrier to the passage of abnormal electrical currents through the heart tissue.
In accordance with another additional aspect of the present invention, a medical device for creating transmural lesions in tissue includes an electrode holder; a plurality of tissue penetrating needle electrodes arranged in a single linear array to create a continuous narrow lesion, each of the needle electrodes having a length sufficient to create a transmural lesion through the tissue of the heart wall; and an energy source connected to each of the needle electrodes.