Pulmonary vein arrhythmia diagnostic device and method for use

#The inventions described below relate to the field of diagnostic medical devices. Specifically the inventions relate to a device and method for diagnosing whether ablation of a portion of the pulmonary vein will eliminate atrial fibrillation originating in the pulmonary vein.

#Atrial fibrillation (AF) is a form of heart disease that afflicts millions of people. It is a condition in which the normal contraction of the heart is interrupted, primarily by abnormal and uncontrolled action of the atria of the heart. The heart has four chambers: the right atrium, right ventricle, the left ventricle, and the left atrium. The right atrium pumps de-oxygenated blood from the vena cava to the right ventricle, which pumps the blood to the lungs, necessary for return flow of de-oxygenated blood from the body. The right atrium contracts to squeeze blood into the right ventricle, and expands to suck blood from the vena cava. The left atrium pumps oxygenated blood from the pulmonary veins (returning from the lungs), necessary for flow of oxygenated blood from the lungs. The left atrium contracts to squeeze blood into the left ventricle, which then pumps the blood into the aorta and thence to the entire body, and expands to suck blood from the pulmonary veins. The contractions of the atria normally occur in a controlled sequence with the contractions of the other chambers of the heart. When the left atrium or the right atrium fails to contract, contracts out of sequence, or contracts ineffectively, blood flow within the heart is disrupted. The disruption of the normal rhythm of contraction is referred to as an arrhythmia. The arrhythmia, known as atrial fibrillation, can cause weakness of the heart due to reduced ventricular filling and reduced cardiac output. Stroke due to clot formation in a poorly contracting atria (which may lead to brain damage and death), and even other life threatening ventricular arrhythmias can also occur.

#There is a broad spectrum of situations which fall under the broad heading of AF. For example, in older patients where there is substantial heterogeneity in the conduction within the atrial tissue, the patient is said to have the tissue substrate for AF such that any trigger will result in maintaining AF. In younger patients, the tissue may have more homogeneous conduction and be less likely to have sustained AF. In the younger patient it may be the often reoccurrence of a premature depolarizing tissue which acts as a trigger that causes the clinical manifestation of problematic episodes of AF. Clearly, there is a continuous spectrum of degrees of triggered AF and conduction heterogeneity which acts as a substrate for this arrhythmia, and it is appropriate that a number of medical therapies are being developed to treat and diagnose this disease.

#FIG. 1 is illustrates the diagnostic catheter designed for use in the pulmonary vein.

#FIG. 2 is cross-sectional view of the left atrium with a guide wire entering the target pulmonary vein through a hole in the atrial septum.

#FIG. 3 illustrates the diagnostic balloon inserted into the target pulmonary vein where the balloon is in the expanded state thereby in contact with the ostium of the target pulmonary vein.

#FIG. 1 shows the preferred embodiment of the diagnostic catheter 1 with the balloon 2 in its inflated state within the pulmonary vein 3. The catheter body 4 includes a fluid supply lumen 5 which extends from the proximal end of the catheter to the balloon, providing a fluid pathway from a fluid reservoir 15 at the proximal end of the catheter to the balloon.

#The diagnostic catheter includes a catheter having a balloon 2 located at the distal end of the catheter. The balloon is adapted to contact the pulmonary vein 3 when the balloon is inflated. The balloon is provided in a conical or frustoconical shape, allowing it to seat against the flared shape of the ostium 14 (the ostium is the junction between the pulmonary vein and the atrium) with the tip of the cone penetrating into the pulmonary vein and the base of the cone having a larger diameter than the pulmonary vein. The base of the cone should have a diameter chosen in relation to the estimated predetermined size of the ostium so that it is about the same or slightly larger than the ostium, and prevents insertion of the base segment into the pulmonary vein. Pores 6 are located on the distal end of the balloon, on the distal tip of the conical segment of the balloon. This distal tip is of the conical segment of the balloon is sized to fit within the pulmonary vein, such that the fluid is only injected into the pulmonary vein when the balloon porous distal end is disposed within the pulmonary vein and fluid is provided to the balloon. The proximal portion of the balloon is water-tight and non-porous, so that it does not permit fluid to exit the balloon near the base of the conical portion of the balloon. The fluid being injected interrupts electrical signals, and identification of a pulmonary vein which contains an arrythmogenic area is facilitated when the only electrical signals being interrupted are those of the pulmonary vein and not of the atrium itself. If the electrical signals of the atrium are inhibited then it is difficult to diagnose whether or not the atrial fibrillation has been prevented because the triggering signal from the pulmonary vein has been prevented or because the fluid has interrupted the atrial fibrillation in the atrium itself.

#FIG. 2 illustrates the method of accessing the pulmonary vein for placement of the diagnostic catheter. The left atrium 7 is laid open to show the openings to the pulmonary veins 8, 9 and 10. The left atrium contains inlets of pulmonary veins which may be accessed from the right atrium (not shown) by passing a catheter 1 through the atrial septum 11 (with the catheter passing through an access hole cut into the atrial septum to allow passage of the catheter). To insert the diagnostic device into the pulmonary vein, access to the left atrium is first gained by percutaneous insertion of a catheter into the left atrium. To accomplish this, a needle catheter is placed through the venous system into the right atrium, and then penetrates the fossa ovalis (the atrial septum) to gain access to the left atrium. Access to the right atrium can be through the femoral vein in the thigh and the inferior vena cava, or may be through the subclavian vein, brachial vein or cephalic vein, etc., in the shoulder and arm, and then through the superior vena cava. A catheter sheath 12, such as a guiding catheter, is advanced over the needle catheter and is inserted into the left atrium. The needle catheter is then removed, and the diagnostic catheter is inserted. The distal end of the catheter is then maneuvered into the left atrium and into the target pulmonary vein. Once the catheter is passed through the access hole, then a guide wire 13 is inserted to locate the target pulmonary vein 8.