Apparatus and method for treating cardiovascular diseases

#The present invention relates to the treatment of cardiovascular diseases, and more particularly relates to an apparatus and method for treating cardiac conditions, such as arrhythmias, heart failure, acute and chronic heart transplant rejection, and pulmonary arterial hypertension.

#The heart is, in essence, a pump that is responsible for circulating blood throughout the body. In a normally functioning heart, such circulation is caused by the generation of electrical impulses that, for example, increase or decrease the heart rate and/or the force of contraction in response to the demands of the circulatory system. If the electrical signal becomes disturbed in some way, the efficient pumping action of the heart may deteriorate, or even stop altogether.

#Disturbance in the regular rhythmic beating of the heart is a common disorder seen in heart disease. Irregular rhythms (arrhythmia) can be a minor annoyance, or may indicate a serious problem. For example, arrhythmias may indicate an underlying abnormality of the heart muscle, valves or arteries, and includes the situation where the heart is beating too slowly (bradycardia) and also where the heart is beating too rapidly (tachycardia).

#The foregoing and other features of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

#FIG. 1A is a perspective view showing an apparatus, in an expanded configuration, for treating cardiovascular diseases constructed in accordance with the present invention;

#FIG. 1B is a perspective view showing an alternative embodiment of the apparatus in FIG. 1A;

#The present invention relates to the treatment of cardiovascular diseases, and more specifically relates to an apparatus and method for treating cardiac conditions, such as heart failure, arrhythmias, acute and chronic heart transplant rejection, and pulmonary arterial hypertension. As representative of the present invention, FIG. 1A illustrates an apparatus 10 for treating cardiac arrhythmias, such as atrial fibrillation (AF). It should be understood, however, that the apparatus 10 disclosed herein may be used to treat other cardiac arrhythmias including, but not limited to, premature atrial contraction, atrial flutter, supraventricular tachycardia, sick sinus syndrome, atrioventricular block, ventricular fibrillation, premature ventricular contraction, ventricular tachycardia, and other cardiovascular diseases such as heart failure, acute and chronic heart transplant rejection, and pulmonary arterial hypertension. Further, it is contemplated that the apparatus 10 may also be useful as a complimentary treatment to pacemaker implantation and/or defibrillator implantation.

#FIG. 2 schematically illustrates a human heart 30 which includes four chambers: the right and left atria 32 and 34, and the right and left ventricles 36 and 38, respectively. The right and left atria 32 and 34 are divided by the interatrial septum 40. The thin-walled right atrium 32 receives deoxygenated blood from the superior vena cava 42, the inferior vena cava 44, and from the coronary sinus (not shown). The thin-walled left atrium 34 receives oxygenated blood from pulmonary veins 46. The right and left ventricles 36 and 38 pump deoxygenated and oxygenated blood, respectively, the right ventricle to the pulmonary circuit and the left ventricle throughout the body, and the pocket-like semilunar pulmonary valve 47 (FIG. 2A) and aortic valve 49 prevent reflux into the ventricles. Atrial blood is pumped through the atrioventricular orifices, guarded by the tri-leaflet tricuspid valve 50 (FIGS. 2 and 2A) on the right side of the heart 36 and the bi-leaflet mitral valve 52 on the left side of the heart, while ventricular blood is pumped through the pulmonary artery 51 (FIG. 2A) and the aorta 53 (FIG. 2A). The leaflets 54 (FIG. 2) of the mitral valve 52 are attached to the papillary muscles 56 in the left ventricle 38 by chordae tendineae 58. The leaflets 54 of the mitral valve 52 extend across an annulus 60, which is an area of heart wall tissue at the junction of the atrial and ventricular walls that is relatively fibrous and significantly stronger than leaflet tissue. Similarly, the leaflets 62 of the tricuspid valve 50 are attached to the papillary muscles 56 in the right ventricle 36 by chordae tendineae 58. The leaflets 62 of the tricuspid valve 50 extend across an annulus 64 (not shown in detail) at the junction of the atrial and ventricular walls.

#As shown in FIG. 1A, the present invention comprises an expandable support member 12 having oppositely disposed proximal and distal end portions 14 and 16 and a main body portion 18 extending between the end portions. The expandable support member 12 is both flexible and resilient, and, as discussed in more detail below, can be made of a shape memory material such as Nitinol, stainless steel, or other suitable medical grade metals or plastics (e.g., poly(cyclohexane-1,4-diylacetone dimethylene ketal) and Polyzene-F) having shape memory characteristics. Additionally, all or only a portion of the expandable support member 12 may be made from a bioabsorbable material including, for example, magnesium alloy, dendrimers, biopolymers, such as thermoplastic starch, polylactides, cellulose, and aliphatic aromatic copolyesters. The expandable support member 12 may also be made of a radio-opaque material or include radio-opaque markers to facilitate fluoroscopic visualization. The flexible and expandable properties of the expandable support member 12 facilitate percutaneous delivery of the expandable support member, while also allowing the expandable support member to conform to a portion of the ostium 66 (FIG. 2) of a blood vessel 68, such as the ostium 70 (FIG. 8) of a pulmonary vein 46.