Abstract: An implantable system for the defibrillation of the atria of a patient's heart comprises (a) a first catheter configured for insertion into the right atrium of the heart, preferably without extending into the right ventricle of the heart; a first atrial defibrillation electrode carried by the first catheter and positioned at the atrial septum of the heart (i.e., an atrial septum electrode); (b) a second atrial defibrillation electrode which together with the first atrial defibrillation electrode provides a pair of atrial defibrillation electrodes that are configured for orientation in or about the patient's heart to effect atrial defibrillation, and (c) a pulse generator operatively associated with the pair of atrial defibrillation electrodes for delivering a first atrial defibrillation pulse to the heart of the patient.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into a wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to the centering catheter distal end portion and configured for positioning within the vessel when in a retracted configuration, and for securing the elongate centering catheter in a substantially axially aligned position with respect to the vessel when the centering element is in an expanded configuration; (c) an ablation catheter slidably connected to the centering catheter the ablation element having a distal end portion, and (d) an expandable ablation element connected to the ablation catheter distal end portion.

Abstract: The present invention provides apparatus and methods for delivering an optimum electrical shock in treating cardiac arrhythmias. The apparatus comprises means for producing an electrical waveform signal at least two electrodes The voltage or current of the signal is then detected to determine the signal time constant. The signal time constant is then used in conjunction with a model time constant to determine when the peak amplitude is reached. The waveform is then interrupted when the peak amplitude is reached. Also provided are methods of selecting a cardiac defibrillator by measuring the impedance of implanted electrodes and then selecting a defibrillator having a capacitor which provides an RC time constant equal to that of a model time constant.

Abstract: An ablation catheter stores a platelet inhibitor substance within a plurality of pockets or recesses of its shaft. The substance is adapted to elute upon contact with biological fluid. In the pocket configuration, the platelet inhibitor substance is in a capsule positioned within the pocket. In the recess configuration, the platelet inhibitor substance is in a hydrogel or silicone-based porous/semi-porous matrix positioned within the recess. Elution of the platelet inhibitor substance prevents or at least substantially minimizes the adhesion of blood platelets on the catheter surface during ablation. In another configuration, the catheter includes an internal lumen network having apertures terminating at the surface of the shaft. The lumen communicates with a source of platelet inhibitor fluid that is forced through the lumen by a variable pump.

Abstract: A conformable catheter comprising a catheter handle, an elongated catheter tube, and a distal tip portion of the catheter tube, capable of assuming a desired pre-programmed shape. A wire member is disposed within the core of the catheter's tip portion and is formed of a material, such as, for example, a shape-memory binary nickel-titanium alloy, that will assume a pre-programmed shape after pre-shaping, heat treatment, cooling and subsequent heating. To pre-program the shape of the wire member, prior to assembly of the catheter, the wire member is wound around a shaped, heat resistant fixture, heated until the temperature of the wire member exceeds the temperature at which the shape of the wire member on the fixture becomes programmed into the wire member, and cooled.

Abstract: A method of reducing the likelihood of pulseless electrical activity (PEA) after defibrillation in a subject comprises administering to a subject afflicted with fibrillation a first treatment waveform, the first treatment waveform insufficient to defibrillate the heart; and then administering to the subject a second treatment waveform that defibrillates the heart and restores organized electrical activity in the heart. The first treatment waveform reduces the likelihood of onset of PEA following the second treatment waveform, as compared to that likelihood which would be present in the absence of the first treatment waveform.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into said wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to said centering catheter distal end portion and configured for positioning within said vessel when in a retracted configuration, and for securing said elongate centering catheter in a substantially axially aligned position with respect to said vessel when said centering element is in an expanded configuration; (c) an ablation catheter slidably connected to said centering catheter said ablation element having a distal end portion, and (d) an expandable ablation element connected to said ablation catheter distal end portion.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into said wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to said centering catheter distal end portion and configured for positioning within said vessel when in a retracted configuration, and for securing said elongate centering catheter in a substantially axially aligned position with respect to said vessel when said centering element is in an expanded configuration; (c) an ablation catheter slidably connected to said centering catheter said ablation element having a distal end portion, and (d) an expandable ablation element connected to said ablation catheter distal end portion.

Abstract: A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into said wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to said centering catheter distal end portion and configured for positioning within said vessel when in a retracted configuration, and for securing said elongate centering catheter in a substantially axially aligned position with respect to said vessel when said centering element is in an expanded configuration; (c) an ablation catheter slidably connected to said centering catheter said ablation element having a distal end portion, and (d) an expandable ablation element connected to said ablation catheter distal end portion.

Abstract: An implantable system for the defibrillation of the atria of a patient's heart comprises (a) a first catheter configured for insertion into the right atrium of the heart, preferably without extending into the right ventricle of the heart; a first atrial defibrillation electrode carried by the first catheter and positioned at the atrial septum of the heart (i.e., an atrial septum electrode); (b) a second atrial defibrillation electrode which together with the first atrial defibrillation electrode provides a pair of atrial defibrillation electrodes that are configured for orientation in or about the patient's heart to effect atrial defibrillation, and (c) a pulse generator operatively associated with the pair of atrial defibrillation electrodes for delivering a first atrial defibrillation pulse to the heart of the patient. The second electrode may be configured for positioning through the coronary sinus ostium and in the coronary sinus or a vein on the surface of the left ventricle, such as the great vein.

Abstract: An implantable system for the defibrillation of the atria of a patient's heart comprises (a) a first catheter configured for insertion into the right atrium of the heart; a first atrial defibrillation electrode carried by the first catheter and positioned to stimulate Bachmann's bundle, or positioned at the atrial septum of the heart (i.e., an atrial septum electrode); (b) a second atrial defibrillation electrode which together with the first atrial defibrillation electrode provides a pair of atrial defibrillation electrodes that are configured for orientation in or about the patient's heart to effect atrial defibrillation, and (c) a pulse generator operatively associated with the pair of atrial defibrillation electrodes for delivering a first atrial defibrillation pulse to the heart of the patient. The second electrode may be configured for positioning through the coronary sinus ostium and in the coronary sinus or a vein on the surface of the left ventricle, such as the great vein.

Abstract: A method of reducing the likelihood of pulseless electrical activity (PEA) after defibrillation in a subject comprises administering to a subject afflicted with fibrillation a first treatment waveform, the first treatment waveform insufficient to defibrillate the heart; and then administering to the subject a second treatment waveform that defibrillates the heart and restores organized electrical activity in the heart. The first treatment waveform reduces the likelihood of onset of PEA following the second treatment waveform, as compared to that likelihood which would be present in the absence of the first treatment waveform.

Abstract: A method of reducing the likelihood of pulseless electrical activity (PEA) after defibrillation in a subject comprises administering to a subject afflicted with fibrillation a first treatment waveform, the first treatment waveform insufficient to defibrillate the heart; and then administering to the subject a second treatment waveform that defibrillates the heart and restores organized electrical activity in the heart. The first treatment waveform reduces the likelihood of onset of PEA following the second treatment waveform, as compared to that likelihood which would be present in the absence of the first treatment waveform.

Abstract: An implantable system for the defibrillation of the atria of a patient's heart comprises (a) a first catheter configured for insertion into the right atrium of the heart, preferably without extending into the right ventricle of the heart; a first atrial defibrillation electrode carried by the first catheter and positioned at the atrial septum of the heart (i.e., an atrial septum electrode); (b) a second atrial defibrillation electrode which together with the first atrial defibrillation electrode provides a pair of atrial defibrillation electrodes that are configured for orientation in or about the patient's heart to effect atrial defibrillation, and (c) a pulse generator operatively associated with the pair of atrial defibrillation electrodes for delivering a first atrial defibrillation pulse to the heart of the patient. The second electrode may be configured for positioning through the coronary sinus ostium and in the coronary sinus or a vein on the surface of the left ventricle, such as the great vein.

Abstract: The present invention provides apparatus and methods for delivering an optimum electrical shock in treating cardiac arrhythmias. The apparatus comprises means for producing an electrical waveform signal at least two electrodes The voltage or current of the signal is then detected to determine the signal time constant. The signal time constant is then used in conjunction with a model time constant to determine when the peak amplitude is reached. The waveform is then interrupted when the peak amplitude is reached. Also provided are methods of selecting a cardiac defibrillator by measuring the impedance of implanted electrodes and then selecting a defibrillator having a capacitor which provides an RC time constant equal to that of a model time constant.

Abstract: An implantable system for the defibrillation of the atria of a patient's heart includes a first pair of atrial defibrillation electrodes configured for delivering a first atrial defibrillation pulse along a first current pathway in the heart, and a pulse generator operatively associated with the first pair of atrial defibrillation electrodes for delivering the first atrial defibrillation pulse. A second pair of atrial defibrillation electrodes configured for delivering a second atrial defibrillation pulse along a second current pathway in the heart is also included, with the second current pathway being different from the first current pathway. A pulse generator is operatively associated with the second pair of atrial defibrillation electrodes for delivering the second atrial defibrillation pulse after the first defibrillation pulse.

Abstract: A conformable catheter comprising a catheter handle, an elongated catheter tube, and a distal tip portion of the catheter tube, capable of assuming a desired pre-programmed shape. A wire member is disposed within the core of the catheter's tip portion and is formed of a material, such as, for example, a shape-memory binary nickel-titanium alloy, that will assume a pre-programmed shape after pre-shaping, heat treatment, cooling and subsequent heating. To pre-program the shape of the wire member, prior to assembly of the catheter, the wire member is wound around a shaped, heat resistant fixture, heated until the temperature of the wire member exceeds the temperature at which the shape of the wire member on the fixture becomes programmed into the wire member, and cooled.

Abstract: An electrode catheter is disclosed for creating a linear lesion in heart tissue of a heart chamber in order to correct cardiac arrhythmia. The catheter is elongated in dimension such that, upon insertion of the catheter in the patient, the catheter substantially continuously contacts either the endocardial or epicardial heart tissue. The catheter includes a plurality of electrodes and the electrodes are positioned at spaced intervals along the catheter. The electrodes are then sequentially energized with a radio frequency in conjunction with a back plate attached to the patient such that the electrodes form a continuous lesion conforming in shape to the shape of the catheter on the heart tissue. This lesion, furthermore, is of sufficient depth such that the lesion interrupts electrical nodal conduction across the lesion.

Abstract: The present invention provides apparatus and methods for delivering an optimum electrical shock in treating cardiac arrhythmias. The invention comprises apparatus for producing an electrical waveform signal at least at two electrodes. The voltage or current of the signal is then detected to determine the signal time constant. The signal time constant is then used in conjunction with a model time constant to determine when the peak amplitude is reached. The waveform is then interrupted when the peak amplitude is reached. Also provided are methods of selecting a cardiac defibrillator by measuring the impedance of implanted electrodes and then selecting a defibrillator having a capacitor which provides an RC time constant equal to that of a model time constant.

Abstract: A closed-heart method for treating ventricular tachycardia in a myocardial infarct patient afflicted with ventricular tachycardia is disclosed. The method comprises, first, defining a thin layer of spared myocardial tissue positioned between the myocardial infarct scar tissue and the inner surface of the myocardium (the endocardium) of the patient, and then ablating the thin layer of spared myocardial tissue by a closed-heart procedure with an ablation catheter. Apparatus for carrying out the method is also disclosed,Also disclosed is a method for prognosing the likelihood of ventricular tachycardia occuring in a myocardial infarct patient not previously diagnosed as afflicted with ventricular tachycardia. The method comprises detecting a thin layer of spared myocardial tissue positioned between the myocardial infarct scar tissue and the inner surface of the myocardium (the endocardium) in the patient.