Abstract: Methods, systems, and computer program products measure electrical activity of the cardiac tissue proximate the lesion site during an ablation treatment, and then compare the measurements to determine whether the lesion is clinically efficacious so as to be able to block myocardial propagation. The methods can include obtaining the measurements and performing the ablation therapy while the subject is experiencing atrial fibrillation and may measure the standard deviation of the electrogram signal.

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: Pacing systems for the heart employ multi-site contact points about desired localized regions to deliver pacing train stimulation pulses to the myocardium. The stimulation pulses can have an electric strength in the range of about 5-10 times the diastolic pacing threshold. The electrodes can be arranged as a single continuous body line electrode or as a plurality of point electrodes and even as contiguous body electrodes occupying increased portions of the myocardium over conventional pacing electrodes. Configuring the electrodes in spaced apart operational pairs (with simultaneous excitation) may capture increased areas of the myocardium. The pacing stimulation may be used as an alternative to conventional defibrillation treatments (shocks) or to reduce the strength of the defibrillation shock pulse.

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 or cardioversion of the atria and the ventricles of a patient's heart comprises: a first catheter configured for positioning in the right ventricle of the heart; a second catheter configured for positioning through the coronary sinus ostium and in the coronary sinus of the heart, with the first and second catheters together carrying at least three defibrillation electrodes; a power supply; and a control circuit operatively associated with the power supply and the electrodes. The control circuit is configured for delivering an atrial defibrillation pulse through at least two of the electrodes, or a ventricular defibrillation pulse through at least two of the electrodes.

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: Pacing systems for the heart employ multi-site contact points about desired localized regions to deliver pacing train stimulation pulses to the myocardium. The stimulation pulses can have an electric strength in the range of about 5-10 times the diastolic pacing threshold. The electrodes can be arranged as a single continuous body line electrode or as a plurality of point electrodes and even as contiguous body electrodes occupying increased portions of the myocardium over conventional pacing electrodes. Configuring the electrodes in spaced apart operational pairs (with simultaneous excitation) may capture increased areas of the myocardium. The pacing stimulation may be used as an alternative to conventional defibrillation treatments (shocks) or to reduce the strength of the defibrillation shock pulse.

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 pair of atrial defibrillation electrodes configured for delivering a first atrial defibrillation pulse in the heart, and a pulse generator operatively associated with the first pair of atrial defibrillation electrodes for delivering the first atrial defibrillation pulse. The pulse generator delivers a second second atrial defibrillation pulse after the first defibrillation pulse without intervening monitoring thereof to reduce the voltage necessary for the shock, and the pain associated therewith.

Abstract: An implantable system for the cardioversion of the heart of a patient in need of such treatment comprises a plurality of primary electrodes, a power supply, and a control circuit. Preferably, at least one auxiliary electrode is also included. The plurality of primary electrodes are configured for delivering a cardiversion pulse along a predetermined current pathway in a first portion of the heart, the current pathway defining a weak field area in a second portion of the heart.

Abstract: An implantable system for the antitachycardia pacing of the heart of a patient in need of such treatment comprises a plurality of primary electrodes, a power supply, and a control circuit. At least one of the primary electrodes is configured for positioning through the coronary sinus ostium and in a vein on the left surface of the patient's heart.

Abstract: A method for predicting the outcome of arrhythmia therapy in a subject in need thereof comprises the steps of: (a) detecting an arrhythmia in the heart of a subject; (b) delivering a first arrhythmia therapy pulse to the heart of the subject; and then (c) determining the presence or absence of overlapping cycles in the heart of the subject, the presence of overlapping cycles indicating that the first arrhythmia therapy pulse did not successfully treat the arrhythmia. Overlapping cycles are preferably determined through the calculation of an overlapping cycles index (OCI). Apparatus for carrying out the method is also disclosed.

Abstract: An implantable system for detecting electrical activity from a patient's heart comprises a first sensing electrode configured for positioning through the coronary sinus ostium and within a vein on the left surface of the left ventricle of the heart for sensing electrical activity from the heart, and a detector operatively associated with the first sensing electrode for determining (e.g., diagnosing or prognosing) a medical condition of the heart with the sensed electrical activity. Typically the system further comprises a second sensing electrode configured for positioning in the right ventricle of the heart, where the detector is operatively associated with both the first sensing electrode and the second sensing electrode. The second sensing electrode may be positioned in other locations as well, such as also within a vein on the left surface of the left ventricle of the heart (although spaced apart from the first sensing electrode), in the right atrium, in the superior vena cava, etc.

Abstract: An implantable system for detecting electrical activity from a patient's heart comprises a first sensing electrode configured for positioning through the coronary sinus ostium and within a vein on the left surface of the left ventricle of the heart for sensing electrical activity from the heart, and a detector operatively associated with the first sensing electrode for determining (e.g., diagnosing or prognosing) a medical condition of the heart with the sensed electrical activity. Typically the system further comprises a second sensing electrode configured for positioning in the right ventricle of the heart, where the detector is operatively associated with both the first sensing electrode and the second sensing electrode. The second sensing electrode may be positioned in other locations as well, such as also within a vein on the left surface of the left ventricle of the heart (although spaced apart from the first sensing electrode), in the right atrium, in the superior vena cava, etc.

Abstract: An implantable system for the defibrillation or cardioversion of the atria and the ventricles of a patient's heart comprises: a first catheter configured for positioning in the right ventricle of the heart; a second catheter configured for positioning through the coronary sinus ostium and in the coronary sinus of the heart, with the first and second catheters together carrying at least three defibrillation electrodes; a power supply; and a control circuit operatively associated with the power supply and the electrodes. The control circuit is configured for delivering an atrial defibrillation pulse through at least two of the electrodes, or a ventricular defibrillation pulse through at least two of the electrodes.

Abstract: An implantable defibrillator/cardioverter which generates a biphasic defibrillation/cardioversion waveform including a pulse generator comprising two capacitors and a pair of switches for connecting the capacitors in parallel during a first phase and in series during a second phase. The first phase has a small "tilt" between the leading edge voltage and the trailing edge voltage. The second phase has a leading edge voltage which is approximately twice the trailing edge voltage of the first phase.

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: An implantable system for the defibrillation or cardioversion of a patient's heart comprises a plurality of electrodes configured for delivering a defibrillation pulse along a predetermined current pathway in the heart. The plurality of electrodes includes a first electrode configured for positioning in the patient's heart. The system includes a power supply and a control circuit. The control circuit is operatively associated with the electrodes and the power supply.