Abstract: In an implantable pacemaker/cardioverter/defibrillator, a system for correlating the delivery of a cardioversion therapy to an optimum point or phase of the respiratory cycle of the patient to effect delivery of the therapy when the impedance between the cardioversion electrodes is minimized. In a first application for use with cardioversion electrodes located substantially in contact with the heart chamber, the optimum point or phase is at the end of inspiration. In a second application for use with at least one cardioversion electrode located remotely from the heart chamber, the optimum point or phase is at end expiration or beginning of inspiration. The cardioversion therapy is delivered in synchrony with a ventricular sense event, if present. If the optimum point or phase of the respiratory cycle cannot be determined during a therapy time, a pre-shock may be delivered to elicit a respiration cycle through a stimulated contraction of the diaphragm.

Abstract: A method an apparatus for treating fibrillation, particularly atrial fibrillation. In response to detection of fibrillation, a high frequency, low energy pulse burst is delivered via pacing electrodes, accompanied by a high energy pulse delivered via defibrillation electrodes. The low energy pulse burst is preferably delivered to an area of the heart which exhibits relatively lower current density during delivery of the high energy pulse.

Abstract: A method and apparatus for treating atrial tachyarrhythmias, particularly atrial fibrillation. High energy pulses are delivered between electrodes located in the right atrium/SVC, the left pectoral region and the coronary sinus/great vein, with the left pectoral and coronary sinus/great vein electrodes connected in common. Optionally a ventricular electrode may also be employed in conjunction with one or more of the other listed electrodes to accomplish ventricular cardioversion or defibrillation.

Abstract: A method and apparatus for treating fibrillation, particularly atrial fibrillation. In response to detection of fibrillation, a series of low energy pulse bursts is delivered, separated by defined inter-burst intervals, and including bursts unsynchronized to heart depolarizations. Detection of termination of fibrillation during inter-burst intervals results in cancellation of further pulse bursts to prevent reinduction of fibrillation.

Abstract: A method and apparatus for treating atrial tachyarrhythmias, particularly atrial fibrillation. High energy pulses are delivered between electrodes located in the right atrium/SVC, the right ventricle and the coronary sinus/great vein, with the right ventricular and coronary sinus/great vein electrodes connected in common. Optionally a subcutaneous electrode, preferably located in the left pectoral area may also be employed, coupled in common to the right atrial/SVC electrode.