Abstract: There is disclosed an atrial defibrillator including a lead system for sensing activity of a heart in or near at least on atrium of the heart, a detector for detecting atrial events from the sensed atrial activity, and a cardioverter for applying cardioverting electrical energy to the atria of the heart when the atria are in need of cardioversion. A timer determines time spans between successive detected atrial events and an inhibit stage precludes the cardioverter from applying cardioverting energy to the heart when a time span is greater than a predetermined limit.

Abstract: A system and method are provided for detecting dislodgment of a right atrial endocardial lead implanted within a heart right atrium wherein the lead includes an electrode. Heart activity of the right atrium of the heart, and heart activity of the right ventricle of the heart, and heart activity with the endocardial lead electrode are sensed during a time period. The sensed heart activity is stored in memory. The stored heart activity is analyzed to establish a first time window from the sensed heart activity of the right atrium and a second time window from the sensed heart activity of the right ventricle. The heart activity sensed with the endocardial lead electrode during the first time window is then compared to the heart activity sensed with the endocardial lead electrode during the second time window.

Abstract: There is disclosed an implantable atrial defibrillator for applying cardioverting electrical energy to the atria of a heart when the atria are in need of cardioversion. The atrial defibrillator includes a sense channel adapted to be associated with at least one atrium of the heart to provide a cardiac signal during a plurality of cardiac cycles of the heart and a timer which determines a cardiac interval duration for each of the cardiac cycles. The defibrillator further includes an atrial detector for analyzing the cardiac signal provided by the sense channel during selected ones of the cardiac cycles wherein each one of the selected ones of the cardiac cycles has a cardiac interval greater than a predetermined duration.A cardioverter applies cardioverting electrical energy to the atria responsive to the atrial detector detecting atrial fibrillation of the heart.

Abstract: An implantable atrial cardiovertor applies cardioverting electrical energy to atria of a heart with reduced discomfort to a patient. The cardiovertor includes a storage capacitor having a capacitance and a discharge control for controlling discharge of the storage capacitor to apply the cardioverting electrical energy to the atria of the heart. The discharge control causes the applied cardioverting electrical energy to have a biphasic waveform having a first phase and a second phase of opposite polarity and equal time duration. The time durations of the first and second phases are each greater than four milliseconds, and the capacitance of the storage capacitor is greater than or equal to 120 .mu.F.

Abstract: An implantable atrial defibrillator includes a lead system having a plurality of electrodes to deliver a cardioverting pulse to atria of a heart, for sensing A waves of the heart, and for sensing R waves of the heart. A first detector detects the A waves sensed by the lead system and a second detector detects the R waves sensed by the lead system. An inhibit stage defines an inhibit time period responsive to each detected R wave and an output provides the cardioverting pulse to the lead system responsive to an A wave being detected. The inhibit stage precludes provision of the cardioverting pulse during each inhibit time period.

Abstract: A method is provided for removing an implanted cardiac lead having a lead body and at least one conductive electrode from a mammalian body. The method includes the steps of providing an indifferent electrode, establishing electrical contact between the indifferent electrode and the body, and providing a generator of electrical energy. The method further includes the steps of coupling the generator between the conductive electrode and the indifferent electrodes and causing the generator to apply electrical energy between the conductive electrode and the indifferent electrode. The energy has a magnitude sufficient to produce gas by electrolysis between the conductive electrode and fibrotic tissue grown around the electrode. Thereafter, the lead body is pulled in an anterior direction relative to the mammalian body to remove the cardiac lead from the mammalian body.

Abstract: A post-surgical atrial cardioverting, atrial pacing, and ventricular pacing system and lead system provides for cardioverting the atria, pacing the atria, and/or pacing the ventricles of the heart of a post-surgical heart patient. The system includes a first lead and a second lead providing a pair of atrial cardioverting electrodes, an atrial pacing electrode, and a ventricular pacing electrode. The electrodes are electrically isolated from each other. The system further includes at least one anchor releasably disposing the electrodes beneath the skin of the patient with each atrial cardioverting electrode electrically contacting a respective given one of the atria, the atrial pacing electrode electrically contacting one of the atria, and the ventricular pacing electrode electrically contacting a ventricle.

Abstract: An implantable defibrillation system includes a lead system for making electrical contact with a heart, an atrial cardiovertor coupled to the lead system for applying cardioverting electrical energy to that is of the heart, and a ventricular defibrillator coupled to the lead system. The ventricular defibrillator includes a ventricular arrhythmia detector responsive to a control signal for detecting for a ventricular arrhythmia of the heart and a ventricular cardiovertor for cardioverting the ventricles of the heart in response to the ventricular arrhythmia detector detecting a ventricular arrhythmia. A ventricular arrhythmia detector enable stage provides the control signal in response to each application of cardioverting electrical energy to the atria by the atrial cardiovertor.

Abstract: A suture sleeve fixes an implanted cardiac device lead to body tissue beneath the skin of a patient. The suture sleeve includes a base, and suture holes permitting the suture sleeve to be suture to the body tissue. A flexible strap member extends from the base for encircling the lead and includes at least one ratchet tooth. A pawl within the base lockingly engages the flexible strap ratchet tooth after the strap is wrapped about the lead.

Abstract: An implantable atrial defibrillator includes a cardiovertor for applying cardioverting electrical energy to the atria of a heart when the atria are in need of cardioversion. The defibrillator further includes a pacer for pacing the atria of the heart immediately after each application of cardioverting electrical energy to the atria of the heart. A rate control commences the pacing at a relatively high first rate and gradually reduces the rate to a lower second rate.

Abstract: A defibrillation system for providing post-cardiac surgery atrial cardioversion includes a lead system having defibrillation electrodes for electrical contact with the heart beneath the skin of a patient and a non-implantable external defibrillator for providing defibrillation electrical energy. An interface unit is coupled between the external defibrillator and the lead system and includes an attenuator circuit for attenuating the defibrillation electrical energy provided by the external defibrillator.

Abstract: An atrial defibrillation system includes an implantable atrial defibrillator including an atrial fibrillation detector and an atrial cardiovertor, and an external communication device dimensioned to be hand-held and including an RF transmitter for transmitting a command signal to the implanted defibrillator. The implantable defibrillator includes a receiver for receiving the command signal, activation means responsive to receipt of the command signal for activating the atrial fibrillation detector and the atrial cardiovertor if the atrial fibrillation detector detects atrial fibrillation, and an RF transmitter for transmitting an acknowledgment signal to the external communication device responsive to the receiver receiving the command signal. The external communication device further includes a receiver for receiving the acknowledgment signal and an indicator for providing a perceptible indication responsive to receipt of the acknowledgment signal.

Abstract: An implantable atrial defibrillator provides adaptive output voltage control. An atrial cardiovertor is responsive to an atrial fibrillation detector for applying a cardioverting voltage having a magnitude to the atria of a heart when the atria are in need of cardioversion. A memory stores data associated with each such voltage application. A computation stage computes from the stored data a percentage of success which is compared to lower and upper limits. The output voltage is incremented or decrement based upon the comparison. The output voltage may further be maintained within a fixed preselected voltage range.

Abstract: A system for use in implanting an implantable cardiac device includes an external device operable to emulate the operation of the implantable cardiac device in accordance with a set of modality and operating parameters. An external programmer includes a transmitter for transmitting the set of operating and modality parameters and the external device includes a receiver for receiving the set of operating parameters transmitted by the external programmer. A memory within the external programmer stores the transmitted set of operating parameters and retransmits the set of operating parameters to the implantable cardiac device after it is implanted. The external programmer and external device each include a telemetry antenna. The external programmer and external device are arranged for aligning the telemetry antennas when the external programmer and external device are being used together.

Abstract: An implantable atrial defibrillator includes a cardiovertor for applying cardioverting electrical energy to the atria of a heart when the atria are in need of cardioversion. The defibrillator further includes a pacer for pacing the atria of the heart immediately after each application of cardioverting electrical energy to the atria of the heart. The atria are paced in a demand mode and for a finite time period.

Abstract: A lead for implantation in a human body exhibits improved combined biodegradation, blood surface compatibility, wear and flexibility characteristics. The lead includes at least one electrode and at least one connector connecting the electrode to a connector at the proximal end of the lead. An outer insulation surrounds the at least one conductor, and includes a first insulation formed of silicone encircling the at least one conductor, and a second insulation formed from polyurethane encircling the silicone rubber insulation.

Abstract: An implantable atrial defibrillator includes a storage capacitor for storing electrical energy. A switch discharges at least a portion of the stored energy into a patient's heart as a discharge voltage and a charger charges the storage capacitor with the stored energy to a peak voltage. A voltage limiter precludes the discharge voltage from exceeding a voltage limit during capacitor discharge to permit a reduced applied cardioverting voltage with a lengthened discharge time. The voltage limit is a substantially constant fraction of the peak voltage.

Abstract: An implantable atrial defibrillator applies cardioverting electrical energy to the atria of a human heart. The atrial defibrillator includes a first detector for sensing depolarization activation waves at a first area of the heart and producing a first signal, a second detector for sensing depolarization activation waves at a second area of the heart and producing a second signal, an analyzing circuit for determining if the first signal satisfies a first criterion and if the second signal satisfies a second criterion. The atrial defibrillator includes a third detector for sensing activity of the heart in at least one of the atria of the heart and an atrial fibrillation detector for determining when the atria of the heart are in need of cardioversion.

Abstract: A defibrillator system includes an implantable defibrillator and a non-implantable external receiver. The implantable defibrillator includes a first sense channel for generating a first electrogram and a second sense channel for generating a second electrogram. The defibrillator further includes a cardioverter for applying cardioverting electrical energy to the heart and a transmitter for transmitting the first and second electrograms. The non-implantable receiver includes a display for simultaneously displaying the first and second electrograms. The implantable defibrillator may further include an event detector having a threshold for detecting cardiac events in one of the electrograms and an event marker generator for generating an event marker for each detected cardiac event. The transmitter transmits the event detection markers and the display displays the event detection markers and the thresholds with the corresponding electrogram.

Abstract: A post-surgical cardioverting system and method applies cardioverting electrical energy to the atria of the heart of a post-surgical heart patient. The system includes a first lead including a first elongated electrode having a proximal end and a distal end, a second lead including a second elongated electrode having a proximal end and a distal end, and sutures for releasably anchoring the distal ends of the first and second electrodes to the pericardium and disposing the first and second electrodes along the pericardium overlying the right and left atria respectively. A non-implantable cardiovertor is coupled to the first and second leads for applying the cardioverting electrical energy to the first and second electrodes. When cardioversion is no longer required, the first and second leads may be pulled out of the patient's chest.