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: 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 defibrillator applies cardioverting electrical energy to the atria of a heart when in need of cardioversion. The atrial defibrillator includes an atrial fibrillation detector for determining if the atria of a heart are in need of cardioversion, and a therapy sequencer for performing a therapy sequence to apply cardioverting electrical energy to the atria when the atria are in need of cardioversion. The therapy sequence is terminated when the atrial fibrillation detector fails at least twice in succession to determine that the atria are in need of cardioversion. As a result, a greater atrial fibrillation detection sensitivity is employed for terminating a therapy sequence as is employed for initiating the therapy sequence.

Abstract: An atrial cardiovertor/defibrillator provides therapy to the atria corresponding to the type of atrial arrhythmia occurring in the atria of the heart. The atrial cardiovertor/defibrillator includes a memory for storing respective different criteria for each of different types of atrial arrhythmia, a sensor for sensing activity of at least one of the atria of the heart to provide an electrogram signal, and a cardiovertor for providing a corresponding therapy to the heart for each of the different types of atrial arrhythmia. The cardiovertor/defibrillator further includes an atrial arrhythmia detector responsive to the electrogram signal and the stored criteria for identifying one of the types of atrial arrhythmia to cause the cardiovertor to provide therapy to the heart corresponding to the identified atrial arrhythmia.

Abstract: A lead is provided which assists in the implantation of the lead within an artery or vein of a human heart. The lead includes a lead body having a distal end and a proximal end and at least one electrode carried by the lead body intermediate the distal end and the proximal end. The lead includes a guide tip carried by the lead body which extends distally from the lead body distal end. The guide tip includes a distal tip end and a tapered portion forming the distal tip end. The tapered portion is curved in a direction of curvature to offset the distal tip end in a direction from the longitudinal center axis of the lead body. The guide tip may further include tines or fibrotic tissue ingrowth sites for retaining the lead in place after implantation.

Abstract: An atrial defibrillator coordinates atrial cardioversion with ischemia detection. The defibrillator includes a plurality of sense amplifiers for sensing electrical activity of a heart. An ischemia detector is responsive to the sensed electrical activity of the heart for detecting ischemia of the heart. An atrial fibrillation detector is responsive to the sensed electrical activity of the heart for determining if the atria are in need of cardioversion, and a cardiovertor applies cardioverting electrical energy to the atria of the heart if the atria of the heart are in need of cardioversion and if the ischemia detector fails to detect ischemia of the heart.

Abstract: An implantable atrial defibrillator provides a pulse of defibrillating electrical energy to the atria of the heart in synchronism with sensed R waves in response to non-coincident sensing of an R wave at first and second areas of the heart. The defibrillating pulse is provided after a predetermined number of consecutive R waves are non-coincidently sensed to assure reliable synchronization. The atrial defibrillator is also operational in a marker mode wherein a number of synchronization marker pulses are delivered to the heart for detection on an externally generated electrocardiogram. The atrial fibrillation detector of the defibrillator is normally disabled and is activated when the sensed ventricular activity indicates a probability of atrial fibrillation to conserve a depletable power source. An endocardial lead is also described which ensures that the delivered atrial defibrillating electrical energy is substantially confined to the atria of the heart.

Abstract: An atrial defibrillator implantable beneath the skin of a patient includes an intervention sequencer for performing an intervention sequence. The intervention sequencer includes an atrial fibrillation detector for determining if atrial fibrillation is present in a patient's heart and a cardiovertor for applying cardioverting electrical energy to the atria of the patient's heart if the atrial fibrillation detector determines that atrial fibrillation is present. A sequence initiating stage includes a receiver for receiving a sequence command generated from external to the patient. The sequence initiating stage causes the intervention sequencer to perform the intervention sequence upon receipt of a sequence command.

Abstract: An atrial defibrillator and method provides cardioverting electrical energy to the atria of a human heart after timing successive R to R intervals. A detector detects ventricular activations of the heart and a timer times intervals between immediately successive ventricular activations. A cardiovertor applies cardioverting electrical energy to the atria of the heart when a second time interval between a third ventricular activation and a second ventricular activation immediately preceding the third ventricular activation satisfies a predetermined criteria with respect to a first time interval between the second ventricular activation and a first ventricular activation immediately preceding the second ventricular activation.

Abstract: An atrial defibrillator implantable beneath the skin of a patient includes an intervention sequencer for performing an intervention sequence. The intervention sequencer includes an atrial fibrillation detector for determining if atrial fibrillation is present in a patient's heart and a cardiovertor for applying cardioverting electrical energy to the atria of the patient's heart if the atrial fibrillation detector determines that atrial fibrillation is present. A sequence initiating stage includes a receiver for receiving a sequence command generated from external to the patient. The sequence initiating stage causes the intervention sequencer to perform the intervention sequence upon receipt of a sequence command.

Abstract: An implantable atrial defibrillator provides a pulse of defibrillating electrical energy to the atria of the heart in synchronism with sensed R waves in response to non-coincident sensing of an R wave at first and second areas of the heart. The defibrillating pulse is provided after a predetermined number of consecutive R waves are non-coincidently sensed to assure reliable synchronization. The atrial defibrillator is also operational in a marker mode wherein a number of synchronization marker pulses are delivered to the heart for detection on an externally generated electrocardiogram. The atrial fibrillation detector of the defibrillator is normally disabled and is activated when the sensed ventricular activity indicates a probability of atrial fibrillation to conserve a depletable power source.

Abstract: An implantable atrial defibrillator provides a pulse of defibrillating electrical energy to the atria of the heart in synchronism with sensed R waves in response to non-coincident sensing of an R wave at first and second areas of the heart. The defibrillating pulse is provided after a predetermined number of consecutive R waves are non-coincidently sensed to assure reliable synchronization. The atrial defibrillator is also operational in a marker mode wherein a number of synchronization marker pulses are delivered to the heart for detection on an externally generated electrocardiogram. The atrial fibrillation detector of the defibrillator is normally disabled and is activated when the sensed ventricular activity indicates a probability of atrial fibrillation to conserve a depletable power source. An endocardial lead is also described which ensures that the delivered atrial defibrillating electrical energy is substantially confined to the atria of the heart.

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.

Abstract: An intravenous lead for use with a cardiac device implantable beneath the skin of a patient provides positive fixation for the lead when implanted in an artery or vein of the heart. The lead includes a lead body adapted to be fed into an artery or a vein of the heart of a patient and at least one electrode carried by the lead body and adapted to be coupled to the implantable cardiac device. The lead body includes a preformed section having a resiliently coiled configuration. The coiled section makes substantially continuous surface contact with inner wall surfaces of the artery or vein after the lead is implanted within the artery or vein for providing positive fixation of the lead.

Abstract: An implantable atrial defibrillator provides a pulse of defibrillating electrical energy to the atria of the heart in synchronism with sensed R waves in response to non-coincident sensing of an R wave at first and second areas of the heart. The defibrillating pulse is provided after a predetermined number of consecutive R waves are non-coincidently sensed to assure reliable synchronization. The atrial defibrillator is also operational in a marker mode wherein a number of synchronization marker pulses are delivered to the heart for detection on an externally generated electrocardiogram. The atrial fibrillation detector of the defibrillator is normally disabled and is activated when the sensed ventricular activity indicates a probability of atrial fibrillation to conserve a depletable power source.

Abstract: An atrial defibrillator reliably detects a depolarization activation wave of the heart and delivers cardioverting electrical energy to the atria of the heart in synchronism with a detected depolarization activation wave. The atrial defibrillator includes a first sensor for producing a first electrical output having a duration substantially equal to the duration of the depolarization activation wave sensed between a first pair of spaced apart locations of the heart. The atrial defibrillator further includes a second sensor for producing a second electrical output having a duration substantially equal to the duration of the depolarization activation wave sensed between a second pair of spaced apart locations of the heart. The spacing between the second pair of locations is greater than the spacing between the first pair of locations.

Abstract: An implantable atrial defibrillator provides cardioverting electrical energy to the atria of a patient's heart in need of cardioversion and a precardioversion warning to the patient. The atrial defibrillator includes a detector for detecting atrial activity of the patient's heart, and an atrial fibrillation detector responsive to the atrial activity detector for determining when the atria of the patient's heart are in need of cardioversion. A cardioverter responsive to the atrial fibrillation detector, applies warning electrical energy to the atria of the patient's heart when the atria are in need of cardioversion and thereafter applies cardioverting electrical energy to the atria. The warning electrical energy is of insufficient quantity to intentionally cardiovert the atria but of sufficient quantity so as to be discernable by the patient.

Abstract: A vascular catheter apparatus for penetration through tissue and for cardiac stimulation, and a methods thereof, are disclosed. The apparatus includes a tubular member having a lumen, and a blunt-end stylet within the lumen. An actuation mechanism causes axial movement of the stylet relative to the catheter tube such that the blunt end of the stylet separate tissue for passage of the catheter through the bored tissue. The stylet itself, or an additional stylet, includes a proximal electrode adapted to be oriented in a cardiac chamber and a distal electrode adapted to be oriented adjacent to the epicardium of the heart to cause cardiac stimulation.

Abstract: A cardiac pacing apparatus and method. A cardiac pacing apparatus (24) provides a cardiac pacing signal to a plurality of electrode pairs (20, 22), each comprising a positive electrode (20a, 22a) and a negative electrode (20b, 22b). A plurality of isolated current sources (30, 32) supply the electrode pairs with separate electric pacing currents, each small enough in magnitude so as to avoid patient discomfort or burning. The plurality of pacing currents delivered to the electrode pairs add to produce a total cardiac pacing current of sufficient magnitude to cause contraction of a heart muscle through which the pacing currents flow.

Abstract: An arrangement and method facilitates the implantation of an electrode of an endocardial or intravenous lead at an implantation site within the heart of a human. The arrangement includes a guide wire which is formed of flexible material and which may be fed along a predetermined path which includes the implantation site. The arrangement further includes a lead formed of flexible material which includes a proximal end, a distal end, and an electrode to be implanted. The lead further includes an integrally formed follower which slidingly engages the guide wire to permit the lead to be guided along the predetermined path until the electrode to be implanted resides at its implantation site. Thereafter, the guide wire is retracted along the predetermined path to cause the electrode to remain at its implantation site.