摘要:
A cardiac pacemaker with a rate stabilization pacing mode. The pacemaker varies the increment following a cycle ending in a sensed depolarization as a function of the underlying heart rate and may additionally vary the increment as a function of the prematurity of the most recently sensed depolarization relative to the preceding depolarization. A greater increment is generally provided if the underlying cycle length is greater, while the increment may be lessened following relatively more premature depolarizations. Prematurity may be determined by comparing the cycle (CLnew) ending in the most recently sensed depolarization with the previous cycle length (CLold), for example by calculating CLnew/CLold or CLold-CLnew. The mechanism for determining the duration of the increment provides for a more rapid return to a lower underlying heart rate, while still avoiding the short-long interval pattern sometimes associated with the onset of tachycardia.
摘要:
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.
摘要:
This disclosure is directed to extra, intra, and transvascular medical lead placement techniques for arranging medical leads and electrical stimulation and/or sensing electrodes proximate nerve tissue within a patient.
摘要:
A method and apparatus for delivering corrective therapy through hormone regulation is provided. Inhibition of sympathetic fibers by spinal cord stimulation is used to regulate the levels of hormones such as catecholamines, renin, and calcitonin gene-related peptide. The invention utilizes a closed or open loop feedback system in which physiological parameters such as the concentrations of hormones and sympathetic indicators such as heart rate and urine production are monitored and used to determine the appropriate level of neurostimulation. The site of electrical stimulation includes, but is not limited to, the spinal cord at levels T7–L2 and the associated neural fibers within a region of the T7–L2 dermatomes
摘要:
A system of performing a medical procedure, such as surgery, is provided. The system comprises a compression member for compressing a body portion and a means for controlling the compression. Methods and devices for performing the medical procedure are also provided.
摘要:
A method of performing a medical procedure, such as surgery, is provided. The spinal cord is stimulated in order to control at least one physiological function. The medical procedure is performed and stimulation of the spinal cord is stopped.
摘要:
A medical device selects the most appropriate among various calculated escape intervals for use in the next cardiac cycle. This is particularly implemented in cardiac event in which a pacemaker is used to prevent multiple tachyarrhythmias. The prevention pacing modes may be simultaneously active, with the escape interval for each mode calculated and updated on a beat-by-beat basis. The medical device selects tachyarrhythmia prevention pacing modality to control the escape interval of the current cardiac cycle in order that a more appropriate method for calculating the escape interval based on the present condition of the patient, may be selected.
摘要:
A method and apparatus for determining the occurrence of a mis-location of an atrial electrode in a cardiac stimulation device having an atrial pulse generator coupled with the atrial electrode and a ventricular sense amplifier coupled to a ventricular electrode. The device paces the atrium in a first pacing mode employing atrial pacing pulses at a first energy level and in a test mode employs higher energy atrial pacing pulses. In the test mode the device measures PR intervals between atrial pacing pulses following sensed ventricular depolarizations and determines that the atrial electrode is mis-located responsive to occurrence of a threshold number of short PR intervals or that the atrial electrode is appropriately located responsive to occurrence of a threshold number of long PR intervals. Operation of the device in the test mode may be pre-conditioned on an absence of atrial tachyarrhythmia.
摘要:
An implantable anti-tachyarrhythmia device which delivers atrial cardioversion or defibrillation pulses heart in response to detection of atrial tachyarrhythmias. The pulses are synchronized to atrial and ventricular events in such a fashion as to assure they occur outside of the vulnerable periods associated with both chambers. The device is provided with a pulse synchronizer which defines a first synchronization interval initiated following a sensed atrial event and a second synchronization interval initiated responsive to a sensed ventricular event and a pulse triggerer which triggers delivery of a cardioversion or defibrillation pulse responsive to the first and second synchronization intervals simultaneously being underway. In particular, the pulse triggerer may be responsive to initiation of the first synchronization interval during the second synchronization interval. In addition, the synchronizer may also define minimum time intervals following ventricular events and the triggerer may additionally be responsive to expiration of a defined minimum time interval following a ventricular event preceding the sensed ventricular event which initiated the second synchronization interval currently underway.
摘要:
A pacemaker provided with a mode switching feature adapted to stabilize ventricular heart rate during atrial fibrillation. In a preferred embodiment of the invention, the device nominally operates in an atrial synchronized pacing mode such as DDD, DDDR, VDD or VDDR. In response to detection of atrial rhythm characteristics consistent with atrial fibrillation, the device switches into a non-atrial synchronized, ventricular rate stabilization pacing mode with the base ventricular pacing rate modulated on a beat by beat basis based upon preceding intrinsic or paced ventricular heartbeat intervals to adjust the pacing interval towards a desired preset rate stabilization target pacing interval which is typically less than the programmed base pacing interval of the device. While the ventricular rate stabilization mode is in effect, the current pacing interval is set equal to the preceding intrinsic or paced interval, with an increment if the preceding interval is less than the desired or target pacing interval, as typically will be the case, or with a decrement if the preceding interval is greater than the desired pacing interval. In a preferred embodiment of the invention, the device paces both the atria and ventricles in a DDI rate stabilization pacing mode with the ventricular pacing interval being modulated.