摘要:
A method for automatically determining the ventilatory (or “anaerobic”) threshold breakpoint for adaptive rate pacing without the need for directly measuring anaerobic threshold or ventilatory threshold comprises: (a) positioning a first sensing electrode in the heart or superior vena cava of a patient carrying an implanted pacemaker, the first sensing electrode connected to the implanted pacemaker; (b) positioning a second sensing electrode in the thoracic region of the patient and spaced apart from the first sensing electrode; (c) determining the chest wall impedance of the patient between the first sensing electrode and the second sensing electrode; (d) measuring the ventilation (e.g., the minute ventilation) of the subject from the chest wall impedance during submaximal exercise by the patient; and then (e) determining the ventilatory threshold breakpoint of the patient from the measured ventilation. In the pacemaker, the adaptive rate pacing is preferably based on measured chest wall impedance, with pacing rate increasing as exercise or metabolic activity sensed thereby increases. The implanted pacemaker is then preferably programmed, preferably automatically, so that the rate of increase in pacing rate in response to increasing ventilation by the pacemaker is attenuated after the breakpoint is reached. Peak ventilation is preferably also determined so that the maximum pacing rate of the pacemaker output is matched to the peak ventilation during adaptive rate pacing from the pacemaker. Apparatus implementing the method is also disclosed.
摘要:
A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into a wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to the centering catheter distal end portion and configured for positioning within the vessel when in a retracted configuration, and for securing the elongate centering catheter in a substantially axially aligned position with respect to the vessel when the centering element is in an expanded configuration; (c) an ablation catheter slidably connected to the centering catheter the ablation element having a distal end portion, and (d) an expandable ablation element connected to the ablation catheter distal end portion.
摘要:
A device and method for programming an implantable pulse generator. In one embodiment, commands are entered designating implantable pulse generator programming variables into programmer memory. At least some of the commands are transformed into an executable macro. The macro is stored in the programmer memory. The macro is executed to transmit the programming variables to the implantable pulse generator.
摘要:
A device and method for programming an implantable pulse generator. In one embodiment, commands are entered designating implantable pulse generator programming variables into programmer memory. At least some of the commands are transformed into an executable macro. The macro is stored in the programmer memory. The macro is executed to transmit the programming variables to the implantable pulse generator.
摘要:
A device and method for programming an implantable pulse generator. In one embodiment, commands are entered designating implantable pulse generator programming variables into programmer memory. At least some of the commands are transformed into an executable macro. The macro is stored in the programmer memory. The macro is executed to transmit the programming variables to the implantable pulse generator.
摘要:
A device and method for programming an implantable pulse generator. In one embodiment, commands are entered designating implantable pulse generator programming variables into programmer memory. At least some of the commands are transformed into an executable macro. The macro is stored in the programmer memory. The macro is executed to transmit the programming variables to the implantable pulse generator.
摘要:
A cardiac ablation apparatus for producing a circumferential ablation that electrically isolates a heart chamber wall portion from vessel such as a pulmonary vein extending into said wall portion comprises (a) an elongate centering catheter having a distal end portion; (b) an expandable centering element connected to said centering catheter distal end portion and configured for positioning within said vessel when in a retracted configuration, and for securing said elongate centering catheter in a substantially axially aligned position with respect to said vessel when said centering element is in an expanded configuration; (c) an ablation catheter slidably connected to said centering catheter said ablation element having a distal end portion, and (d) an expandable ablation element connected to said ablation catheter distal end portion. The ablation element is configured to form a circumferential ablation on the wall around the elongate centering catheter when the centering catheter is axially aligned with respect to the vessel. In a further embodiment, a non-expandable, compliant centering element is employed, such as an elastic finger. Systems incorporating such an apparatus and methods of use thereof are also disclosed.
摘要:
An implantable cardiac stimulation device and method treats intrinsic ventricular rhythms lacking atrial transport to the heart. Once an arrhythmia detector detects an intrinsic ventricular rhythm lacking atrial transport, an atrial pulse generator paces the atria to restore atrial transport. The pacing is maintained at a constant rate for a first time period after which the pacing rate is decreased over a recovery time period. The device and method may also be employed for treating accelerated junctional rhythms, accelerated idioventricular rhythms, and first degree AV block, all of which result in inhibition of a dual-chamber pacemaker.