摘要:
An implantable cardiac device that is adapted to periodically measure a body parameter, such as transthoracic impedance, at time periods selected so that the body parameter is primarily indicative of the respiration of the patient. In this way, a ventilation parameter, such as minute ventilation, can be reconstructed from the signals without requiring filtering of the sampled signals. In one embodiment, the implantable cardiac device measures transthoracic impedance during each quiescent period of the heart and thereby obtains a plurality of transthoracic impedance data points which are then used to reconstruct a ventilation signal. As the transthoracic impedance data points are obtained during the quiescent period, the contribution of the heart to the resulting transthoracic impedance measurement can be ignored and the resulting measurements are indicative of the action of the heart. In another embodiment, the implantable cardiac device obtains transthoracic impedance signals during the zero crossings of the measured impedance signal. As the transthoracic signal is measured during the zero crossing of the measured impedance signal, the heart component of the signal is filtered out.
摘要:
A pyroelectric suppressor circuit for preventing undesirable thermally induced signals generated by a piezoelectric physical activity sensor from reaching processor circuitry within an implantable medical device is provided. The thermally induced signals typically have frequencies below a frequency in the range from about 0.1 mHz to about 10 mHz. The suppressor circuit provides a high-pass filter that rejects signals that have frequencies associated with thermally induced signals. Signals having frequencies greater than a frequency in the range from about 0.1 mHz to about 10 mHz, which correspond to patient activity, are passed on to processing circuitry of the implantable medical device.
摘要:
Methods and apparatus are provided for measuring the impedance of a patient's body. Pulse generating circuitry within a rate-responsive pacemaker is used to generate an impedance measurement signal that is applied to the body of the patient with conventional pacemaker leads. The impedance measurement signal contains a series of multiphasic impedance measurement waveforms, which have no net DC value and zero value after second integration. The impedance measurement signal allows the impedance of the body to be measured without interfering with external cardiac monitoring equipment such as electrocardiogram machines.
摘要:
Methods and apparatus are provided for measuring the impedance of a patient's body. Pulse generating circuitry within a rate-responsive pacemaker is used to generate an impedance measurement signal that is applied to the body of the patient with conventional pacemaker leads. The impedance measurement signal contains a series of multiphasic impedance measurement waveforms, which have no net DC value and zero value after second integration. The impedance measurement signal allows the impedance of the body to be measured without interfering with external cardiac monitoring equipment such as electrocardiogram machines.
摘要:
A leadless intra-cardiac medical device (LIMD) includes an electrode assembly configured to be anchored within a first wall portion of a first chamber of a heart. The electrode assembly includes an electrode main body having a first securing helix, an electrode wire segment extending from the body, and a first segment-terminating contact positioned on the electrode wire segment. The device further includes a housing assembly configured to be anchored within a second wall portion of a second chamber of the heart. The housing assembly includes a body having a second securing helix, a housing wire segment extending from the body, and a second segment-terminating contact positioned on the housing wire segment. The device also includes a connector block that electrically connects the electrode wire segment to the housing wire segment by retaining the first and second segment-terminating contacts.
摘要:
A leadless implantable medical device (LIMD) includes a housing formed from a battery and an end cap. A proximal end of the end cap forms an LIMD proximal end and a distal end of the battery case forms an LIMD distal end. A non-conductive coupler mechanically secures a terminal end of the battery case to a mating end of the end cap, while maintaining the battery case and end cap electrically separated. A first electrode projects from the proximal end of the end cap. An intra-cardiac (IC) device extension projects from the distal end of the battery case. The extension includes a second electrode that is electrically connected to the battery case. The second electrode is located remote from the LIMD distal end. An electronics module is located within an internal cavity of the end cap and communicates with the first and second electrodes.
摘要:
Systems and methods are provided for detecting the orientation and/or movement of a patient having an implantable cardiac stimulation device and evaluating whether a change in the patient's cardiac activity can be at least in part due to a change in the patient's orientation. In one particular embodiment, signals from an orientation sensor and/or a pressure sensor are evaluated to determine static positional orientation of the patient and determine based on the static orientation whether the patient's cardiac activity is abnormal.
摘要:
A leadless intra-cardiac medical device (LIMD) configured to be implanted entirely within a heart of a patient includes a housing configured to be securely attached to an interior wall portion of a chamber of the heart, and a stabilizing intra-cardiac (IC) device extension connected to the housing. The stabilizing IC device extension may include a stabilizer arm, and/or an appendage arm, or an elongated body or a loop member configured to be passively secured within the heart.
摘要:
A leadless intra-cardiac medical device includes a housing that is configured to be implanted entirely within a single local chamber of the heart. A first electrode is provided on the housing at a first position such that when the housing is implanted in the local chamber, the first electrode engages the local wall tissue at a local activation site within the conduction network of the local chamber. An intra-cardiac extension is coupled to the housing and configured to extend from the local chamber into an adjacent chamber of the heart. A stabilization arm of the intra-cardiac extension engages the adjacent chamber. A second electrode on the intra-cardiac extension engages distal wall tissue at a distal activation site within the conduction network of the adjacent chamber.
摘要:
An implantable physiologic sensor assembly is configured to be implanted within a patient. The assembly includes a module that houses an internal operative chamber, and a flexible pressure-detecting member connected to the module. The module and the pressure-detecting member are separated before implantation into the patient. At least a first end of the pressure-detecting member is configured to be inserted into an artery of the patient and a second end of the pressure-detecting member is connected to the module. The module is configured to be subcutaneously positioned within the patient.