Implantable medical device system with method for determining lead condition
First Claim
1. An implantable pacemaker system, comprising a pacemaker and a lead, the pacemaker having means for delivering pace pulses to a patient'"'"'s heart through the lead and the pacemaker having means for sensing patient heart signals through the lead, the system having lead impedance means for obtaining a measure of a lead impedance, said lead impedance means further comprising a controllable burst generator for delivering to said lead an AC burst having a duration in a range of 50-125 ms and a limited current, and timing means for controlling the timing of said burst to follow a delivered pace pulse so that said burst is delivered substantially within a refractory period of the patient'"'"'s heart following delivery of said pace pulse.
1 Assignment
0 Petitions
Accused Products
Abstract
In an implantable medical device system such as a pacemaker system, there is provided a system and method for measuring lead impedance so as to obtain reliable data concerning any indication of the need to replace the lead. A relatively short duration low current AC burst is delivered after a standard pacing pulse, at a time to coincide with the heart'"'"'s refractory period. The pulse is long enough in duration, e.g., 50-125 ms and preferably around 100 ms, to achieve the benefit of substantially steady state measurement, but short enough to substantially avoid the possibility of inducing any cardiac arrhythmia. The current level of the burst is limited to about 30 microamps, providing a further factor of safety against inducing an unwanted arrhythmia. The PPAC technique is adaptable for automatic measurement within an implantable device, or for implementation involving an external programmer which triggers the test.
-
Citations
17 Claims
- 1. An implantable pacemaker system, comprising a pacemaker and a lead, the pacemaker having means for delivering pace pulses to a patient'"'"'s heart through the lead and the pacemaker having means for sensing patient heart signals through the lead, the system having lead impedance means for obtaining a measure of a lead impedance, said lead impedance means further comprising a controllable burst generator for delivering to said lead an AC burst having a duration in a range of 50-125 ms and a limited current, and timing means for controlling the timing of said burst to follow a delivered pace pulse so that said burst is delivered substantially within a refractory period of the patient'"'"'s heart following delivery of said pace pulse.
-
11. A method of determining the impedance of a pacing lead in a pacemaker system, comprising the steps of:
-
delivering a stimulus pulse through said lead; generating and delivering a constant current AC burst following delivery of said stimulus pulse, said generating including limiting said burst to a time duration of about 50-125 ms and limiting the peak-to-peak current of said burst to about 30 microamps, and measuring the voltage across said lead during delivery of said burst, thereby obtaining a measure of said lead impedance. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
Specification