Automatic sensitivity control for a pacemaker
First Claim
1. An automatic sensitivity control for an implantable pacemaker comprising means for sensing a cardiac signal, means for amplifying said cardiac signal, means for comparing the amplified cardiac signal with a threshold value for determining the occurrence of a cardiac event, means for measuring the peak amplitude of said amplified cardiac signal for the determined cardiac event, means for deriving a value representative of the average of the measured peak amplitudes during a preceding time interval which is at least a few minutes long, and means for varying the gain of said amplifying means in accordance with said derived value.
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Accused Products
Abstract
An implantable pacemaker in which the sensitivity is automatically controlled. The peak value of each R wave is measured, and a long-term average is derived. The gain of the sense channel is adjusted automatically in accordance with the average of the measured peak values.
63 Citations
10 Claims
- 1. An automatic sensitivity control for an implantable pacemaker comprising means for sensing a cardiac signal, means for amplifying said cardiac signal, means for comparing the amplified cardiac signal with a threshold value for determining the occurrence of a cardiac event, means for measuring the peak amplitude of said amplified cardiac signal for the determined cardiac event, means for deriving a value representative of the average of the measured peak amplitudes during a preceding time interval which is at least a few minutes long, and means for varying the gain of said amplifying means in accordance with said derived value.
- 7. A method for improving the determination of the occurrence of a cardiac event comprising the steps of sensing a cardiac signal, amplifying said cardiac signal, comparing the amplified cardiac signal with a threshold value for determining the occurrence of a cardiac event, deriving a value representative of the average of the measured peak amplitudes during a preceding time interval which is at least a few minutes long, and varying the gain of said amplifying means in accordance with said derived value.
Specification