Cardiac Devices · Module 5 of 7
Sensing, Capture & Thresholds
Master the language of device work: sensing, capture, pacing threshold, oversensing and undersensing.
Learning objectives
SensingDistinguish detecting intrinsic activity from delivering pacing output.
CaptureRecognize the myocardial response to a pacing stimulus.
ThresholdUnderstand threshold as a measured minimum under specified test conditions.
Three terms that should never be mixed up
SensingThe device detects intrinsic cardiac electrical activity.
CaptureA pacing stimulus successfully depolarizes the intended myocardium.
ThresholdThe minimum tested pacing output that consistently produces capture under the defined test conditions.
Oversensing vs undersensing
Oversensing
The device detects signals/events that should not be counted as the intended cardiac event, potentially altering device timing or therapy behavior.
Undersensing
The device fails to detect an intrinsic cardiac event that should have been sensed.
A pacing stimulus occurs but no expected myocardial depolarization follows. Which concept is most relevant?
Educational scope: Device programming, implant decisions, therapy changes, alerts and patient management require appropriately credentialed clinicians, institutional protocols, and current manufacturer instructions.
Lesson progress
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