What can cause pacemaker oversensing?

What can cause pacemaker oversensing?

• A. Lead fracture
• B. Myopotentials or external electrical interference
• C. Battery depletion
• D. Coronary artery disease

Answer: (B)

Over-sensing happens when the pacemaker’s sensing circuit picks up electrical signals that are not actual heartbeats, causing it to misinterpret intrinsic activity as already paced activity and inhibit pacing or mis-timed firing. The classic source of this misinterpretation is noncardiac electrical activity, such as myopotentials from chest muscles during movement or external electrical interference from nearby equipment. When these muscle or environmental signals are detected as cardiac events, the device may inappropriately withhold pacing or deliver pacing at the wrong times, leading to pauses or bradycardia. Lead problems like fracture can also introduce noise that the device may mistake for cardiac signals, but the scenario most commonly tested is oversensing due to myopotentials or EMI. To manage, clinicians may adjust the device’s sensitivity, reprogram the settings, verify lead integrity, and minimize exposure to sources of interference.

Over-sensing happens when the pacemaker’s sensing circuit picks up electrical signals that are not actual heartbeats, causing it to misinterpret intrinsic activity as already paced activity and inhibit pacing or mis-timed firing. The classic source of this misinterpretation is noncardiac electrical activity, such as myopotentials from chest muscles during movement or external electrical interference from nearby equipment. When these muscle or environmental signals are detected as cardiac events, the device may inappropriately withhold pacing or deliver pacing at the wrong times, leading to pauses or bradycardia. Lead problems like fracture can also introduce noise that the device may mistake for cardiac signals, but the scenario most commonly tested is oversensing due to myopotentials or EMI. To manage, clinicians may adjust the device’s sensitivity, reprogram the settings, verify lead integrity, and minimize exposure to sources of interference.