A high sensitivity number in pacing means:

A high sensitivity number in pacing indicates that the device is capable of sensing more events. This means that the pacing device can detect a wider range of electrical signals from the heart. Higher sensitivity allows for the detection of subtler cardiac signals, enabling prompt pacing to be initiated even with low-amplitude signals. This is particularly useful in clinical situations where precise heart rhythm management is critical.

In contrast, a lower sensitivity number could result in the device missing important heartbeats, which could lead to inadequate pacing or failure to respond to arrhythmias. Thus, a high sensitivity number is a vital characteristic in ensuring effective and reliable pacing therapy.