Boston Scientific ICDs use audible alert tones. A typical alert is a set of sixteen tones that repeats roughly every six hours until the device is checked.
It is worth knowing that having an MRI scan permanently disables the beeper on these devices. If that applies to you, your clinic will usually recommend relying on remote monitoring so that alerts are still picked up.
If you hear an alert, contact your ICD clinic. To hear what your device sounds like, ask for a demonstration at a clinic visit. Our ICD sounds and alerts page has more detail.