Medtronic ICDs can alert you with both audible tones and vibration. A common pattern is a six-second vibration, then sixteen seconds of silence, then a further six-second vibration, then ten seconds of silence, after which the pattern repeats.
A solid, continuous tone is the magnet alert tone, which you may hear when a magnet is placed over the device. These tones are programmable, so your clinic can adjust them or switch them off, and your own device may sound different.
If you hear an alert, contact your ICD clinic. To hear exactly what your device sounds like, ask for a demonstration at your next appointment. Our ICD sounds and alerts page has example recordings.