It sounds like you're saying the ticking clock is present along with (on top of) the heartbeat, so removing the ticks would leave gaps..? If that's the case, the tool you really need is spectral processing, which is usually found in audio repair software suites, like iZotope's RX7. Spectral processing *might* be able to remove the ticks while stitching up the audio underneath to avoid gaps -- it would depend on the specific audio. Unfortunately audio repair software can be pricey, but there may be some relatively inexpensive options..
To get a sense of whether that would apply to your recording, these videos show examples of spectral processing in action [in RX7], removing various noises from audio recordings..