Uhhh. I'm not too sure. But as far as I know, it's anytime anything happens in WoW. So a new chat message, a new WoWObject pops up. You can change when it pulses, just a little bit of tinkering and it'll get the job done.
Seems to depend on what the bot is doing. I see it 'pulse' every ~200ms while fighting but gets lower when travelling. Best way to see it pulse: Will print something like Pulse! 123 Pulse! 42 Pulse! ... Open your log file to see the current datetime for each pulse.
It ticks 20 times per second at max. If a CC or plugin blocks the thread it will decrease the tickrate. That's why we advise against using Thread.Sleep in pulses/combat etc.
