Player is required to actively participate in the healing process in some manner, either simply pressing some button down until healing is done or working in some minigame, usually blocking normal gameplay for the duration.
The first video game about Active healing was released on September 2005.
Combining with gradual healing may imply that player may stop the process midway producing partial health restoration. Alternatively with added delayed healing, the effect starts after the process has ended. Essentially simulating the fact that no matter how good the healer is, people don't immediately feel up for the next beating.