Implantable system for stimulating a human heart or an animal heart

An implantable system for stimulating a heart including a human heart or an animal heart, the implantable system comprising:

• a processor;
• an atrial stimulator;
• a detector for detecting atrial tachycardia,
• a memory storing a computer-readable program prompting said processor to carry out the following steps when the computer-readable program is being executed on said processor:
• detecting by way of said detector whether the atrial tachycardia to be treated is present in the human heart or the animal heart;
• applying atrial antitachycardia pacing by way of the atrial stimulator when the atrial tachycardia to be treated is present;
• and
• carrying out an atrial post-treatment stimulation after the atrial antitachycardia pacing has been applied only when no tachycardiac intrinsic atrial activity is present, wherein the atrial post-treatment stimulation is applied with the atrial stimulator and is configured to be within a range of 1 minute up to 7 days, and the atrial post-treatment stimulation uses a stimulation rate of less or equal to 200 bpm.