Purpose: Effectiveness of implantable defibrillators ( ICD) has been proven with large randomized trials. Unfortunately, ICD discharge is painful and potentially threatening for the patient despite its life saving effects. We analyzed influence of the clinical parameters present before implantation on the effectiveness of antitachycardia pacing therapy (ATP) in terminating ventricular tachycardia (VT) slower than 200 bpm in the coronary artery disease patients with prophylactic implanted ICD in a single centre retrospective trial. Patients/methods: We analyzed 121 consecutive coronary disease patients with ICD implanted in primary prophylaxis between 2001 and 2007, with the mean age of 62 +/- 10 years. The mean follow- up was 876 +/- 538 days. Results: 32 of them had VT. In 27 persons (84.4%) at least one ATP attempt terminate VT. ATP was always successful in 21 patients. We analyzed age, sex, LVEF, NYHA class, widening of QRS complex, atrial fibrillation, type of myocardial infarction or diabetes. There were no significant differences in clinical features between patients with successful and unsuccessful ATP therapy. Conclusions: High effectiveness of ATP was shown in this group. There were no clinical factors indicating success of this type of therapy. That could justify programming ATP as the first line therapy in the VT zone in primary prophylaxis coronary artery disease patients to reduce application of shock therapy. It should be possible to apply a single mode of programming when discharging patients after the implantation procedure regardless of the patient's clinical condition. This could help to control and programme the devices, thus reducing the risk of errors. (C) 2014 Published by Elsevier Urban & Partner Sp. z o.o. on behalf of Medical University of Bialystok.