The use of pacemakers has been a major advance in the treatment of different forms of bradycardias and tachyarrhythmias. The main objectives for cardiac pacing in heart block are to improve the chances of survival and to prevent disabling symptoms, especially Stokes-Adams attacks. The long-term follow-up results of cardiac pacing are affected by different factors, in particular age and underlying heart disease; major technical aspects include pulse generator, lead and electrode longevity, and the pacing mode (VVI, atrioventricular sequential pacing, rate response stimulation, etc.). - Sinoatrial dysfunction is a relatively benign condition. Hence, pacing should probably not be adopted as a routine measure but should be reserved for patients with clinical (troublesome) symptoms. Based on earlier studies it can be concluded that patients with complete heart block and second degree atrioventricular block (Mobitz Type II) should be treated with pacemakers from the prognostic point of view. During chronic rate-responsive pacing improvement of exercise capacity can be expected in patients with sinus node disease and after His-bundle ablation. In patients with complete AV-block or bradycardia rate-responsive pacing can increase exercise tolerance and improve clinical symptoms as well. The automatic implantable cardioverter/defibrillator prevents sudden death over a long-term follow-up period in a high risk group of patients suffering from life-threatening ventricular tachyarrhythmias.